JPH10308697A - Time division digital moving radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To distribute load on all moving stations executing communication by switching moving stations (clock masters) emitting a synchronous radio wave at prescribed timing at the time of executing communication between moving stations. SOLUTION: A clock master gives a switching request to moving stations in a slave mode (S52) when a station in use satisfies the condition that a clock master witching request can be transmitted because of deterioration of capability as a clock master (S51). Then, in response to the switching request, a moving station in the slave mode, which satisfies the condition of a clock master switching response transmission and has the maximum capability as a clock master, makes response to the switching request (S56 and S57). Thus, the present clock master becomes a moving station in the slave mode (S54) and the moving station in the slave mode becomes a new clock master (S58).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time division digital mobile radio communication system comprising a plurality of radio mobile stations and performing digital mobile communication between radio mobile stations using a time division radio communication system.

[0002]

2. Description of the Related Art Conventionally, in a digital mobile communication system including a base station connected to an exchange via a line and a plurality of radio mobile stations, TDMA (Time Division) has been used.
There has been known an apparatus employing a time-division wireless communication system of a Multiple Access (TDD) (Time Division Duplex) system.

In the TDMA / TDD system, as shown in FIG. 9 which is an explanatory diagram of the present invention, one frame is composed of, for example, four time slots T1 to T4 and the same number of time slots R1 to R4. This is a method of realizing communication by four multiplexing using slots T1 and R1, T2 and R2, T3 and R3, and T4 and R4 in pairs. In such a system, transmission and reception are performed with time separation in the transmission slot (T) and the reception slot (R).
The transmission frequency and the reception frequency can be the same frequency, and the frequencies can be used effectively.

[0004] Japanese Patent Application Laid-Open No. Hei 8-251653 discloses a configuration in which mobile stations can directly communicate with each other in a digital mobile radio communication system using the TDMA / TDD system. In this configuration, the mobile station has two modes, a master mode and a slave mode. When the mobile station is in the master mode, it determines a communication slot at its own timing. By synchronizing with a signal transmitted by a station, communication between mobile stations without passing through a base station can be realized. At this time, the communication slot between the base station and the mobile station which is already communicating is continuously used and used for the mobile station-mobile station communication, thereby preventing the communication from being disabled for the time required for determining whether the slot is usable. I have.

[0005]

However, in the digital mobile radio communication system disclosed in the above publication, in an environment where there is no base station, a mobile station in master mode is in slave mode until one communication is completed. Can't switch. In other words, the mobile station once in the master mode must continue to transmit the synchronization radio wave for defining the frame timing until the communication ends. Therefore, there is a problem that the load is concentrated only on the mobile station in the master mode, such as consumption of the battery due to emission of the synchronization radio wave.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a means for switching clock masters at a predetermined timing so as to cover all mobile stations performing communication. An object of the present invention is to provide a time division digital mobile radio communication system capable of distributing a load.

[0007]

In order to achieve the above object, a time division digital mobile radio communication system according to the present invention comprises a time division digital mobile radio communication system having a plurality of mobile stations. In each of the above mobile stations, in order to establish synchronization required for time-division communication, a master mode that operates by defining the frame timing with a free-running clock, and a synchronization signal pattern transmitted from the mobile station in the master mode It has two operation modes, a slave mode operating synchronously, and one of the plurality of mobile stations.
One is a clock master operating in the master mode, and the other mobile station is operated in the slave mode, so that when performing wireless communication between the plurality of mobile stations, the mobile station in the slave mode is used during communication. At the same time, one of all the mobile stations in the slave mode other than the clock master is switched to the master mode to be the next clock master.

According to the above configuration, since each mobile station has two operation modes, a master mode and a slave mode, if one of a plurality of mobile stations is a clock master, the base station Wireless communication can be performed between mobile stations without going through.

At this time, switching of the clock master can be realized during communication, so that the load does not concentrate on only the mobile station in the master mode. This makes it possible to distribute the load applied to all mobile stations. Further, it is possible to provide the best communication environment according to the communication state that changes in real time and the state of the mobile station.

In the time-division digital mobile radio communication system according to the second aspect, in addition to the configuration according to the first aspect, the clock master operated in the master mode first is powered on among all the mobile stations. Thus, the mobile station is first activated. According to this, since a clock master already exists for the mobile station that has been activated next, communication can be performed smoothly and communication can be performed efficiently.

[0011] In the time division digital mobile radio communication system according to the third aspect, in addition to the configuration according to the first aspect, the clock master operated in the master mode first among all the mobile stations first. The mobile station is characterized by the need for data transmission. According to this, a mobile station that does not perform data transmission even when it is in an operating state when the power is turned on does not become a clock master, and does not give an excessive load to the mobile station due to becoming a clock master.

At this time, there are three ways of switching the clock master. That is, the first concept is that, as described in claim 4, the current clock master issues a switching request to all the mobile stations in the slave mode before the own station switches to the slave mode. The mobile station in the slave mode which first responds to the current clock master among all the mobile stations becomes the next clock master.

[0013] The switching request from the current clock master is transmitted when (currently) the current clock master no longer holds the transmission data, and when the current clock master emits a synchronization radio wave. (Claim 7) When the current clock master relays data from the mobile station in the slave mode for a certain time, (Claim 8) The current clock master transmits a certain amount of data from the mobile station in the slave mode. (9) When the current clock master detects that the current clock master has not relayed data for a certain period of time, (Claim 10) When it is determined that the current clock master has reduced its ability as a clock master, (Claim 1
1) It is desirable that the processing be performed when the current clock master detects the interference, or (claim 12) when the mobile station in the current slave mode detects the interference of the current clock master.

Here, in claim 10, the clock master with reduced capability includes the following seven states.

(1) A clock having a lower CPU performance than that required to operate as a clock master when the performance as a clock master is expressed by the performance of a CPU mounted on the clock master. Master. (2) A clock master having a free memory capacity smaller than the free memory capacity required to operate as a clock master, when the capacity as the clock master is represented by the free capacity of the memory mounted on the clock master. (3) A clock master having a remaining battery capacity smaller than that required to operate as a clock master when the capacity as a clock master is expressed by the remaining capacity of a built-in battery mounted on the clock master. (4) When the ability as a clock master is represented by the received electric field strength from the mobile station in the slave mode, the received electric field from all the mobile stations in the slave mode is smaller than the received electric field strength necessary to operate as the clock master. A clock master with at least one of the intensities reduced. (5) When the capability as the clock master is expressed by the error occurrence rate of the data received from the mobile station in the slave mode, the error occurrence from all the mobile stations in the slave mode is higher than the error occurrence rate operable as the clock master. A clock master with at least one of the rates increased. (6) When the capability as a clock master is represented by the propagation delay time of the received data from the mobile station in the slave mode, the propagation delay from each mobile station in the slave mode is shorter than the propagation delay time operable as the clock master. A clock master that has grown in at least one of the times. (7) When the capability as a clock master is represented by the number of retransmission requests for received data from the mobile station in the slave mode, the number of retransmission requests from all mobile stations in the slave mode is greater than the number of retransmission requests operable as the clock master. A clock master that has increased at least one of the times.

The response of the mobile station in the slave mode to the switching request from the current clock master is the mobile station having the best capability as the clock master among all the mobile stations in the slave mode. Item 14) Among all the mobile stations in the slave mode, the mobile station having the best transmission / reception state with another mobile station, or (Claim 15) Among all the mobile stations in the slave mode, the environmental change due to the switching of the clock master is minimized. It is preferable that the mobile stations in the slave mode be serially numbered by assigning serial numbers to the mobile stations.

A second concept of the method of switching the clock master is that, as described in claim 17, the mobile station in the slave mode in which the clock master should become the next clock master before the station itself switches to the slave mode. , And the mobile station in the slave mode that has received the nomination becomes the next clock master.

[0018] The next clock master is nominated as (Claim 18) a mobile station having the best capability as a clock master among all mobile stations in slave mode, and (Claim 19) among all mobile stations in slave mode. The mobile station having the best transmission / reception state with another mobile station, or (claim 20), among all the mobile stations in the slave mode, the one whose environment change due to the switching of the clock master is the smallest, or (Claim 21) It is preferable that serial numbers are given to all the mobile stations in the slave mode so that the mobile stations are sequentially performed in accordance with the numbers.

Here, in claim 13 or 18, the mobile station having the best capability as a clock master includes the following three states.

(1) A mobile station having the highest CPU performance among all the mobile stations in the slave mode, when the capability of the mobile station is represented by the performance of the CPU mounted on the mobile station. (2) A mobile station having the largest free memory capacity among all the mobile stations in the slave mode, when the capability of the mobile station is represented by the free capacity of the memory mounted on the mobile station. (3) A mobile station having the largest remaining battery capacity among all the mobile stations in the slave mode, when the capability of the mobile station is represented by the remaining capacity of a built-in battery mounted on the mobile station.

Further, in claim 14 or 19, the mobile station having the best transmission / reception state with another mobile station includes the following eight states.

(1) When the transmission / reception state is represented by the sum of deviations of the received electric field strength from one mobile station to another mobile station, the smallest sum of deviations among all the mobile stations in the slave mode is calculated. Mobile station having. (2) When the transmission / reception state is represented by the total value of the deviations of the error occurrence rates of the data received from one mobile station with respect to another mobile station, the smallest total deviation value among all the mobile stations in the slave mode is calculated. Mobile station having. (3) When the transmission / reception state is represented by the sum of deviations of propagation delay time of received data from one mobile station to another mobile station, the smallest total deviation among the mobile stations in the slave mode is calculated. Mobile station having. (4) The mobile station having the best transmission / reception state with the other mobile station is defined as a state in which the transmission / reception state is represented by the total value of deviations of the number of retransmission requests for reception data from another mobile station with respect to one mobile station. A mobile station having the smallest total deviation value among all mobile stations in the slave mode. (5) A mobile station having the largest total value among all the mobile stations in the slave mode when the transmission / reception state is represented by the total value of the received electric field strength from one mobile station to another mobile station. (6) When the transmission / reception state is represented by the total value of the error occurrence rates of data received from one mobile station from another mobile station, the mobile station having the smallest total value among all the mobile stations in the slave mode . (7) When the transmission / reception state is represented by a total value of propagation delay times of received data from one mobile station to another mobile station, the mobile station having the smallest total value among all the mobile stations in the slave mode. . (8) When the transmission / reception state is represented by the total number of retransmission requests of received data from another mobile station to one mobile station, the mobile station having the smallest total value among all the mobile stations in the slave mode .

[0023] Further, in claim 15 or 20, the mobile station having the minimum environmental change due to the switching of the clock master includes the following four states.

(1) When the environmental change is represented by the received electric field strength from the mobile station in the slave mode with respect to the radio wave received from the current clock master, the electric field strength for the current clock master among all the mobile stations in the slave mode becomes larger. The largest mobile station. (2) When the environmental change is represented by the error rate of data received from the mobile station in the slave mode with respect to the radio wave received from the current clock master, the error rate of the current clock master among all the mobile stations in the slave mode Is the smallest mobile station. (3) When the environmental change is represented by the propagation delay time of the received data from the mobile station in the slave mode with respect to the radio wave received from the current clock master, the propagation delay time for the current clock master among all the mobile stations in the slave mode Is the smallest mobile station. (4) When the environmental change is represented by the number of retransmission requests for received data from the mobile station in the slave mode with respect to the radio wave received from the current clock master, the number of retransmission requests for the current clock master among all the mobile stations in the slave mode Is the smallest mobile station.

A third concept of the method of switching the clock master is that, as described in claim 22, the mobile station in the slave mode issues a switching request to the current clock master, and the slave mode in the slave mode in which the request was made. The mobile station is the next clock master.

The switching request to the current clock master is issued when (claim 23) a mobile station having better performance than the current clock master is detected among all the mobile stations in the slave mode, or (claim 24). The transmission / reception state with other mobile stations among all the mobile stations in the slave mode is performed when a mobile station superior to the current clock master is detected. The serial number is assigned to the mobile station in order according to the serial number, or (claim 26) when communication is to be performed between two mobile stations in the slave mode, the mobile station is obtained through the current clock master. When the transmission / reception state obtained when performing direct communication between two mobile stations is better than the transmission / reception state between two mobile stations,
It is desirable that this is performed by one of the two mobile stations.

Here, in claim 23, the mobile station having a higher performance than the current clock master is defined as the following 3
There are three states.

(1) A mobile station having higher CPU performance than the current clock master when the performance of the mobile station is represented by the performance of the CPU mounted on the mobile station. (2) A mobile station having a free memory capacity larger than that of the current clock master when the capability of the mobile station is represented by a free capacity of a memory mounted on the mobile station. (3) A mobile station having a remaining battery capacity greater than that of the current clock master when the capability of the mobile station is represented by the remaining capacity of a built-in battery mounted on the mobile station.

In the twenty-fourth aspect, the following eight states can be cited as the mobile stations that are superior to the current clock master in the transmission / reception state with other mobile stations.

(1) When the transmission / reception state is represented by the sum of the deviations of the received electric field strength from one mobile station with respect to another mobile station, the mobile station having the total sum of the deviations of the received electric field strength smaller than that of the current clock master. Bureau. (2) When the transmission / reception state is represented by the sum of the deviations of the error occurrence rate of the data received from one mobile station from another mobile station, the mobile station having the deviation sum of the error occurrence rate smaller than that of the current clock master. Bureau. (3) When the transmission / reception state is expressed by the total value of the deviation of the propagation delay time of the received data from one mobile station to another mobile station, the mobile having the total value of the deviation of the propagation delay time smaller than that of the current clock master. Bureau. (4) When the transmission / reception state is represented by the sum of deviations of the number of retransmission requests for received data from another mobile station with respect to one mobile station, a mobile station having a total deviation of the number of retransmission requests smaller than the current clock master. Bureau. (5) A mobile station having a total value of the received electric field strength greater than that of the current clock master when the transmission / reception state is represented by the total value of the received electric field strength of one mobile station from another mobile station. (6) A mobile station in which the current clock master also has a small total error occurrence rate when the transmission / reception state is represented by the total error occurrence rate of data received from one mobile station from another mobile station. (7) A mobile station having a total propagation delay time smaller than that of the current clock master when the transmission / reception state is represented by a total value of propagation delay times of received data from one mobile station to another mobile station. (8) A mobile station having a total number of retransmission requests smaller than that of the current clock master when the transmission / reception state is represented by the total number of retransmission requests for received data from one mobile station from another mobile station.

Furthermore, in claim 26, the favorable transmission / reception state includes the following four states.

(1) A state in which the electric field strength between only two mobile stations is larger than the average value of each electric field strength between the current clock master and the two mobile stations. (2) A state in which the error occurrence rate obtained when direct communication is performed between two mobile stations is smaller than the error occurrence rate of received data between the two mobile stations obtained via the current clock master. (3) A state in which the propagation delay time obtained when direct communication is performed between two mobile stations is smaller than the propagation delay time of received data between the two mobile stations obtained via the current clock master. (4) A state in which the number of retransmission requests obtained when direct communication is performed between two mobile stations is smaller than the number of retransmission requests obtained between the two mobile stations obtained through the current clock master.

[0033]

Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 20, 24, and 25.
It is as follows.

As shown in FIG. 2, this time-division digital mobile radio communication system includes, for example, mobile stations 1 to 4 which are four digital mobile radio communication terminals.
In FIG. 1, for simplicity, the digital mobile radio communication system is assumed to be composed of four mobile stations 1 to 4, but the number of mobile stations may be any number as long as it is plural.

Each of the mobile stations 1 to 4 has two operation modes of a master mode and a slave mode. When the mobile station is in the master mode, the frame timing is specified at its own timing and a synchronization radio wave (synchronization signal) is emitted. In the slave mode, the frame synchronization is performed with the synchronization radio wave transmitted by the master mode mobile station. I do. still,
Hereinafter, a mobile station in the master mode is referred to as a clock master.

