JPH04124921A - Time division communication system for mobile communication - Google Patents

Abstract

PURPOSE:To construct a system strong against interference disturbance by shifting automatically a time slot to the time slot of longer guard time when radio interference arises and communication quality is deteriorated, and if the time slot can not be shifted, narrowing the width of the time slot by lowering highest frequency by a low pass filter. CONSTITUTION:An interference disturbance detector is installed previously in mobile radio equipment or a radio base station, and when it is detected that the disturbance arises, the time slot during communication is changed successively to the slot of the longer guard time. If it is impossible because of the congestion of traffic, the low pass filter is inserted in respect of a signal to be inputted to a signal velocity conversion circuit 51a. Simultaneously with this, an instruction to increase time compression ratio (1/n) 2.4/3.0-times higher than 1/n in the past is given to the signal velocity conversion circuit 51a-1. The guard time between the time slot SDa-1 and the time slot immediately before it is greatly increased, and the radio disturbance to the time slot SDa-1 due to multi-frequency propagation is greatly reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the effective use of the multiple load advantage 1q of a time compression multiplexed signal as a modulated signal in a time division communication system for a wireless communication channel in mobile communication. More specifically, one system accommodates mobile radios with different service targets, such as car phone communication terminals and mobile phones, and one of these mobile radios is given a certain radio channel, When another mobile radio starts communicating with another radio base station using the same radio channel while setting up a radio line and communicating with the opposing radio base station using this, the frequency Eliminate any adverse effects on communication between mobile radios and radio base stations due to effective utilization or radio wave propagation characteristics, and at the same time effectively utilize frequencies by reducing transmission output. The aim is to provide an economical system that improves gender performance.

[Prior Art] In mobile communication using voice using a small zone method, 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 – Time and minute!! IJ time –
Proposal of a compression FM modulation method-” IEICE technical report RC38
9-11 July 1989 document 2. Ito ``Study of mobile phone system - theoretical study of time-division time compression FM modulation system'' IEICE technical report RC389-3
9 October 1989 document 3. Ito "Study of mobile phone system - Study of multiple wave propagation characteristics of time division time compression multiplexing FM system -" IEICE Technical Report R
C389-47 January 1990 document 4. Ito “Elucidation of the multiple load gain of time division time compression multiplexed telephone signals and its application to FM mobile communications” IEICE Technical Report RC389-65 March 1990 Reference 5. Co-channel interference when time division time compression multiplexing telephone signals are applied to the small zone system is divided into predetermined time intervals and stored in a memory circuit, and when read out, it is read out at a predetermined time slot at a speed n times faster than the speed at which it is stored in the memory circuit, and is accommodated by the first time slot. a radio receiving circuit having receiving mixers that are built into a mobile radio device and a radio base station and communicate with each other in a manner that angle-modulates or amplitude-modulates a carrier wave with a signal and transmits and receives the signal intermittently; A switch circuit is provided for a wireless transmitting circuit having a transmitting mixer, a synthesizer applying voltage to the receiving mixer of the wireless receiving circuit, and a synthesizer applying voltage to the transmitting mixer of the wireless transmitting circuit, and intermittent the output of the synthesizer applied to each. The state is synchronized for both transmission and reception, and the same intermittent transmission and reception as described above is synchronized with that of the mobile radio for the wireless base station communicating with the opposite side, and the reception side is accommodated in the predetermined time slot. In order to extract only the signal that is present, the radio reception circuit is opened and closed to receive it, and the signal obtained by demodulation is stored in a memory circuit, and when it is read out, it is read out at a low speed of 1/0 of the speed at which it is stored in this memory circuit. An example of a system has been reported in which a system is constructed that can reproduce the baseband signal, which is the original signal that was transmitted, by reading the baseband signal.

Next, in Document 2, there is a study of adjacent channel interference and co-channel interference, which are problems when applying the above-mentioned TCM (time division time compression multiplexing > -FM method) to small zones, and the system Possibilities of realizing the system have been shown by appropriately selecting parameters.

In addition, Reference 3 examines the effect of multipath fading that occurs when a TCM signal is transmitted through space, and sets a card time between time slots as a measure to eliminate or reduce this effect. is proposed.

Furthermore, in Document 4, it is revealed that the multiple load gain 1q, which was known to exist in conventional FDM (frequency division multiplexing) signals, is also included in the time division time compression multiplexing (TCM> method), similar to the multiple load gain as in FDM signals. The book also explains its quantification and system operation examples.If this multiload gain is used to increase the depth of FM modulation, it is possible to significantly reduce the transmission power, making it possible to It has been reported that it is expected that significant power savings will be possible in radio equipment.

Reference 5 conducts a theoretical analysis of co-channel interference when TCM signals are applied to a small zone system, and shows that if multiple load gain is used to increase the depth of FM modulation, the transmission power can be significantly reduced. At the same time, it is explained that it has strong interference resistance against co-channel interference, and its strength becomes stronger as the multiple load gain becomes larger.

[Problem to be solved by the invention] In the system construction examples shown in the above-mentioned documents A to 3,
Although the basic configuration and basic operation of the system are explained, no effective measures to eliminate or reduce the effects of multipath (multiple wave) fading are disclosed.

Similarly, Document 4 only provides a basic explanation and does not disclose any application thereof.

Document 5 also only provides a basic explanation, and does not disclose any countermeasures when multiple wave propagation occurs.

