JPH03237826A - Time division communication system for mobile communication - Google Patents

Abstract

PURPOSE:To attain the utilization of a high frequency without generation of interference by using different time slots when adjacent radio base stations use a same radio channel. CONSTITUTION:A radio channel through which signals timewise compressed and divided in a form of time slots SU are sent is used for the communication with a radio base station 30. When the radio base station 30 uses a same radio channel in a radio zone having a possibility of interference, each of the radio base stations 30 use a different time slot SU. Thus, an independent radio line is set by using a same radio channel between other mobile radio equipment 100 and the radio base station 30 without giving adverse effect on the communication of the same radio channel in use.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a time division communication system for wireless communication channels in mobile communication. More specifically, each wireless base station that covers multiple zones and constitutes a service area is given a certain wireless channel, and is used to select one of the many mobile wireless devices within the service area. When one of the mobile radios requests communication using the same radio channel while one of the mobile radios is setting up a radio line and communicating with the opposing radio base station, regardless of the radio wave propagation conditions. , without adversely affecting the communication between the mobile radio and the radio base station that is already in communication, or the communication on the same radio channel that is being used by an adjacent radio base station, and the communication between other mobile radios and the radio base station. The present invention relates to a time-division communication system using the same radio channel that makes it possible to set up independent radio lines between stations using the same radio channel.

[Prior Art] Regarding mobile communication using voice to which a small zone method is applied, a method employing a time division time compression multiplex signal is described in the following document.

Literature 1. Furnace layer “Study of mobile phone system - Proposal of time-division time-open compression FM modulation system - IEICE technical report RC389-1
1 July 1989 text M2. Furnace layer “Study of mobile phone system - Theoretical study of time-division time compression FM modulation system” IEICE technical report RC38
9-39 October 1989 In other words, in Document 1, a transmission signal (baseband signal) is divided into predetermined time intervals and stored in a storage circuit, and when read out, the speed is faster than the speed at which it is stored in the storage circuit. Mobile radios and radio base stations read out at a predetermined time slot at n times higher speed, angle-modulate or amplitude-modulate the carrier wave with the signal accommodated by this time slot, and transmit and receive intermittently in time. A radio receiving circuit that has a receiving mixer that communicates with each other and a radio transmitting circuit that has a transmitting mixer, which is built in the radio receiving circuit, and a synthesizer that applies the voltage to the receiving mixer of the wireless receiving circuit and a transmitting mixer of the wireless transmitting circuit. A switch circuit is provided for each synthesizer to intermittent the output of the synthesizer applied to each, and this intermittent state is synchronized for both transmission and reception, and the same intermittent transmission and reception as described above is transmitted to the wireless base station communicating with the opposite mobile radio. In order to extract only the signal accommodated in the predetermined time slot, the receiving side opens and closes the radio receiving circuit to receive the signal, demodulates the signal, and stores the obtained signal in the storage circuit. By storing it and reading it out at a low speed that is 1/n of the speed at which it is stored in this storage circuit,
An example of a system has been reported in which a system is constructed that can reproduce the baseband signal that is the original signal that has been transmitted.

In addition, in Document 2, the above-mentioned time-division time compression multiplexing FM
Adjacent channel interference and co-channel interference, which are problems when applying the method to small zones, have been studied.
It has been shown that it is possible to realize a system that eliminates the problems by appropriately selecting system parameters.

However, in the system construction example described above, the influence of the multiwave radio wave propagation characteristics suffered by time division time compression multiplexed signals transmitted from a radio base station to a large number of mobile radio devices is not taken into account at all. There was an issue that needed to be resolved in that there were no clear measures to be taken in the event that communications quality was seriously affected by interference.

[Means for solving the problem 1: In one frame in which a time-division time compression multiplex signal is transmitted, there is a difference in the size of the guard time set between each time slot. If the distance between the radio base station and the mobile radio is relatively small and the influence of multiple wave propagation is small, use a time slot with a small guard time. If the time slot used for communication is automatically shifted to a time slot with a large guard time, and the time slot used for communication is automatically shifted to a time slot with a large guard time, In terms of configuration, when adjacent or nearby M-line base stations use the same radio channel, time slots are allocated so that they use different time slots to improve the efficiency of frequency utilization. It has become possible to construct a system that is both high-performance and highly resistant to interference.

1 Effect 1 TCM-FM (time-division time compression multiplexing-frequency modulation) signal undergoes multiple wave propagation (multipath facing) while propagating in space, and the amplitude and phase change. If this degree is large, the This causes interference to the demodulated signal in the form of distortion noise and thermal noise.Among these, changes in phase have a particularly large effect, so as a countermeasure to this, guard and A method to prevent the time from increasing has been clarified.

Furthermore, when neighboring radio base stations use the same radio channel, they use different time slots, making it possible to provide a system that can obtain high frequency utilization without causing interference. Ta.

Embodiment FIGS. 1A, 1B, and 1C show a system configuration for explaining an embodiment of the present invention.

In FIG. 1A, 10 is a general telephone network, and 20 is a gateway exchange for connecting the telephone network 10 and a wireless system. 30 is a wireless base station and a barrier switch 20
It includes an interface with the mobile radio, a circuit that converts the signal speed, a circuit that allocates and selects time slots, a control unit, etc.
00 (100-1 to 100-n>) and has a wireless transmitting/receiving circuit that transmits and receives wireless signals.

Here, between the barrier switch 20 and the wireless base station 30,
There are transmission lines for transmitting communication signals 22-1 to 22-m including communication signals of communication channels day 0 1 to day C n and control signals.

FIG. 1B shows a circuit configuration of mobile radio device 100 that communicates with radio base stations 30-1 to 30n. Received signals such as control signals and call signals received by the antenna section enter a radio reception circuit 135 that includes a reception mixer 136 and a reception section 137, and the communication signal that is the output thereof is sent to a speed recovery circuit 138 and a clock regenerator 141. The signal is input to the reception quality monitoring section 158. The clock regenerator 141 regenerates a clock from the received signal and applies it to the speed restoration circuit 138, the control section 140, the timing generator 142, and the speed conversion circuit 131.

The speed restoration circuit 138 restores the speed (pitch in the case of an analog signal) of each compressed and separated communication signal in one time slot in the received signal of one channel to generate a continuous signal. obtained,
It is input to the telephone unit 101 and the control unit 140.

The communication signal output from the telephone unit 101 is divided into predetermined time intervals by a speed conversion circuit 131, and the speed (pitch in the case of an analog signal) is made high (compressed) and sent to a transmission mixer 133. The transmission signal is applied to the radio transmitting circuit 132 including a section 134, and the transmission signal is sent out from the antenna section using one time slot and received by the plurality of radio base stations 30.