Each of the mobile stations 1 to 4 has the configuration shown in FIG. That is, each of the mobile stations 1 to 4
1, RF (Radio Frequency) unit 12, modem unit 13, T
It includes a DMA / TDD processing unit 14, an audio processing unit 15, a speaker 16, a microphone 17, a control unit 18, and an operation unit 19, respectively.

The TDMA / TDD processing unit 14
/ TDD system for wireless access,
Set the time slot for transmission and reception. As shown in FIG. 9, one frame is composed of eight slots, the first four slots are slot T, and the second four slots are slot R.
And Here, when the mobile station is a clock master, data is transmitted using slot T, and data is received using slot R. On the other hand, when the mobile station is a slave mode mobile station, data is transmitted using slot R, It is assumed that reception is performed using the slot T.

As shown in FIG. 1, the control unit 18 receives a key input from the keyboard 19a of the operation unit 19 at the time of calling or receiving a call, and forms various command signals to be transmitted to the transmission / reception partner. At this time, the above commands and the like are displayed on the display 19b of the operation unit 19.

When a communication state is established, the control unit 18 controls the RF unit 12, the modem unit 13, the TDMA / TDD processing unit 14, and the audio processing unit 15 in synchronization with the set transmission / reception time slot. . As a result, the audio signal from the microphone 17 processed by the audio codec 15a of the audio processing unit 15 is transferred to the TDMA / TDD processing unit 14, and is modulated by the modulation unit 13b of the modem unit 13.
The signal is transmitted to another mobile station (hereinafter, referred to as another station) during the transmission slot period via the F unit 12 and the antenna 11. On the other hand, a signal transmitted from another station during the reception slot is received through the antenna 11 and the RF unit 12, is demodulated by the demodulation unit 13a of the modem unit 13, and is transmitted to the TDMA / TDD processing unit 14 and the audio codec 15a. As a result, the signal is reproduced as an audio signal and supplied to the speaker 16.

Here, the control unit 18 includes a reception level detection unit 21, an error detection unit 22, a propagation delay time measurement unit 23, and a synchronization signal detection unit in order to perform a clock master switching process which is a feature of the present invention. 24, built-in timer 25, battery capacity monitoring unit 26, CPU monitoring unit 27, ROM (Read On
ly Memory) 28, CPU (Central Processing Unit) 2
9 and a RAM (Random Access Memory) 30.

The reception level detection section 21 detects the electric field strength of the reception data transmitted from another station. The error detection unit 22 is for detecting an error in received data transmitted from another station. The propagation delay time measuring section 23 is for measuring the difference between the time at which the other station transmits data and the time at which the own station receives the data, that is, the propagation delay time. The synchronization signal detector 24 is for detecting a synchronization radio wave emitted by the clock master. The built-in timer 25 is manufactured so that 0:00 of the world standard time is counted up as 0.
The battery capacity monitoring unit 26 is for monitoring the capacity of a built-in battery mounted on the mobile station. CPU monitoring unit 2
Reference numeral 7 is for monitoring the performance level of the CPU 29.

The ROM 28 stores synchronization radio wave emission intervals A1 and data relayable times A, which are control values shown in FIG.
3, a data non-transmission confirmation time A4, a CPU performance monitoring time A5, a reception error measurement interval A7, a measurement data emission interval A9, a clock master switching interval A10, a relayable data amount A11, and a retransmission request count measurement interval A12.
CPU performance limit value C1, free memory capacity limit value C2, remaining battery capacity limit value C3, electric field strength limit value C4, reception error rate limit value C5, propagation delay limit value C shown in FIG.
6 and an area for the retransmission request count limit value C7. These control values are set at the time of manufacture and have a structure that cannot be changed by the user.

The synchronization radio wave emission interval A1 is set to an interval at which synchronization radio waves are emitted. Also, the data relayable time A3, the data non-transmission confirmation time A4, the clock master switching interval A10, and the relayable data amount A11 are set to appropriate time / interval / amount. The CPU performance monitoring time A5, the reception error measurement interval A7, and the retransmission request count measurement interval A12 are set to intervals necessary for measuring a CPU performance value, a reception error rate, and the number of retransmission requests described later. The measurement data emission interval A9 is set to an interval at which control data D17 (see FIG. 8 (g)) of a test data emission request to be described later for measuring the transmission / reception state with another station is emitted.

The CPU performance limit value C1, the free memory capacity limit value C2, the battery remaining capacity limit value C3, and the electric field strength limit value C4 are the CPU performance, free memory capacity, and battery required to operate as a clock master, respectively. Set the remaining capacity and the limit value of the electric field strength. Further, the reception error rate limit value C5 and the propagation delay limit value C
6 and the retransmission request count limit value C7 are set to limit values of the reception error rate, propagation delay time, and retransmission request count that can operate as a clock master.

The RAM 30 includes a CPU performance table B1, a free memory capacity table B2, a remaining battery capacity table B3, and a plurality of electric field strength tables B of the same number as the maximum mobile station number shown in FIG.
4, a plurality of reception error rate tables B5, a plurality of propagation delay time tables B6, a plurality of retransmission request number tables B7, and P shown in FIG.
There is an area for storing a correspondence table between S-IDs (Personal Station-Identification) and mobile station numbers.
The numerical values in these tables can be freely read and written by the CPU 29.

The PS-ID is a second-generation cordless telephone system standard (R) issued by the Radio Industry Association specific to mobile stations.
CR STD-28).
Has been written to. The mobile station numbers “1” are assigned to the clock master, and the mobile station numbers “2” to “N + 1” are assigned to the PS-ID for each mobile station in the N (three in this embodiment) slave mode mobile stations. Assigned.

Here, the maximum value of the mobile station number is set to “25”.
4 ", up to 254 existing in the network
Mobile stations. Therefore, the number of the tables B4 to B7 at this time is 254.

The CPU 29 is for instructing the switching of the clock master by controlling each section in the control section 18.

FIGS. 7 and 8 show communication data D1, control data D2 to D6, and control data D1 in control unit 18.
1 shows the format of D21. As shown in FIG. 7 (a), each of these communication / control data is 20 bytes, and the transmission destination 51 for setting the mobile station number of the destination to be transmitted in one byte is set in the other one byte. A source 52 for setting the mobile station number of the own station, and an information / control unit 53 for setting what control is to be performed on another byte.
A transmission data section 54 for setting transmission data is allocated to the remaining 17 bytes.

At this time, if "0" is set in the information / control unit 53, it indicates that normal communication is performed without performing control. When "1" is set, it indicates that control of a mobile station number request / response is performed.
If “2” is set, the clock master ID
Indicates that notification control is to be performed. When "3" is set, it indicates that the control of the clock master switching request / response is performed. If “6” is set, the CPU
This indicates that notification of parameters such as performance, available memory capacity, remaining battery capacity, electric field strength, reception error rate, propagation delay time, or number of retransmission requests is controlled.
If “7” is set, it indicates that control of a test data emission request / response, interference detection notification, or retransmission request is performed. The numbers set in the information / control unit 53 are merely examples, and the numbers are not limited to these.

The communication data D1, the control data D2
To D6, the detailed configuration of each transmission data section 54 of the control data D11 to D21, the communication data D1, the control data D
2 to D6 and each control by the control data D11 to D21 will be described later.

(1) Determination of Clock Master The operation of determining a mobile station to be a clock master among a plurality of mobile stations (here, mobile stations 1 to 4) will be described.

At first, none of the mobile stations 1 to 4 emits a synchronization radio wave, and communication cannot be performed as it is. Therefore, it is necessary to determine a mobile station that emits a synchronization radio wave as a clock master.

Here, the synchronizing radio wave means that the clock master is controlled by the CPU 29 in the control unit 18 by the TDMA / TDD processing unit 14, the modem unit 13, the RF unit 12, and the antenna 1
1 is controlled by the clock master ID notification control data D4 that is emitted every time set in the synchronization radio wave emission interval A1 using one of the time-divided slots T1 to T4 shown in FIG. (See FIG. 7E).

The transmission data part of the control data D4 is P
It has a 28-bit area D4a for setting the S-ID. Also, “255” indicating broadcast is set as the transmission destination of the control data D4, and the mobile station number “1” indicating the clock master is set as the transmission source.

(1-1) Determination of Clock Master by Turning on Power Based on the flowchart of FIG.
A case will be described in which the mobile station that is first turned on from the state where 4 (see FIG. 2) is OFF becomes the clock master. Here, it is assumed that the mobile station 1 is first turned on.

When the power of the mobile station 1 is turned on (S 1), the mobile station 1 uses the synchronization signal detection section 24 in the control section 18 to
It is checked whether or not synchronization radio waves have been emitted from the other mobile stations 2 to 4 (S2).

If no synchronizing radio wave is detected in S2, it determines itself as a clock master, and the CPU 29 controls the TDMA / TDD processing unit 14, modem unit 13, RF unit 1
2, and the antenna 11 is controlled to emit a synchronization radio wave using the time-divided slot T1 (S3).

On the other hand, if the synchronizing radio wave is detected in S2, it is determined that the clock master already exists, the self is determined to be in the slave mode, and the clock master detected by the synchronizing signal detecting unit 24 is transmitted. The operation of the CPU 29 is set so as to emit a radio wave at a timing synchronized with the synchronizing radio wave (S4).

(1-2) Determining Clock Master Based on Retention of Transmission Data Except for the example in (1-1) in which the mobile station first turned on becomes the clock master, retaining the data to be transmitted. , The case where the mobile station that needs to start communication first becomes the clock master will be described based on the flowchart of FIG. Here, it is assumed that the mobile station 1 has the data first.

First, it is determined whether or not the mobile station 1 needs to start communication, that is, the CPU in the control unit 18 in the mobile station 1
29 determines whether or not transmission data exists in the RAM 30 (S11). When the transmission data is held in S11, the mobile station 1 checks by the synchronization signal detection unit 24 in the control unit 18 whether or not the synchronization radio wave is emitted from the other mobile stations 2 to 4. (S12).

If no synchronizing radio wave is detected in S12, it determines itself as a clock master, and the CPU 29 controls the TDMA / TDD processing unit 14, modem unit 13, RF unit 1
2, and the antenna 11 is controlled, and a synchronization radio wave is emitted using the time-divided slot T1 (S13).

On the other hand, if the transmission data is not held in S11, it is not necessary to become the clock master, so that it determines itself as the slave mode, and if the synchronization radio wave is detected in S12, It determines that the master already exists and determines itself to be in slave mode. Then, the operation of the CPU 29 is set so that the radio wave is emitted at a timing synchronized with the radio wave emitted by the clock master, detected by the synchronization signal detection unit 24 (S14).

As described above, by determining the clock master by one of the above two methods, the clock master shown in FIG.
, For example, the mobile station 1 among the mobile stations 1 to 4 becomes the mobile station CM of the clock master, and the other three mobile stations 2 to 4
The mobile station SL ₁ to SL ₃ of each slave mode. Then, radio waves emitted by the mobile station CM are used as synchronization radio waves, so that mobile stations can communicate with each other without passing through the base station.

(2) Radio Communication Between Mobile Stations Next, an operation of performing communication between mobile stations using the mobile stations CM and SL _{1 to} SL ₃ without going through a base station will be described. At this time, as shown in FIG. 9, the slot T1 is used for emission of synchronization radio waves of the mobile station CM and data transmission of the mobile station CM, and the slot R1 is used for data reception of the mobile station CM. The slot R1 is used for data transmission of the station SL.
And the slot T1 is used for data reception of the mobile station SL. The mobile station SL is a mobile station SL ₁
And to indicate any mobile station of to SL _3.

First, the setting of the mobile station number will be described with reference to FIG. When setting the mobile station number,
The control data D2 and D3 shown in FIGS. 7C and 7D are used. The transmission data portion of the control data D2 has an area D2a for setting a number “0” indicating control of a mobile station number request, and a 28-bit area D2b for setting a PS-ID of the own station. The transmission data portion of the control data D3 includes an area D3a for setting a number “1” indicating control of mobile station number response, an area D3b of 2 bytes for setting a mobile station number, and a PS-ID of the own station. And a 28-bit area D3c to be set.

The mobile station CM, which has become the clock master,
The mobile station number "1", which means a clock master, corresponding to the S-ID is registered in the RAM 30 of the mobile station CM (S2).
1). Thereafter, as described above, the mobile station CM emits a synchronization radio wave at every time set at the synchronization radio wave emission interval A1 (S22).

When the mobile station SL receives the synchronization radio wave (S25), the PS of the mobile station CM included in the synchronization radio wave is received.
-ID is acquired (S26), and "1" representing the clock master is registered as the mobile station number in the correspondence table shown in FIG. 6 in the RAM 30 in association with the PS-ID (S2).
7).

The mobile station SL sets "1" representing the clock master as the transmission destination of the control data D2 for the mobile station number request in order to obtain the mobile station number of the mobile station SL, and obtains the control data D2. Is transmitted to the mobile station CM (S28). At this time, since the mobile station SL has not yet acquired the mobile station number, “0” is set as the transmission source of the control data D2.

When receiving the control data D2 (S23), the mobile station CM refers to the correspondence table in the RAM 30 and sets "2".
The lowest available mobile station number among the mobile station numbers No. to "4" is set in the area D3b, and the control data D of the mobile station number response is set.
3 is transmitted (S24). At this time, control the destination of the data D3 to set the mean broadcast "255" in order to receive the data to all mobile station SL ₁ to SL ₃ slave mode, the sender represent clock master "1 "Is set.

All mobile stations SL _{1 to} SL _{3 in} slave mode
Since the transmission destination of the control data D3 is "255", after receiving this control data D3 (S29), the mobile station number is stored in association with the PS-ID of the correspondence table in each RAM 30. (S30).

As a result, the mobile station CM is assigned “1”, and the mobile stations SL _{1 to} SL ₃ are assigned mobile station numbers “2” to “4” for each mobile station corresponding to the PS-ID. so that the all of the mobile station number of the mobile station CM · SL ₁ ~SL ₃ is set.

Next, transmission and reception of data used between ordinary applications will be described.

In the case of normal data transmission / reception, FIG.
The communication data D1 shown in (b) is used. Communication data D
"1" to "1" corresponding to the mobile station to be transmitted
The mobile station number “4” is set, the mobile station number assigned to itself is set as the transmission source, and the data used for actual communication is set in the transmission data section.

The operation of the mobile station CM will be described first with reference to FIG. The mobile station CM checks whether the mobile station SL is transmitting the communication data D1 using the slot R1 (S31). As a result of the reception check in S31, if the communication data D1 from the mobile station SL has been received, whether the data is data addressed to the mobile station CM (own station) based on the setting contents of the transmission destination of the communication data D1 It is determined whether the data is addressed to another mobile station SL (S3).
2).

If the data is addressed to the own station in S32, the mobile station CM processes the data (S33). S in FIG.
L ₂ → CM shows an example in which data is transmitted from the mobile station SL ₂ to the mobile station CM. If the data is addressed to another mobile station SL in S32, the received data is transmitted as it is using the slot T1 (S34). SL in FIG.
₂ → (CM) → example data to the mobile station SL ₃ via the mobile station CM from the mobile station SL ₂ is transferred to the SL _3, SL ₂
→ (CM) → SL ₁ shows an example in which data is transferred from the mobile station SL ₂ to the mobile station SL ₁ via the mobile station CM.

Thereafter, it is checked whether the mobile station CM itself has transmission data (S35). If there is no transmission data in S35, a synchronization radio wave is emitted (S3).
6). On the other hand, if the transmission data is held in S35, the data is transmitted using the slot T1 (S3).
7). For example, the destination "2", is set to "1" to the transmission source, the data is transmitted from the mobile station CM to the mobile station SL ₁ (see CM → SL ₁ in FIG. 15). As a result of the reception check in S31, if data from the mobile station SL has not been received, the processing in S35 is performed without performing the processing in S32 to S34.