[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. If radio interference occurs due to the influence of multiplex wave propagation and communication quality deteriorates, the time slot used for communication is automatically shifted to a time slot with a larger guard time, and this countermeasure is taken if necessary. If this is not possible, use a low-pass filter to reduce the highest frequency of the signal to be transmitted in the time slot with degraded communication quality, increase the time compression ratio of the signal, and narrow the width of the time slot. The guard time provided between adjacent time slots is increased to reduce interference from adjacent time slots, and at the same time, the multiload gain is increased by decreasing the highest frequency of the signal. By increasing the modulation deviation, the effective frequency utilization is increased.
This also 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, it will cause interference in the received demodulated signal as distortion noise and thermal noise. Among these, changes in phase have a particularly large effect, so as a countermeasure to this problem, even if the high frequency band components of the signal to be transmitted are removed and the time compression ratio of the signal is increased, the maximum By keeping the frequency almost the same as the previous state, the guard time is increased while minimizing the negative effects of high-frequency component removal of the original signal, and the maximum frequency of the signal is reduced. The amount of modulation deviation of FM modulation for the signal was increased to increase interference resistance.

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

In FIG. 1A, 10 is a general telephone network, 11 is an exchange on the side of the telephone network 10, and 20 is a gateway exchange for connecting the exchange 11 and a wireless system. The gateway switch 20 connects a plurality of wireless bases 8 in order to set up and release wireless lines, and perform channel switching in conjunction with zone migration.
30 and many mobile radio devices, and includes radio base stations 30-1 and 30-1, which are shown for convenience of explanation.
A communication control unit 21 that controls two stations 0-2, an ID identification unit 24 that identifies the identification number of the mobile radio, and a communication control unit 21 that controls the two stations 0-2, an ID identification unit 24 that identifies the identification number of the mobile radio, and transmits the transmitted waves from the mobile radio to each radio base station 301 and 30-2.
S/N monitoring unit 2 that monitors communication quality when receiving
5 and each wireless base station 30- under the control of the communication control unit 21.
1.30-2 and the exchange 11, and a switch group 23 necessary for communication system switching is included.

However, since the switch group 23 in FIG. 1A is simple, only three incoming lines from the exchange 11 are shown, and the wireless base station 30-
Communication signal 22-1-1.22-1 to 1 and 30-2
-2 to 22-1-m and 22-2-1.22-2-2
The outgoing line for transmitting .about.22-2-m is the m line.

The wireless base station 30 includes a group of communication path switches that interface with the gateway exchange 20, a communication path control unit that controls the communication path, an ID identification storage unit, a circuit that performs signal speed conversion, and time slot assignment and selection. It includes a circuit for transmitting and receiving multiple wireless channels, a control unit, and a device for transmitting and receiving multiple wireless channels.
In addition to setting and canceling wireless lines, many mobile radio devices1
It has a wireless transmitting/receiving circuit that transmits and receives wireless signals to and from 00.

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 CHm and control signals.

FIG. 1B shows a circuit configuration of a mobile radio Ifll 00 that communicates with a radio base station 30-1 or 30-2. Received signals such as control signals and call signals received by the antenna section enter a radio receiving circuit 135 including a receiving mixer 136 and a receiving section 137, and the output communication signals are sent to a speed restoration circuit 138-1, 138-2 and It is input to the clock regenerator 141. In the clock regenerator 141,
A speed restoration circuit 138-1, 138-2, a control unit 140, a timing generator 142, and a speed conversion circuit 131-1, 131-2 reproduce a clock from the received signal and convert it into a speed restoration circuit 138-1.
is applied to.

In the speed recovery circuit 138-1.138-2, in two time slots in the received signals of the two channels,
The speed of two communication signals each compressed and separated (
In the case of an analog signal, the pitch) is restored to obtain a continuous signal, which is mixed by a signal mixing circuit 152 and sent to the telephone unit 101, the speech quality monitoring unit 157. and is input into the ID information verification storage section 182.

The communication signal output from the telephone unit 101 is divided into two signals by a signal division circuit 139, and each communication signal is separated at a predetermined time interval by a speed conversion circuit 131-1, 131-2, and the speed ( In the case of an analog signal, the pitch) is set to high speed (compression), and the transmission mixer 133 and transmitter 1
34, and the transmission signal is sent out from the antenna section using two time slots and received by the plurality of wireless base stations 30. Speech quality monitoring unit 1 to which the output of the signal mixing circuit 152 is applied
At 57, the call quality during communication is constantly monitored, and when it deteriorates, it is reported to the control unit 140. The ID information verification storage unit 182 stores the ID (identification information) of the mobile radio 11100 itself, and identifies and stores which zone it is in.

The 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 this timing generator 142, the clock regenerator 14
1 and a control signal from the control section 140, the transmission/reception intermittent controller 123. Speed conversion circuit 131-1.
It supplies necessary timing to 131-2 and speed restoration circuits 138-1 and 138-2.

This mobile radio device 100 further includes synthesizers 121-1 to 121-4 and changeover switches 122-1, 122-4 to enable simultaneous transmission and reception of two channels.
2, and a transmission/reception intermittent controller 123 that generates signals for switching the changeover switches 122-1 and 122-2, respectively.
and a timing generator 142, which includes synthesizers 121-1 to 121-4 and a transmission/reception intermittent controller 12.
3 and the timing generator 142 are controlled by the control section 140. Each synthesizer 1211-121-
4 is supplied with a reference frequency from a reference crystal oscillator 120. With such a configuration, it is possible to communicate with a plurality of wireless base stations 30 using two channels.