A reception quality monitoring unit 158 to which part of the output of the reception unit 137 is applied monitors the reception quality (signal-to-noise ratio and occurrence of interference) of the input signal.Furthermore, a reception mixer is installed at the antenna reception end. An interference detector 162 is configured to be connected in parallel with the input to 136;
This is used to detect interference with one's own communication on the same channel and same time slot used for other communications, either in other systems or within the same system. This interference detector 162 monitors the presence or absence of interference during communication, and if it detects interference of a certain amount or more, reports it to the control unit 140.

In the timing generator 142, the transmission/reception intermittent controller 123. The speed conversion circuit 131 supplies necessary timing to the speed restoration circuit 138.

This mobile radio 100 includes synthesizers 121-1 and 1 to enable transmission and reception of roughly one channel.
21-3, a changeover switch 1221, 122-2, and a transmission/reception intermittent controller 123 that generates signals for switching the changeover switches 122-1 and 122-2, respectively. 121 - 3 , the transmission/reception intermittent controller 123 , and the timing generator 142 are controlled by the controller 140 . Each synthesizer 121 and 121-3 includes a reference crystal oscillator 120.
The reference frequency is supplied from With such a configuration, it is possible to communicate with the wireless base station 30 using one channel.

A wireless base station 30 is shown in FIG. 1C.

Communication signal 22 of m channel between barrier exchange 1!120
-1 to 22-m are connected to a signal processing unit 31 forming an interface through transmission lines.

Now, the communication signal 22- sent from the opening switch 20
1 to 22-m are input to the signal processing unit 31 of the wireless base station 30. The signal processing section 31 is equipped with an amplifier for compensating for transmission loss, and also performs so-called 2-wire to 4-wire conversion. In other words, the input signal and output signal are mixed and separated, and the barrier is exchanged! The input signal from 120 is sent to signal speed conversion circuit group 51 .

Further, the output signals from the signal speed restoration circuit group 38 are exchanged at the signal processing section 31 as communication signals 22-1 to 22-m using the same transmission path as the input signals! 1120.

Among the above input signals from the gateway exchange 20, the input signals are input to a signal speed conversion circuit group 51 including many signal speed conversion circuits 51-1 to 51-m, and speed (pitch) conversion is performed at predetermined time intervals. receive.

In addition, for the signal transmitted from the radio base station 30 to the barrier exchange II 20, the output of the radio reception circuit 35 is input to the signal speed restoration circuit group 38 via the signal selection circuit group 39, and the signal is speed (pitch) converted. After that, through the switch group 83,
The signal is input to the signal processing section 31.

Now, the control of the M-line duplication circuit 35 or the output of the speech signal is carried out by the signal selection circuit 3, which selects signals for each time slot.
The signal is input to a signal selection circuit group 39 including 9-1 to 39-m, where the speech signal is separated corresponding to each speech channel, C day 1 to CHm.

This output is restored to a signal speed (pitch) by a signal speed restoration circuit group 3B including signal speed restoration circuits 38-1 to 38-m provided corresponding to each call signal, and then processed by a signal processing unit. 31, and after undergoing 4-wire 2-wire conversion, this output is sent as communication signal 22-1 to 22-m to barrier exchange l1N20.
Sent as .

The transmission quality monitoring section 34 has the functions of both the reception quality monitoring section 158 and the interference detection section 162 of the mobile radio device 100,
When deterioration in reception quality or interference is detected, the control unit 40
will be reported to.

Further, the signal processing section 31 has a function of allowing two channels to be used simultaneously for the designated mobile radio device 100 according to instructions from the control section 40. This is used for simultaneous communication using different radio channels within the same zone during communication, or for simultaneous communication using different time slots of the same channel, and is used for simultaneous communication using different radio channels within the same zone.
This is a function used to enable communication in slots).

Here, the specific configuration of each radio receiving circuit 35 is as follows.
This is the same as the radio receiving circuit 135 of the mobile radio device 100 shown in the figure.

Next, the functions of the signal speed conversion circuit group 51 will be explained.

By storing input signals such as audio signals and control signals divided into a certain length of time in a storage circuit, and changing the speed when reading them out, for example, reading them out at a speed 15 times faster than when they were stored, the signal can be read out. It becomes possible to compress the time length. The principle of the signal speed conversion circuit H151 is the same as when playing back audio recorded by a tape recorder at high speed.
rgeCoupled Device), BAD
(Bucket BrigadeDevice > can be used, and the memory used in television receivers and tape recorders that compress or expand the time axis of conversation can be used (References Nikosaka et al. “Time axis of conversation A tape recorder that compresses/expands
Nikkei Electronics July 26, 1976 92
〜133 pages〉.

The circuit using the COD/BBD exemplified in the signal speed conversion circuit group 51 can be used as it is in the signal speed restoration circuit group 38 as described in the above-mentioned literature. This can be achieved by making the reading speed slower than the writing speed by receiving a timing signal from a timing generation circuit 42 that generates timing based on the clock and a control signal from the control section 40.

The control or call signal output from the open gate exchange 111120 via the signal processing section 31 is sent to the signal speed conversion circuit group 5.
1, and after undergoing speed (pitch) conversion processing, is applied to a signal allocation circuit group 52 that allocates signals for each time slot. This signal allocation circuit group 52 is a buffer memory circuit, Memorize each section of high-speed signals output from the signal speed conversion circuit group 51, read out the signals in the buffer memory using timing information from the timing generation circuit 42 given in accordance with instructions from the control section 40, The timing information is transmitted to the wireless transmission circuit 32. When viewed in terms of call signals, this timing information is arranged in series without overlapping in chronological order, and the control signal or the control signal and the call signal, which will be described later, are all implemented. In this case, it becomes like a continuous signal wave.

The state of this compressed signal is shown and explained in FIGS. 2A and 2B.

The output signal of the signal speed conversion circuit group 51 is sent to the signal assignment circuit group 5.
2 and are given time slots in a predetermined order. Figure 2A (a> SDl, SD2
．． , SDn indicate that the speed-converted communication signals are allocated to each time slot at the output of the wireless transmission circuit 32-1, 32-2 (simply shown as 32).

Here, as shown in the figure, one time slot accommodates a synchronization signal and a control signal or a call signal (and a control signal).If the call signal is not implemented, the synchronization signal alone is used to generate the call signal. In this case, an empty slot signal is added to the service zone of another wireless base station 30 in the same system so as not to cause radio interference to communications using the same radio channel and the same time slot. In order to achieve this, it is also possible to make the signals included in empty time slots only the first part of each slot length (for example, about 5% of the total), and no radio waves are transmitted for the rest. In this way, Figure 2A (
As shown in a), in the radio transmission circuit 32, signals forming one frame are applied to the modulation circuit in time slots SD1 to SDn. In addition, Figure 2A (a
) to (b), the time slots are written as being adjacent and there is no guard time, but as will be explained later (
5-1 of time slots, as shown in Figure 2D.
A guard time of 0% is provided and is omitted in the drawing.

The time-series multiplexed signal to be transmitted is angularly modulated in the radio transmission circuit 32, and then sent out into space from the antenna section.

