JPH03210839A - Time division communication system for mobile object communication - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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, a certain radio channel is given, and a wireless link is set up and communicated with one of the many mobile radios in the service area or with an opposing radio base station using this channel. In addition, when another mobile radio device requests to communicate using the same radio channel, regardless of the radio wave propagation conditions, communication between the mobile radio device that is already communicating and the radio base station is adversely affected. The present invention relates to a time-division communication system using the same radio channel that makes it possible to set up an independent radio line between another mobile radio device and the radio base station using the same radio channel without having to use the same radio channel.

[Prior Art] In 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. Ito “Study of mobile phone system – Proposal of time-division time compression FM modulation system” IEICE technical report RC389-1
1 Literature dated July 1989 2. Ito "Study of mobile phone system - Theoretical study of hour/minute/11 hour compression degree system" IEICE technical report RC3
89-39 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 this method to small zones, are being investigated.
It has been shown that it is possible to realize a system that eliminates the problems by appropriately selecting system parameters.

[Problems to be Solved by the Invention] However, in the above system construction example, 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 considered 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 communication quality was seriously affected by interference.

[Means for solving the problem] In one frame in which a time-division time compression multiplex signal is transmitted, the size of the guard time set between each time slot is made different, and the wireless base station and mobile 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. When wireless interference occurs due to multiple wave propagation and communication quality deteriorates, the time slot used for communication is automatically shifted to a time slot with a larger guard time, increasing the efficiency of frequency usage. , and made it possible to construct a system that is resistant to interference.

[Operation] A TCM-FM (time-division time compression multiplexing-frequency modulation) signal undergoes multiple wave propagation (multipath fading) while propagating in space, and its amplitude and phase change. If this level is large, the received demodulated signal will have the effect of causing interference as distortion noise or thermal noise. Among these, changes in phase have a particularly large effect, so as a countermeasure, guarding and
A method to prevent the time from increasing has been clarified.

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 an open 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 CH1 to CHn and control signals.

FIG. 1B shows a circuit configuration of mobile radio device 100 that communicates with radio base stations 30-1 to 30-n. 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 output communication signal is received by a speed recovery circuit 138 and a clock regenerator 141. It is input to the 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 section 158 to which a portion of the output of the reception section 137 is applied monitors the reception quality (signal-to-noise ratio and presence or absence of interference) of the input signal. Further, an interference detector 162 is connected to the antenna receiving end in parallel with the input to the receiving mixer 136,
This is used to detect interference with own communication in other systems or within the same system (in the same channel and same time slot used for other communication). This interference detector 162 The presence or absence of interference during communication is monitored, and if a certain amount or more of interference is detected, it is reported 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 also includes synthesizers 121-1 and 1 to enable transmission and reception of 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. 3, the transmission/reception intermittent controller 123, and the timing generator 142,
It is controlled by a control section 140. A reference frequency is supplied from a reference crystal oscillator 120 to each synthesizer 121 and 121-3. 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 22-1 of m channel with gateway exchange 20
22-m are connected to the signal processing section 31 forming an interface through a transmission path.

Now, the communication signal 22- sent from the barrier 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. That is, the input signal and the output signal are mixed and separated, and the input signal from the barrier exchange 11120 is sent to the signal speed conversion circuit group 51.

Further, the output signal from the signal speed restoration circuit group 38 is transmitted to the barrier exchange 20 as communication signals 22-1 to 22-m by the signal processing unit 31 using the same transmission path as the input signal.

Among the above, the input signal from the gate opening exchange 20 is input to the signal speed conversion circuit group 51 including many signal speed conversion circuits -1 to 51-m, and is divided into speeds (pitch) at predetermined time intervals. undergo transformation.

Furthermore, the signal transmitted from the radio base station 30 to the barrier switch 2o is determined by the output of the radio receiving circuit 35 being transmitted from the signal selection circuit group 39.
is input to the signal speed restoration circuit group 38 via the signal speed (
The pitch) converted bond passes through the switch group 83 and is input to the signal processing section 31 .

Now, the control of the radio reception circuit 35 or the output of the call signal is performed by a signal selection circuit 39 that selects a signal for each time slot.
-1 to 39-m is input to the signal selection circuit group 39,
Here, speech signals are separated corresponding to each speech channel, CH1 to CHm.

This output is a signal speed restoration circuit group 3 including signal speed restoration circuits 38-1 to 38-m provided corresponding to each call signal.
8, after the signal speed (pitch) is restored, it is input to the signal processing unit 31, and after undergoing 4-wire to 2-wire conversion, this output is sent to the barrier exchange 2o as communication signals 22-1 to 22-m. 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 the slot.

