JPH04290017A - Mobile communication method - Google Patents

Abstract

PURPOSE:To improve in maximum the utilizing efficiency of a communication channel without concentration of a traffic of a communication channel onto one base station and increase in the control load of a host station and in a traffic of control information between the host station and the base station. CONSTITUTION:A central processing unit 11 compares a reception level of a desired wave and a reception level of an interference wave based on the reception level of the desired wave and the interference wave of a communication channel from a communication use transmitterreceiver 15 during communication. Then the quality of communication is warranted for a specified period to judge whether or not other idle communication channel having a closer value based on a predetermined threshold level and controls a control use transmitter-receiver 17 based on the affirmative result to select the communication channel.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention is utilized in a mobile communication channel allocation system for a mobile radio communication system. In particular, in a mobile radio communication system consisting of a base station and a mobile station that communicate on a communication channel, the desired wave-to-interference wave ratio (DU ratio) of the communication channel during communication is constant at the time of communication channel allocation and during communication. The present invention relates to a mobile communication channel allocation method that performs channel selection so that the DU ratio is close to a standard DU ratio, and utilizes intra-zone channel switching for channel reselection.

0002

2. Description of the Related Art FIG. 9 is a schematic diagram of a fixed channel allocation system for mobile communication systems. FIG. 10 is a schematic diagram of a channel allocation method by an upper station in a mobile communication system. FIG. 11 is a schematic diagram of a method for allocating a communication channel with the minimum D/U ratio in a mobile communication method. FIG. 11(A) is a schematic diagram of a mobile communication system, and FIG. 11(B) is a diagram showing a communication channel allocation method.

[0003] Conventionally, in mobile communication systems, the usable communication channels at each base station are limited, and it is not possible to allocate communication channels that are not in use at neighboring base stations to mobile stations within the own zone. , a so-called fixed channel arrangement method was used. In FIG. 9, mobile station 304 is trying to make a call in zone 20A, but since the other mobile stations 301 to 303 have used up the communication channels f1, f2, and f3 assigned to zone 20A, the mobile station 20B, communication channel f4,
Even if communication channels f5, f6, and communication channels f7, f8, and f9 are unused in the adjacent zone 20C, channel assignment to the mobile station 304 cannot be performed.

[0004] Thus, in the fixed channel arrangement method,
Since it is not possible to deal with traffic concentration, the upper station 40 monitors and controls the communication channels of multiple base stations 10A to 10D, and allocates unused communication channels in the surrounding zone to mobile stations that make and receive calls. A method has been proposed. The situation is shown in FIG. The upper station 40 receives reports on the usage status of communication channels from each of the zones 20A to 20D under its control, and allocates vacant communication channels f4, f5, and f6 to the mobile stations 30 that make and receive calls.

[0004] Although this method makes it possible to maximize the efficiency of communication channel use, this method also causes problems such as an increase in the control burden on the upper station and an increase in control information traffic between the upper station and the base station. There are many problems that arise when actually operating the system. As a specific example, in a system that uses 2000 channels in total, if a call occurs once every 100 seconds for each communication channel, the higher-level station will process the call at a frequency of 40 times/second, including the incoming and outgoing calls. It will have to be done.

[0005] In order to avoid the above-mentioned problems, a system has been devised in which autonomous distributed control is performed on a base station basis. That is, as shown in FIG. 11, among the communication channels that satisfy the communication quality, the communication channel with the minimum (worst) DU ratio is selected and allocated, and the communication channel is used effectively.
This method suppresses the increase in control burden and control traffic described above. In FIG. 11, the base station 10 stores the U-wave levels of each vacant communication channel in the channel management table 11a in descending order of the value, and when the mobile station 301 requests the use of the communication channel, the base station 10 Estimate the D wave level, calculate D/K=U0 (K is the minimum value of the DU ratio necessary for communication at a predetermined threshold), and use it to calculate the value of the U wave level. The communication channel fk with the highest U wave level is assigned among the communication channels f1 to fk with the lowest level. Here, the high U wave level means that there is interference waves from nearby zones.
Using a common communication channel in zones as close as possible can increase the efficiency of communication channel utilization.