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

m-channel communication signal 22- with barrier exchange 1120;
1 to 22-m are connected to a signal processing section 31 forming an interface through transmission lines.

Now, the communication signal 22 sent from the barrier exchange 1120
−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 20 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 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.

Furthermore, the signal transmitted from the radio base station 30 to the gateway exchange 20 is determined by the output of the radio receiving circuit 35 being transmitted to the signal selection circuit group 39.
is input to the signal speed restoration circuit group 38 via the signal speed (
After being converted (pitch), it is input to the signal processing section 31 through a switch group 83.

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, the signal 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 20 as communication signals 22-1 to 22-m. Sent as .

The transmission quality monitoring unit 34 has the functions of both a reception quality monitoring unit 158 and an interference detection unit 162 of the mobile radio 1ioo,
When deterioration of 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 group 51 is the same as when playing back audio recorded by a tape recorder at high speed, and in reality, for example, COD (Charge
CoupledDevice), BBD (Bu
cket Brigade Device) 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 (References: Koita et al. ``Duration of Conversation''"Tape recorder that compresses/expands the shaft" Nikkei Electronics July 26, 1976 92-1
Page 33) COD YaB illustrated in signal speed conversion circuit group 51
As described in the above-mentioned document, the circuit using the BD can be used as it is for the signal speed restoration circuit group 38, and in this case, the circuit using the clock from the clock generator 41 and the control signal from the control section 40 can be used as is. This can be achieved by making the reading speed slower than the writing speed in response to a timing signal from the timing generation circuit 42 that generates timing.

Control or call signals outputted from the barrier exchange R20 via the signal processing section 31 are input to the signal speed conversion circuit group 51, and after speed (pitch) conversion processing is performed, the signals are converted 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 is arranged in series without overlapping in chronological order when viewed in response to call signals, and when the control signal or control signal and call signal described later are all implemented, it is as if it were a continuous signal. It becomes like a 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. SDl and SD2 in Figure 2A (a)
．． -, 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 30 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;
It is written that there is no guard time, but as shown below (see Figure 2D)
% 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.

FIG. 1D shows an example of a detailed circuit configuration of the wireless transmission circuit 32. The signal from the signal allocation circuit group 52 is FM
It is modulated by a modulator 161, and its output is mixed with a signal from a local oscillator 167 by a transmission mixer 133, amplified by a power amplifier 159, and sent to the antenna section. Here, the gain control section 168 controls the gain of the power amplifier 159 to increase as much as a specific time slot is transmitted based on the control signal from the control section 40.

FIG. 1E shows an example of a detailed circuit configuration of the wireless transmission circuit 32. The signal from the signal allocation circuit group 52 is sent to the FM modulator 161 by a modulation deviation amount control section 169.
The output is mixed with a signal from the local oscillator 167 in the transmission mixer 133, amplified by the power amplifier 159, and sent to the antenna section. Here, based on the control signal from the control unit 40, the modulation deviation amount control unit 169 outputs a control signal for increasing the modulation deviation amount to the FM modulator 161 only when transmitting a specific time slot. ing.

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 in the figure, the low frequency side (250Hz) 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 and transmit the two, and the circuit in this case is The configuration is shown in Figure 2E (
Shown in b). FIG. 2E(b) shows an example of a case where an audio signal is digitized by a digital encoding circuit 91, and a data signal is multiplexed and converted by a multiplex conversion circuit 92, and then applied to a modulation circuit included in the wireless transmission circuit 32. It is.

However, in digital data signals, there is usually no multiple load gain when multiplexing analog signals, which will be described later, so this point must be kept in mind when designing the system.

Then, it is received by the opposite receiver, and the second E
The audio signal and the control signal can be extracted separately by performing the operation opposite to that shown in FIG. 3(b).

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. SU2. ...S
un is a mobile radio device 100-1, 100-2°...,
100-n shows a transmission signal addressed to the wireless base station 30.

Also, each time slot 5tJ1. SU2,...,s
If the contents of un are shown 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 short distance between the radio base station 30 and the mobile radio device 100 or the signal speed, it is possible to omit the synchronization signal. Furthermore, the waveform of the radio carrier wave of the above-mentioned uplink radio signal within a time slot is schematically 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. Further, the call signal 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 has the function of performing inverse conversion of the speed conversion circuit 131 (FIG. 1B) in the mobile radio 11100 on the transmitting side, and as a result, the original signal is faithfully reproduced and transmitted to the gateway exchange 20. Become.

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 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 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 signal (0.3k) 12~3.0kH
FIG. 3B shows the frequency distribution on the output side when signal 2) passes through the signal speed conversion circuit group 51 (FIG. 1C). That is, if the audio signal is converted 15 times as described above, the frequency distribution of the signal is 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. Assume that among these signals, a control signal (0, 2 to a, 0 kHz>) and a speech signal CH1 (4, 5 to 45 kHz, expressed as SDl) are accommodated in a time slot, for example, SDl.・Slot SD2~SD
The same applies to the audio signal contained in n.

That is, time slot SDi (i=2°3, -
, n) accommodate a control signal (0.2 to 4°0kHz) and a communication signal C'Hi (4.5 to 45kHz). 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 modulation section included in the above, the required transmission band requires at least fo+45kHz. 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 five signal speed conversion circuit groups is limited to a certain value due to the limitations on these frequency intervals. The frequency interval of multiple wireless channels is f
rep 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 1120.

FIG. 1F shows an embodiment 30B of a wireless base station. Here, the difference from the wireless base station 30 shown in FIG. 1C is that there are two signal selection circuit groups 39a and 39b and a signal speed restoration circuit group 38a.