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 group 51 is the same as when playing back audio recorded by a tape recorder at high speed, and in reality, for example, COD (Char
geCoupled Device), BBD
(Bucket BrigadeDevice> can be used, and the memory used in television receivers and tape recorders that compress or expand the time axis of conversations can be used. (Reference M: Kosaka et al.
“Tape recorder that compresses/expands the time axis of conversations Nikkei Electronics July 26, 1976 92-13
3 pages〉.

The circuit using COD or 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, and in this case, the circuit using COD or BBD as exemplified in the signal speed conversion circuit group 51 can be used as it is in the signal speed restoration circuit group 38. 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.

Control or call signals output from the barrier switch 20 via the signal processing section 31 are input to the signal speed conversion circuit group 51, where speed (pitch) conversion processing is performed and the signals are converted into signals for each time slot. Signal assignment circuit group 52 to be assigned
is applied to The signal allocation circuit group 52 is a buffer memory circuit that stores each section of high-speed signals output from the signal speed conversion circuit group 51, and outputs signals to the timing generation circuit 42 according to instructions from the control section 40.
The signal in the buffer memory is read out using the timing information from and transmitted to the wireless transmission circuit 32. This timing information corresponds to a call signal (is arranged in series with no overlap in time), and if the control signal or control signal and call signal described later are all implemented, it will appear as if it were a continuous signal wave. Like (Naru)

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> SDI, SD2
．． -, SDn indicate that the speed-converted communication signals are allocated to each time slot at the output of the wireless transmission circuits 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 control signal). If the call signal is not implemented, only the synchronization signal is added and the empty slot signal is added to the call signal portion. In this case, in the service zone of another wireless base station 3o in the same system, the same wireless channel, the same time,
In order to avoid causing radio interference to communications using the slots, the signals contained in empty time slots are limited to only the first part of each slot length (for example, about 5% of the total). It is also possible to prevent the remaining radio waves from being transmitted at all. In this way, FIG. 2A (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, Fig. 2A (a)
In ~(b), each time slot is adjacent;
Although it is written that there is no guard time, as will be explained later (see Figure 2D), time slots 5 to 10
% guard time 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, FIG. 3(a) shows an example of an out-of-band signal, and as shown in the figure, there are signals on the low frequency side (250Hz>) and on 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 the mobile radio device 100 is received by the antenna section of the radio base station 30 and input to the radio reception circuit 35. FIG. 2A (b) schematically shows this upstream input signal.

That is, time slot SU1.5LJ2. ...
s u n C indicates transmission signals addressed to the radio base station 30 from the mobile radio devices 100-1, 100-2°, . . . , 100-n. Also, each time slot sui, su2,...
. . , sun in detail. As shown in the lower left of FIG. 2A (b), it consists of a synchronization signal and a control signal or/and a telephone call signal.

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).

Of the input signals that arrive 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 magnitude 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 performing similar processing on the call signal. Regarding the call signal, 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 4o. A synchronization signal, a control signal, or a speech signal is separated and output for each time slot 5tJ1 to Sun. Each of these signals is input to a signal speed restoration circuit group 38. This circuit is a speed conversion circuit 13 in the mobile radio device 100 on the transmitting side.
1 (FIG. 1B), thereby faithfully reproducing the original signal and transmitting it 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 section 40 is applied to the wireless transmission circuit 32 in parallel with the output of the signal allocation circuit group 52. However, depending on the magnitude 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 device 100 also has a circuit configuration required when the radio base station 30 has one communication channel among its functions.

Original signal, for example, audio image @ (0.3KHz ~ 3.0KH
2) passes through the signal speed conversion circuit group 51 (FIG. 1C), the frequency distribution on the output side is as shown in FIG. 3B. In other words, if the audio signal is converted 15 times as described above, the frequency distribution of the signal will be as shown in Figure 3B.
This means that the frequency is expanded to 4.5KHz to 45KHz. The figure shows a case where the control signals are simultaneously transmitted using the lower frequency band of the audio signal. It is assumed that among these signals, a control signal (0.2 to 4.0 KHz) and a speech signal CH1 (4.5 to 45 KHz, expressed as SD1) are accommodated in a time slot, for example, SD1. other time slot S[)2
The same applies to the audio signals accommodated in ~SDn.

That is, time slot SDi (i=2°3, -
, n) accommodate a control signal (0.2 to 45 KHz > and a communication signal CHi (4.5 to 45 K)lz). However, the signals within each time slot are chronological (
The signals in more than one time slot at a time are not applied to the radio transmitter circuit 32 at the same time.