Next, the operation of the mobile station SL will be described with reference to FIG. The mobile station SL checks whether the mobile station CM has not transmitted the communication data D1 using the slot T1 (S41). Mobile station CM in S41
If the communication data D1 has been received, it is determined whether or not the data is addressed to the own station based on the setting contents of the transmission destination of the communication data D1 (S42). If the data is addressed to the own station in S42, the data processing is performed in the mobile station SL (S43).

After the processing in S43, if the data is not addressed to the own station in S42, or if the communication data D1 is not received in S41, the data is transmitted to the mobile station CM or another mobile station SL. It is checked whether or not the data is held (S44). If the transmission data is not held in S44, the process returns to the reception check processing in S41. On the other hand, if the transmission data is held in S44, the data is transmitted in S45 and the process returns to S41. For example, when the mobile station SL ₂ transmits data to the mobile station SL ₃ is the destination of the communication data D1 "4", set "3" to the sender, transmitting the data using the slot R1 I do.

(3) Switching of Clock Master During Communication Switching of the mobile station CM during communication will be described. In the present embodiment, the mobile station SL that first responds to the switching request from the mobile station CM becomes the next clock master.
That is, the mobile station CM recruits the next clock master, and the mobile station SL that first responds to the next clock master becomes the new clock master.

When switching the clock master, control data D5 and D6 shown in FIGS. 7F and 7G are used. The transmission data portion of the control data D5 has an area D5a in which a number “0” indicating the control of the clock master switching request is set. The transmission data portion of the control data D6 has an area D6a in which a number “1” indicating the control of the clock master switching response is set.

As shown in FIG. 17, when the mobile station CM wants to switch the operation as the clock master to another mobile station SL, that is, when the mobile station CM satisfies the condition for transmitting the clock master switching request (S51). Using the slot T1, "255" is set as the transmission destination of the control data D5 of the clock master switching request, and the control data D5 is transmitted (S52, see the first row in FIG. 16).

The transmission destination in the control data D5 is "25".
5 ", all the mobile stations SL _{1 to} SL _{3 in} the slave mode.
Receives the control data D5 (S55). Control data D
5 among the mobile stations SL _{1 to} SL ₃ that have received the clock master switching response (S56).
Transmits the control data D6 of the clock master switching response to the mobile station CM using the next slot R1 (S57,
(See the second row in FIG. 16).

Upon receiving the control data D6 (S53), the mobile station CM switches to the mobile station in the slave mode (S54). On the other hand, the mobile station S that transmitted the control data D6
L becomes the new clock master (S58).

The new clock master uses the next slot T1 to set the transmission destination of the control data D4 of the clock master ID notification, which is the radio wave for synchronization, to “255”, and transmits the control data D4 (FIG. 16). 3rd stage). In addition, to change the mobile station number of all mobile stations CM · SL ₁ ~SL _3.

With reference to FIG. 18, a description will be given of the change of the mobile station number when the mobile station CM switches to the mobile station in the slave mode and the mobile station SL becomes the new clock master. Here, a case where there are five mobile stations will be described as an example.

As shown in FIG. 18A, the initial PS-I
When the mobile station whose D is “a” is operating as a clock master, the mobile station number of “a” is “1” and P
It is assumed that the mobile station numbers of the mobile stations in the slave mode whose S-IDs are "b" to "e" are "2" to "5", respectively.

Then, as shown in FIG. 18B, for example, when the mobile station “c” becomes the new clock master,
The mobile station number of "c" changes from "3" to "1", and the mobile station number of "a" switched from the clock master to the mobile station in slave mode has the largest mobile station number in the mobile station in slave mode. Change to station number. That is, here, “1”
→ It becomes “5”. A mobile station whose PS-ID is larger than the PS-ID of the mobile station that has become the new clock master before the new clock master moves up the PS-ID, and the PS-ID of the smaller mobile station does not change. Here, "d", "e"
Are "3" and "4", respectively, and "b"
Mobile station remains at “2”.

(3-1) Conditions for Transmission of Clock Master Switching Request The conditions for transmission of the clock master switching request by the mobile station CM in S51 of FIG. 17 are described below. That is, FIG.
When any of [Condition 1] to [Condition 8] shown in FIG. 4 is satisfied, the mobile station CM transmits the control data D5 of the clock master switching request.

[Condition 1] The mobile station CM, which does not have transmission data,
When detecting that no transmission data exists in M30,
The control data D5 is transmitted.

[Condition 2] Radio wave emission for synchronization for a fixed time The mobile station CM uses the built-in timer 25 in the controller 18 to
The time elapsed since the mobile station CM started operating as a clock master, that is, the time elapsed since the mobile station CM started emitting synchronization radio waves, was measured, and the elapsed time was set to the clock master switching interval A10. When control data D5 is detected, control data D5 is transmitted.

[Condition 3] Data relay for a fixed time The mobile station CM uses the built-in timer 25 in the control unit 18 to
When the accumulated time of relaying data between the mobile stations SL since the mobile station CM started operating as the clock master is measured, and when it is detected that the accumulated time exceeds the time set in the data relayable time A3, The control data D5 is transmitted.

[Condition 4] A certain amount of data relay The mobile station CM measures the amount of data relayed between the mobile stations SL by the CPU 29 in the control unit 18 since the mobile station CM started operating as a clock master. When it is detected that the data amount exceeds the data amount set in the relayable data amount A11, the control data D5 is transmitted.

[Condition 5] Data not transmitted for a fixed time The mobile station CM uses a built-in timer 25 in the control unit 18 to
After the mobile station CM relays the data between the mobile stations SL, the time until the next data is relayed is measured. Even if the time exceeds the time set in the data non-transmission confirmation time A4, the next time. When it is detected that the data relay is not performed, the control data D5 is transmitted.

[Condition 6] Deterioration of ability as clock master When the mobile station CM determines that its own ability as a clock master has decreased, it transmits control data D5 to the mobile station SL. Here, the ability as a clock master includes the high performance of the CPU 29 mounted on the mobile station, the free memory capacity of the RAM 30, the remaining capacity of the built-in battery,
It is represented by the electric field strength of the received data from another station, the error occurrence rate of the received data, the propagation delay time of the received data, or the number of retransmission requests of the received data.

[Condition 6a] CPU Performance Deterioration The mobile station CM measures the time during which the CPU 29 is idle within the time set in the CPU performance monitoring time A5 by the CPU monitoring unit 27 in the control unit 18. A CPU performance value represented by "CPU idle time / CPU performance monitoring time" is calculated.
This CPU performance value has become equal to or less than the value set in the CPU performance limit value C1,
When it is detected that the time during which the U 29 is idle due to other operations is reduced and the operation of the CPU 29 is no longer available, the control data D 5 is transmitted.

[Condition 6b] Decrease in free memory capacity The mobile station CM uses the CPU 29 in the
A free memory capacity value represented by “free memory capacity ÷ total memory capacity” of M30 is calculated. When it is detected that the free memory capacity value has become equal to or less than the value set in the free memory capacity limit value C2, that is, when it is detected that there is no more free space in the RAM 30, the control data D5 is transmitted.

[Condition 6c] Internal battery capacity drop The mobile station CM uses the battery capacity monitoring unit 26 in the control unit 18 to calculate the “current voltage 現在 voltage at full charge” of the internal battery installed in the mobile station CM. Calculate the remaining battery value represented by When it is detected that the remaining battery capacity value has become equal to or less than the value set in the remaining battery capacity limit value C3, that is, when it is detected that the capacity of the built-in battery has run out, the control data D5 is transmitted.

[Condition 6d] Reduction in Received Electric Field Strength The mobile station CM measures the electric field strength of the data received from the mobile station SL by using the reception level detection unit 21 in the control unit 18. This electric field intensity value has become equal to or less than the value set in the electric field intensity limit value C4, that is, at least one mobile station S
When it is detected that the electric field strength between L and L causes a problem in data relaying, control data D5 is transmitted.

[Condition 6e] Increase in reception errors The mobile station CM uses the error detection unit 22 in the control unit 18 to determine the number of errors occurring in the data received from the mobile station SL.
Measurement is performed for the time set in the reception error measurement interval A7, and a reception error rate value represented by “the number of data in which a reception error has occurred / the number of data received in the reception error measurement interval” is calculated. This reception error rate value becomes equal to or more than the value set in the reception error rate limit value C5, that is, the error occurrence rate of the reception data with at least one mobile station SL increases, which hinders the data relay. Is transmitted, the control data D5 is transmitted.

[Condition 6f] Increase in propagation delay time When measuring the propagation delay time, control data D17 and D18 shown in FIGS. 8 (g) and 8 (h) are used. The transmission data portion of the control data D17 has an area D17a for setting a number “0” indicating control of a test data emission request, and an area D17b for setting values of parameters for inspection. The transmission data portion of the control data D18 has an area D18a for setting a number “1” indicating control of the inspection data emission response, and an area D18b for setting values of parameters for inspection.

The mobile station CM sets “255” as the transmission destination and sets the value of the built-in timer 25 when transmitting data to the area D17b for each time set in the measurement data emission interval A9. The control data D17 of the inspection data emission request is transmitted, and all the mobile stations SL in the slave mode are transmitted.
Requesting transmission of control data D18 for test data fired response to ₁ to SL _3. Each of the mobile stations SL _{1 to} SL ₃
The internal timer value when receiving the control data D17 is set in the area D18b, and the control data D18 is transmitted to the mobile station CM.

The mobile station CM has a built-in timer value set in the control data D18 transmitted from the mobile station SL by the propagation delay time measuring section 23 in the control section 18 and a built-in timer of its own station (mobile station CM). Calculate the propagation delay value represented by the difference from the value. This propagation delay time value is the propagation delay limit value C6.
, That is, at least 1
The control data D5 is transmitted when it is detected that the data propagation delay time between one mobile station SL and the other mobile station SL is large, which causes a problem in data relay.

[Condition 6g] Increase in the number of retransmission requests When measuring the number of retransmission requests, control data D20 shown in FIG. 8 (j) is used. The transmission data part of the control data D20 has an area D20a in which a number “3” indicating the control of the retransmission request is set.

When the mobile station CM detects by the error detection section 22 in the control section 18 that an error has occurred in the data received from the mobile station SL, it transmits the control data D20 of the retransmission request to the mobile station SL. And request retransmission of data. The number of times such a retransmission request has been made is measured during the time set in the retransmission request measurement interval A12. This retransmission request count value has become equal to or greater than the value set in the retransmission request count limit value C7, that is, at least one mobile station SL.
The control data D5 is transmitted when it is detected that the number of times of data retransmission increases between the two and causes trouble in data relay.

[Condition 7] Interference detection by clock master In the mobile station CM, the error detection unit 22 in the control unit 18 measures the number of slots where a slot error has occurred in 1.2 seconds of available slots. This measured value is the mobile station CM
Channel switching FER (Frame Erro
r Rate) or more, that is, the second generation cordless telephone system standard version 2 (RCRSTD-2
When the interference defined in 8) is detected, the control data D5
Send

[Condition 8] Detection of Interference by Mobile Station in Slave Mode When the mobile station CM is notified of interference detection from the mobile station SL, it transmits control data D5. When the mobile station SL notifies the mobile station CM of the interference detection, the control data D19 shown in FIG. 8 (i) is used. The transmission data section of the control data D19 has an area D19a in which a number “2” indicating the control of the interference detection notification is set.

That is, in the mobile station SL, the error detecting unit 22 in the control unit 18 measures the number of slots in which a slot error has occurred among the valid slots for 1.2 seconds. This measured value is used for the channel switching F preset in the mobile station SL.
When the interference exceeds the ER threshold, that is, when the interference defined by the second generation cordless telephone system standard version 2 (RCR STD-28) is detected, the control data D19 of the interference detection notification to the mobile station CM. Send Mobile station CM
When the control data D19 is received, the control data D5
Send

(3-2) Conditions for transmitting clock master switching response The conditions for transmitting the clock master switching response by the mobile station SL in S56 of FIG. 17 are described below. That is, FIG.
When any of [Condition 1] to [Condition 4] shown in No. 5 is satisfied, the mobile station SL transmits the control data D6 of the clock master switching response.

[Condition 1] Maximum capacity as clock master The mobile station SL is composed of all the mobile stations SL _{1 to} SL in the slave mode.
_{When the} own station determines that the capability as the clock master is the maximum in 3, the control data D6 is transmitted to the mobile station CM. Here, the ability as a clock master is (3-
This is as shown in [Condition 6] of 1).

[Condition 1a] The mobile station SL having the largest CPU performance measures the time during which the CPU 29 is idle within the time set in the CPU performance monitoring time A5 by the CPU monitoring unit 27 in the control unit 18. Then, a CPU performance value represented by "CPU idle time / CPU performance monitoring time" is calculated.
This CPU performance value is the previous value (currently, RAM
30 stored in the RAM 3).
CPU performance table B1 in 0 (see FIG. 5A)
, The new CPU performance value is stored in a location corresponding to the mobile station number of the own station.

Further, the mobile station SL uses its control data D11 shown in FIG.
Notify U performance. The transmission data portion of the control data D11 has an area D11a for setting a number “0” indicating control of CPU performance notification, and an area D11b for setting a CPU performance value.

That is, the mobile station SL transmits “255” to the destination of the control data D11 with the calculated CPU performance value set in the area D11b, and transmits the CPU performance of its own station to all other mobile stations. Notify. on the other hand,
When the control data D11 is received from another station, the CPU performance value of the other station is stored in a location corresponding to the mobile station number set as the transmission source of the control data D11 in the CPU performance table B1. In this way, the CPU performances of all the mobile stations are grasped.

The mobile station SL has a CPU performance table B
The control data D6 is transmitted when the CPU performance value of the own station is compared with the CPU performance value of the other station and the CPU performance value of the own station is detected.

[Condition 1b] The mobile station SL owns the largest free memory capacity.
A free memory capacity value represented by “free memory capacity ÷ total memory capacity” of M30 is calculated. If the free memory capacity value has changed from the previous value, the new free memory capacity is stored in the free memory capacity table B2 in the RAM 30 (see FIG. 5B) at a location corresponding to the mobile station number of the own station. Stores the capacity value.

The mobile station SL uses the control data D12 shown in FIG. 8 (b) to notify all other mobile stations of its free memory capacity. The transmission data part of the control data D12 has a number “1” indicating the control of the free memory capacity notification.
And an area D12b for setting a free memory capacity value.

That is, the mobile station SL transmits “255” to the destination of the control data D12 with the calculated free memory capacity value set in the area D12b, and transmits the free space of the own station to all other mobile stations. Notify the memory capacity. On the other hand, when the control data D12 is received from another station, the free memory capacity table B2
, The free memory capacity value of the other station is stored at a location corresponding to the mobile station number set as the transmission source of the control data D12. In this way, the free memory capacity of each mobile station is grasped.

The mobile station SL compares the free memory capacity value of its own station with the free memory capacity value of another station stored in the free memory capacity table B2, and determines that the free memory capacity of its own station is the largest. Is transmitted, the control data D6 is transmitted.

[Condition 1c] The mobile station SL owns the maximum built-in battery capacity. The battery capacity monitoring section 26 in the control section 18 uses the battery capacity monitoring section 26 of the mobile station SL to calculate the “current voltage ÷ full charge time” Calculate the remaining battery value of "voltage". When this battery remaining capacity value has changed from the previous value, the RAM 3
In the remaining battery capacity table B3 within 0 (see FIG. 5C),
The new battery remaining capacity value is stored in a location corresponding to the mobile station number of the own station.

The mobile station SL uses the control data D13 shown in FIG. 8C to notify all the other mobile stations of the remaining battery capacity of the mobile station SL. The transmission data part of the control data D13 includes an area D13a for setting a number “2” indicating the control of the remaining battery capacity notification, and an area D for setting the remaining battery capacity value.
13b.