When making or receiving a telephone call, the wireless base station 30
Regarding the transmission of control signals between the mobile radio device 100 and the mobile radio device 100, it is possible to use either within the telephone signal band or outside the telephone signal band.

Figure 3A shows these frequency relationships. In other words, the figure (a>) is an example of an out-of-band signal, and as shown, the low frequency side (250H2) and the high frequency side (3850Hz>
can be used. This signal is used, for example, when it is desired to send a control signal during a call.

FIG. 3A (b) shows an example of an in-band signal, which is used when making and receiving calls.

Although the above examples were all tone signals, it is possible to transmit many types of signals at high speed by increasing the number of tone signals or by modulating the tone and making it into a subcarrier signal.

The above was a case of analog signals, but if a digital data signal is used as a control signal, it is also possible to digitally encode the audio signal and time-division multiplex the two to transmit. The circuit configuration of is shown in FIG. 3C. FIG. 3C shows an audio signal digital encoding circuit 9.
This is an example of a case in which the data signal is digitized at 1, multiplexed with a data signal by a multiplex conversion circuit 92, and applied to a modulation circuit included in the wireless transmission circuit 32.

Then, it is received by the opposite receiver, and the 3rd C
By performing the operation opposite to that shown in the figure, it is possible to extract the audio signal and the control signal separately.

On the other hand, the signal sent from mobile mm1oo is 5Ii
1 is received by the antenna section of the base station 30, and is transmitted to the radio receiving circuit 3.
5. FIG. 2A (b) schematically shows this upstream input signal.

That is, time slot SU1. SU2. ...s
un is mobile radio 100-1.100-2°...,
100-n shows a transmission signal addressed to the wireless base station 30.

Also, each time slot su1. su2,...,su
If the contents of n are shown in detail, it consists of a synchronization signal and a control signal or/and a telephone call signal, as shown in the lower left of FIG. 2A (b).

However, depending on the distance between the radio base station 30 and the mobile radio device 100 or the signal speed, the synchronization signal may be omitted. Roughly speaking, the waveform of the radio carrier wave of the above-mentioned uplink radio signal within a time slot is schematically shown as shown in FIG. 2B (C).

Now, among the input signals that have arrived at the wireless base station 30, the control signal is immediately sent to the control unit 40 from the wireless receiving circuit 35.
added to. However, depending on the size of the speed conversion rate, it is also possible to apply the output of the signal speed restoration circuit group 38 to the control unit 40 after the call signal has been subjected to similar processing. Also, regarding the call signal, it is applied to the signal selection circuit group 39.

A timing signal from a timing generation circuit 42 that generates a predetermined timing is applied to the signal selection circuit group 39 according to a control signal instruction from the control unit 40, and a synchronization signal and a control signal are generated for each time slot SU1 to Sun. The signal or speech signal is separated and output. Each of these signals is input to a signal speed restoration circuit group 38. This circuit is a speed conversion circuit 131 (
It has a function of performing the inverse conversion shown in FIG. 1B, so that the original signal is faithfully reproduced and transmitted to the gateway exchange 2o.

The manner in which signals are transmitted in the signal space according to the present invention will be explained below using the required transmission band and the relationship between this and adjacent wireless channels.

As shown in FIG. 1C, the control signal from the control unit 4o is applied to the wireless transmission circuit 32 in parallel with the output of the signal allocation circuit group 52. However, depending on the size of the speed conversion rate, it is also possible to apply the signal to the wireless transmission circuit 32 from the output of the signal allocation circuit group 52 after performing the same processing as the call signal.

Next, as shown in FIG. 1B, the mobile radio m1oo also has a circuit configuration that is required when the communication path is one channel among the functions of the radio base station 30.

Figure 3B shows the frequency distribution on the output side when the original signal, for example, a voice signal @ (0.3KHz~3.OK) passes through the signal speed conversion circuit group 51 (Figure 1C). In other words, if the audio signal is converted 15 times as described above, the frequency distribution of the signal is as shown in Figure 3B.
4.5 will be expanded to day 2 to day 45. The figure shows a case where the control signals are simultaneously transmitted using the lower frequency band of the audio signal. Of this signal, the control part @ (0,2 to 4.0KH2) and the call signal 0 days 1 (represented as sDl in 4,5 to 45KH2) are accommodated in a time slot, for example, SDI. Other time slots SD2-S
The same applies to the audio signal accommodated in Dn.

That is, time slot sor <r=2゜3,・
, n) contain a control signal (0.2 to 4.03 days 2) and a communication signal CHi (4.5 to 45KH7).

However, the signals in each time slot are arranged in chronological order, and the signals in multiple time slots are not applied to the wireless transmission circuit 32 at the same time.

These call signals are sent to the wireless transmission circuit 32 along with control signals.
When added to the angle modulator included in the angular modulator, the required transmission band requires at least fo±45 days. However, fo is a radio carrier frequency. If there are a plurality of wireless channels given to the system, the speed-up of the signal by the signal speed conversion circuit group 51 is limited to a certain value due to the limitations on these frequency intervals. The frequency interval of multiple wireless channels is f
,. , and the maximum signal speed due to the above-mentioned speed increase of the audio signal is fH, then the following inequality must hold between the two.

f > 2 f H ep On the other hand, in digital signals, audio is usually digitized at a speed of about 64 kb/s, so read by raising the scale on the horizontal axis in Figure 3B, which explains the case of analog signals, by about one digit. Although necessary, the relationship in the above equation also holds true in this case.

Further, the control signal input from the mobile radio device 100 to the radio base station 30 is input to the radio reception circuit 35, but a part of the output is input to the control unit 40, and the other part is input to the signal selection circuit group 39. The signal is sent to the signal speed restoration circuit group 38 via the signal speed restoration circuit group 38. After the latter control signal undergoes a speed conversion (conversion to a low speed signal) that is completely opposite to that at the time of transmission, it becomes the same signal speed as that used in the general telephone network 10 and is transmitted via the signal processing section 31. Sent to barrier exchange l1120.

Next, the call originating/receiving operation of the system according to the present invention will be explained by taking the case of a voice signal as an example.

(1> Call origination from mobile radio device 100 This will be explained using the flowcharts shown in FIGS. 4A and 4B.

When the mobile radio device 100 is powered on, the first
In the wireless receiving circuit 135 in Figure B, the downlink (wireless base station 30
→Mobile radio 100) Starts capturing the control signal contained in the radio channel (Channel C port 1). If the system is provided with multiple radio channels, the maximum reception input Wireless channel i showing electric field
A wireless channel (iii) that is instructed by a control signal included in the wireless channel; a wireless channel (hereinafter referred to as channel C port 1> reception state. This is possible by capturing the synchronization signal within the time slot SDr shown in FIG. 2A (a). −
A control signal is sent to the switch 122-1 so as to generate a local frequency that enables reception of the radio channel C port 1, and the switch 122-1 is also fixed in the position of the synthesizer 121-1.

Therefore, when the receiver of the telephone unit 101 goes off-hook (starts making a call) (S201, FIG. 4A), the synthesizer 121-3 of FIG. A control signal is received from the control section 140 to generate the following.