These call signals together with control signals (wireless transmission circuit 32
(if added, the required transmission band is at least fo±45K)-iZ included in the angle modulation section. However, fC is the radio carrier frequency. Here, if there are multiple wireless channels given to the system, the speedup of the signal by the signal speed conversion circuit group 51 is limited to a certain value due to the limitations of these frequency intervals. The frequency interval of the wireless channel is f
,. . If fH is the maximum signal speed resulting from the speed increase of the audio signal described above, the following inequality must hold between the two.

f > 2 f u ``ep'' On the other hand, in digital signals, audio is usually digitized at a speed of about 64 kb/s, so raise the scale on the horizontal axis by about one digit in Figure 3B, which explains the case of analog signals. Although it is necessary to read it, 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. It is sent to the barrier exchange 20.

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 device 100) Start capturing the control signal included in the radio channel (channel CH1). If the system is provided with multiple radio channels, i) radio channel 11 exhibiting the highest received input field;
iii) A radio channel (hereinafter referred to as channel CH1). This is possible by capturing the synchronization signal within the time slot SDi shown in FIG. 2A(a). In the control unit 140, the synthesizer 121-
A control signal is sent to the synthesizer 122-1 to generate a local frequency that enables reception of the radio channel CH1, 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 is off-hook (starts making a call) (3201, FIG. 4A), the synthesizer 121-3 of FIG. 1B generates a local frequency that enables transmission of the wireless channel CH1. A control signal is received from the control section 140 to cause the control to occur.

Further, the switch 122-2 is also turned to the synthesizer 121-3 side and becomes fixed. Next, wireless channel CH1
The call control signal outputted from the telephone unit 101 is sent using the telephone unit 101. 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 if the amount of information in the signal is too large to be accommodated in one time slot, the next frame will be sent after one frame or roughly. Transmitted using the same time slot.

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.
By receiving this, frame synchronization becomes possible. Roughly speaking, this control signal includes control information such as currently used time slots and unused time slots (empty time slot display). Depending on the system, the time slot SDI (+=1.2°...
・When n) is used by other communications,
In some cases, it only contains a synchronization signal and a call signal;
Even in such cases, the unused time slots usually contain a synchronization signal and a control signal, and by receiving this control signal, the mobile radio@100 determines which time slot to use to send the calling signal. It is possible to know whether to send the .

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 audio multiplex signal SDI that follows.

SD2. ..., it is necessary to search for the presence of SDn 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 the uplink signal is an empty slot, it is decided to use this empty time slot, and the call control signal is sent out and the necessary timing is determined from the response signal from the radio base station 30. burst-like control signals can be sent out.

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 further reduced, the following method may be used. If the mobile radio device 100 finds an empty time slot in which it can make a call, it does not use the entire time slot, but rather uses only the first half of the time slot for some mobile radio devices and only the second half for other mobile radio devices. This is a method that allows you to use it. In other words, the time signal is used as a calling signal.
Divide the used portion of the slot into several types, use this to classify a large number of mobile radio devices into groups, and place one of the slots in each group.
This method gives the time period within one time slot.

Another method is to create many different frequencies for the control signal,
This is a method of dividing a large number of mobile wireless devices into groups and applying this 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 (3202). Find the time slot in which you are. The time slot given to the mobile radio device 100 may be Sun, but a search is performed just to be sure. It is mobile radio 11
100, it is also used to accommodate simultaneous calls from other mobile radios, and to provide time slots suitable for service types and service classifications.

As a result, if the time slot SD1 is vacant, for example, the time slot SD1 of the radio channel CHI is used for the mobile radio device 100, and the time slot uplink (mobile radio device 100 → radio base station 30 )SLll.

and instructs to use the corresponding downlink (radio base station 30 → mobile radio device 100) SDl (3203
>. In response, the mobile radio 11100 transitions to a state in which it can receive data in the designated time slot SD1, and at the same time, it shifts to a state in which it can receive data in the designated time slot SD1, and at the same time, the mobile radio 11100 shifts to a state in which it can receive data in the designated time slot SD1, and at the same time, the mobile radio 11100 shifts to a state in which it can receive data in the designated time slot SD1.
(See Figure A (b)). At this time, the mobile radio 110
In the control unit 140 of 0, the transmission/reception intermittent controller 123
, and switches 122-1 and 122-2 start operating (3204). At the same time, it sends a slot switching completion report to the wireless base station 30 using uplink time slot SU1 (5205>) and waits for a dial tone (5206>).

Time slot SU of the radio carrier of this upstream radio signal
The state of No. 1 is schematically shown in FIG. 2B (C). In addition to the time slot SU1, the radio base station 30 receives an uplink signal SU3 and Sun included in one frame from another mobile radio l1j1100.

The radio base station 30 that has received the slot switching completion report (
S207), the calling signal is sent to the barrier exchange 1fi20 (3208), and the barrier exchange 1120 that receives this detects the ID of the mobile radio 1100 and selects the necessary switch from the switch group included in the barrier exchange 1120. Turn it on (S209>, and send out a dial tone (S210)
, Figure 4B).