That is, the mobile station SL transmits "255" to the destination of the control data D13 with the calculated remaining battery capacity value set in the area D13b, and transmits the battery of the own station to all other mobile stations. Notify the remaining capacity. On the other hand, control data D
In the case where 13 is received, the remaining battery value of the other station is stored in the remaining battery capacity table B3 at a location corresponding to the mobile station number set as the transmission source of the control data D13.
In this way, the remaining battery levels of all mobile stations are grasped.

The mobile station SL compares the battery remaining capacity value of its own station with the battery remaining capacity value of another station stored in the battery remaining capacity table B3, and determines that the battery remaining capacity of the mobile station SL is the largest. Is transmitted, the control data D6 is transmitted.

[Condition 2] The state of transmission and reception with other mobile stations is the best. The mobile station SL is composed of all the mobile stations SL _{1 to} SL in the slave mode.
_When it is determined that the own station has the best transmission / reception state in ₃ , the control data D6 is transmitted to the mobile station CM.

Here, the state of transmission / reception to / from another station includes the total value of the deviation of the electric field strength of each data transmitted from all mobile stations to the own station, the total value of the deviation of the reception error rate of each data, The total value of the deviation of the propagation delay time of each data, the total value of the deviation of the number of retransmission requests of each data, the total value of the electric field strength of each data, the total value of the reception error rate of each data, the each data , Or the total value of the number of retransmission requests for each data.

The sum of the deviations due to the above various parameters means that the smaller the sum of the deviations, the more the mobile stations existing in the network have the same capacity. That is, a mobile station having a small total deviation value can perform good communication with any mobile station.

[Condition 2a] The total value of the deviation of the electric field strength is minimum The transmission / reception state with another station is evaluated based on the total value of the deviation of the electric field strength of the received data of the own station with respect to the other station.

Here, each mobile station CM · SL ₁ -SL
_3, each electric field strength table within RAM30 respectively corresponding to each mobile station CM · SL ₁ ~SL ₃ B4 (FIG. 5 (d)
Reference). Specifically, as shown in FIG. 20, four electric field strength tables B4 _(CM) , B4 _(SL1) , B4
_(SL2) and B4 _(SL3) .

The mobile station CM sets the transmission destination to “255” and transmits the control data D17 of the inspection data emission request at each time set in the measurement data emission interval A9,
Requesting transmission of control data D18 for test data fired response to all mobile station SL ₁ to SL ₃ in slave mode. Each of the mobile stations SL _{1 to} SL ₃ sets the transmission destination to “255” in the order of the mobile station numbers and transmits the control data D18 of the test data emission response (see FIG. 19).

The mobile station SL _{1 that} has received the control data D 18 from the mobile station SL ₂ is sent to the reception level detection unit 21 in the control unit 18 and the slot R normally used by the mobile station CM is used.
Use 1 measures the field intensity of the own station to the mobile station SL _2. When this electric field strength value (for example, X) has changed from the previous value, the electric field strength table B4 of the own station (mobile station SL ₁ ).
_(SL1) (see FIG. 20 (b)), the portion corresponding to that mobile station number "3" is set to the transmission source of the control data D18 from the mobile station SL _2, and stores the electric field intensity value X .

[0130] The mobile station SL ₁ uses the control data D14 shown in FIG. 8 (d), all other mobile stations CM · SL
₂ · SL ₃ is notified of the electric field strength (electric field strength value X) of mobile station SL ₁ with respect to mobile station SL ₂ . The above control data D
The transmission data section 14 includes an area D14a for setting a number "3" indicating control of electric field strength notification, an area D14b for setting a mobile station number, and an area D for setting an electric field strength value.
14c.

That is, the mobile station SL ₁ transmits the control data D 14
And the mobile station number “3” set as the transmission source of the control data D18 in the area D14b.
Send by setting the field strength value X to the area D14C, to all other mobile stations CM · SL ₂ · SL _3, and notifies the field strength value X. On the other hand, control of the mobile station SL ₁ data D14
The mobile stations CM, SL _2, and SL ₃ that have received the “.” Receive the field strength table B4 _(SL1) corresponding to the mobile station number “2” set as the transmission source of the control data D14 (FIGS. 20A and 20C ₎ . )
In (d), the electric field strength value X is stored in a location corresponding to the mobile station number “3”.

Similarly to the above, the electric field strength value (for example, Y) of the mobile station SL ₁ with respect to the mobile station SL ₃ is changed to the mobile station CM.
It is stored in · SL ₁ each electric field strength to SL ₃ Table B4 _(SL1). Incidentally, the electric field intensity of the mobile station SL ₁ to the mobile station CM is measured when it receives the control data D17 for test data launch request, the electric field intensity value (e.g., Z) likewise each field strength table B4 _{( SL1)} .

Each mobile station S other than the mobile station SL ₁
Similarly, the electric field strength is measured for L ₂ and SL ₃ .
In this way, all mobile stations mutually grasp their own electric field strength with respect to other stations.

[0134] Then, using an electric field intensity value X · Y · Z of the field strength table B4 _(SL1), computing the variation of the field strength of the mobile station SL ₁ to the mobile station SL ₂ · SL ₃ · CM (the deviation), respectively I do. Similarly, the electric field strength table B4 _(SL2) of the mobile station SL _2, the mobile station S from the field strength table B4 _(SL3)
L ₃ of variations in the electric field strength is calculated.

The mobile station SL compares the total value of the deviation of the electric field strength of its own station with the total value of the deviation of the electric field strength of the other station, and determines that the total value of the deviation of the electric field strength of its own station is the smallest. When detected, the control data D6 is transmitted.

[Condition 2b] The total value of the deviation of the reception error rate is minimum The transmission / reception state with another station is evaluated based on the total value of the deviation of the error rate of the reception data of the own station with respect to the other station.

As in the case of the above [condition 2a], the mobile station CM transmits the control data D17 of the test data emission request, and each of the mobile stations SL _{1 to} SL ₃ transmits the control data D18 of the test data emission response. Send.

Control data D18 of inspection data emission response
Is received by the error detecting unit 22 in the control unit 18 using the slot R1.
The presence / absence of a frame error is checked, and the reception error rate is calculated for each time set in the reception error measurement interval A7. If this reception error rate value changes from the previous value,
The receiving error rate table B5 of the own station in the RAM 30 (FIG. 5E)
), The reception error rate value is stored in a location corresponding to the mobile station number set as the transmission source of the received control data D18.

The mobile station SL uses the control data D15 shown in FIG. 8 (e) to notify all other mobile stations of its own reception error rate with respect to other stations. The transmission data part of the control data D15 includes an area D15a for setting a number “4” indicating control of notification of a reception error rate, an area D15b for setting a mobile station number, and an area D15c for setting a reception error rate value. Have.

That is, the mobile station SL sets “255” as the transmission destination of the control data D15 and the mobile station number set as the transmission source of the control data D18 received in the area D15b.
A reception error rate value is set in the area D15c and transmitted, and all other mobile stations are notified of their own reception error rate with respect to other stations. On the other hand, the other mobile stations SL that have received the control data D15 are listed in the reception error rate table B5 corresponding to the mobile station number set as the transmission source of the control data D15. As in the case of B5, the reception error rate value is stored.

In this manner, the reception error rate values are calculated for all the mobile stations SL _{1 to} SL _{3 in} the slave mode, and the reception error rates of the mobile stations relative to each other are grasped among all the mobile stations.

Thereafter, each of the mobile stations SL _{1 to} SL ₃ sends each mobile station SL to another station based on the reception error rate table B5.
Variations in the reception error rate of ₁ to SL ₃ (the deviation) is calculated. The mobile station SL compares the total value of the deviation of the reception error rate of its own station with the total value of the deviation of the reception error rate of the other station, and determines that the total value of the deviation of its own reception error rate is the smallest. When detected, the control data D6 is transmitted.

[Condition 2c] The total value of the deviation of the propagation delay time is minimum The transmission / reception state with another station is evaluated based on the total value of the deviation of the propagation delay time of the reception data of the own station with respect to the other station.

As in the case of the above [Condition 2a], the mobile station CM transmits the control data D17 of the test data emission request, and each of the mobile stations SL _{1 to} SL ₃ transmits the control data D18 of the test data emission response. Send. Here, when the mobile station SL transmits the control data D18 of the test data emission response, the value of the built-in timer 25 of the own station when the control data D17 is received is set in the area D18b.

Control data D18 of inspection data emission response
The mobile station SL, which has received the data, transmits the propagation delay time, which is the difference between the built-in timer value of the control data D18 and the built-in timer value of the own station, using the slot R1 by the propagation delay time measuring unit 23 in the control unit 18. Is calculated. When this propagation delay time value has changed from the previous value, it is set as the transmission source of the received control data D18 in the propagation delay time table B6 (see FIG. 5F) of the own station in the RAM 30. The propagation delay time value is stored in a location corresponding to the mobile station number.

The mobile station SL uses the control data D16 shown in FIG. 8 (f) to notify all other mobile stations of its own propagation delay time with respect to other stations. The transmission data portion of the control data D16 includes an area D16a for setting a number “5” indicating control of notification of a propagation delay time, an area D16b for setting a mobile station number, and an area D16c for setting a propagation delay time value. Have.

That is, the mobile station SL sets “255” as the transmission destination of the control data D16, the mobile station number set as the transmission source of the control data D18 received in the area D16b, and stores the propagation delay time in the area D16c. Set the value and send,
All other mobile stations are notified of their own propagation delay time with respect to other stations. On the other hand, the other mobile stations SL that have received the control data D16 are in the propagation delay time table B6 corresponding to the mobile station number set as the transmission source of the control data D16,
As in the case of the propagation delay time table B6 of the mobile station SL,
The above propagation delay time value is stored.

In this way, the propagation delay time is calculated for all the mobile stations SL _{1 to} SL _{3 in} the slave mode, and the propagation delay time of the own station with respect to another station is grasped between all the mobile stations.

Thereafter, each of the mobile stations SL _{1 to} SL ₃ transmits each mobile station SL to another station based on the propagation delay time table B6.
The variation (deviation) of the propagation delay time of each of _{1 to} SL ₃ is calculated. The mobile station SL compares the total value of the deviation of the propagation delay time of its own station with the total value of the deviation of the propagation delay time of the other station, and determines that the total value of the deviation of the propagation delay time of its own station is the smallest. When detected, the control data D6 is transmitted.

[Condition 2d] The total value of the deviation of the number of retransmission requests is minimum. The transmission / reception state with another station is evaluated based on the total value of the deviation of the number of retransmission requests of the own station with respect to the other station.

As in the case of [condition 2a], the mobile station CM transmits the control data D17 of the test data emission request, and each of the mobile stations SL _{1 to} SL ₃ transmits the control data D18 of the test data emission response. Send.

Control data D18 of inspection data emission response
Is received by the error detecting unit 22 in the control unit 18 using the slot R1.
The presence / absence of a frame error is checked. When a frame error is detected, control data D20 for a retransmission request is transmitted, and the number of retransmission requests is calculated at each time set in the retransmission request number measurement interval A12. If this retransmission request count value has changed from the previous value, it is set as the source of the received control data D18 in the retransmission request count table B7 (see FIG. 5 (g)) of the own station in the RAM 30. The number of retransmission requests is stored in a location corresponding to the mobile station number.

Further, the mobile station SL notifies all other mobile stations of the number of retransmission requests of the own station to other stations, using the control data D21 shown in FIG. 8 (k). The transmission data portion of the control data D21 includes an area D21a for setting a number “6” indicating control of the retransmission request number notification, an area D21b for setting a mobile station number, and an area D21c for setting a retransmission request number value. Have.

That is, the mobile station SL sets “255” as the transmission destination of the control data D21 and the mobile station number set as the transmission source of the control data D18 received in the area D21b.
A retransmission request count value is set in area D21c and transmitted, and all other mobile stations are notified of their own retransmission request count for other stations. On the other hand, the other mobile stations SL that have received the control data D21 include the retransmission request frequency table B7 of the mobile station SL in the retransmission request frequency table B7 corresponding to the mobile station number set as the transmission source of the control data D21. As in the case of (1), the retransmission request count value is stored.

In this way, the number of retransmission requests for all the mobile stations SL _{1 to} SL _{3 in} the slave mode is calculated, and the number of retransmission requests of the own station to other stations is grasped between all the mobile stations.

Thereafter, each of the mobile stations SL _{1 to} SL ₃ sends each mobile station SL to another station based on the retransmission request count table B7.
The variation (deviation) of the number of retransmission requests for _{1 to} SL ₃ is calculated. The mobile station SL compares the total value of the deviation of the number of retransmission requests of its own station with the total value of the deviation of the number of retransmission requests of the other station, and determines that the total value of the deviation of the number of retransmission requests of its own station is the smallest. When detected, the control data D6 is transmitted.

[Condition 2e] The total value of the electric field strength is maximum The transmission / reception state with another station is evaluated based on the total value of the electric field strength of the own station with respect to the other station.

In the same manner as in the above [condition 2a], the electric field strengths are calculated for all the mobile stations SL _{1 to} SL _{3 in} the slave mode, and the electric field strengths of the mobile stations relative to each other are grasped among all the mobile stations. .

[0159] Then, based on the electric field strength table B4 in each mobile station SL ₁ to SL _3, each mobile station SL ₁ ~ to other stations
The sum of the electric field strengths of SL ₃ is calculated. The mobile station SL transmits the control data D6 when comparing the total value of the electric field strength of its own station with the total value of the electric field strengths of the other stations and detecting that the total value of the electric field strength of its own station is the largest. I do.

[Condition 2f] The total value of the reception error rate is minimum The transmission / reception state with another station is evaluated based on the total value of the reception error rate of the reception data of the own station with respect to the other station.

In the same manner as in the above [Condition 2b], the reception error rates are calculated for all the mobile stations SL _{1 to} SL _{3 in} the slave mode, and the reception error rates of the own station with respect to other stations are mutually determined between all the mobile stations. Figure out.

Thereafter, each of the mobile stations SL _{1 to} SL ₃ sends each mobile station SL ₁ to another station based on the reception error rate B5.
ＳＬSL ₃ are calculated.
The mobile station SL compares the total value of the reception error rate of its own station with the total value of the reception error rates of the other stations, and when it detects that the total value of its own reception error rate is the smallest, Send D6.

[Condition 2g] The total value of the propagation delay time is minimum The transmission / reception state with another station is evaluated based on the total value of the propagation delay time of the reception data of the own station with respect to the other station.

In the same manner as in the above [Condition 2c], the propagation delay time is calculated for all the mobile stations SL _{1 to} SL _{3 in} the slave mode, and the propagation delay time of the own station with respect to another station is calculated between all the mobile stations. Figure out.

Thereafter, based on the propagation delay time table B6 in each of the mobile stations SL _{1 to} SL ₃ , each mobile station SL with respect to another station
The total value of the propagation delay times of _{1 to} SL ₃ is calculated. The mobile station SL compares the total value of the propagation delay time of its own station with the total value of the propagation delay time of the other stations, and when it detects that the total value of its own propagation delay time is the smallest, Send D6.

[Condition 2h] The total value of the number of retransmission requests is minimum The transmission / reception state with another station is evaluated by the total value of the number of retransmission requests of the own station's received data to the other station.

In the same manner as in the above [Condition 2d], the number of retransmission requests for all the mobile stations SL _{1 to} SL _{3 in} the slave mode is calculated, and the number of retransmission requests of the own station with respect to other stations is calculated between all the mobile stations. Figure out.

Thereafter, each of the mobile stations SL _{1 to} SL ₃ transmits each mobile station SL to another station based on the propagation delay time table B7.
The total value of the number of retransmission requests of ₁ to SL ₃ to be calculated. The mobile station SL compares the total value of the number of retransmission requests of its own station with the total value of the number of retransmission requests of other stations, and when it detects that the total value of the number of retransmission requests of its own station is the smallest, Send D6.