[0006]

[Problems to be Solved by the Invention] However, in such conventional mobile communication systems, the fixed channel allocation method has the problem that it cannot cope with traffic concentration, and the channel allocation method by the upper station has the problem that the upper station There were problems in actual operation, such as an increase in control burden and an increase in control information traffic between the upper station and the base station. Furthermore, the method in which base stations allocate the communication channel that provides the minimum DU ratio at the time of incoming and outgoing calls using an autonomous decentralized method does not take into consideration the usage status of other communication channels during communication, and therefore does not allow for optimal use of the communication channel. There were some problems that could occur.

[0007] FIG. 12 is a diagram showing the transition of the communication channel usage status when the communication channel with the minimum DU ratio of the mobile communication system is allocated. In FIG. 12, zone 2 is one-dimensionally
0A to 20F are connected, and there are two communication channels fX and fY that can be used for communication. Assuming that communication channels are reused for each of the three zones,
First, use communication channel fX in zone 20A (12
a) Next, when a call is made or received in zone 20F,
The communication channel fX with the minimum U ratio is used (12b). Next, when a call is made or received in zone 20C, the communication channel fX
is unavailable, so another communication channel fY is used (12c). If a call is made or received in zone 20D in this state, a communication channel cannot be assigned because both communication channels fX and fY are unusable (12d). Conventionally, a method has been proposed in which an upper station monitors the channel usage status across multiple zones, performs intra-zone channel switching, and allocates communication channels fX and fY to a call occurring in zone 20D.

[0008] The present invention solves the above problems.
Communication channel traffic is not concentrated on one base station, there is no control burden on the upper station, there is no increase in control information traffic between the upper station and the base station, and communication channel usage efficiency is maximized. The purpose is to provide an improved mobile communication system.

[0009]

Means for Solving the Problems The present invention provides a plurality of base stations that utilize a control channel and a plurality of communication channels;
and a mobile station that is placed within the zone of the plurality of base stations and capable of communicating on the plurality of communication channels, and the transmitting/receiving means of the base station transmits the reception level of the interference wave of the idle communication channel of the own station at a predetermined period. a first determining means for determining the reception level of a desired wave of a communication channel to be allocated from a mobile station that starts communication at the time of communication channel allocation; A mobile station that starts communication on a communication channel whose reception level ratio between a desired wave and an interference wave based on the judgment results of a judgment means and a second judgment means guarantees communication quality and is close to a predetermined threshold value. In a mobile communication system including a first allocation means for allocating a channel to another free communication channel within the same base station during communication, the transmitting/receiving means of the base station includes a third determination means for determining the reception level of the desired wave and the interference wave of the communication channel; control means that guarantees communication quality periodically, determines whether there is another free communication channel with a value closer to the predetermined threshold value, and controls the switching means to switch to the communication channel based on a positive result; It is characterized by containing.

Further, in the present invention, the predetermined threshold value may be a minimum value that guarantees the quality of communication.

Furthermore, the present invention provides a ratio of the interference wave determined by the first determining means, the desired wave determined by the second determining means, and the predetermined threshold value, and and a storage means for storing a ratio between the determined desired wave and the predetermined threshold value, a channel code of the corresponding communication channel, and a flag indicating whether or not the communication channel is currently in use; It can include means for making a determination based on the contents of this storage means.

0012

[Operation] The transmitting/receiving means of the base station determines the reception level of desired waves and low waves of the communication channel from the mobile station in communication by the third determining means, and the control means determines the determination result of the third determining means. The quality of communication is guaranteed at a specified period by comparing the reception level ratio of the desired wave and the interference wave based on the ratio, and it is determined whether there is another free communication channel with a value closer to the predetermined threshold value, and it is confirmed. Depending on the result, the switching means is controlled to switch to that communication channel.

[0013] As a result of the above, the traffic of the communication channel is not concentrated on one base station, the control burden on the upper station and the traffic of control information between the upper station and the base station are not increased, and the use of the communication channel is improved. Maximize efficiency.