In addition, the switch 122-2 is also turned to the synthesizer 1213 side and becomes fixed. Next, the calling control signal output from the telephone unit 101 is sent out using the wireless channel CH1. This control signal uses the frequency band shown in FIG. 3A (b) and is transmitted using, for example, time slot Sun.

The transmission of this control signal is limited to time slot Sun, and is sent in bursts, and no signal is transmitted during other time slots, so it does not adversely affect other communications. However, if the speed of the control signal is relatively slow or the amount of information in the signal is large and cannot be accommodated in one time slot, the same time slot of the next frame will be displayed after one frame or roughly. - Transmitted using slots.

Specifically, the following method is used to capture the time slot Sun. The control signal transmitted from the radio base station 30 includes a synchronization signal and a subsequent control signal, as shown in FIG. becomes possible.

Furthermore, this control signal includes control information such as currently used time slots and unused time slots (empty time slot display). Depending on the system, time slots SDi (i=1 ．2゜...
, n) may contain only synchronization and speech signals when they are being used by other communications; By receiving this control signal, the mobile radio device 100 can know which time slot should be used to send out the calling signal.

Note that if all time slots are in use,
It is not possible to make a call on this radio channel and it is necessary to sweep and search for another radio channel.

In other systems, there may be no empty slot indication in any of the time slots, in which case the following audio multiplex signals SD1, SD2 . ..., S
It is necessary to search for the presence of Dn one after another and check for empty time slots.

Now, returning to the main topic, the mobile radio device 100, which has received the control information sent from the radio base station 30 by one of the above methods, determines in which time slot it should send the call control signal. It is possible to make a judgment including the transmission timing.

Therefore, assuming that the time slot Sun for uplink signals is an empty slot, it is decided to use this empty time slot, and the necessary timing is determined from the response signal from the radio base station 30 by sending out a control signal for calling. It is also possible to send out burst-like control signals.

If there is a call from another mobile radio at the same time, the calling signal will not be properly transmitted to the radio base station 30 due to call collision, and the operation will have to be restarted from the beginning, but this probability is When viewed as a system, this value is kept to a sufficiently small value. If call collisions are to be significantly reduced, the following method may be used. If a mobile radio l1100 finds an empty time slot in which it can make a call, it does not use the entire time slot, but uses only the first half for some mobile radios and the second half for others. This is the way to do it. In other words, the portion of the time slot used as a calling signal is divided into several types, and this is used to classify a large number of mobile radios into groups, and each group is assigned a time period within that one time slot. It is a way of giving. Another method is to create many types of frequencies for control signals, group a large number of mobile radios, and give these to each group. According to this method, even if control signals of different frequencies are transmitted simultaneously using the same time slot, no interference will occur at the radio base station 30. The above two methods may be used separately, or when used together, the effects will increase synergistically.

Now, suppose that the call control signal from the mobile radio device 100 is successfully received by the radio base station 30 and the ID (identification number) of the mobile radio device 100 is detected (32O2). Search for a time slot.The time slot given to mobile radio 100 may be Sun, but just to be sure, perform a search.
In addition to 00, this is also used to respond to simultaneous calls from other mobile radios, and to provide time slots suitable for service types and service classifications.

As a result, for example, if the time slot SD1 is vacant, the time slot SD1 of the Cth radio channel 1 is used for the mobile radio II1100, and the time slot upstream (mobile radio vs100→
Wireless base J430) SUI.

and instructs to use the corresponding downlink (radio base station 30→mobile radio 1100) SDl (S203
>. In response, the mobile radio device 100 transitions to a state in which it can receive data in the instructed time slot SD1, and at the same time, the mobile radio device 100 shifts to a state in which it can receive data in the instructed time slot SD1, and also changes the time slot 5UI (FIG. 2A), which is a time slot for an uplink radio channel corresponding to the downlink time slot SD1. (b)>. At this time, the control section 140 of the mobile radio device 100 operates the transmission/reception intermittent controller 123 and starts operating the switches 122-1 and 122-2 (3204>. At the same time, the Sends a switching completion report to the radio base station 30 using uplink time slot SU1 (3205) and waits for a dial tone (3205).
S206>.

Time slot SU of the radio carrier of this upstream radio signal
The state of I is schematically shown in FIG. 2B (C). In addition to the time slot SU1, the radio base 830 receives an uplink signal SU3 from another mobile radio 100.
Ya Sun is included in one frame and sent.

The radio base station 30 that has received the slot switching completion report (
3207>, sends a calling signal to the gateway exchange 20 5208>, upon receiving this, the gateway exchange 20 detects the ID of the mobile radio 100 and selects the necessary switch from the switch group included in the open gate exchange 1N2O. Turn on (S2
09>, sends a dial tone (S210, fourth
Figure B〉.

This dial tone is transmitted by the radio base station 30.
At t'L (S211>, mobile radio 1110C), it is confirmed that a communication path has been set (S212>).

When transitioning to this state, the telephone unit 1 of the mobile radio device 100
Since a dial tone is heard from the 01 handset, the dial signal begins to be sent. This dial signal is speed-converted by the speed conversion circuit 131 and sent out from the wireless transmission circuit 132 including the transmission section 134 and the transmission mixer 133 using the uplink time slot SU1 (S213>. Thus, the transmitted dial signal is It is received by the radio receiving circuit 35 of the base station 30.The radio base station 30 has already responded to the calling signal from the mobile radio l1100,
In addition to giving the time slot to be used, the signal selection circuit group 39 and signal allocation circuit group 5 of the wireless base station 30
2 is operated to receive the uplink time slot SU1 and to transmit the signal of the downlink time slot SDI. Therefore, the dial signal transmitted from the mobile radio IIa 100 is transmitted to the signal selection circuit group 39.
After passing through the signal selection circuit 39-1, it is input to the signal speed restoration circuit group 38, where the original transmission signal is restored and the signal
It is transferred to the gateway exchange 20 as a call signal 22-1 via the processing unit 31 (S214>, and a call path to the telephone network 10 is set (3215>).

On the other hand, an input signal from the barrier switch 20 (initial control signal,
When a call is started, the call signal) undergoes speed conversion at the signal speed conversion circuit group 51 in the radio base station 30, and is given a time slot SDI by the signal allocation circuit 52-1 of the signal allocation circuit group 52. ing. Then, the time slot SD of the wireless channel downstream from the wireless transmission circuit 32
It is transmitted to the mobile radio device 100 using I. The mobile radio 41100 is waiting for reception in the time slot SDI of the radio channel C port 1, and is received by the radio receiving circuit 135, the output of which is input to the speed restoration circuit 138. In this circuit, the original signal of the transmission is restored and input to the handset of the telephone section 101. Thus, a call is started between the mobile radio device 100 and a regular telephone within the regular telephone network 10 (3216>).