This dial tone is transferred by the wireless base station 30 (S211>, and the mobile wireless device 100 confirms that the communication path has been set (3212>).

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 SL+1 (3213>).

Thus, the transmitted dial signal is received by the radio receiving circuit 35 of the radio base station 30. This radio base station 30 has already responded to the calling signal from the mobile radio 100,
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 SD1. Therefore, the dial signal transmitted from the mobile radio l11100 is transmitted to the signal selection circuit group 39.
After passing through the signal selection circuit 39-1, the signal is input to the signal speed restoration circuit group 38, where the original transmission signal is restored, and transferred to the gateway exchange 20 as a call signal 22-1 via the signal processing section 31. (3214>, a call path to the telephone network 10 is set (S215>).

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
1 to the mobile radio 1J1100.

The mobile radio device 100 is waiting for reception in the time slot SD1 of the radio channel CH1, and is received by the radio reception circuit 135, the output of which is sent to the speed recovery circuit 138.
is input. 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 11100 and a regular telephone within the regular telephone network 10 (S216>).

The call is terminated by turning on the receiver of the telephone unit 101 of the mobile radio device 100 (5217), and the end of the call signal and the on-hook signal from the control unit 140 are transmitted to the speed conversion circuit 1.
31 from the wireless transmission circuit 132 to the wireless base station 30 (8218>), and the control unit 140 stops the operation of the transmission/reception intermittent controller 123 and switches the switches 122-1 and 122-2 to the synthesizer. It is fixed to the output ends of 121-16 and 121-3.

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 (3220>. 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 are exchanged between the radio base station 30 and the mobile radio device 100 by the signal rate 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) Mobile radio I! It is assumed that the mobile radio 100 receiving the call to 1100 is on standby with the power turned on. In this case mobile radio I! As explained in the section regarding the call origination from 1100, the mobile station is in a waiting state to receive a downlink control signal of the wireless channel CH1 according to the procedure defined by the system.

Gateway exchange from general telephone network 10! Assume that an incoming call signal to the mobile radio 100 arrives at the radio base station 30 via the mobile radio 120. These control signals are transmitted as communication signals 22 to the control unit 40 (FIG. 1C) via the signal rate conversion circuit group 51 and the signal allocation circuit group 52, similarly to the voice signals. Then, the control unit 40 uses an empty slot among the downlink time slots of the radio channel CH1 addressed to the mobile radio device 100, for example, SDl, to determine the ID of the mobile radio device 100.
Signal 10 Incoming call signal display Signal 10 Time slot usage signal (
For example, SDI is used for transmission from the mobile radio II1100.
(using SUl corresponding to ).

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. The control unit 140 transmits this signal to its own mobile radio 111.
To confirm that it is an incoming call signal to 00, telephone section 1
At the same time, the switch 122 operates the transmission/reception intermittent controller 123 to stand by at the designated time slots SD1 and SU1.
-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 performed in good condition using this system and does not adversely affect other wireless channels in the system, so it is 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 TCM-FM waves affected by multiplex radio wave propagation (3,1) Effects of multiplex radio wave propagation on TCM-FM waves Figure 2C (a> is transmitted from the wireless base station 30 TCM
- FM (time division time compression multiplexing - frequency modulation) wave is a schematic diagram showing the wave. Figure (b) shows a mobile radio l located far away.
11 is a schematic diagram showing the waveform of a signal wave received by the l1100. 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 In addition to S1,
You will receive the following unnecessary signals at the same time.

i) Signal sl (t-τ1) (τ1<t<T) of signal @S1 delayed by time T due to multiple reflections; ii) Signal component S of time slot SDn immediately before time slot SD1. The interference signal S, (j+T□−τ.) (Q<t<τ.), is delayed by time τ1, exceeding the guard time and falling into the time slot SDl. This is similar to echo distortion in the FM system, and includes components that become echo distortion and a useful signal that differs only in phase from the original signal, but ii) is an extremely harmful signal. It is necessary to pay attention to

(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.

1 D(t) = '()in[1 -1・+2 Σ n (mπ) sin (mπn-
1) m=1 n-1) mp t ] X5in (Ω1↑+51(
t)>(1) However, IOI is the magnitude of the amplitude, Ω1 is the carrier angular frequency,
s and (t) indicate signals (including control signals). 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 wave represented 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, the TCM waves transmitted from the radio base station 30 are expressed as
The desired wave when received at 0 - this can be thought of as a direct wave - is D, and the reflected wave affected by multiple radio wave propagation is generally a combination of many reflected waves. The echo wave■, TC transmitted from the same wireless base M30
Among the M signals, a signal in an adjacent time slot that has undergone propagation delay and falls within its own time slot is referred to 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 time-dominant interval of the TCM wave is appropriately selected, the desired wave D, echo wave V, and interference wave U can be expressed as in the following equation.