[0014]

Embodiments Examples of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a mobile communication system according to an embodiment of the present invention.

In FIG. 1, the mobile communication system includes a plurality of base stations 10 that utilize a control channel and a plurality of communication channels, and a mobile station that is located within a zone 20 of the base station 10 and that can communicate using the plurality of communication channels. 30, the transmitting/receiving means of the base station 10 includes an electric field monitoring device 14 and a part of the central processing unit 11 as a first determining means for determining the reception level of interference waves of the idle communication channel of the base station at a predetermined period. and a mobile station 30 that starts communication when a communication channel is allocated.
The communication transmitting/receiving device 15 serves as a second determining means for determining the reception level of the desired wave of the communication channel scheduled to be allocated from
, 16 (or the control transmitting/receiving device 17) and a part of the central processing unit 11, and at the start of communication, the received level of the desired wave and the interference wave is determined based on the determination results of the first determining means and the second determining means. A part of the control transmitting/receiving device 17 and the central processing unit 11 serves as a first allocating means for allocating a communication channel whose ratio is close to a predetermined threshold value to guarantee the quality of communication to the mobile station 30 that starts communication. , includes a control transmitting/receiving device 17 and a part of the central processing unit 11 as a switching means for switching to another vacant communication channel within the same base station 10 during communication.

The feature of the present invention is that the transmitting/receiving means of the base station 10 acts as a third determining means for determining the reception level of the desired wave and interference wave of the communication channel from the mobile station 30 in communication. The communication transmitting/receiving devices 15, 16 and a part of the central processing unit 11 check the quality of communication at a specified period in comparison with the reception level ratio between the desired wave and the interference wave based on the judgment result of this third judgment means. is guaranteed, and it is determined whether there is another free communication channel with a value closer to the predetermined threshold value, and based on the positive result, the control transceiver device 1
7 and a part of the central processing unit 11 as a control means for controlling the communication channel and switching to that communication channel.

[0017] Furthermore, the predetermined threshold value is a minimum value that guarantees the quality of communication.

Furthermore, the interference wave determined by the first determining means, the ratio of the desired wave determined by the second determining means to a predetermined threshold value, and the ratio between the desired wave determined by the third determining means and the predetermined threshold value are determined. A channel quality control memory 12 is a part of the central processing unit 11 as a storage means for storing the ratio to the threshold value, the channel code of the corresponding communication channel, and a flag indicating whether the communication channel is currently in use. and an in-use channel management memory 13, and the central processing unit 11 includes means for determining based on the contents of the channel quality management memory 12 and the in-use channel management memory 13.

The operation of the mobile communication system having such a configuration will be explained. FIG. 2 is a sequence diagram of each signal when performing temporary transmission and reception using the communication channel of the present invention and measuring the D wave level. FIG. 3 is a configuration diagram of a data module stored in a channel quality control memory of the mobile communication system of the present invention. FIG. 4 is a block configuration diagram of a communication transmitting/receiving device for a mobile communication system according to the present invention. FIG. 5 is a configuration diagram of a data module stored in the in-use channel management memory of the mobile communication system of the present invention. FIG. 6 is a flowchart showing the operation of the mobile communication system of the present invention. FIG. 6(A) is a flowchart showing an operation for determining the reception level of a U wave on an empty communication channel, and FIG. 6(B) is a flowchart showing an operation for determining a desired wave and an interference wave during communication. FIG. 7 is a sequence diagram of transmitted and received signals between a base station and a mobile station in the mobile communication system of the present invention. FIG. 8 is a diagram showing the transition of the communication channel usage status of the mobile communication system of the present invention.