No moving for the end of the episode! When the handset of the telephone unit 101 of the I device 100 is turned on-hook (3217>), the end-of-call signal and the on-hook signal from the control unit 140 are sent to the wireless base station from the wireless transmission circuit 132 via the speed conversion circuit 131. 3
0 (3218>, control unit 140
Then, the operation of the transmission/reception intermittent controller 123 is stopped, and the switches 122-1 and 122-2 are fixed to the output terminals of the synthesizers 121-1 and 121-3, respectively.

On the other hand, in the control unit 40 of the radio base station 30, the mobile radio device 1
When the call termination signal is received from 00, the call termination signal is forwarded to the barrier switch 20.3219>, switch group (not shown)
The switch is turned off to end the call (S220>. At the same time, the signal selection circuit group 39 and signal allocation circuit group 52 in the wireless base station 30 are opened.

In the above explanation, control signals between the radio base station 30 and the mobile radio device 100 are controlled by the signal speed conversion circuit group 51. Although it was explained that the signal speed restoration circuit group 38 etc. are not passed through,
This is for convenience of explanation, and communication can be carried out without any problem even through the signal speed conversion circuit group 51, signal speed restoration circuit group 38, control signal speed conversion circuit 48, or signal processing section 31, as with audio signals. .

(2) Incoming call to mobile radio 100 The mobile radio 11100 is on standby with the power turned on. In this case, as explained in the section regarding the call origination from the mobile radio device 100, the mobile radio device 100 is in a state of waiting to receive the downlink control signal of the radio channel 0 and 1 in accordance with the procedure determined by the system.

Assume that an incoming call signal to the mobile radio 11100 arrives at the radio base station 30 from the general telephone network 10 via the barrier exchange vs20. These control signals are transmitted as communication signals 22 to the control section 40 (FIG. 1C) via the signal speed conversion circuit group 51 and the signal allocation circuit group 52, in the same way as voice signals.Then, the control section 40 An empty slot among the downlink time slots on day 0 and 1 of the wireless channel addressed to the radio 100, for example, using SDl, the mobile radio 100
A D signal, an incoming call signal display signal, and a time slot usage signal (for example, SUl corresponding to SDl is used for transmission from the mobile radio device 100) are transmitted.

In the mobile radio device 100 that receives this signal, it is transmitted from the receiving section 137 of the radio receiving circuit 135 to the control section 140. In the control unit 140, this signal is transmitted to the own mobile radio device 10.
The telephone unit 10 confirms that it is an incoming call signal to 0.
At the same time, the transmission/reception intermittent controller 123 is operated to stand by at the designated time slot SD1.3-1, and the switch 122-
1°122-2 starts turning on and off. In this way, the state has shifted to a state in which calls can be made.

Note that it is theoretically explained in Reference 2 that signal transmission is carried out in good condition using this system and that it does not adversely affect other wireless channels in the system, so it will be omitted here. A specific explanation will be given of how large the guard time should be depending on the multiple wave propagation characteristics applied to the present invention.

(3) Mathematical representation of CM-FM waves affected by multiple wave propagation (3,1) Regarding the influence of multiple radio wave propagation on CM-FM waves Figure 2C (a) is transmitted from the wireless base station 30 TCM to be
-FM (Time Division Time Compression Multiplexing - Frequency Modulation) wave. FIG. In this case, the mobile radio device 100 wants to receive only the signal S1 of time slot SD1 among the TCM (time division time compression multiplexing) signals transmitted from the radio base station 30, but due to multiple reflections in the transmission medium, the signal S1 In addition, the following unnecessary signals will be received at the same time.

〉Signal S1 delayed by time T due to multiple reflections of signal S (t-τ1〉 (τ1< t < T) 11> Signal component S0 of time slot SDn immediately before time slot SD1 delayed by time τ1 Therefore, the interference signal sn (t+T□−τ.〉 (Oat<τ.〉) which exceeded the guard time and fell into the time slot SDi is the same as the echo distortion in the current analog FM system. This includes components that cause echo distortion and useful signals that differ only in phase from the original signal, but it must be noted that all of ii) are harmful signals.

(3, 2) Mathematical representation of TCM-FM waves The voice (or control signal) transmitted from the wireless base station 30 to one opposing mobile radio device 100 is expressed mathematically as shown in the following formula according to Document 2. Become.

D(t) = I n” [1 1 xcos mp t ] xsin (Ω1 j + S1
(t) > (1) However, IOI is the magnitude of the amplitude, Ω1 is the carrier angular frequency,
51(t) indicates a signal (including a control signal). n is the number of slots (equal time intervals) within one frame, p is the switching angular frequency, and m is a positive odd number.

Although the radio modulated waves expressed by the following equation (1) will be affected by various adverse effects within the spatial medium, the following analysis will be limited to multiple wave propagation.

Now, in order to express it using a clear mathematical formula,
When the mobile wireless device 100 receives the TCM wave transmitted from 0, the desired wave - which can be considered a direct wave - is D, and the reflected wave affected by multiplex radio wave propagation - this is generally a large number. The echo wave ■ is probably a combination of the reflected waves of The signal that has fallen into the slot is expressed as an interference wave U. Also, if there is no direct wave or it is weak compared to the reflected wave, the same analysis can be performed by treating the largest reflected wave as the direct wave and shifting the time axis by the amount of delay of the reflected wave. It becomes possible.

(3, 3) Change in amplitude due to interference If the interval of time t for the TCM wave is appropriately selected, the desired wave D, echo wave V, and interference wave can be expressed as in the following equation.

Desired wave 1) sinθd=Dsin (Ωj+51 (t)
)(2> (nTt≦t≦T+nTt) Echo wave Vsinθ =Vsin (Ω(trl)+51(j-
τ1)) (3) (r 1 + n T t≦t≦(n+1)Tt) Interference wave U sinθ =Usin (Ωlj+T□ rl)
+so (t+To-τ1)) <4> (nT ≦t≦r 1 + n T t ) However,
The following assumptions are made: 1) The delay amount of the echo wave generated in each time slot is shorter than one time slot. In other words, although interference waves from adjacent time slots are received in each time slot,
There are no interfering signals from more than one time slot away. This can be satisfied by appropriately selecting the scheme design parameters.

2) The amount of delay due to multiple propagation that each time slot receives becomes constant if time t is determined. In other words, the above formula (3)
Although τ1 in the equation (4) may differ strictly from τ1 in the equation (4), it may be allowed on the assumption that they are adjacent time slots and have the same delay time.

3) The time length of the echo wave and interference wave is the signal wave (time
slot length). To be precise, it is a combination of many reflected waves, and the time length is assumed to be longer than the signal wave, but for convenience of calculation, it is set as above. As a result,
Although the calculation results may be slightly lenient, it is practically negligible.

4) Desired wave D, echo wave V, and interference wave U do not coexist at the same time. This can be satisfied in terms of system design.

Now, the composite wave of equations (2) and (3) is given by the following equation.