[Condition 3] Environment change due to switching of clock master is minimum. Mobile station SL is composed of all mobile stations SL _{1 to} SL in the slave mode.
_{When the} local station determines that the environmental change due to the switching of the clock master is the smallest among the _three , it transmits the control data D6 to the mobile station CM.

Here, the environmental change due to the switching of the clock master is represented by the electric field strength for the clock master, the reception error rate for the clock master, the propagation delay time for the clock master, and the number of retransmission requests for the clock master.

[Condition 3a] The electric field strength with respect to the clock master is maximum The environmental change caused by switching the mobile station CM is evaluated based on the electric field strength of the mobile station SL with respect to the mobile station CM.

Similarly to the above [condition 2a], the mobile station CM transmits the control data D17 of the test data emission request, and each of the mobile stations SL _{1 to} SL ₃ transmits the control data D18 of the test data emission response. Send.

[0173] The mobile station CM is the reception level detection unit 21 in the control unit 18 measures the field intensity of the control data D18 for test data launch a response from the mobile station SL ₁ to SL _3, respectively. When these electric field strength values have changed from the previous value, the control data D received in the area D14b is set to “255” as the transmission destination of the control data D14 for the electric field strength notification.
The mobile station number set as the transmission source of No. 18 is
Send by setting the field intensity values measured 14c, notifies the field strength of the mobile station SL for the mobile station CM to all the mobile station SL ₁ to SL ₃ in slave mode. On the other hand, mobile station CM
Each of the mobile stations SL _{1 to} SL ₃ receiving the control data D14 of the electric field intensity notification from the mobile station stores the electric field intensity values in the electric field intensity table B4 corresponding to the mobile station CM among the plurality of electric field intensity tables B4. I do. In this way, the electric field strength of the mobile station SL with respect to the mobile station CM is grasped among all the mobile stations.

When the mobile station SL compares the electric field strength of its own station with the mobile station CM and the electric field strength of another station with respect to the mobile station CM, and detects that the electric field strength of its own station is the largest, the control data D6. Send

[Condition 3b] The reception error rate with respect to the clock master is the minimum The environmental change due to the switching of the mobile station CM is evaluated based on the reception error rate of the reception data of the mobile station SL with respect to the mobile station CM.

As in the case of the [condition 2a], the mobile station CM transmits the control data D17 of the test data emission request, and each of the mobile stations SL _{1 to} SL ₃ transmits the control data D18 of the test data emission response. Send.

The mobile station CM checks the presence / absence of a frame error in the control data D18 of the test data emission response from each of the mobile stations SL _{1 to} SL ₃ by using the error detection unit 22 in the control unit 18 to measure the reception error. The reception error rate is calculated for each time set in the interval A7. If the reception error rate value has changed from the previous value, "255" is set as the transmission destination of the control data D15 of the reception error rate notification, and the mobile station set as the transmission source of the control data D18 received in the area D15b. The mobile station SL in the slave mode is transmitted by setting the calculated reception error rate value in the area D15c.
And notifies the reception error rate of the mobile station SL for the mobile station CM to ₁ to SL _3. On the other hand, each of the mobile stations SL _{1 to} SL that has received the control data D15 of the reception error rate notification from the mobile station CM.
L ₃ is the mobile station CM of a plurality of reception error rate table B5
Are stored in the reception error rate table B4 corresponding to the above. In this way, the reception error rate of the mobile station SL with respect to the mobile station CM is grasped among all the mobile stations.

The mobile station SL compares the reception error rate of its own mobile station CM with the reception error rate of the other station's mobile station CM, and when it detects that the reception error rate of its own station is the smallest, The control data D6 is transmitted.

[Condition 3c] Propagation delay time to clock master is minimum Environment change due to switching of mobile station CM is evaluated based on propagation delay time of received data of mobile station SL to mobile station CM.

Similarly to the above [condition 2a], the mobile station CM transmits the control data D17 of the test data emission request, and each of the mobile stations SL _{1 to} SL ₃ transmits the control data D18 of the test data emission response. Send. Here, when the mobile station SL transmits the control data D18 of the test data emission response, the value of the built-in timer 25 of the own station when the control data D17 is received is set in the area D18b.

The mobile station CM uses the propagation delay time measuring unit 23 in the control unit 18 to control the built-in timer value of the control data D18 of the test data emission response from each of the mobile stations SL _{1 to} SL ₃ and the built-in timer of its own station. Calculate the propagation delay represented by the difference between the values. If this propagation delay time value has changed from the previous value, "255" is transmitted to the transmission destination of the control data D16 of the propagation delay time notification, and the control data D received in the area D16b.
The mobile station number set as the transmission source of No. 18 is stored in the area D1.
6c, the calculated propagation delay time value is set and transmitted,
All mobile stations SL _{1 to} SL ₃ in the slave mode have mobile stations CM.
Is notified of the propagation delay time of the mobile station SL. on the other hand,
Control data D16 for notification of propagation delay time from mobile station CM
Each mobile station SL ₁ to SL ₃ which has received the propagation delay time table B6 corresponding to the mobile station CM of a plurality of propagation delay time table B6, and stores the propagation delay time value, respectively. In this way, the propagation delay time of the mobile station SL with respect to the mobile station CM is grasped among all the mobile stations.

When the mobile station SL compares the propagation delay time of its own station with the mobile station CM and the propagation delay time of another station with respect to the mobile station CM, and detects that the propagation delay time of its own station is the smallest, The control data D6 is transmitted.

[Condition 3d] The Number of Retransmission Requests to the Clock Master is Minimum The environmental change due to the switching of the mobile station CM is evaluated based on the number of retransmission requests of the mobile station SL to the mobile station CM.

Similarly to the above [condition 2a], the mobile station CM transmits the control data D17 of the test data emission request, and each of the mobile stations SL _{1 to} SL ₃ transmits the control data D18 of the test data emission response. Send.

The mobile station CM uses the error detector 22 in the controller 18 to control the control data D1 of the test data emission response.
8 is checked for frame errors. When a frame error is detected, control data D20 for a retransmission request is transmitted, and the number of retransmission requests is calculated for each time set in the retransmission request frequency measurement interval A12. When the retransmission request count value changes from the previous value, “255” is set as the transmission destination of the control data D21 of the retransmission request count notification, and the transmission source of the control data D18 of the inspection data emission response received in the area D21b. the mobile station number is set, and transmits the set of calculated the number of retransmission requests value to the area D21c, the number of retransmission requests of the mobile station SL for the mobile station CM to all the mobile station SL ₁ to SL ₃ slave mode Notify. On the other hand, mobile station CM
Each of the mobile stations SL _{1 to} SL ₃ receiving the control data D21 of the retransmission request notification from the mobile station CM stores the retransmission request frequency value in the retransmission request frequency table B7 corresponding to the mobile station CM in the plurality of retransmission request frequency tables B7. Store each. In this way, the number of retransmission requests of the mobile station SL to the mobile station CM is grasped between all the mobile stations.

The mobile station SL compares the number of retransmission requests for its own mobile station CM with the number of retransmission requests for other mobile stations CM, and when it detects that its own retransmission request number is the smallest, The control data D6 is transmitted.

[Condition 4] The order of the numbers assigned to the mobile stations The response of the mobile station SL is based on the mobile station number. That is, when detecting that the mobile station number of the mobile station SL is “2”, the mobile station SL transmits the control data D6.

As described above, the time-division digital mobile radio communication system according to the present embodiment includes a plurality of mobile stations, and each of the above-mentioned mobile stations uses a free-running clock for establishing synchronization required for time-division communication. And a slave mode that operates in frame synchronization with a synchronization signal pattern transmitted from a mobile station in the master mode.

Here, one of the plurality of mobile stations is used as a clock master operating in a master mode, and the remaining mobile stations are operated in a slave mode to perform wireless communication between the plurality of mobile stations. In this case, during communication, the clock master is switched to the mobile station in the slave mode, and at the same time, one of all the mobile stations in the slave mode other than the clock master is switched to the master mode to be the next clock master. Features.

According to this, since each mobile station has two operation modes, a master mode and a slave mode, if one of a plurality of mobile stations is used as a clock master, the mobile station must pass through the base station. Wireless communication between mobile stations.

Since the switching of the clock master can be realized during the communication, the load does not concentrate only on the mobile station in the master mode. This makes it possible to distribute the load applied to all mobile stations.

Further, for example, when communication is performed between a clock master and a mobile station in a slave mode, if one of the mobile stations moves and the communication state between the two mobile stations is deteriorated, the conventional technique is used. In the configuration, since the clock master cannot be switched during communication, communication may be interrupted. On the other hand, in the configuration of the present application, the clock master can be switched during communication, so that continuous communication is possible by using another mobile station as the clock master even in the above case.

The clock master that is operated in the master mode first is the mobile station that has been first activated by turning on the power among all the mobile stations. According to this, the mobile station that will be in the next operating state can communicate smoothly, and can communicate efficiently.

[0194] The clock master operated in the master mode first may be the mobile station that first needs to transmit data among all the mobile stations. According to this, a mobile station that does not perform data transmission even when it is in an operating state when the power is turned on does not become a clock master, and does not give an excessive load to the mobile station due to becoming a clock master.

The switching method of the clock master is as follows. The current clock master issues a switching request to all the mobile stations in the slave mode before the own station switches to the slave mode, and the current clock master among all the mobile stations in the slave mode receiving the request. The mobile station in the slave mode which first responds to the current clock master becomes the next clock master.

A switching request from the current clock master is:
(1) When the current clock master no longer holds the transmission data, (2) When a certain time has elapsed since the current clock master radiated the radio wave for synchronization, (3) When the current clock master is transmitted from the mobile station in the slave mode. (4) When the current clock master has relayed a certain amount of data from the mobile station in the slave mode, and (5) It has been detected that the current clock master has not relayed data for a certain time. Time point, (6) time point at which the current clock master is judged to have reduced its ability as a clock master, (7)
This is performed when the current clock master detects the interference or (8) when the mobile station in the current slave mode detects the interference of the current clock master.

In the case of the above (1), when there is no transmission data, a standby state is set, and there is no need to be a clock master, so that the battery of such a mobile station is not unnecessarily consumed. In the case of (2), the period of being the clock master is the same for all mobile stations in the network, so that the battery consumption of each mobile station can be averaged. (3) In the case of (4), the load of data relay is dispersed, so that the battery consumption of each mobile station can be averaged. In the case of (5), when there is no data to be relayed, the emission of the synchronization radio wave does not need to be continued, and the emission of the synchronization radio wave can be stopped to prevent the battery from being consumed. In the case of (6), for example, when the free memory capacity of the RAM becomes small, relaying becomes impossible, so that the clock master which interferes with communication is switched, so that good communication can be maintained. (7) In the case of (8), the clock master which interferes with communication due to interference is switched, so that good communication can be maintained.

The response of the mobile station in the slave mode to the switching request from the current clock master includes (1) the mobile station having the best clock master capability among all the mobile stations in the slave mode, and (2) the slave station. The mobile station with the best transmission / reception status with other mobile stations among all mobile stations in the mode,
(3) Among mobile stations in the slave mode, the environment change due to switching of the clock master is performed by the mobile station with the minimum, or (4) A serial number (mobile station number) is assigned to all the mobile stations in the slave mode. Are performed in order according to the number.

In the case of the above (1), the new clock master does not hinder communication, so that good communication can be maintained. In the case of (2), the mobile station having the same capability as the other station in the network becomes the new clock master, so that the new clock master can perform good communication with any mobile station. it can. (3)
In the case of (1), the change in environment due to the switching of the clock master can be suppressed as much as possible, so that the occurrence of an error due to the switching can be minimized. In the case of (4), since the order of the clock masters is determined, the amount of battery consumption of each mobile station can be averaged. Further, the response time in the slave mode can be reduced as compared with the cases (1) to (3).

[Embodiment 2] The following will describe Embodiment 2 of the present invention with reference to FIGS. 21 and 26. For the sake of convenience of explanation, the same members as those shown in the drawings of the above embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The time division digital mobile radio communication system of the present embodiment has the same configuration as that of the first embodiment.
The process (1) for determining the clock master and the process (2) for the wireless communication between the mobile stations are the same as those in the first embodiment.
(3) The switching process of the clock master during the communication is different.

Therefore, only the switching process of the mobile station CM during communication will be described here. The present embodiment is characterized in that the mobile station CM nominates the mobile station SL to be the next clock master, and the nominated mobile station SL becomes the new clock master.

As shown in FIG. 21, there is a mobile station SL that satisfies the conditions for the mobile station CM to make a nomination (S6).
1) Using the slot T1, the mobile station SL of the mobile station SL satisfying the nomination condition is set as the transmission destination of the control data D5 of the clock master switching request, and the control data D5 is transmitted (S62).

The mobile station SL having received the control data D5
The control data D6 of the clock master switching response is transmitted to the mobile station CM using the next slot R1 (S65, S65).
66).

Upon receiving the control data D6 (S63), the mobile station CM switches to the slave mode mobile station (S64). On the other hand, the mobile station S that transmitted the control data D6
L becomes the new clock master (S67).

As in the first embodiment, the new clock master uses the next slot T1 to set the transmission destination of the control data D4 of the clock master ID notification, which is the radio wave for synchronization, to “25”.
5 is set to ", and transmits the control data D4. In addition, to change the mobile station number of all mobile stations CM · SL ₁ ~SL _3.

Next, the nomination condition of the clock master in S61 of FIG. 21 will be described. That is, when any of [Condition 1] to [Condition 4] shown in FIG.
M transmits control data D5 of the clock master switching request.

[Condition 1] The maximum capacity as a clock master The mobile station CM includes all mobile stations SL _{1 to} SL in the slave mode.
When detecting the mobile station SL having the maximum capability as a clock master in ₃ , the control data D5 is transmitted. Here, the ability as a clock master is as shown in [Condition 6] of (3-1) of the first embodiment.

[Condition 1a] Maximum CPU Performance Possibility As in the case of [Condition 1a] in (3-2) of the first embodiment, the mobile station SL calculates a CPU performance value,
The CPU performance value is stored in the CPU performance table B1. That is, the mobile station SL sets C
The PU monitoring unit 27 measures the time during which the CPU 29 is idle within the time set in the CPU performance monitoring time A5, and calculates a CPU performance value represented by “CPU idle time / CPU performance monitoring time”. . If this CPU performance value has changed from the previous value (the value currently stored in the RAM 30), the new CPU is placed in the location corresponding to the mobile station number of the own station in the CPU performance table B1 in the RAM 30. Stores performance values.

Then, the mobile station CM is notified of its own CPU performance using the control data D11 of the CPU performance notification. That is, the mobile station SL transmits “1” representing the clock master to the transmission destination of the control data D11 by setting the calculated CPU performance value in the area D11b and transmits the CPU performance of the own station to the mobile station CM. Notice.

On the other hand, the mobile station CM that has received the control data D11 stores the CPU performance value of the mobile station SL in a location corresponding to the mobile station number set as the transmission source of the control data D11 in the CPU performance table B1. Is stored. In this way, the mobile station CM is, to grasp all the CPU performance of the mobile station SL ₁ ~SL ₃ of the slave mode.

The mobile station CM has a CPU performance table B
1, all the mobile stations SL _{1 to} SL in the slave mode
_{When the} mobile station SL having the highest CPU performance among the _three is detected, the control data D5 is transmitted to the mobile station SL.

[Condition 1b] Owning the maximum free memory capacity In the same manner as in the case of [Condition 1b] in (3-2) of the first embodiment, the mobile station SL calculates the free memory capacity value and calculates the free memory capacity table. The free memory capacity value is stored in B2. Then, the mobile station CM is notified of its free memory capacity using the control data D12 of the free memory capacity notification. Mobile station C
When M receives the control data D12, the mobile station C
M grasps the free memory capacity of all the mobile stations SL _{1 to} SL _{3 in} the slave mode. The mobile station CM includes mobile stations SL ₁ to SL ₁ .
Among the SL _3, when detecting a mobile station SL most free memory capacity is large, it sends the control data D5 to the mobile station SL.