Desired wave [) sin θ6 = DS! 11 (Ωj + 51(1
)) (2) <nTt≦t≦T+nTt) Echo wave Vs+n θ8=Vsin (Ω(t-τ1) +s (-τ)) (3) 1 (τ +nTt≦t≦(n+1) Tt) Interference wave U sinθu = U sin (Ω(t+To-
τ1) + S n (t + T (>-τ1)) (4
) (nTt≦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 Equation (4) may be strictly different from τ1 in Equation (4), it may be allowed on the assumption that they are adjacent time slots and have equal delay times.

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.

−81(t> ) ]1/2xsin (θd+φ1)
(5) φ, = jan' [(-XSin (Ωr+81
(t)st(t-τ) ) )X (1+Xcos (
Ωτ+s 1 (t) Sl (t − τ)
) ) −'] (6) However, X=V/D In other words, the amplitude envelope is R1=D [1+X +2XCOS (Ωτ+S1 (t)1/2 −s1 (−τ))] = D (1+x2 > 1/2 x (1+2Xcos 1411) "2(7) ψ1-Ωτ+51 (t) 51 (t-τ)(8
) Next, the composite wave of equations (2) and (4) is given by the following equation.

R2S! nθ, 2=Dsinθ6+Usinθ.

-D[1+Y2 +2Ycos ((T(>-τ1)Ω +S, (t+To-τ1) -5(t))]""xsin(θd+φ2) (9) φ2 = jan' [(Ysin (Ω(To-rl)
)+S, (t+To-τ1)-8, (t))X(1+
YCO3(Ω(To-τ1) + S, (j + T□-τ1) -s (t)))'] (10) However, Y-U/D is noted in equation (7) or (9) This is the case where the value within the square root is O1, that is, the signal is suppressed due to the influence of interference waves. 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 by a factor of two. 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 D, ■, or U waves as vectors.

First, the D wave is DeXI)(jθ, 1) −DeXD(j (Ωt
+51 (t) ) ) (11) Similarly, from equation (3) or (4), v and U waves are vex
p(jθ, ) −V exp[j (Ω(t−rl)
181 (−τ1))] (12) Uexp(jθ.) −Ll eXI)[j (Ω(t
+T0-τQ)+S, (t+To-τ1))](13
), so the instantaneous phase θr1 . of the composite vector of v, D and U can be expressed as follows. Find θr2.

First, for D and V, RleXD(Jθ, ) −DeXl) (jθd)
x [1 +
-○, 1 + I□gloo[1 +X exp(j (-Ωt+S1 (t-41))
) ] (15) Xku1, 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) becomes as follows. .

X n exp (j nα1 ) Xn5in nα1 (16) Here, α1=−Ωτ1+51 (−τ1) (17) Expanding the right side of equation (16), (18) The first term is an effective signal component, and the second term and subsequent terms seem to be interference outputs, but in reality, the second term, that is, X5in α1=X5in(-Ωτ +51(j-τ)) (19) is equal to Contains signal components for radicals. This will be explained in the numerical calculation example section below. Similarly, the instantaneous phase θ,2 of the combined vector of D and U is given by the following equation.

R28XE) (jθr2> −o exp (jθd)
x [1+Y exp(j (Ω(To-τ)+S
n (j + T ()-τ0)-8, (t)))]
(20) When Y<1, τ1)51(t>(2
2) 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 θ of the first term.

is independent from the second and subsequent terms that give a change in phase due to delay time. This means that the frequency component of the demodulated signal is
If it is different from the phase change due to the delay time, this shows that it can be separated by a filter.

By the way, the frequency components after the second term on the right side of equation (21) are related to the moving speed of the mobile radio device 100, the operating frequency, and roughly the topography and terrestrial features. It is expected that the frequency will be approximately proportional to 40 Hz). Mobile radio! I1
If the Doppler frequency takes a value one digit larger than the Doppler frequency depending on the state of the surrounding topographical features that move, it would be about 4008Z, and even if an abnormal state higher than that is shown, it would be 1K.
It can be considered to be less than H2.

On the other hand, since the signal frequency components are time-compressed, they shift to a considerably higher frequency band. For example, at a compression rate of 10, the audio frequency is 3KH2 to 30KH2.

Therefore, even if a frequency of 1KH2 or less is added as noise, it can be easily filtered. The higher the compression ratio, the easier this separation will become.

Below, we will conduct a quantitative study to clarify the multiplex radio wave propagation characteristics in TCM-FM waves.