38b, two sets of signal speed conversion circuit groups 51a, 5, respectively.
1b and signal assignment circuit groups 52a and 52b@A, and the configuration is substantially the same as that shown in FIG. 1C. The radio base station 30B is a mobile radio 1100
This is particularly useful when the mobile phone terminal 1 is a terminal with different service targets, such as an image terminal and a car telephone terminal, and the composite service for these terminals will be described later.

Below, unless otherwise specified, wireless base station 30.30
8 are collectively referred to simply as the wireless base station 30.

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
→11 mobile devices 100) Wireless channel (channel CH1
start capturing the control signals contained in the If the system is provided with multiple radio channels, i) the radio channel i exhibiting the highest received input electric field;
i) Wireless channels instructed by control signals included in the wireless channels; i) Channels with empty time slots among the time slots in the i-line channel, etc. according to the procedures determined by each system. (hereinafter referred to as channel CH1). This is possible by capturing the synchronization signal within the time slot SDi shown in FIG.
A control signal is sent to the synthesizer 122-1 so as to generate a local frequency that enables reception of the radio channel CHI, 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 the amount of information in the signal is large and cannot be accommodated in one time slot, the next frame will be Transmitted using the same time slot.

Specifically, the following method is used to capture the time slot Sun. As shown in FIG. 2A (a), the control signal transmitted from the radio base station 30 includes a synchronization signal and a subsequent control signal, and the mobile radio device 100 receives this signal to perform 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 (i=1.2°...
n) may only contain 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 another system, there may be no empty slot indication in any of the time slots, and in this case, the following audio multiplex signals SD1, SD2, . ..., S
Is it 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 a call is made from another mobile radio at the same time, the calling signal will not be properly transmitted to the radio base station 30 due to a call collision, and the operation will have to be restarted from the beginning.This probability is When viewed as a system, it 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, the call control signal from the mobile radio device 100 is successfully received by the radio base station 30, and the ID (WL) of the mobile radio device 100 is
If a different number) is detected (3202), the control unit 40
Now, search for a currently vacant time slot. Just to be sure, a search is performed to see if the time slot given to the mobile radio device 100 can be Sun. This is to accommodate simultaneous calls from other mobile radios in addition to the mobile radio 100, 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 ) SUl.

and instructs to use the corresponding downlink (radio base station 30 → mobile radio device 100) SDl (3203
>. In response, the mobile radio device 100 transitions to a state in which it can receive data in the instructed time slot SDI, and also transfers the time slot 5U1 (FIG. 2A), which is the time slot for the uplink radio channel corresponding to the downlink time slot SD1. (b)). At this time, the control unit 140 of the mobile radio device 100 operates the transmission/reception intermittent controller 123 and starts operating the switches 122-1 and 122-2 (5204>. At the same time, a slot switching completion report is sent to the uplink time slot SU1. 3205> and waits for dial tone (
S206>.

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 from another mobile radio 1100.
It is sent as being included in one frame.

The radio base station 30 that has received the slot switching completion report (
8207>, sends a calling signal to the gateway exchange 20 3208>, upon receiving this, the gateway exchange 20 detects the ID of the mobile wireless device 100 and selects the necessary one from among the switch group included in the gateway exchange 1fi20. Turn on the switch (3
209>, a dial tone is sent (S210, FIG. 4B).

This dial tone is transferred by the wireless base station 30 (3211), and the mobile wireless device 100 confirms that the communication path has been established (3212>).

When this state is reached, a dial tone is heard from the handset of the telephone section 101 of the mobile radio t1100, and the transmission of a dial signal begins. 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 upstream time slot SU1 (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 100 passes through the signal selection circuit 39-1 of the signal selection circuit group 39, and then passes through the signal speed restoration circuit group 3.
8, the original transmission signal is restored here, and sent to the gateway exchange 20 as a call signal 22-1 via the signal processing section 31.
(S214>, and a call path to the telephone network 10 is set (S215>).

On the other hand, the input signal from the barrier exchange 1120 (initial control signal, call signal when a call is started) undergoes speed conversion at the signal speed conversion circuit group 51 at the wireless base station 30, and then
The time slot SDI is provided by the signal allocation circuit 52-1 of the signal allocation circuit group 52. Then, the time slot S of the wireless channel downstream from the wireless transmission circuit 32
It is transmitted to the mobile radio 1100 using D1. The mobile radio device 100 is on standby for reception in time slot SD1 of radio channel CH1 and is received by radio reception circuit 135, the output of which is input to 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 $1100 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 (3217>), 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 (3218>), and the control unit 140 stops the operation of the transmission/reception intermittent controller 123 and switches 1221 and 122-2 to the synthesizer 1.
It is fixed to the output ends of 21-1 and 121-3.

On the other hand, the control unit 40 of the radio base station 30 controls the mobile radio 11
When the call termination signal is received from 00, the call termination signal is forwarded to the barrier switch 20. 5219>, 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 device 100 The mobile radio device 100 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 waiting state to receive a downlink control signal of the radio channel CH1 in accordance with the procedure defined by the system.

Assume that an incoming call signal to the mobile radio device 100 arrives at the radio base station 30 from the general telephone network 10 via the barrier switch 20. 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 control the mobile radio device 100(7)I.
D signal 10 Incoming call signal display Signalman time slot usage signal (for example, SDl
(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. 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 SDI, SU1, 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.

(3) Channel switching method during a call between adjacent wireless zones
The operation when switching the speech (communication) channel so as to communicate with the user will be explained.