In FIG. 1, a mobile station 30 is capable of communication using multiple carrier waves using a built-in synthesizer. Currently, the mobile station 30 is communicating with the base station 10 using the communication channel f1. In the zone 20, the mobile station 30 receives the reception level at the base station 10 of the control channel sent from the mobile station 30 at the time of starting communication, or receives a temporary communication channel from the base station 10 as shown in FIG. (2b), cause the mobile station 30 to temporarily transmit (2c), and determine the D wave by means such as determining the reception level,
By measuring U waves using the electric field monitoring device 14,
It is assumed that the communication channel with the minimum DU ratio among the allocatable communication channels is allocated. The central processing unit 11 of the base station 10 uses the electric field monitoring device 14 to monitor the reception level of communication channels that are not currently used by the base station at predetermined intervals, and stores the results in the channel quality management memory 12. The format of one module of data stored in channel quality control memory 12 is shown in FIG. 1 module contains a channel code 3a, the current U wave level and (D wave level in use) /K=U0 3b, a flag 3c indicating whether the communication channel is currently in use, and the following: The channel data storage address 3d consists of four fields.

On the other hand, the communication transmitting/receiving device 15 currently in use has a configuration as shown in FIG. , the reception level of the U wave is determined from the eye pattern during demodulation of the received wave. In FIG. 4, radio waves transmitted from a mobile station 30 are received by an antenna 4a, amplified by a reception amplifier 4b, and then converted to a frequency that is easy to process by a mixer 4c and a filter 4d. is sent to a reception level measuring device 4h via a full-wave rectifier circuit 4f and a low-pass filter 4g.

[0022] When the received levels of the D wave and the U wave are detected by the above procedure, the received level of the U wave and (D wave level of the channel in use)/K=U0 are stored in the channel quality control memory, and each The storage destination address is stored in the in-use channel management memory 13. Free channel U
The wave level, the U wave level of the channel in use, and (the D wave level of the channel in use)/K=U0 are stored in the channel quality control memory 12 in descending order of the value of U0.

FIG. 5 shows the format of one module of data stored in the busy channel management memory 13. The data module has channel code 5 for the communication channel.
a, the address 5b where the U wave level data of this communication channel is stored, and the D/K of this communication channel =
It consists of four fields: address 5c where U0 is stored and address 5d of the next channel data.

The central processing unit 11 refers to the channel quality management memory 12 and the in-use channel management memory 13 at regular intervals, and selects the U closest to D/K=U0 (≧U0
) is selected. To do this, it is sufficient to sequentially check from address 5c to address 5b to see if there is an empty channel. A flowchart of the above procedure is shown in FIG.

After selecting a new channel f2 to be used for communication, the control transceiver 17 exchanges signals as shown in FIG. 7 including the channel designation for the mobile station 30, and intra-zone channel switching is performed. Communication using the new communication channel is started. That is, first, the base station 10 transmits a channel switching request 7a to the mobile station 30. The mobile station 30 switches to the communication channel designated by the base station 10, and after synchronizing (7b, 7c), performs communication using the new communication channel.

As described above, in this embodiment, each communication channel can be used repeatedly over the shortest distance while maintaining communication quality, thereby improving the efficiency of communication channel use. FIG. 8 shows the effect of applying the procedure of this embodiment. In zones 20A to 20F, the channel reuse interval is three zones. First, a call occurs in zone 20A, and communication channel fX is assigned (8a). Next, zone 20F
A call occurs, and the communication channel fX is assigned as the communication channel with the minimum DU ratio (8b). next,
A call occurs in zone 20C, and communication channel fX cannot be assigned, so another communication channel fY is assigned (8
c). At this stage, intra-zone channel switching occurs, and the communication channel used for the call occurring in zone 20F is switched from communication channel fX to fY based on the minimum DU ratio criterion (8d). Next, when a call occurs in zone 20D, the communication channel fX is assigned to the call (
8e). The number of communication channels is smaller than the example shown in FIG. 12. The present invention is equally applicable to analog mobile communications and digital mobile communications.

[0027]

As explained above, the present invention eliminates the concentration of communication channel traffic on one base station, reduces the control burden on the upper station, and reduces the traffic of control information between the upper station and the base station. This has the excellent effect of not increasing communication channel usage efficiency and maximizing the use efficiency of communication channels.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a mobile communication system according to an embodiment of the present invention.

FIG. 2 is a sequence diagram of each signal when performing temporary transmission and reception using the communication channel of the present invention and measuring the D wave level.