(4) Quantitative study of multiplexed radio wave propagation distortion using a specific system example and countermeasures for propagation distortion removal (4,1) Setting of system parameters Since no TCM method has been put into practical use, the number of multiplexes n is 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 To/T...inter-slot overlap rate TOVR
...Overlap time length T ALD...Delay time tolerance due to multiplex propagation■,...Synchronization pulse time length Td...Data signal time slot length η...Frame efficiency, fo... Carrier wave frequency fH...Modulation signal frequency.

Md...Modulation depth Standard modulation deviation fUN...Modulation signal frequency of interference wave It is.

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

2) Phase distortion due to interference The phase distortion due to D wave and V wave already mentioned in (3) is (18
) and expressed as S/N, Figure 7A is obtained. 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 difference 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 30dB or more is secured, but 10μse
When exceeding c, it gradually decreases to 25 dB in 15 μsec.
It will be about. 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. The figure shows that even if an interference wave with the same amplitude as the own signal is superimposed due to delay (
Y=1>, S/N if delay time is 15 μsec or less
It can be seen that 20 dB is secured.

(4, 3) Measures to remove propagation distortion Measures to remove or reduce the phase distortion of the TCM-FM signal 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 multiple wave propagation path because it is subjected to reflection, double diffraction, scattering, 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 include reflected waves from other mobile radios traveling nearby, but the amount is small and 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 wave relative to the direct wave is
The distance between the 1100 and the
The maximum time is about 0°5 μsec, and when driving in a city using a car phone, it is about 1 to 2 μsec. However, values of 10 to 20 μsec have been reported in suburban areas, especially in areas with mountains and hills such as basins.

When the above actual measurement results are applied to the system of the present invention, an extremely rational design is possible. Among the systems having various parameters shown in FIG. 5, system 1000 will be taken 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 can also make and receive calls outdoors on the road, and can even be carried into a car. Assume 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 help of other wireless devices. 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 1 μsec, and the guard time of the time slots belonging to one group is 1 μsec. The guard time of the time slot to which it belongs is 5 μsec.

In addition, other values are set to 10.20 μsec.

On the other hand, in the mobile radio device 100 or the radio base station 30,
An interference detector 162 shown in FIG. 1B is installed,
When it is detected that interference has occurred, the call time slot is changed sequentially to a slot with a large guard time. With such a system configuration, k, indoors as described above.

It becomes possible to use the mobile radio m''+oo, which can make and receive calls, without interference even if it is carried anywhere on the road or in a car.

It will be explained that the control signal used in the present invention exhibits strong resistance even if radio interference occurs due to other communication while the mobile radio device 100 is talking in a certain radio zone, and at the same time avoids interference. Therefore, within the same zone (time and
A method for implementing slot switching will be explained.

It is assumed that the mobile radio 111100 is communicating using time slot 301°SU1 belonging to group 1 with a short guard time length Tg. At this time, it is assumed that the interference detector 162 of the mobile radio *ioo shown in FIG. 1B detects interference based on multiple wave propagation.

Then, the mobile radio device 100 uses the out-of-band control signal of the call signal to determine the guard time length T for the radio base station 30.
g is long, e.g., reports that switching of a certain time slot in group 2 should be performed.

Here, even though the audio signal within each time slot is considerably degraded by radio interference, the control signal within the same slot is highly resistant to this. Therefore, various measures have been taken to make tone signals and digital signals less susceptible to interference, such as using low-speed data, error correction, and retransmission.

In the event that the control signal from the wireless base station 30 becomes completely unreceivable, this fact is reported using the control signal in the upstream time slot SU1. Then, the radio base station 30 stops transmitting the call signal, and transmits an instruction to the mobile radio 11100 in the time slot SD1 in the form of a control signal that is easy to receive by the mobile radio 11100. This signal can be easily received by mobile radio 111100 even if it is under interference.

Now, the radio base station 3o, which has received a control signal notifying the occurrence of interference from the mobile radio device 100 or has itself recognized the occurrence of radio interference, is currently using the guard time length Tg within the same radio channel. groups longer than those of
For example, when we investigated whether there was an empty time slot in group 2, we found that the time slot SDI was 2,5LJI.
2 is found to be usable (Fig. 2D(a)).

(see (b)). Then, the mobile radio device 100 is instructed to transmit and receive using this.

Therefore, the control unit 140 of the mobile radio 100 changes from the state in which the synthesizer 121-1 was used to receive the transmission wave from the radio base station 30 in the time slot SD1 of the channel CHI to the state in which the same signal is received. The timing generator 142 and the transmission/reception intermittent controller 123 are instructed to enable reception of the incoming time slot 5D12.