In addition, the feature of the present invention, which is that there is no instantaneous interruption due to channel switching, will also be explained.

The mobile radio device 100 includes a synthesizer 121-1゜121
-3, the radio receiving circuit 135, and the radio transmitting circuit 132.
Slot upstream 5U1-1. It is assumed that communication is in progress using downlink 5D1-1. The mobile radio device 100 is a radio base station 30
Assume that the mobile terminal moves away from -1 and approaches the wireless base station 30-2. Then, as the relative distance between the mobile radio device 100 and the radio base station 30-1 increases, the call quality begins to deteriorate. The S/N monitoring unit 25 detects deterioration in the quality of the transmission signal from the radio device 100 (decreased to level 1 or less). Note that even the level L1 is set to exceed the value required for the line. All nearby wireless base stations 30 are requested to measure the quality of the transmitted signal from the mobile wireless device 100.

In response to this request, each radio base station 30 sends the measured value to the barrier switch 20, so the S/N monitoring unit 25 of the barrier switch 20 starts comparing the level L2 of the communication quality standard. As a result of the comparison, the measurement result of the wireless base station 30-2 has the best value, and the quality standard is level 12 or higher, but L2
If it is confirmed that >Ll is satisfied, the mobile radio device 100 determines that it has moved to the communication zone (Zone 2) of the radio base station 30-2, and decides to perform channel switching. Then, use the free time in zone 2.
As a result of investigating communication channels having slots, it is learned that wireless channel CH2 is usable. Therefore, time slot 5 of the downlink radio channel CH1 currently in use
Using control signals D1-1 and 5U1-1, the mobile radio R100 is instructed to prepare for transmission and reception in, for example, time slots 5D2-2 and 5U2-2 of radio channel CH2.

At the same time, time slot 5D2-2.5U2-2 of wireless channel CH2 is transmitted to wireless base station 30-2.
Instructs to send and receive data using .

After issuing these instructions, the barrier switch 20 turns on switches 5WI-1-1 and 5W2-1-1 of the switch group 23 at the same time, and also sends the wireless base station to the wireless base station 30-2. It starts sending out the same call signal as station 30-1. Also, since it is a matter of course, both radio base stations 30-1.3
0-2 modulation depth of the modulator, as well as the length of the time slot.

The number within one frame, the timing of each wireless channel, etc. are also the same.

In order to realize the transmission of this control signal, specifically, when the control signal is an analog signal, as shown in FIG. (For example about 100H2> or high frequency fD1.fD2.fD3...fD8 (for example 3.
8 from 8kHz to 4.5kHz2 at 0.1kHz7 intervals
waves).

When there are many items to be controlled, that is, many control data, the control frequency f. The wave number of ~fD8 may be further increased, or a subcarrier format may be used. At this time, more control data can be transmitted by applying frequency modulation or amplitude modulation to one or more waves of fDo- and -fD8, for example.

FIGS. 2C and 2D show timing charts before and after channel switching in this system.

In FIG. 2C (C), downlink time slot 5D1
-1 is the time slot of radio channel CH1 that the radio base station 30-1 uses as a transmission signal to the mobile radio '100, and the other time slots are used for other mobile radios. (including empty slots). Similarly, in FIG. 2C (d), the time slot 5D2-2 is the time slot of the radio channel CH2 that the radio base station 30-2 with which the new communication is to be made uses as a transmission signal addressed to the mobile radio device 100. Suppose it is a slot.

Mata, Figure 2D (7) (e) and (f) are shown in Figure 2C (
These are signals transmitted from the opposing mobile radio device 100 that receives the outputs of c) and (d), respectively.

Therefore, the time slots used are 5LJ1-1 (, CHl >, 5U2-2 (CH
2>, and the others are used for other communications (including empty slots).

In FIGS. 2C (C) and (e), the radio base station 30-1
Channel CH used between the mobile radio 11100 and
S/ of the barrier switch 20 indicates that the quality of time slot 5D1-1゜5UI-1 of time slot 1 has decreased to level 11 or lower.
The N monitoring unit 22 detects the time and
Using time slot 5D1-1 of channel CH1, instruct mobile radio device 100 to start preparations to enable parallel reception of transmitted radio waves from radio base station 30-2 in slot 5U2-2. .

Therefore, the control unit 140 of the mobile radio Wt100 uses only the synthesizer 121-1 until then to
Radio base station 3 with time slot 5DI-1 of H1
From the state of receiving the transmission wave from radio base station 30-1, synthesizer 121-2 is also operated, and time slot 5D2 of channel CH2 transmitted from radio base station 30-2.
The synthesizer 121-2 is made to generate a frequency that makes it possible to receive the transmission wave of the -2 frequency G2 as well.

Channel CH1 transmitted from the wireless base station 30-1
Due to the quality degradation in time slot 5D1-1 of
00, the transmission/reception intermittent controller 123 is activated to repeatedly switch the changeover switch 122-1. At the same time, the synthesizer 121-4 is also started from the state where only the synthesizer 121-3 was operating and transmitting to the radio base #30-1 using time slot 5U11 of the radio channel CH1. , wireless base station 30-
2 for time slot 5U2- of channel CH2
2 to a state where it can transmit using frequency 02. The outputs of the synthesizers 121-3 and 121-4 used for this transmission are also repeatedly switched by the signal from the transmission/reception intermittent controller 123 by the changeover switch 122-2.