RIS! nθr 1 = D S j nθd+ 'J
Slnθ8=D[1+X” +2Xcos(-Ωτ+s1 (t-τ〉1/2
・s (t))] xs+n(θd+φ1〉(5) φ1 = jan-' [(XS!n (Ωr+81
(t>-sl (t-τ) ) ) X (1+XCO
3(Ωτ1 +s (t)-sl (t-τ)〉)](6〉 However, X=V/D In other words, the amplitude envelope is R1=D[1+×2 +2Xcos(Ωτ+51 (t>=D (1 + It is given by the following formula.

R25Inθr2 = Ds i nθd + USjnθ.

=D[1+¥2 +2Ycos ((T□-τ1)Ω +s, (t+To-τ1〉 1/2 ・-5(t))] xs+n(θd+φ2) (9) φ = tan-1[(Ysin (Ω (To−τ1〉
+s, (tenTo−τ1) 51(t))X (1+
Ycos (Ω(To−τ1〉+S, (T
+ TO This is a case where the signal is suppressed. This phenomenon seems to be unavoidable in a multi-wave propagation system, as seen from equations (7) and (9). However, this phenomenon is not limited to TCM-FM, but also occurs in analog (SCPC) systems that are in practical use. However, in the case of TCM, signal components are spread over a wide range of sidebands, and this is expected to have a greater degree of negative influence than in conventional systems.

Exactly, experimental investigation is required, but it can be estimated as follows. Since the spread of the sideband is proportional to the compression ratio N, the possibility of interference to the signal increases N times. On the other hand, considering the time rate at which the signal is transmitted, it is 1/N, and the signal is not transmitted at all at other times. The probability of receiving interference from both of these does not change per unit baseband frequency.

However, the effects of selective fading on wideband signals need to be considered separately.

(3,4) Phase change due to interference Consider displaying a V or a beam as a vector.

First, the D wave is expressed as □exp(jθd) =D eXp(j
(t) > ) (11> Similarly, from equation (3> or <4>), v and u waves are expressed as yex
p(jθ8) =V exp[j (Ω(t-rl)+
s B−τ1))] (12〉 Uexp(jθ ) =U eXl)[j (Ω(t+
T.

τ )+s (t+T□−τ1>)]n (13>) Therefore, the instantaneous phases θrl′ and θr2 of the composite vector of V, D, and U are determined as follows.

First, for D and V, R1eXl)(Jθ,)−Dexp(jθd)x [1
+x exp(j (-Ωτ1+S (t-τ1))
)] (14> θ = Imac+log(Rexp(jθ, 1)) rl
1 =θd+ Imag l0cI [1 +X exp(j (-Ωj+S1 (t -τ1)
))] (15> X × 1, that is, when the echo signal is smaller than the desired signal, θ, 1 (PM receiver output, obtained by differentiating with time t in the case of FM reception) is as follows. .

XXn5in ncx Here, α1=-Ωτ1 +51 (-τ1) (16> Expand the right-hand side of the equation, (16> (17) XX' eXp(J ncrl ) (18) Among the outputs shown on the right-hand side of the above equation The first term is an effective signal component, and the second term and subsequent terms seem to be interference outputs, but in reality it is the second term, that is, X5In (2, =
〉) (19) contains some useful signal components. This will be explained in the numerical calculation example section below. Similarly, the instantaneous phase θr2 of the combined vector of D and U is given by the following equation.

R2eXp(Jθr2) = Dexp(Jθd
〉x [1+Y exp(j (Ω(To−τ)+S
n (t + T (>-τ0)Sl (t)))
] When Y<1, (20> xYnexp(j nα2 > n · In the case of equation (21), unlike equation 18), it is clear that everything after the second term on the right side becomes an interference output. (
As is clear from the right side of Equation 18> or Equation (21), the signal component θd of the first term is independent from the second term and subsequent terms that give a change in phase due to the delay time. This excludes the fact that the frequency components of the demodulated signal can be separated by a filter if they differ from the phase change due to the delay time.

By the way, the frequency components after the second term on the right-hand side of equation (21) are related to the moving speed of the mobile radio 100, the frequency used, and roughly the topography and features. It is expected that the frequency will be approximately proportional to the frequency (approximately 40Hz).Mobile Radio I!1
If the Doppler frequency takes an order of magnitude higher than the Doppler frequency depending on the state of the surrounding topographical features around which the 00 moves, it would be around 400H2, and even if it shows a more abnormal condition, it can be considered to be less than 1 day Z. Dew.

On the other hand, since the signal frequency components are time-compressed, they shift to a considerably higher frequency band. For example, at the compression rate IQ, the audio frequency is 3 to 30KH2.

Therefore, even if a frequency of 1KH7 or less is added as noise, it can be easily filtered. The higher the compression ratio, the easier this separation will become.

Below, we would like to conduct a stationary study to clarify the multiple radio wave propagation characteristics in TCM-FM waves.

(4) Quantitative study of multiplexed radio wave propagation distortion using specific system examples and countermeasures for propagation distortion removal (4,1) Setting of system parameters What is the practical implementation of the TCM method? 1
The multiwave propagation distortion is determined when the value is changed in three ways: 0, 100, and 1000, and other system parameters are set to values as shown in FIG. Here, T...frame length, T...time slot length, guard time length, n...voice multiplicity. /T...Slot overlap rate T OVR
...Overlap time length T11. ...Under the allowable delay time due to multiple propagation, ...Synchronization pulse time length Td...Data signal time slot length η...Frame efficiency, fC...Carrier frequency fH...Modulation signal frequency.

Md...Modulation depth Standard modulation deviation f(IN... is the modulation signal frequency of the interference wave.

Furthermore, in the above system example, the explanation has been made on the assumption that the radio carrier wave is transmitted only within the time slot, and that the signal is not transmitted during the guard time period.

(4,2) Example of calculating the amount of interference 1) Change in amplitude due to interference Based on the parameters shown in Figure 5, calculations were performed by substituting numerical values into equation (7).The results are shown in Figures 6A and 6B. Here, aIf in FIG. 68 represents the amplitude range.

2) Phase distortion due to interference The phase distortion due to the D wave and V wave mentioned in (3) is (18
Figure 7A is obtained by calculating using the formula and expressing it as S/N. However, since this effect hardly appears in systems 10 and 100, the case of system 1000 was determined.

From the same figure, even if the size of the reflected wave is the same as that of the direct wave (X-1), if the delay time τ is 5 μsec or less, the S/N is
It can be seen that more than 30 dB is secured, but 10. us
When it exceeds ec, it gradually decreases to 25d at 15μsec.
It will be about B. This means that as τ increases in equation (19) above, the useful signal component decreases.

When the interference between the D wave and the adjacent time slot wave is calculated as S/N, Figure 7B is obtained. From the figure, even if an interference wave with the same amplitude as the own signal is superimposed due to delay (
Y=1>, if the delay time is 15μsec or less, S
It can be seen that 20 dB is secured as /N.