[Condition 1c] Owning the Largest Built-in Battery Capacity As in the case of [Condition 1c] in (3-2) of the first embodiment, the mobile station SL calculates the remaining battery capacity value and calculates the remaining battery capacity table. The battery remaining capacity value is stored in B3. Then, the mobile station CM is notified of the remaining battery level of the own station by using the control data D13 of the remaining battery level notification. When the mobile station CM receives the control data D13
, The mobile station CM grasps the remaining battery capacity of all the mobile stations SL _{1 to} SL _{3 in} the slave mode. When detecting the mobile station SL having the largest remaining battery capacity among the mobile stations SL _{1 to} SL ₃ , the mobile station CM transmits control data D5 to the mobile station SL.

[Condition 2] The state of transmission and reception with other mobile stations is the best. The mobile station CM has all the mobile stations SL _{1 to} SL in the slave mode.
_{When the} mobile station SL that has the best transmission / reception state with other stations in ₃ is detected, the control data D5 is transmitted to the mobile station SL. Here, the transmission / reception state with another station is as shown in [condition 2] of (3-2) of the first embodiment.

[Condition 2a] The total value of the deviation of the electric field strength is minimum The transmission / reception state with another station is evaluated by the total value of the deviation of the electric field strength of the reception data of the own station with respect to the other station.

As in the case of [condition 2a] of (3-2) in the first embodiment, the mobile station SL measures its own electric field strength value with respect to another station, and stores it in its own electric field strength table B4. Stores the electric field strength value. That is, the mobile station SL that has received the control data D18 of the test data emission response measures the electric field strength of its own station with respect to other stations by using the slot R1 by the reception level detection unit 21 in the control unit 18. If the electric field strength value has changed from the previous value, the calculated electric field strength value is set at a location corresponding to the mobile station number set as the transmission source of the control data D18 in the local station electric field strength table B4. Is stored.

Then, the control data D14 of the electric field intensity notification
Is used to notify the mobile station CM of its own field strength with respect to other stations. That is, the mobile station SL sets “1” as the transmission destination of the control data D14, sets the mobile station number set as the transmission source of the control data D18 in the area D14b, and sets the calculated electric field strength value in the area D14c. Mobile station C
M is notified of its own field strength relative to other stations.

[0219] On the other hand, the mobile station CM that has received the control data D14 uses the case of the electric field strength table B4 of the mobile station SL in the electric field strength table B4 corresponding to the mobile station number set as the transmission source of the control data D14. The electric field strength value is stored in the same manner as in the above. In this way, the mobile station CM grasps the electric field strength for the other stations of the whole mobile station SL ₁ to SL ₃ in slave mode.

[0220] Based on the electric field strength table B4 in the mobile station CM, the mobile station CM transmits each of the mobile stations SL _{1 to} SL _{3 to} other stations.
When the mobile station SL having the smallest sum of the electric field strength deviations with respect to the other stations among all the mobile stations SL _{1 to} SL ₃ in the slave mode is detected, the control data is calculated. Send D5.

[Condition 2b] The total value of the deviation of the reception error rate is minimum The transmission / reception state with another station is evaluated based on the total value of the deviation of the error rate of the reception data of the own station with respect to the other station.

The mobile station SL calculates the reception error rate value and stores the reception error rate value in the reception error rate value table B5 in the same manner as in the case of [condition 2b] of (3-2) of the first embodiment. I do. Then, the mobile station CM is notified of its own reception error rate with respect to other stations using the control data D15 of the reception error rate notification. When the mobile station CM receives the control data D15, the mobile station CM operates in all slave stations SL in the slave mode.
To grasp the reception error rate for the other stations of ₁ to SL _3. The mobile station CM calculates the variation (deviation) of the reception error rate of each of the mobile stations SL _{1 to} SL ₃ with respect to other stations based on the reception error rate value table B5 in the mobile station CM, and performs all the movements in the slave mode. when the total value of the deviation of the reception error rate for the other stations in the station SL ₁ to SL ₃ detects the smallest mobile station SL, transmits the control data D5.

[Condition 2c] The total value of the deviation of the propagation delay time is minimum The transmission / reception state with another station is evaluated based on the total value of the deviation of the propagation delay time of the reception data of the own station with respect to the other station.

The mobile station SL calculates the propagation delay time value and stores the propagation delay time value in the propagation delay time value table B6 in the same manner as in the case of [condition 2c] of (3-2) of the first embodiment. I do. Then, the mobile station CM is notified of its own propagation delay time with respect to other stations by using the control data D16 of the propagation delay time notification. When the mobile station CM receives the control data D16, the mobile station CM starts to operate in all slave stations SL in the slave mode.
Grasp the propagation delay times for other stations ₁ to SL _3. The mobile station CM calculates the variation (deviation) of the propagation delay time of each of the mobile stations SL _{1 to} SL ₃ with respect to the other stations based on the propagation delay time value table B6 in the mobile station CM, and performs all movements in the slave mode. when the total value of the deviation of the propagation delay time for the other stations in the station SL ₁ to SL ₃ detects the smallest mobile station SL, transmits the control data D5.

[Condition 2d] The total value of the deviation of the number of retransmission requests is minimum The transmission / reception state with another station is evaluated based on the total value of the deviation of the number of retransmission requests of the own station with respect to other stations.

The mobile station SL calculates the number of times of retransmission request in the same manner as in the case of [condition 2d] of (3-2) of the first embodiment, and transmits it to the number of times of retransmission request table B7 (see FIG. 5). Stores the delay time value. Then, using the control data D21 of the retransmission request number notification shown in FIG. 8, the mobile station CM is notified of its own retransmission request number for the other station. By mobile station CM receives control data D21, the mobile station CM grasps the number of retransmission requests for other stations of all the mobile stations SL ₁ to SL ₃ in slave mode. The mobile station CM calculates the variation (deviation) of the number of retransmission requests of each of the mobile stations SL _{1 to} SL ₃ with respect to another station based on the retransmission request number table B7 in the mobile station CM, and performs all the movements in the slave mode. Stations SL _{1 to} SL
₃ , when the mobile station SL that has the smallest total deviation of the number of retransmission requests to other stations is detected, the control data D
Send 5

[Condition 2e] The total value of the electric field strength is maximum The transmission / reception state with another station is evaluated based on the total value of the electric field strength of the own station with respect to the other station.

In the same manner as in the above [Condition 2a], all the mobile stations SL _{1 to} SL _{3 in} the slave mode respectively calculate the electric field strength, and notify the mobile station CM of the calculation result. Represents all mobile stations S in the slave mode.
To grasp the electric field strength for the other stations of L ₁ to SL _3.

The mobile station CM has the electric field strength table B of the mobile station CM.
4 on the basis of the total value of the electric field strength of each mobile station SL ₁ to SL ₃ for other stations were calculated respectively, the total value of the electric field intensity with respect to the other stations in the entire mobile station SL ₁ to SL ₃ slave mode When the largest mobile station SL is detected, control data D5 is transmitted.

[Condition 2f] The total value of the reception error rate is minimum The transmission / reception state with another station is evaluated based on the total value of the reception error rate of the reception data of the own station with respect to the other station.

In the same manner as in the above [Condition 2b], all the mobile stations SL _{1 to} SL _{3 in} the slave mode respectively calculate the reception error rate and notify the mobile station CM of the calculation result. CM grasps the reception error rate for the other stations of the whole mobile station SL ₁ to SL ₃ in slave mode.

[0232] The mobile station CM sets each of the mobile stations SL _{1 to} SL to other stations based on the reception error rate table B5 in the mobile station CM.
The total value of the reception error ratio of L ₃ were calculated respectively, when the total value of the received error rate for the other stations in the entire mobile station SL ₁ to SL ₃ slave mode detects the smallest mobile station SL, control data Send D5.

[Condition 2g] The total value of the propagation delay time is minimum The transmission / reception state with another station is evaluated based on the total value of the propagation delay time of the reception data of the own station with respect to the other station.

As in the case of the above [Condition 2c], all the mobile stations SL _{1 to} SL _{3 in} the slave mode each calculate the propagation delay time, and notify the mobile station CM of the calculation result. CM grasps the propagation delay times for other stations of all the mobile stations SL ₁ to SL ₃ in slave mode.

Based on the propagation delay time table B6 in the mobile station CM, the mobile station CM sends each of the mobile stations SL _{1 to} SL to other stations.
L ₃ of the sum of the propagation delay time calculated respectively, when the total value of the propagation delay time for the other station detects the smallest mobile station SL in the entire mobile station SL ₁ to SL ₃ slave mode, the control data Send D5.

[Condition 2h] The total number of retransmission requests is minimum The transmission / reception state with another station is evaluated based on the total number of retransmission requests of own station's received data to other stations.

In the same manner as in the above [condition 2d], all the mobile stations SL _{1 to} SL _{3 in} the slave mode each calculate the number of retransmission requests, and notify the mobile station CM of the calculation result. CM is to grasp the number of retransmission requests for other stations of all the mobile stations SL ₁ to SL ₃ in slave mode.

[0238] The mobile station CM, based on the number of retransmission requests Table B7 in the mobile station CM, each mobile station SL ₁ to S for other stations
The total value of the number of retransmission requests of L ₃ were calculated respectively, when the total value of the number of retransmission requests to the other station detects the smallest mobile station SL in the entire mobile station SL ₁ to SL ₃ slave mode, the control data Send D5.

[Condition 3] Environment change due to clock master switching is minimal. The mobile station CM is the mobile station S that has the smallest environmental change due to clock master switching among all the mobile stations SL _{1 to} SL _3.
When detecting L, control data D5 is transmitted to the mobile station SL. Here, the environmental change due to the switching of the clock master is as shown in [condition 3] of (3-2) of the first embodiment.

[Condition 3a] The electric field strength with respect to the clock master is maximum The environmental change due to switching of the mobile station CM is evaluated based on the electric field strength of the mobile station SL with respect to the mobile station CM.

As in the case of [condition 3a] of (3-2) in the first embodiment, the mobile station CM sets the mobile stations SL _{1 to} SL as follows.
Field strength for the mobile station CM of L ₃ measured respectively. If these field strength values change from the previous value,
The mobile station CM respective field strength table corresponding to the mobile station SL ₁ to SL ₃ within B4, and stores the electric field intensity values, respectively. In this way, the mobile station CM grasps the electric field strength for all the mobile stations SL _{1 to} SL _{3 in} the slave mode.

When the mobile station CM detects the mobile station SL having the highest electric field strength for the mobile station CM among all the mobile stations SL _{1 to} SL _{3 in} the slave mode based on the electric field strength table B4, the control data Send D5.

[Condition 3b] The reception error rate with respect to the clock master is minimum. The environmental change due to the switching of the mobile station CM is evaluated based on the reception error rate of the reception data of the mobile station SL with respect to the mobile station CM.

As in the case of [condition 3b] of (3-2) of the first embodiment, the mobile station CM transmits the mobile stations SL _{1 to} SL
Calculating a reception error rate for the mobile station CM of L _3. These reception error rate value if changed from the previous value, the mobile station SL ₁ to SL ₃ each receiving an error rate table B5 corresponding to within the mobile station CM, stores the received error rate value respectively. In this way, the mobile station CM grasps the reception error rates for all the mobile stations SL _{1 to} SL _{3 in} the slave mode.

When the mobile station CM detects the mobile station SL having the lowest reception error rate for the mobile station CM among all the mobile stations SL _{1 to} SL _{3 in} the slave mode based on the reception error rate table B5, The control data D5 is transmitted.

[Condition 3c] The propagation delay time to the clock master is minimum The environmental change due to the switching of the mobile station CM is evaluated based on the propagation delay time of the received data of the mobile station SL to the mobile station CM.

As in the case of [condition 3c] of (3-2) of the first embodiment, the mobile station CM sets the mobile stations SL ₁ -SL
Calculating a propagation delay time for the mobile station CM of L _3. These propagation delay time value if changed from the previous value, the mobile station the mobile station SL ₁ to SL respective propagation delay time table B6 corresponding to ₃ within CM, stores the propagation delay time value, respectively. In this way, the mobile station CM grasps the propagation delay time for all the mobile stations SL _{1 to} SL _{3 in} the slave mode.

When the mobile station CM detects a mobile station SL having the shortest propagation delay time with respect to the mobile station CM among all the mobile stations SL _{1 to} SL _{3 in} the slave mode based on the propagation delay time table B6, The control data D5 is transmitted.

[Condition 3d] The Number of Retransmission Requests to the Clock Master is Minimum The environmental change due to the switching of the mobile station CM is evaluated based on the number of retransmission requests of the mobile station SL to the mobile station CM.

As in the case of [condition 3d] of (3-2) in the first embodiment, the mobile station CM transmits the mobile stations SL _{1 to} SL.
To calculate the number of retransmission requests for the mobile station CM of L _3. These retransmission request count value if changed from the previous value, the mobile station each number of retransmission requests Table B7 corresponding to the mobile station SL ₁ to SL ₃ within CM, stores the number of retransmission requests values, respectively. In this way, the mobile station CM grasps the number of retransmission requests for all the mobile stations SL _{1 to} SL _{3 in} the slave mode.

When the mobile station CM detects the mobile station SL having the smallest number of retransmission requests for the mobile station CM among all the mobile stations SL _{1 to} SL _{3 in} the slave mode based on the retransmission request number table B7, The control data D5 is transmitted.

[Condition 4] The order of the numbers assigned to the mobile stations The next clock master nomination shall follow the mobile station number. That is, when detecting the mobile station SL having the mobile station number “2”, the mobile station CM transmits the control data D5.

As described above, in the time-division digital mobile radio communication system according to the present embodiment, the clock master is switched in the slave mode to be the next clock master before the clock master switches to the slave mode. It is assumed that the mobile station is designated and the designated mobile station in the slave mode becomes the next clock master.

The nomination of the next clock master is (1)
The mobile station having the best clock master capability among all the mobile stations in the slave mode, (2) the mobile station having the best transmission / reception state with other mobile stations among all the mobile stations in the slave mode, or (3) Among the mobile stations in the slave mode, the environment change due to the switching of the clock master is performed for the mobile station with the smallest change, or (4) a serial number (mobile station number) is assigned to all the mobile stations in the slave mode. Are performed in order according to the number.

In the case of the above (1), the new clock master does not hinder communication, so that good communication can be maintained. In the case of (2), the mobile station having the same capability as the other station in the network becomes the new clock master, so that the new clock master can perform good communication with any mobile station. it can. (3)
In the case of (1), the change in environment due to the switching of the clock master can be suppressed as much as possible, so that the occurrence of an error due to the switching can be minimized. In the case of (4), since the order of the clock masters is determined, the amount of battery consumption of each mobile station can be averaged. Further, compared to the cases (1) to (3), the processing time for the clock master to nominate the next clock master can be reduced.

[Embodiment 3] The following will describe Embodiment 3 of the present invention with reference to FIG. 22, FIG. 23 and FIG. For the sake of convenience of explanation, the same members as those shown in the drawings of the above embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The time division digital mobile radio communication system according to the present embodiment has the same configuration as that of the first embodiment.
The process (1) for determining the clock master and the process (2) for the wireless communication between the mobile stations are the same as those in the first embodiment.
(3) The switching process of the clock master during the communication is different.

Therefore, only the switching process of the mobile station CM during communication will be described here. The present embodiment is characterized in that the mobile station SL issues a switching request to the mobile station CM, and the mobile station SL that has made the request becomes the next clock master.