During this switching transmission/reception period in which channels CH1 and CH2 are transmitted and received in parallel, the time slot 5U2-2 of channel CH2 is confirmed, and the barrier switching center 20 confirms that the quality of the channel is at a certain level 12 or higher. Continues until confirmed, then channel CH1 time slot 5D
I-1, 5U1-1 is opened, and communication between the radio base station 30-2 and the mobile radio 100 continues without momentary interruption only through time slot 5D2-2.5U2-2 of channel CH2. .

The switching frequency f1 of the changeover switch 122-1 or 122-2 during this switching transmission/reception period is a value determined for each system, and the number of time slots in one frame included in the wireless channel CH1 is n, 1. time·
Letting the time interval of the slots be T1, it is given by f1=(nT1).

58 to 5D are flow charts showing the flow of operations when switching channels during calls between adjacent wireless zones.

Gateway exchange 20. The radio base station 30-1. Communication is in progress with 100. For this communication, a wireless channel CH instructed by the communication control unit 21 included in the barrier exchange 20 is used.
1 time slot 5D1-1.5U1-1. Either the downlink frequency F1 or the uplink frequency f1 is used (S101,
Figure 5A).

From the wireless base station 30-1 that is in communication, the mobile wireless 1
A reception status report is issued from 1100 (S102>), and the S/N monitoring unit 25 of the barrier switch 20 receives this report and monitors whether the call quality has deteriorated below level L1 (3103 ).

If the call quality had deteriorated below level L1 (81
03YES), from the communication control unit 21 to the wireless base station 30
-1 to the wireless base station 30 in the vicinity of the wireless base station 3
0-1 and the mobile radio device 100, the uplink frequency f1. An instruction is given to monitor and receive the signal of time slot 5U1-1 (3104).

Each surrounding wireless base station 30 that has received an instruction to monitor reception (for example, in 30-2>, monitor and receive the signal of frequency f1.time slot 5U1-1 3105), transmits the result to the S/N of the barrier switch 20. Please report to the monitoring department 2551
06), the monitor reception quality from each radio base station 30 is measured and compared, and it is detected that, for example, the speech quality of the radio base station 30-2 is better than a certain standard level L2 and is the best (3107YES).

Therefore, the communication control unit 21 allows the mobile radio device 100 to move from the zone covered by the radio base station 30-1 to the radio base station 30-2.
3108 seems to have moved to the zone covered by
, FIG. 5B), searches 510 for a channel with a free time slot that can be used by the wireless base station 30-2 to switch to communication with the wireless base station 30-2.
9), so that time slot 5 of channel CH2
D2-2,5LI2-2 is determined (S110).

The communication control section 21 provides the control section 140 with the mobile radio device 1.
00 transmitter 132 (132-2> and receiver 13
5 (135-2) to prepare for communication in time slots SD2 to 2.5U2-2 of channel CH2 (S111).

Time slot 5D2-2, 5 of this channel CH2
The communication preparation command for using U2-2 is sent to the wireless base station 3.
0-2, time slot 5 of channel CH2
Prepare communication by D2-2 and 5U2-2 (S11
2>. This command is simultaneously sent from the radio base station 30-1 in time slot 5DI-1 of channel CH1 (3113). The mobile radio 100 uses this channel C
H2, time slot 5D2-2.5U2-2, receive communication preparation command on frequency G2 (5114), channel CH2, time slot 5D2-2.5LI2-
Preparation for enabling communication between the synthesizers 121-2 and 1.21-2 from the control unit 140;
4 to receive frequency G2 and transmit at frequency 92, and transmit/receive intermittent controller 123 instructs time slot 5D2-2. The operation using SU2-2 begins (3115, Fig. 5C).

Channel CH2 time slot 5D2-2°5tJ
When ready to communicate using 2-2, mobile radio 1
00 reports completion of preparation to the wireless base station 30-2 using time slot 5U2-2 of channel CH2 (3116).

Upon receiving this report, the wireless base station 30-2 performs step 51.
Time slot 5D22.5U2-2 prepared in 12
After confirming the completion of preparations within the radio base station 30-2, a report is sent to Kanmon Traffic @R20 (S117).

When the gateway exchange 1120 confirms the completion of communication preparation between the radio base station 30-2 and the mobile radio device 100 using the time slot 5D2-2.5U2-2 (8118)
, the switch 5W1-1-1 of the switch group 23 is left on, and the switch 5W2-1-1 is also turned on (51
19). Therefore, the communication control unit 2 included in the barrier switch 20
1 is a mobile radio device 100 for a radio base station 30-2.
time slot 5D2-2. SL, 12-2
A command is given to start communication using (S120).

Upon receiving this communication start command (S121>, the wireless base station 30-2 transmits the communication start command to time slot 5D2-
2 (S122).

The mobile radio device 100 receives the time slot 5D2-2 using an ID signal which is an identification signal for identifying the mobile radio device.
．． Please confirm the start of communication by 5U2-2 5123>,
Using time slot 5U2-2, 1. The radio base station 30-2 transmits a communication signal including the D signal 5124>, and receives this communication signal in the time slot 5D2-
2. Report that communication has started at 3'tJ2-2 (
5125>.

Having received this report, the S/N monitoring unit 22 of the barrier exchange R20 confirms the start of communication in the time slot 5D2-2. Measure the quality level of communication between
When a certain quality level of 12 or higher is detected (S
127YES, FIG. 5D), time slot 5D1-1 between radio base station 30-1 and mobile radio Fj 1100
．． The wireless base stations 30-1 and 30-2 are instructed to stop the communication that was being performed using the '5L111 (S128>).