(4, 3) Measures to remove propagation distortion between time slots within the same radio channel Measures to remove or reduce phase distortion between time slots within the same radio channel of TCM-FM signals will be described below.

In general, the generation of multiple waves received when radio waves propagate in land space occurs through the following mechanism.

The land mobile propagation path becomes a multiwave propagation path because it is subjected to nine reflections, two diffraction, two losses, etc. due to the topography and terrestrial objects around the mobile radio device 100. In this case, a large number of radio waves arriving from various directions interfere with each other around the mobile radio device 100, forming a random standing wave electromagnetic field distribution. The arriving waves may also include reflected waves from other mobile radios traveling nearby, or they may be so small that they can be ignored. The mobile radio device 100 moves through such a standing wave electromagnetic field distribution.
As the wave moves, the envelope and phase of the received wave fluctuate randomly as shown in FIG. 6A. a in the figure is the amplitude of the standing wave.

According to actual measurement results published in academic papers and the like, the delay time of the above reflected waves relative to the direct waves is
00 is several tens of meters to 100 meters at most, and the maximum distance is 0.5 μsec, and when driving in a city using a car phone, it is about 1 to 2 μsec.

However, in suburban areas, especially in areas with mountains and hills such as basins,
Values of 10-20 μsec have been reported.

Applying the above actual measurement results to the system of the present invention enables extremely rational design as follows. Among the systems having the various parameters shown in FIG. 5, system 1000 will be described as an example.

In this system 1000, the guard time length Tg is 1
Since the time is set to 0 μsec, there is no problem with indoor cell phones or car phones in the city. However, further improvements are required for effective frequency utilization.

On the other hand, when a car is driving in a suburban area such as a mountainous area, it is subject to interference from delayed waves from adjacent time slots.

Now, there is a convenient mobile radio that can not only be used indoors or anywhere inside a large building, but also be able to make and receive calls outdoors on the road, and even be carried into a car. Suppose that it is possible to communicate with a wireless base station installed on the roof of a building or on a pillar on the road side without the aid of a wireless device. In such a system, TCM-F
We will explain how to select the guard time of M to make it possible to construct a system that has high frequency utilization efficiency and is resistant to interference.

It is clear that the narrower the guard time, the better, if only to improve the effective utilization of frequencies. This is because if the sum of the guard time within one frame and the time slot for transmitting the signal is constant, the time compression rate of the signal is the smallest when the guard time is zero, so the modulated signal The highest sideband frequency is the smallest, and if the proportion occupied by the guard time is increased to 50% of the total, the highest sideband frequency will be doubled.

However, if the guard time is set to zero, it is inevitable that delayed waves due to multiple waves will enter adjacent time slots, making it unusable.

On the other hand, from the viewpoint of eliminating interference, the larger the guard time, the better.

FIG. 2D shows an example of means for solving the above two contradictory matters. That is, in the figure, the time slots accommodated in one frame are divided into several groups, and the guard time of the time slots belonging to one group is 1μ5eC1 belonging to another group. Set guard time of time slot to 5
μsec, and other values are set to 10.20 μsec.

On the other hand, in the mobile radio device 100 or the radio base 830,
An interference detector 162 shown in FIG. 1B is installed,
When it is detected that interference has occurred, the call time slot is sequentially changed to a slot with a larger guard time. With such a system configuration, as mentioned above, it can be used indoors.

The mobile radio device 100, which can make and receive calls, can be used without interference even when carried anywhere on the road or in a car.

The above description is based on the fact that the standard modulation deviation Md of the frequency of FM modulation in the system according to the present invention is shown in FIG.
This was a small case of 1.75 rad (rms). However, in the present invention, this can be made considerably large, and in that case, there is almost no need to take the guard time, which will be explained using FIG.

FIG. 8 is a calculation result showing co-channel interference D/U (desired signal to interference signal ratio) and S/(signal to noise ratio) using modulation deviation Δf as a parameter. , shows the relationship between D/U and S/ when the standard modulation deviation Md in FIG. When using this for inter-time slot interference, it is important to consider the case where the adjacent time slot completely overlaps with its own time slot. Figure 8 shows that the same D/U is, for example, D/U=1.
When compared at 0d13, the modulation deviation amount △f is 0.875r
ad (rms), the D/U was about 20 dB, but every time the modulation deviation amount Δf doubles, the S/
This shows that the address to B is improving.

Therefore, it can be seen that instead of increasing the guard time to remove or reduce phase distortion, the same effect can be obtained by increasing the modulation deviation amount Δf.

In particular, when the modulation deviation amount Δf is set to 20 times (26 dB) or more the standard modulation deviation Md in FIG. 5, the guard time becomes
In many systems, it is almost unnecessary.

(4,4) Measures to prevent interference between adjacent (next adjacent) zones
In some cases, the same radio channel is used in the next adjacent zone, etc., and a method for preventing co-channel interference that occurs in this case will be explained.

First, it is assumed that the standard modulation deviation Md is small, as shown in FIG.

Co-channel interference occurs when the present invention is applied to a small zone system, and radio waves from the same radio channel used in another zone, which is located in a different location, mix into the radio channel being used in a certain radio zone. This occurs due to

In FIG. 9A, a small zone covered by each wireless base station 30 is shown as a regular hexagon, and each wireless base station 30 is located at the center of the small zone.
is located. In this example, each of the radio base stations located in zone numbers 1 to 3 shown within the thick line frame uses a different radio channel, and the number of repetitions is 3.

In FIG. 9A, when the distance between two wireless base stations 30 that use the same wireless channel (the shortest distance from the center of regular hexagon 1 to other regular hexagons 1) is d, the allowable distance is d. It is necessary to find the value of D/U (value of the ratio of desired wave input level D to interfering wave input level U).To do this, it is necessary to determine the frequency used for the system, the transmission output (size of the wireless zone), Once the radio wave propagation state is known, the D/U value can be determined.In conventional analog systems, the interference value is known for the D/U value obtained in this way;
In the present invention, the modulation mechanism is completely different, and in general, even if the allowable D/U value is smaller than that of the conventional system, communication quality equivalent to that of the conventional system can be ensured. However, we will not go into this here; A radio channel interference prevention method is explained.

If it is assumed that co-channel interference does not occur in the arrangement of the radio base stations 30 shown in FIG. 9A, each radio base station 30 located at the center of all the hexagonal small zones shown in FIG. Even if several radio channels are arranged, no interference will occur if time slots are allocated as shown in FIG. 10A.

This is because in Figure 10A, all wireless bases J
i430-1.2. In 3 and 3, it is assumed that frame synchronization (time slot synchronization) is performed, and the transmission time of each time slot is as follows:
m+1, at the wireless base station 30-2, SC2, SC5, .
-----, SC3m+2, S at wireless base station 30-3
It is limited to C3, SC6, . Therefore, if co-channel interference occurs, it is a signal from the next adjacent radio base station 30, and this is exactly the same format as that transmitted from the radio base station 30 with the number of repetition zones 3 described above. The above description has been made regarding the case where the radio base 830 transmits, but it also applies to the case where the mobile radio 11100 transmits. It is the opposite wireless base station 3
This is because the same time slot number as 0 is used, so the conditions regarding radio interference are almost the same.