As shown in FIG. 22, when the mobile station SL satisfies the condition for transmitting the clock master switching request (S7
1) Using the slot R1, the control data D5 of the clock master switching request is set to “1” indicating the clock master, and the control data D5 is transmitted (S7).
2, see the first stage in FIG. 23).

The mobile station CM that has received the control data D5
Using the next slot T1, the mobile station SL that has transmitted the control data D5 receives the control data D of the clock master switching response.
6 is transmitted (S75, S76, see the second row in FIG. 23).

When receiving the control data D6 (S73), the mobile station SL becomes a new clock master (S7).
4). On the other hand, the mobile station CM transmitting the control data D6
The mobile station is switched to the slave mode mobile station (S77).

As in the first embodiment, the new clock master uses the next slot T1 to set the transmission destination of the control data D4 of the clock master ID notification, which is the radio wave for synchronization, to “25”.
5 is set to ", (see the third stage of FIG. 23) to the control data D4. In addition, to change the mobile station number of all mobile stations CM · SL ₁ ~SL _3.

Next, conditions for transmitting a clock master switching request by the mobile station SL in S71 of FIG. 22 will be described. That is, when any of [Condition 1] to [Condition 4] shown in FIG. 27 is satisfied, the mobile station SL transmits the control data D5 of the clock master switching request. When there are a plurality of mobile stations SL satisfying the transmission of the clock master switching request, the mobile station SL having the best capability, transmission / reception state, or environmental state among the mobile stations SL issues the switching request.

[Condition 1] Good performance as clock master When the mobile station SL determines that its own performance as a clock master is superior to the mobile station CM, the mobile station SL
To the control data D5. Here, the ability as a clock master is as shown in [Condition 6] of (3-1) of the first embodiment.

[Condition 1a] CPU Performance is Large [0265] The mobile station CM calculates a CPU performance value in the same manner as in the case of [Condition 1a] in (3-2) of the first embodiment. That is, the mobile station CM uses the CPU monitoring unit 27 in the control unit 18 to measure the time during which the CPU 29 is idle within the time set for the CPU performance monitoring time A5. Calculate the CPU performance value expressed in "time".

When the CPU performance value has changed from the previous value (the value currently stored in the RAM 30), all the mobile stations SL _{1 to} SL ₃ in the slave mode are controlled using the control data D11 of the CPU performance notification. Notify its own CPU performance. That is, mobile station CM
Transmits “255” to the transmission destination of the control data D11 with the calculated CPU performance value set in the area D11b, and transmits all the mobile stations SL _{1 to} SL in the slave mode.
₃ is notified of the CPU performance of the mobile station CM.

On the other hand, the mobile station SL that has received the control data D11 stores the CPU performance value of the mobile station CM in a location corresponding to the mobile station number “1” representing the clock master in the CPU performance table B1. Thus, all mobile stations SL _{1 to} SL in the slave mode
₃ grasps the CPU performance of the mobile station CM.

The mobile station SL calculates its own CPU performance value in the same manner as in the case of the mobile station CM, and detects that the CPU performance of the mobile station SL has become higher than the CPU performance of the mobile station CM. At this time, the control data D5 is transmitted to the mobile station CM.

[Condition 1b] Free memory capacity is large The mobile station CM calculates a free memory capacity value in the same manner as in [Condition 1b] of (3-2) of the first embodiment. If this free memory value has changed from the previous value, and notifies the free memory capacity of the mobile station, to all the mobile station SL ₁ to SL ₃ slave mode using the control data D12 of free memory. All the mobile stations SL _{1 to} SL ₃ receive the control data D12 and thereby grasp the free memory capacity of the mobile station CM.

The mobile station SL calculates the free memory capacity of its own station in the same manner as in the case of the mobile station CM, and determines that the free memory capacity of its own station has become larger than the free memory capacity of the mobile station CM. Is detected, the control data D5 is transmitted to the mobile station CM.

[Condition 1c] The built-in battery capacity is large The mobile station CM calculates the remaining battery value in the same manner as in the case of [Condition 1c] in (3-2) of the first embodiment. When the remaining battery value changes from the previous value, all mobile stations SL in the slave mode are used by using the remaining battery control data D13.
Notifying the remaining battery of the mobile station, to ₁ to SL _3. All mobile stations S
L ₁ to SL ₃ by receiving the control data D13, to grasp the residual battery capacity of the mobile station CM.

The mobile station SL calculates the remaining battery level of its own station in the same manner as in the case of the mobile station CM, and finds that the remaining battery capacity of its own station has become larger than the remaining battery capacity of the mobile station CM. Is detected, the control data D5 is transmitted to the mobile station CM.

[Condition 2] When the transmission / reception state with another mobile station is good The mobile station SL detects that the transmission / reception state with respect to the other station of the mobile station is better than the transmission / reception state with respect to the other station of the mobile station CM. And the control data D5 to the mobile station CM. Here, the transmission / reception state with another station is as shown in [condition 2] of (3-2) of the first embodiment.

[Condition 2a] The total value of the deviation of the electric field strength is small. The transmission / reception state with another station is evaluated based on the total value of the deviation of the electric field strength of the reception data of the own station with respect to the other station.

In the same manner as in the case of [condition 2a] of (3-2) of the first embodiment, the mobile station CM measures its own electric field strength value with respect to other stations. That is, the mobile station CM that has received the control data D18 of the test data emission response measures the electric field strength of its own station with respect to other stations by the reception level detection unit 21 in the control unit 18. If this field strength value has changed from the previous value, and notifies the field strength of the mobile station CM to the other station to all the mobile station SL ₁ to SL ₃ slave mode using the control data D14 of the field intensity notification. That is, mobile station CM
Transmits “255” as the transmission destination of the control data D14, the mobile station number set as the transmission source of the control data D18 in the area D14b, and the calculated electric field strength value in the area D14c, and transmits the same. Notify all the mobile stations SL _{1 to} SL ₃ of the electric field strength of the mobile station CM with respect to other stations.

On the other hand, the mobile station SL that has received the control data D14 matches the mobile station number set as the transmission source of the received control data D14 in the electric field strength table B4 of the mobile station number “1” representing the clock master. The measured electric field strength value is stored in the corresponding location. In addition, mobile station SL
Also, the electric field strength of the control data D18 transmitted by another mobile station SL is measured using the slot R1 normally used by the mobile station CM. When the electric field strength value has changed from the previous value, the measured electric field strength value is stored in the electric field strength table B4 of the own station. Thus, all the mobile stations SL _{1 to} SL ₃ in the slave mode grasp the electric field strength of the mobile station CM with respect to other stations and the electric field strength of the mobile station CM with respect to other stations.

[0277] The mobile station SL, based on the electric field strength table B4 in the mobile station SL, each mobile station CM · SL ₁ ~ to other stations
Variations in the electric field strength of SL ₃ (the deviation) were calculated, respectively, detected that the total value of the deviation of the electric field intensity with respect to another station of the own station is smaller than the sum of the deviation of the electric field intensity with respect to another station of the mobile station CM Then, the control data D is transmitted to the mobile station CM.
Send 5

[Condition 2b] The total value of the deviation of the reception error rate is small. The transmission / reception state with another station is evaluated based on the total value of the deviation of the error rate of the reception data of the own station with respect to the other station.

By the same procedure as in the above [Condition 2a], all the mobile stations SL _{1 to} SL _{3 in} the slave mode receive the reception error rate for the other station of the mobile station CM and the reception error rate for the other station of the own station. Figure out.

Based on the reception error rate table B5 in the mobile station SL, the mobile station SL sends each mobile station CM / SL to another station.
The variation (deviation) of the reception error rates of _{1 to} SL ₃ is calculated, and the total value of the deviation of the reception error rate of the own station with respect to the other station is calculated from the total value of the deviation of the reception error rate of the mobile station CM with respect to the other station. Is smaller than the mobile station CM.
To the control data D5.

[Condition 2c] The total value of the deviation of the propagation delay time is small. The transmission / reception state with the other station is evaluated based on the total value of the deviation of the propagation delay time of the reception data of the own station with respect to the other station.

By the same procedure as in the above [Condition 2a], all the mobile stations SL _{1 to} SL _{3 in} the slave mode transmit the propagation delay time to the other station of the mobile station CM and the propagation delay time to the other station of the own station. Figure out.

The mobile station SL determines whether each mobile station CM / SL with respect to another station is based on the propagation delay time table B6 in the mobile station SL.
The variation (deviation) of the propagation delay times of _{1 to} SL ₃ is calculated, and the sum of the deviations of the propagation delay time of the own station with respect to other stations is calculated from the sum of the deviations of the propagation delay times of the mobile station CM with respect to other stations. Is smaller than the mobile station CM.
To the control data D5.

[Condition 2d] The total value of the deviation of the number of retransmission requests is small. The transmission / reception state with another station is evaluated based on the total value of the deviation of the number of retransmission requests of the own station with respect to other stations.

By the same procedure as in the above [Condition 2a], all the mobile stations SL _{1 to} SL _{3 in} the slave mode make the number of retransmission requests to other stations of the mobile station CM and the number of retransmission requests to other stations of the own station. Figure out.

[0286] The mobile station SL transmits each mobile station CM / SL to another station based on the retransmission request count table B7 in the mobile station SL.
The variation (deviation) of the number of retransmission requests for _{1 to} SL ₃ is calculated, and the total value of the deviations of the number of retransmission requests to the other station of the mobile station is calculated from the total value of the deviation of the number of retransmission requests to the other station of the mobile station CM. Is smaller than the mobile station CM.
To the control data D5.

[Condition 2e] The total value of the electric field strength is large The transmission / reception state with another station is evaluated based on the total value of the electric field strength of the own station with respect to the other station.

As in the case of the [condition 2a], all the mobile stations SL _{1 to} SL _{3 in} the slave mode are connected to the mobile station CM.
Of the other station, and the electric field strength of the own station to the other station.

[0289] The mobile station SL, based on the electric field strength table B4 in the mobile station SL, each mobile station CM · SL ₁ ~ to other stations
When the sum of the electric field strengths of SL ₃ is calculated and the sum of the electric field strengths of the own station and the other stations is larger than the sum of the electric field strengths of the mobile station CM and the other stations, the mobile station CM To the control data D5.

[Condition 2f] The total value of the reception error rate is small The transmission / reception state with another station is evaluated based on the total value of the reception error rate of the reception data of the own station with respect to the other station.

As in the case of the [condition 2b], all the mobile stations SL _{1 to} SL _{3 in} the slave mode are connected to the mobile station CM.
The receiving error rate for the other station and the receiving error rate for the own station for the other station are grasped.

Based on the reception error rate table B5 in the mobile station SL, the mobile station SL sends each mobile station CM / SL to another station.
Calculate the sum of the reception error rates of _{1 to} SL ₃ respectively,
The total value of the reception error rate of the own station with respect to another station is equal to the mobile station C.
When detecting that the reception error rate is smaller than the total value of the reception error rates for the other stations of M, the control data D5 is transmitted to the mobile station CM.

[Condition 2g] The total value of the propagation delay time is small. The transmission / reception state with another station is evaluated based on the total value of the propagation delay time of the reception data of the own station with respect to the other station.

In the same manner as in the above [condition 2c], all the mobile stations SL _{1 to} SL _{3 in} the slave mode are connected to the mobile station CM.
The propagation delay time for the other station and the propagation delay time for the own station to the other station are grasped.

Based on the propagation delay time table B6 in the mobile station SL, the mobile station SL sends each mobile station CM / SL to another station.
Calculate the total value of the propagation delay times of _{1 to} SL ₃ respectively,
The total value of the propagation delay time of the own station with respect to another station is equal to the mobile station C.
When it is detected that M is smaller than the total value of the propagation delay time for the other stations, the control data D5 is transmitted to the mobile station CM.

[Condition 2h] The total value of the number of retransmission requests is small. The transmission / reception state with another station is evaluated based on the total value of the number of retransmission requests of the reception data of the own station to the other station.

As in the case of [condition 2d], all the mobile stations SL _{1 to} SL _{3 in} the slave mode are connected to the mobile station CM.
The number of retransmission requests to other stations and the number of retransmission requests to other stations of the own station are grasped.

The mobile station SL sends each mobile station CM / SL to another station based on the retransmission request count table B7 in the mobile station SL.
The total value of the number of retransmission requests of ₁ to SL ₃ were respectively calculated,
The total value of the number of retransmission requests to the other station of the own station is equal to the mobile station C.
When detecting that it is smaller than the total value of the number of retransmission requests to the other stations of M, the control data D5 is transmitted to the mobile station CM.

[Condition 3] In order of the numbers assigned to the mobile stations The clock master switching request transmission of the mobile station SL is based on the mobile station number. That is, the mobile station SL having the mobile station number “2” measures the elapsed time since the mobile station CM operates as the clock master using the built-in timer in the control unit 18.
When detecting that the elapsed time has exceeded the time set in the clock master switching interval A10, the control data D5 is transmitted.

[Condition 4] In a case where communication between two mobile stations SL having good transmission / reception state by communication between mobile stations in the slave mode is to be performed,
The mobile station SL is connected to the mobile station S obtained via the mobile station CM.
It was determined that the transmission / reception state obtained when directly communicating between the mobile station SL and the communication partner mobile station SL without passing through the mobile station CM was better than the transmission / reception state between the L-communication partner mobile station SL. At this time, the control data D5 is transmitted to the mobile station CM so that communication can be performed directly without passing through the mobile station CM.

Here, the good transmission / reception state is determined by the mobile station CM.
Are evaluated based on the difference in electric field strength, the difference in reception error rate, the difference in propagation delay time, and the difference in the number of retransmission requests depending on the presence or absence of relaying.

[Condition 4a] The transmission / reception state in which the electric field strength in the slave mode inter-mobile station communication is good is evaluated based on the difference in the electric field strength depending on the presence or absence of the relay of the mobile station CM.

In the same manner as in the above [Condition 2a], the mobile station CM measures its own electric field strength value with respect to the other stations, and when this electric field strength value has changed from the previous value, the mobile station CM sends an electric field strength notification. and notifies the field strength of the mobile station CM to the other station to all the mobile station SL ₁ to SL ₃ slave mode using the control data D14. Further, the mobile station SL that has received the control data D14 stores the measured electric field intensity value in the electric field intensity table B4 of the own station (mobile station SL).

At the same time, the mobile station SL
, The slot R1 normally used by the mobile station CM is received.
Of the control data D18 to be transmitted. When this electric field strength value has changed from the previous value, the above measured electric field strength value is stored in the electric field strength table B4 of the own station (mobile station SL). Thereby, the electric field strength between the mobile station SL and the communication partner mobile station SL is obtained.

Based on the electric field strength table B4, the mobile station SL determines the electric field strength (s) between the mobile station CM and its own station and the mobile station CM.
-Compare the average value ((s + t) / 2) with the electric field strength (t) between the communication partner mobile station SL and the electric field strength (u) between the own station and the communication partner mobile station SL, Partner mobile station SL
When detecting that the electric field strength between them is large, that is, satisfying the relationship of (s + t) / 2 <u, the control data D5 is transmitted to the mobile station CM.

[Condition 4b] A good transmission / reception state in which the reception error rate due to communication between mobile stations in the slave mode is good is evaluated based on a difference in reception error rate depending on whether or not the mobile station CM is relayed.

The mobile station CM measures its own reception error rate with respect to other stations in the same manner as in the above [condition 2b].
If the received error rate value has changed from the previous value, the mobile station CM to the other station to all the mobile station SL ₁ to SL ₃ slave mode using the control data D15 of the reception error rate notifications
Notify the reception error rate. The mobile station SL that has received the control data D15 stores the measured reception error rate value in the reception error rate table B5 of its own station (mobile station SL).

At the same time, the mobile station SL
The slot R1 normally used by the mobile station CM is received by the error detection unit 22 in the above, and the presence or absence of a frame error in the control data D18 transmitted by the communication partner mobile station SL is measured, and the reception error measurement interval A7 is set. Calculate the reception error rate for each time period. If the reception error rate value has changed from the previous value, the calculated reception error rate value is stored in the reception error rate table B5 of the own station (mobile station SL).