As a result, the radio base station 30-1 turns off the communication using the time slot 5D1-1. transfers the command (5130), and when the mobile radio R100 receives the command to stop communication on channel C)-11 (S13).
1), the operation of synthesizers 121-1 and 121-3 is stopped, and the changeover switch 122-1 is set to
The selector switch 122-2 is switched on and off at a predetermined timing between the synthesizer 121-4 side and the synthesizer 121-2 side.
Continuing off, channel CH2 time slot 5D
2-2. Only 5U2-2 is operated, and a channel CHI communication stop report is sent using time slot 5U2-2 of channel CH2 (S132). The radio base station 30-2 that received this transfers this channel CH1 communication stop report (S133).

The communication control unit 21 of the barrier exchange 20 that received the channel CHI communication stop report controls the switch 5W21 of the switch group 23.
-1 remains on, and the switch 5W1-1-1 is turned off (3134).

This ends the channel switching operation period, and with switch 5W2-1-1 in the on state, mobile radio device 100 communicates with radio base station 30-2 using channel CH2, down frequency G2, and up frequency g2. In between, the -shun disconnection,
Communication can be continued without noise (S1
35).

The above description has been made on the assumption that the same radio channel is not allocated between adjacent zones when switching channels during a call in the system of the present invention. In actual small zone systems currently in use, this is strictly adhered to. However, when time-division communication is performed as in the present invention, the above conditions do not necessarily have to be complied with even in the case of a small zone system. In other words, even if two adjacent zones use the same wireless channel,
This is because if the time slots are made different, there is no risk of radio interference occurring as described above.

(4) Channel (time slot) switching during a call within the same radio zone Next, the present invention can also be used when radio interference occurs due to other communication while the mobile radio 100 is talking in a certain radio zone. It will be explained that the control signals used in the present invention exhibit strong immunity, and at the same time it will be explained how to implement the switching of radio channels or time slots within the same zone to avoid interference.

First, in the mobile radio device 100, for the radio base station 30,
An out-of-band control signal of the speech signal is used to report that a time slot switch 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. Since the radio base station 30 has a fixed location, it generally has a lower probability of receiving interference than the mobile radio 11100, and can receive this control signal better.

Then, the wireless base station 30 stops transmitting the call signal,
An instruction to be described below is transmitted to the mobile radio device 100 in the form of a control signal that the mobile radio device 100 can easily receive in all time slots SD1. This signal is transmitted to the mobile radio 100
can be easily received even under interference.

Now, upon receiving the control signal notifying the occurrence of interference from the mobile radio 111100, or recognizing the occurrence of radio interference itself, the radio base station 30 investigates whether there is an empty time slot within the same radio channel. ,time·
Slot SD2. Assume that it is determined that SU2 is usable (see FIGS. 2A and 2B). Then, the mobile radio device 100 is instructed to use this for transmission and reception.

Therefore, the control unit 140 of the mobile radio device 100 changes the state in which the synthesizer 121-1 is used to receive the transmission wave from the radio base station 30 in the time slot 5DI-1 of the channel CH1 to The timing generator 142 and the transmission/reception intermittent controller 123 are instructed to make it possible to receive the time slot 5D1-2 in which the signal is sent.

When the radio base station 30 emits a transmission wave in time slot 5D12, the mobile radio t1100 changes the operation of the transmission/reception intermittent controller 123 to 1 and radio channel C.
A transition is made from a state in which the signal was being transmitted to the radio base station 30-1 using time slot 5U1-1 of channel CH1 to a state in which the same signal can be transmitted using time slot 5U1-2 of channel CH1. Thus, time slots 5U1-1, 5u1-2, 5D1-1.3D1-2
During this switching transmission/reception period, in which the signals are transmitted and received in parallel, the time slot SU of the channel CH1 is confirmed as 2, and the quality of the time slot is constant.
This continues until the wireless base station 30 confirms that the above is true, and then the channel CH1 time slot 5D1-
1.3U1-1 is opened, and communication is continued without momentary interruption using only time slots 5D1-2 and 5U1-2 of channel CH1.

The switching frequency f1 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 n, and the time interval between one time slot is T1, then f1 = (nT1) - 1X
It is given by 2.

68 to 6E are flow charts showing the flow of operations when switching channels when co-channel interference occurs during a call.

Gateway exchange 20. Radio base station 30 and mobile radio device 10
0 has started operating, the switch 5W1-1-1 of the switch group 23 included in the barrier exchange 20 is on, and communication is in progress between the radio base station 30 and the mobile radio 100. For this communication, time slots 5D1-
1.5U1-1. Downstream frequency F1 and upstream frequency f1 are used (S351, FIG. 6A).

The mobile radio device 100 is constantly connected to the radio base station 30 in communication.
reception status reports from, for example, fading or
A report indicating that reception is not possible due to interference is issued by a control signal in each time slot used for communication (3352), and the radio base station 30 receiving this report,
Transmission quality monitoring unit 34 within the own station (this is the mobile radio 1110
0 (which has the function of both the reception quality monitoring unit 158 and the interference detection unit 162), and determines whether to execute busy zone switching or time slot switching within the same zone. do. If the cause of the inability to receive is due to a decrease in the received electric field, step 5102 (FIG. 5A)
to 3135 (Fig. 5D) (S35
3 YES).

If the cause of the inability to receive is not due to a drop in the receiving electric field (3353 NO), check whether it is due to co-channel interference (S354, Figure 6B), and if it is co-channel interference (S354 YES), It is determined that the time slot needs to be changed (5355) and reports to the radio base station 30 that the time slot should be changed to a communication channel or a remote time slot due to interference (S35).
6).