If, due to system design conditions, repeating 3 zones as shown in Figure 9A causes co-channel interference, increase the number of repeating zones as shown in Figure 9B, for example, 7 zones. You can use repetition. In this case, when all the radio base stations 30 use the same radio channel, the time slot arrangement in the radio zone of the radio base station 30 is as shown in FIG. , SD8.・----, SC7m+1,
In radio zone 2, time slot SD2°SC
In radio zone 7, time slots SD7, 5D14°, SC7m+7 are used.

In the above explanation, the influence of multiple wave propagation explained in section (4, 3) was not taken into account. Since this cannot be ignored in an actual system, the time slot arrangement will be explained in consideration of this. As already explained in Section (4, 3), in order to avoid the effects of multiple wave propagation, it is sufficient to provide a guard time, so if this is incorporated into the time slot arrangement in Figure 10A, the result will be as shown in Figure 10C. It becomes like that.

That is, the guard time Tg is set at the transmission time timing of SDI and SC2, SC2 and SC3, SC3 and SDl.
will be established. Although the specific value of the guard time varies depending on the system conditions, 0.2 μS to 10 μsec may be sufficient.

The above description is based on the fact that in the system according to the present invention, the standard modulation deviation Md of the frequency of FM modulation is shown in FIG. 5<1.
This was a case where the speed was as small as 75 rad (rms).

However, in the present invention, this can be made considerably large, in which case there is no need to take guard time.
Conversely, it is even possible to take an apparently negative card time.

FIG. 10D shows the time slot arrangement when the guard time Tg is negative. That is, in FIG. 10D, the guard time Tg between time slots SD1 and SC2 is negative; During the period, two wireless base stations, for example, 3
This means that signals in time slots 0-1 and 30-2 may be being sent. The zone configuration in this case is an example of a three-zone configuration as shown in FIG. 9A. For example, two signals with different contents from adjacent radio base stations 30-1 and 30-2 are transmitted at adjacent times. However, the two time slots partially overlap, and the mobile radio device 100 that receives it is located in the vicinity of the service zone of the two radio base stations 30-1 and 30-2. Even if the radio base station 30-1 is in communication with the radio base station 30-1, the signal time within the time slot occupies a large portion of the signal time only from the radio base station 30-1 that is communicating with the radio base station 30-1. If so, the wireless base station 30
This means that mobile radio R100 communicating with R100 is capable of communication of better quality than that required by the system.

The physical reason for this is that the amount of modulation shift is large, similar to the case of co-channel interference shown in FIG.

However, in the signal demodulation stage after receiving the signal, some consideration must be given to signal processing, and if the interference is large, it may be necessary to perform time slot switching within the same zone. However, these are possible with existing technology. The reason for providing a negative guard time is that the guard time has already been set.
As explained in the time setting section, this is done to improve the effective utilization rate of frequencies.

Further, the present invention is also applicable to a system in which the radio base station 30 and the mobile radio device 100 use the same radio frequency (so-called ping-pong transmission system), and all available frequency bands are used for ping-pong transmission. in case of,
The frequency utilization efficiency is maximized.

[Effect of the invention] As is clear from the above explanation, the mobile communication system,
In particular, by applying the present invention to a so-called small zone system in which a service area is configured by covering a plurality of zones, it becomes possible to eliminate the effects of co-channel interference and phase distortion due to multi-wave propagation. , it has become possible to construct a system with higher frequency usage efficiency than conventional systems. When radio interference occurs, time slot switching within a single channel within the same radio zone is possible without any adverse effect on the signal and without momentary interruption, so the effects of the present invention are extremely significant.

[Brief explanation of drawings]

Fig. 1A is a block diagram showing the connection relationship between the gateway exchange, telephone network, and radio base station in the system of the present invention, Fig. 1B is a circuit block diagram of a mobile radio device used in the system of the present invention, and Fig. 1C 2A is a circuit configuration diagram of a wireless base station used in the system of the present invention, FIG. 2A is a time slot structure diagram for explaining time slots used for transmission of time division time compression multiplexed signals, and FIG. 2B 2C and 2D are time slot structure diagrams for explaining the time slots used in the system of the present invention, and FIGS. 3A and 3B are waveform diagrams showing the radio signal waveforms of time slots. is a spectrum diagram showing the spectrum of a call signal and a control signal, FIG. 3C is a circuit configuration diagram for multiplexing a voice signal and a data signal, and FIGS. 4A and 4B are a flowchart of a calling operation of the system according to the present invention. Flowchart, FIG. 5 is a parameter number one direct diagram showing examples of various parameters used in a time division time compression multiplex communication system, FIGS. 6A and 6B are amplitude change diagrams showing changes in amplitude due to multiple wave propagation, Figures 7A and 7B are S/N diagrams representing S/N due to multiwave propagation distortion; Figure 8 is an S/N diagram representing S/N with respect to changes in D/U using modulation shift as a parameter; 9A and 9B are configuration diagrams showing a small zone configuration to which the present invention is applied, and FIGS. 10A, 108, 10C, and 10D are time slot configuration diagrams using a single radio channel. be. 10... Telephone network 20... Gateway switchboard 22
-1 to 22-n...Communication signal 30...Radio base station 31...Signal processing section 32
... Wireless transmission circuit 34 ... Transmission quality monitoring section 35
...Radio receiving circuit 38...Signal speed restoration circuit group 38-1 to 38-m...Transmission speed restoration circuit 39...
Signal selection circuit group 39-1-39-m...Signal selection circuit 40...Control section 41...Clock generator 42...Timing generation circuit 51...Signal speed conversion circuit group 51-1... 51-m...Signal speed conversion circuit 52...
Signal assignment circuit group 52-1 to 52-m...Signal assignment circuit 91...-Digital encoding circuit 92...Multiple conversion circuit 100.100-1 to 100-n-...Mobile radio device 10
1...Telephone unit 120...Reference crystal oscillator'
121-1.121-3...Synthesizer 122-1
, 122-2...Switch 123-...Transmission/reception intermittent controller 131...Speed conversion circuit 132...Wireless transmission circuit 133...Transmission mixer 134...Transmission section 135
... Radio reception circuit 136 ... Reception mixer 137.
...Receiving section 138...-Speed restoration circuit] 41.
. . . Clock regenerator 158 . . . - Reception quality monitoring unit 162 . . . Interference detector.

Claims (1)

[Scope of Claims] Each radio base means (30) each covers a plurality of zones and constitutes a service area, and a timer for moving across the plurality of zones and communicating with the radio base means. - Each mobile radio means (100) using a radio channel carrying time-compressed and segmented signals in slots.
In a mobile communication system using barrier exchange means (20) for exchanging communications between A time division communication system for mobile communications in which each of the radio base means uses a different time slot.