FIG. 3 is a configuration diagram of a data module stored in a channel quality control memory of the mobile communication system of the present invention.

FIG. 4 is a block configuration diagram of a communication transmitting/receiving device for a mobile communication system according to the present invention.

FIG. 5 is a configuration diagram of a data module stored in an in-use channel management memory of the mobile communication system of the present invention.

FIG. 6 is a flowchart showing the operation of the mobile communication system of the present invention.

FIG. 7 is a sequence diagram of transmission and reception signals between a base station and a mobile station in the mobile communication system of the present invention.

FIG. 8 is a diagram showing the transition of the communication channel usage status of the mobile communication system of the present invention.

FIG. 9 is a schematic diagram of a fixed channel arrangement method for a mobile communication system.

FIG. 10 is a schematic diagram of a channel allocation method by an upper station in a mobile communication system.

FIG. 11 is a schematic diagram of a method for allocating a communication channel with a minimum DU ratio in a mobile communication method.

FIG. 12 is a diagram showing changes in communication channel usage when a communication channel with the minimum DU ratio of a mobile communication system is allocated.

[Explanation of symbols]

10, 10A to 10D Base station 11 Central processing unit 12 Channel quality management memory 13 Channel management memory in use 14 Electric field monitoring device 15, 16 Communication transmitting/receiving device 17 Control transmitting/receiving device 20, 20A to 20F Zone 30, 301 to 305 Movement Station 40 Upper station 2a Communication channel use request 2b Temporary transmission/reception channel code notification 2c Temporary transmission 3a, 5a Channel code 3b U wave level and D/K=U0 3c Used/vacant flag 3d, 5d Next channel data address 4a
Antenna 4b Reception amplifier 4c Mixer 4d Filter 4e Demodulation circuit 4f Full-wave rectification circuit 4g Low-pass filter 4h Reception level measuring device 5b U wave data address 5c D/K=U0 address 7a Channel switching request 7b Synchronization signal 7c Synchronization complete Signal 11a Channel management table 11b Communication channel that satisfies communication quality 11c Communication channel with the minimum DU ratio among the communication channels that satisfy communication quality

Claims (3)

[Claims] 1. A mobile station comprising: a plurality of base stations that utilize a control channel and a plurality of communication channels; and a mobile station that is located within a zone of the plurality of base stations and is capable of communicating on the plurality of communication channels; The transmitting/receiving means includes a first determining means that determines the reception level of interference waves of an idle communication channel of its own station at a predetermined period, and a request for a communication channel to be allocated from a mobile station that starts communication at the time of communication channel allocation. A second determining means for determining the received level of the wave, and a ratio of the received level of the desired wave and the interference wave based on the determination results of the first determining means and the second determining means at the start of communication determines the quality of communication. a first allocation means that guarantees and allocates a communication channel with a value close to a predetermined threshold value to a mobile station that starts communication; and a switching means that switches the channel to another vacant communication channel within the same base station during communication. In the mobile communication system, the transmitting/receiving means of the base station includes a third determining means for determining the reception level of desired waves and interference waves of the communication channel from the mobile station in communication, and a third determining means for determining the reception level of the desired wave and interference wave of the communication channel from the mobile station in communication. The communication quality is guaranteed at a specified period by comparing the received level ratio of the desired wave and the interference wave based on the judgment result, and it is determined whether there is another free communication channel with a value closer to the above predetermined threshold value. and control means for controlling the switching means to switch to the communication channel based on a positive result. 2. The mobile communication system according to claim 1, wherein the predetermined threshold value is a minimum value that guarantees communication quality. 3. The ratio of the interference wave determined by the first determining means, the desired wave determined by the second determining means, and the predetermined threshold value, and the desired signal determined by the third determining means. storage means for storing a ratio of a wave to the predetermined threshold value, a channel code of a corresponding communication channel, and a flag indicating whether or not the communication channel is currently in use; 2. The mobile communication system according to claim 1, further comprising means for determining based on the content of the mobile communication system.