The mobile station SL determines from the reception error rate table B5 that
"1- {1- (Reception error rate between mobile station CM and own station)"}
× {1− (Reception error rate between mobile station CM and communication partner mobile station SL)} ”and the reception error rate between the own station and communication partner mobile station SL are compared. Then, when detecting that the reception error rate between the own station and the communication partner mobile station SL is large, the control data D5 is transmitted to the mobile station CM.

[Condition 4c] The transmission / reception state in which the propagation delay time due to the communication between mobile stations in the slave mode is small and good is evaluated based on the difference in the propagation delay time depending on whether or not the mobile station CM is relayed.

In the same manner as in the above [condition 2c], the mobile station CM measures its own propagation delay time with respect to other stations, and
When this propagation delay time value has changed from the previous value, all the mobile stations SL _{1 to} SL ₃ in the slave mode are transmitted to the mobile stations CM for the other stations using the control data D16 of the propagation delay time notification.
Of the propagation delay time. The mobile station SL that has received the control data D16 stores the measured propagation delay time value in the propagation delay time table B6 of its own station (mobile station SL).

At the same time, the mobile station SL
Normally, the mobile station CM
Receives the slot R1 used by the
The propagation delay time, which is the difference between the built-in timer value of the control data D18 transmitted by L and the built-in timer value of the own station, is calculated.
When the propagation delay time value has changed from the previous value, the calculated propagation delay time value is stored in the propagation delay time table B6 of the own station (mobile station SL).

[0313] The mobile station SL determines from the propagation delay time table B6 that
The sum of the propagation delay time between the mobile station CM and the own station and the propagation delay time between the mobile station CM and the communication partner mobile station SL;
The propagation delay time between the communication partner mobile stations SL is compared. When detecting that the propagation delay time between the own station and the communication partner mobile station SL is large, the control data D5 is transmitted to the mobile station CM.
Send

[Condition 4d] The number of retransmission requests by the inter-mobile-station communication in the slave mode is small.
L is the number of retransmission requests between the mobile station CM and its own station and the mobile station CM.
A total value of the number of retransmission requests between the communication partner mobile stations SL,
The number of retransmission requests between the own station and the communication partner mobile station SL is compared. When detecting that the number of retransmission requests between the own station and the communication partner mobile station SL is large, the control data D5 is transmitted to the mobile station CM.

As described above, as a method of switching the clock master in the time division digital mobile radio communication system of the present embodiment, the mobile station in the slave mode issues a switching request to the current clock master, The mobile station in the mode is assumed to be the next clock master.

The switching request to the current clock master is issued when (1) a mobile station having a higher capability than the current clock master is detected among all the mobile stations in the slave mode, or (2) all mobile stations in the slave mode are detected. The mobile station performs transmission / reception with another mobile station when a mobile station superior to the current clock master is detected, or (3) serial numbers (mobile station numbers) for all mobile stations in the slave mode. Or (4) when communication is to be performed between two mobile stations in the slave mode, the two mobile stations obtained via the current clock master are used. When the transmission / reception state obtained when performing direct communication between two mobile stations is better than the transmission / reception state of the above, the transmission / reception is performed by one of the two mobile stations. .

In the case of the above (1), a mobile station having a better clock master capability than the current clock master becomes the new clock master, so that good communication can always be performed. In the case of (2), the mobile station having the same capability as the other station in the network becomes the new clock master, so that the new clock master can perform good communication with any mobile station. it can. In the case of (3), the order of the clock masters is determined, so that the battery consumption of each mobile station can be averaged. Further, the processing time required for the mobile station in the slave mode to issue a switching request can be reduced as compared with the cases (1) and (2). In the case of (4), without going through the current clock master,
Since direct communication can be performed between the mobile stations in the slave mode, no error due to relay occurs and good communication can be performed. Further, it is possible to prevent the battery of the current clock master that does not need to perform communication from being consumed.

[0318]

As described above, in the time-division digital mobile radio communication system according to the first aspect of the present invention, each mobile station uses a free-running clock to establish synchronization required for time-division communication. It has two operation modes, a master mode that operates by defining timing and a slave mode that operates in frame synchronization with a synchronization signal pattern transmitted from a mobile station in the master mode. 1
One is a clock master operating in the master mode, and the other mobile station is operated in the slave mode, so that when performing wireless communication between the plurality of mobile stations, the mobile station in the slave mode is used during communication. And at the same time, one of all the mobile stations in the slave mode other than the clock master is switched to the master mode to be the next clock master.

There are three ways to switch the clock master. That is, the first concept is that the current clock master issues a switching request to all the mobile stations in the slave mode before the own station switches to the slave mode, and the current clock master among all the mobile stations in the slave mode receiving the request. The slave mode mobile station that first responds to the master becomes the next clock master.

The second concept is that the clock master nominates a mobile station in the slave mode to be the next clock master before the own station switches to the slave mode, and the mobile station in the slave mode that has received the nomination becomes the next clock master. It is the master.

The third concept is that the mobile station in the slave mode issues a switching request to the current clock master, and the mobile station in the slave mode that has made the request becomes the next clock master.

Thus, the switching of the clock master can be realized during communication, so that the load is not concentrated only on the mobile station in the master mode, and the load applied to all the mobile stations can be distributed. This has the effect of being possible.

Also, the conditions for transmitting the switching request from the clock master, the response conditions of the mobile station in the slave mode to the switching request from the clock master, the nominating conditions for the next clock master, or the conditions for transmitting the switching request to the clock master are described below. By making various settings, it is possible to provide the best communication environment according to the communication state that changes in real time and the state of the mobile station.

[0324] In the time division digital mobile radio communication system according to the second aspect, in addition to the configuration according to the first aspect, the clock master operated in the master mode first is powered on among all the mobile stations. Thus, the mobile station is initially operated.

[0325] Thus, since a clock master already exists for the mobile station that has been activated next, communication can be performed smoothly and communication can be performed efficiently. It works.

In the time-division digital mobile radio communication system according to the third aspect, in addition to the configuration according to the first aspect, the clock master operated in the master mode first among all the mobile stations first. In this configuration, the mobile station needs to transmit data.

Thus, a mobile station that does not transmit data even when the power is turned on and does not transmit data does not become a clock master, and the mobile station does not receive an excessive load due to becoming a clock master. To play.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a mobile station included in a time-division digital mobile radio communication system according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a communication state between the mobile stations.

FIG. 3 is a block diagram showing control values stored in a ROM in the mobile station.

FIG. 4 is a block diagram showing other control values stored in the ROM.

FIG. 5A to FIG. 5G are RAMs in the mobile station.
FIG. 4 is an explanatory diagram showing a table stored in the table.

FIG. 6 is an explanatory diagram showing a correspondence table between PS-IDs and mobile station numbers stored in the RAM.

FIGS. 7A to 7G are explanatory diagrams showing a configuration of communication data or control data.

FIGS. 8A to 8K are explanatory diagrams showing still another configuration of each control data.

FIG. 9 is an explanatory diagram showing time slots in the communication between mobile stations.

FIG. 10 is a flowchart showing an operation of determining a clock master upon power-on.

FIG. 11 is a flowchart showing an operation of determining a clock master based on possession of transmission data.

FIG. 12 is a flowchart showing a mobile station number setting operation.

FIG. 13 is a flowchart showing a data transmission / reception operation of the clock master.

FIG. 14 is a flowchart showing a data transmission / reception operation of a mobile station in a slave mode.

FIG. 15 is an explanatory diagram showing a data transmission / reception operation of the inter-mobile station communication.

FIG. 16 is an explanatory diagram showing time slots when a mobile station in a slave mode responds to a switching request from a clock master.

FIG. 17 is a flowchart in a case where a clock master switching operation is performed in response to a switching request from a clock master.

FIG. 18A shows a correspondence table between PS-IDs and mobile station numbers before the clock master switching operation, and FIG. 18B shows a correspondence table in which the mobile station numbers are changed by the clock master switching operation. FIG.

FIG. 19 is an explanatory diagram showing time slots when transmitting and receiving control data of a test data emission request and control data of a test data emission response.

FIG. 20A is an explanatory diagram showing a table stored in a RAM of a clock master, and FIGS. 20B to 20D are tables showing tables stored in a RAM of each mobile station in a slave mode.

FIG. 21 is a flowchart in a case where a clock master appoints a next clock master to perform a clock master switching operation in the time division digital mobile radio communication system according to the second embodiment of the present invention.

FIG. 22 is a flowchart in the case where a clock master switching operation is performed in response to a switching request from a slave mode mobile station in the time division digital mobile radio communication system according to the third embodiment of the present invention.

FIG. 23 is an explanatory diagram showing time slots when a clock master responds to a switching request from a mobile station in a slave mode.

FIG. 24 is an explanatory diagram showing conditions for transmitting a clock master switching request by the clock master.

FIG. 25 is an explanatory diagram showing conditions for transmitting a clock master switching response of a mobile station in a slave mode in response to a switching request from a clock master.

FIG. 26 is an explanatory diagram showing a nomination condition of a clock master.

FIG. 27 is an explanatory diagram showing conditions for transmitting a clock master switching request by a mobile station in a slave mode.

[Explanation of symbols]

 Reference Signs List 18 control unit 21 reception level detection unit 22 error detection unit 23 propagation delay time measurement unit 24 synchronization signal detection unit 25 built-in timer 26 battery capacity monitoring unit 27 CPU monitoring unit 28 ROM 29 CPU 30 RAM

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhiro Tsubaki Sharp Corporation 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka

Claims (26)

[Claims] 1. A time-division digital mobile radio communication system having a plurality of mobile stations, wherein each of the mobile stations operates by defining a frame timing by a free-running clock in order to establish synchronization required for time-division communication. And a slave mode that operates in frame synchronization with a synchronization signal pattern transmitted from a mobile station in the master mode. One of the plurality of mobile stations is operated in the master mode. As a clock master to be operated, by operating the remaining mobile stations in slave mode, when performing wireless communication between the plurality of mobile stations, at the same time as switching the clock master to a mobile station in slave mode during communication, One of all the mobile stations in the slave mode other than the clock master is switched to the master mode to be the next clock master. Divided digital mobile radio communication system when said and. 2. The clock master operated in the master mode first is a mobile station which is first activated by turning on power among all the mobile stations.
2. A time-division digital mobile radio communication system according to claim 1. 3. The time-sharing method according to claim 1, wherein the clock master operated in the master mode first is a mobile station which first needs to transmit data among all the mobile stations. Digital mobile radio communication system. 4. The switching of the clock master,
The current clock master issues a switching request to all the mobile stations in the slave mode before the own station switches to the slave mode, and first responds to the current clock master among all the mobile stations in the slave mode that have received the request. 4. The time division digital mobile radio communication system according to claim 1, wherein the mobile station in the slave mode becomes the next clock master. 5. The switching request from the current clock master,
5. The time-division digital mobile radio communication system according to claim 4, wherein the transmission is performed when the current clock master no longer holds transmission data. 6. The switching request from the current clock master,
5. The time-division digital mobile radio communication system according to claim 4, wherein the communication is performed when a predetermined time has elapsed since the current clock master emitted the synchronization radio wave. 7. The clock master has a function of relaying data transmitted from a mobile station in a slave mode and transferring the data to another mobile station in a slave mode. The switching request from the current clock master is 5. The time-division digital mobile radio communication system according to claim 4, wherein the transmission is performed when the current clock master relays data from the mobile station in the slave mode for a predetermined time. 8. The clock master has a function of relaying data transmitted from a mobile station in slave mode and transferring the data to another mobile station in slave mode. The switching request from the current clock master is 5. The time division digital mobile radio communication system according to claim 4, wherein the communication is performed when the current clock master relays a certain amount of data from the mobile station in the slave mode. 9. The clock master has a function of relaying data transmitted from a mobile station in a slave mode and transferring the data to another mobile station in a slave mode. The switching request from the current clock master is 5. The time division digital mobile radio communication system according to claim 4, wherein the communication is performed when it detects that the current clock master has not performed data relay for a predetermined time. 10. The time division digital mobile communication system according to claim 4, wherein the switching request from the current clock master is made when it is determined that the current clock master has reduced its ability as a clock master. Wireless communication system. 11. The time division digital mobile radio communication system according to claim 4, wherein the switching request from the current clock master is made when the current clock master detects interference. 12. The switching request from the current clock master is made when a mobile station in the current slave mode detects interference of the current clock master.
2. A time-division digital mobile radio communication system according to claim 1. 13. The mobile station in the slave mode in response to the switching request from the current clock master is performed by the mobile station having the best clock master capability among all the mobile stations in the slave mode. Claim 4
2. A time-division digital mobile radio communication system according to claim 1. 14. A response of the mobile station in the slave mode to the switching request from the current clock master is performed by the mobile station having the best transmission / reception state with another mobile station among all the mobile stations in the slave mode. 5. The time division digital mobile radio communication system according to claim 4, wherein: 15. A response of the mobile station in the slave mode to the switching request from the current clock master is that, among all the mobile stations in the slave mode, the mobile station having the smallest environmental change due to the switching of the clock master is performed. The time-division digital mobile radio communication system according to claim 4, wherein: 16. The mobile station in the slave mode in response to the switching request from the current clock master is serially assigned to all the mobile stations in the slave mode, and the mobile stations in the slave mode are sequentially performed in accordance with the numbers. Item 4
2. A time-division digital mobile radio communication system according to claim 1. 17. In the switching of the clock master, the clock master nominates a mobile station in the slave mode to be the next clock master before the own station switches to the slave mode, and the mobile station in the slave mode that has received the nomination is designated. 2. A clock master as the next clock master.
4. The time-division digital mobile radio communication system according to any one of claims 3 to 3. 18. The mobile station according to claim 17, wherein the next clock master is designated to the mobile station having the best clock master among all the mobile stations in the slave mode. Time division digital mobile radio communication system. 19. The mobile station according to claim 17, wherein the next clock master is nominated among all the mobile stations in the slave mode, the mobile station having the best transmission / reception status with another mobile station. 2. A time-division digital mobile radio communication system according to claim 1. 20. The mobile station according to claim 17, wherein the next clock master is nominated among mobile stations in the slave mode, the mobile station having the smallest environmental change due to the switching of the clock master. A time-division digital mobile radio communication system as described. 21. The time-division digital mobile station according to claim 17, wherein the next clock master is nominated in sequence according to the serial number assigned to all the mobile stations in the slave mode. Wireless communication system. 22. In the switching of the clock master, the mobile station in the slave mode issues a switching request to the current clock master, and the mobile station in the slave mode that has made the request becomes the next clock master. The time-division digital mobile radio communication system according to claim 1. 23. A request for switching to the current clock master is made by the mobile station when a mobile station having better performance than the current clock master is detected among all mobile stations in slave mode. 23. A method according to claim 22.
2. A time-division digital mobile radio communication system according to claim 1. 24. The switching request to the current clock master is issued when a mobile station having better transmission / reception status with other mobile stations than all the mobile stations in the slave mode is detected. 23. The time division digital mobile radio communication system according to claim 22, which is performed by a station. 25. The time-division digital mobile station according to claim 22, wherein the switching request to the current clock master is sequentially performed in accordance with the serial numbers by assigning serial numbers to all the mobile stations in the slave mode. Wireless communication system. 26. The clock master has a function of relaying data transmitted from a mobile station in a slave mode and transferring the data to another mobile station in a slave mode. In a case where communication is to be performed between mobile stations in a certain two slave modes, the transmission and reception state between the two mobile stations obtained through the current clock master is more significant when communication is directly performed between the two mobile stations. When the transmission / reception status is better,
23. The time division digital mobile radio communication system according to claim 22, wherein the communication is performed by one of the two mobile stations.