When the radio base station 30 emits a transmission wave in time slot 5D12, the mobile radio device 100 changes the operation of the transmission/reception intermittent controller 123 to transmit the transmission wave to the radio channel CH1.
Using the time slot sU1 of the wireless base station 30-
From the state where it was transmitting to CH1, the time of channel CH1
The slot 5U12 is brought into a state where the same signal can be transmitted. Thus, time slot SUI
.

SUL2. During this switching transmission/reception period in which SDl and SDI 2 are transmitted and received in parallel, channel CH
The process continues until the radio base station 30 confirms that the quality of the time slot 5U12 of CH1 is at a certain level 12 or above, and then releases the channel CHI time slots SD1 and 5L11. , communication continues without momentary interruption only by time slot 5D12.5U12 of channel CH1.

The switching frequency f of the changeover switch 122-1 or 122-2 during this switching transmission/reception period should be twice the value before the start of the switching operation.

That is, if the number of time slots in one frame included in the wireless channel CHI is the time interval tT1 of 011 time slots, then f - (nT1>-'X
It is given by 2.

FIGS. 88 to 8E are flow charts showing the flow of operations when switching channels when co-channel interference occurs during a call in the system shown in FIGS. 18 to 1C. ing.

Opening exchange! 1120. The radio base station 30 and the mobile radio 100 start operating, the switch group included in the barrier exchange 120 is on, and the radio base station 30 and the mobile radio 111
Communication is in progress with 00. For this communication, a radio channel CH instructed by the control unit 40 of the radio base station 30 is used.
I time slot SD1.5L11. Downlink frequency F
1 and upstream frequency f1 are used (S351, 8th A
figure).

The mobile radio 1l11 is constantly connected to the radio base station 30 in communication.
A reception status report from 00, for example, a report indicating that reception is not possible due to fading or interference, is issued by a control signal in each time slot used for communication (S352), and is received. In the radio base station 30, the transmission quality monitoring unit 34 (this is the mobile radio 1l
Reception quality monitoring unit 158 and interference detection unit 16 of 1100
2) and determines whether to perform busy zone switching or time slot switching within the same zone. If the cause of unreceivable reception is a drop in the received electric field (3353 YES), the process shifts to a separately determined busy zone switching operation (3353 YES).

If the cause of the inability to receive is not due to a decrease in the received electric field (3353 NO>), it is checked whether it is due to co-channel interference (S354, Figure 8B), and it is determined that it is necessary to change the time slot within the same channel.5355 ), reports to the wireless base station 30 that it should change to a communication channel or another time slot due to interference using a control signal outside the band of time slot 5L11 (3
356). Therefore, the control unit 40 of the radio base station 30 that received this (S357) determines that there is co-channel interference (interference in the same time slot) (S354).
YES), the presence or absence of an empty time slot is searched and the time slot SDI 2,5U12 is determined (33
5B>. The control section 40 controls the transmission section 13 of the mobile radio device 100.
2 and the receiving unit 135 to prepare for communication in time slot 12 of channel CH1, that is, 5D12, 5U12 (5359, FIG. 8C). This command is sent by a control signal outside the band of time slot SDI, and the mobile radio 11100 receives this communication preparation command (3360) in channel CH1° time slot SD12. Preparations are made to enable communication by SUL 2, that is, the control section 140 causes the transmission/reception intermittent controller 123 to enter an operation that also uses time slots 5D12 and 5U12 (S361).

On the other hand, the wireless base station 30 also uses time slot SD1.
12. In order to prepare for parallel communication by SU1 and SU12, signal selection circuits 3B-1 and 38-2 of signal selection circuit group 38,
Signal speed restoration circuit 3B-1 of signal speed restoration circuit group 38,
38-2, the signal speed conversion circuits 51-1 and 51-2 of the signal speed conversion circuit group 51, and the signal allocation circuit group 52
The control unit 40 instructs the signal processing unit 31 to receive the signals in parallel by the signal allocation circuits 52-1 and 52-2 (33
62).

When the mobile radio 100 is ready to communicate using time slots 5D12 and 5U12 of channel CH1, the mobile radio! The l1100 reports the completion of preparation to the wireless base station 30& using the out-of-band control signal of the time slot SU1 (S363). The radio base station 30 that received this report transmits the time slot SDI 2.
Preparation for parallel transmission and reception by SUl 2 is complete 3364
), starts parallel transmission and reception (3365, Figure 8D). That is, 5D12 sends a communication signal including an ID signal, and the mobile radio device 100 receiving this communication signal (S3
66) , time slot 5D1 addressed to the wireless base station 30
2 signal is good (after confirming that it was received) (S36
7), a confirmation signal is transmitted by the control signal of time slot 5L112 (S368); At the wireless base station 30,
Upon receiving this report (3369), the transmission quality of time slot 5U12 is checked by transmission quality monitoring unit 34 (S370), and time slot SD1.5LJ1 between radio base station 30 and mobile radio device 100 is The mobile radio device 100 is commanded to stop the communication being carried out using the mobile radio device 100 (337
1, Figure 8E). No movement after receiving this! ! 11100
Then (8372), time slot SD1. Communication by SU1 is turned off (S373). That is, the control unit 140 controls the transmission/reception intermittent controller 123 to operate only the time slot SD12°5U12, and also operates the time slot 5tJ1. An SDI communication stop report is sent using time slot 5L112 of channel CH1 (S374). Wireless base station 3 that received this
0 (S375), the own station executes similar measures (3
376).

This ends the period of channel switching operation, and the mobile J! ! 1150 can continue communication with the wireless base station 3o without momentary disconnection or noise mixing (3377).

In addition, when changing the time slot during a call as described above, how large the amount of interference has to be before changing the time slot is as follows:
This is important for system operation and has a great impact on the effective use of frequencies.

In other words, it is clear that if slot changes are not made even if a small amount of interference occurs, the effective use of frequencies will be increased. When determining the vam of this operation, the already explained FIGS. 7A and 7B provide very useful data. Using the graphs in these figures, it is possible to change the time slot at the S/N value within the limit allowed by the system.

[Effects of the Invention] As is clear from the above explanation, by applying the present invention to a mobile communication system, it becomes possible to remove the influence of phase distortion due to multiple wave propagation, and it is more effective than the conventional system. It has become possible to construct a system with high frequency usage efficiency. When radio interference occurs, time slot switching within the same channel within the same radio zone is possible without any adverse effect on the signal and without any interruption, so the effects of the present invention are extremely large.

[Brief explanation of drawings]

FIG. 1A is a block diagram showing the configuration of a barrier switch and the connection relationship with a telephone network and a wireless base station in the system of the present invention; FIG. 1B is a circuit diagram of a mobile radio device used in the system of the present invention; Figure 1C is a circuit configuration diagram of a wireless base station used in the system of the present invention; Figure 2A is a time slot structure diagram for explaining time slots used for transmission of time division time compression multiplexed signals; 2B is a waveform diagram showing the radio signal waveform of a time slot, FIGS. 2C and 2D are time slot structure diagrams for explaining the time slot used in the system of the present invention, and FIGS. 3A and 2D are time slot structure diagrams for explaining the time slot used in the system of the present invention. Figure 3B is a spectrum diagram showing the spectrum of the call signal and control signal, Figure 3C is a circuit configuration diagram for multiplexing the voice signal and data signal, and Figures 4A and 4B are the flow of the calling operation of the system according to the present invention. 5 is a parameter value 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 multiplex wave propagation; Figures 7A and 7B are S/N diagrams representing S/N due to multiwave propagation distortion, Figures 8A, 8B, 8C, 8D, and 8E.
The figure is a flowchart showing the flow of time slot switching operations for dealing with interference during a call in the system according to the present invention. 10... Telephone network 20... Gateway switchboard 22
-1 to 22-n...Communication signal 30...Radio base station 31-...Signal W1 Science Department 32...Radio transmission circuit 34...Transmission quality monitoring section 5...Radio reception circuit 8 ... Signal speed restoration circuit group 8-1 to 38-m ... Transmission speed restoration circuit 9 ... Signal selection circuit group 9-1 to 39-m ... Signal selection circuit O ... Control section 1 ...Clock generator 2...Timing generation circuit 1...Signal speed conversion circuit group 1-1 to 51-m...Signal speed conversion circuit 2...Signal allocation circuit group 2-1 to 52-m m...Signal allocation circuit 1...Digital encoding circuit 2...Multiple conversion circuit 00.100-1 to 100-n...Mobile radio device 01.
...Telephone unit 20...Reference crystal oscillator 21-1, 121-3...Synthesizer 22-1, 1
22-2...Switch 23...Transmission/reception intermittent controller 131...Speed conversion circuit 132...Wireless transmission circuit 134...Transmission section 136...Reception mixer 138...Speed restoration circuit 141. . . . Clock regenerator 158 . . . Reception quality monitoring unit 162 . . . Interference detector. 133... Transmission mixer 135... Radio receiving circuit 137... Receiving section

Claims (1)

[Claims] Each radio base means (30), each covering a plurality of zones to constitute a service area, and time slots of a frame for moving across said plurality of zones and communicating with said radio base means. In a mobile communication system using a barrier exchange means (20) for exchanging communication between each mobile radio means (100) using a radio channel carrying compressed and delimited signals, When at least one of the radio base means and the mobile radio means detects that the communication quality has deteriorated from a predetermined value due to multiple wave propagation, the time
A time division communication system for mobile communication using time slots with a large guard time length between slots.