Therefore, the control unit 40 of the radio base station 30 that has received this (S357) searches for the presence or absence of an empty time slot, and determines the time slots 5D1-2 and 5U1-2 (S358). The control unit 40 instructs the transmitting unit 132 and the receiving unit 135 of the mobile radio device 100 to prepare for communication in time slot 2 of channel CH1, that is, 5D1-2, 5U1-2 (3359, Figure 6C).

This command is sent by a control signal in time slot 5D1-1, and mobile radio 11100 receives this communication preparation command (5360), enabling communication through channel CH1 and time slots 5D1-2 and 5U1-2. In other words, time slots 5D1-2, 5L11- are sent from the control unit 140 to the transmission/reception intermittent controller 123.
2 (3361).

On the other hand, at the wireless base [30, time slot 5DI-
1, 1-2, 5U1-1. In preparation for parallel communication by 1-2, the signal selection circuit 38-1 of the signal selection circuit group 38
．． 38-2, signal speed restoration circuit 38-1.38-2 of signal speed restoration circuit group 38 receives in parallel, signal speed conversion circuit 51-1.51-2 of signal speed conversion circuit group 51, signal allocation circuit group The control unit 4o instructs the signal processing unit 31 to receive the signal in parallel by the signal allocation circuits 52-1 and 52-2 of 52 (S362).

When the mobile radio 100 is ready to communicate using the time slots 5DI-2 and 5U1-2 of the channel CH1, the mobile radio 100 sends a control signal in the time slot 5U1-1 to report the completion of preparation. is used to report to the wireless base station 30 (3363). Upon receiving this report, the radio base station 30 selects the time slot 5D1-2.5U.
Preparation for parallel transmission and reception by 1-2 is complete 5364),
Parallel transmission and reception is started (S365, FIG. 6D).

That is, 5D1-2 sends a communication signal including an ID signal, and mobile radio R100 receiving this communication signal (
3366), time slot 5D to wireless base station 30
After confirming that the signal 1-2 was received well (S
367), and a confirmation signal is transmitted by a control signal in time slot 5U1-2 (3368).

When the wireless base station 30 receives this report (S369
), the transmission quality of the time slot 5U1-2 is confirmed by the transmission quality monitoring unit 34 (S370>, the wireless base station 30
and the mobile radio 100 time slot 5D1-
Mobile radio to stop communication that was performed using 1,5U1-1! command to fi100 (8371, Figure 6E).

Upon receiving this (S372), the mobile radio device 100 turns off communication using time slot 5D1-1.5U1-1 (3373). That is, the control unit 140 controls the transmission/reception intermittent controller 123 to set the time slot 5DI-
In addition, only time slots 2 and 5U1-2 are operated, and a communication stop report for time slots 5U1-1 and 5D1-1 is sent using time slot 5U1-2 of channel CH1 (3374). The radio base station 30 that received this (S375) executes similar measures at its own station (S37).
6>.

As a result, the channel switching operation period ends, and the mobile radio device 50 is disconnected from the radio base station 30 for an instant.
Communication can be continued without noise (33
77).

In the above description, in the system of the present invention, when performing channel switching during a call within the same zone, time slot switching is performed on the same radio channel. However, this does not necessarily have to be done within the same radio channel; different radio channels may be used.

However, in that case, synthesizers 121-1 and 121
Since it is necessary to change the frequency generated at -3 depending on the radio channel, it is necessary to provide a synthesizer with a fast rise characteristic.

Next, we will theoretically explain how this system can be used to perform signal transmission in good conditions without adversely affecting other wireless channels within the system. for that,
Let us take an example of an uplink radio signal (transmitted by the mobile radio device 100 and received by the radio base station 30).

First, assume that all upstream radio signals are idle lines, that is, all time slots are not used. The mobile radio device 100 desiring to make a call uses a control signal in, for example, time slot SD1 in the downlink radio channel, so that the mobile radio device 100 can select an available time slot (for example, time slot 5D1) in the uplink radio channel. is selected, the radio transmitter circuit 132 sends a control signal (a call signal if a call path is set) to the radio base station 30 in response to a signal from the timing generation circuit 142.

Similarly, if there is a call originating (terminating) from another mobile radio, a control or conversation signal is sent to the radio base station 30 as an uplink radio signal using another time slot on the same radio channel.

Signal transmission is carried out in good condition using this system,
Moreover, it is theoretically explained in Document 2 that there is no adverse effect on other wireless channels in the system. In addition, how large the guard time should be in accordance with the multiwave propagation characteristics in the system applied to the present invention is as follows.
Based on document 3, a rough judgment can be made, so TCM-F
Measures to remove or reduce the phase distortion of the M signal will be described below.

(5) Measures to remove multiple wave propagation distortion (5, 1) Effects of multiple radio wave propagation on TCM-FM waves Figure 2F (a> is the TCM transmitted from the wireless base station 30
- FM (time division time compression multiplexing - frequency modulation) wave is a schematic diagram showing the wave. FIG. 2B is a schematic diagram showing the waveform of a signal wave received by the mobile radio device 100 that is distant from the mobile radio device 100. In this case, the mobile radio OO wants to receive only the time slot SDI signal S1 of the TCM (time division time compression multiplexing) signal transmitted from the radio base station 30, but due to multiple reflections in the transmission medium, In addition to the signal S1, the following unnecessary signals will be received at the same time.

> Signal S1 delayed by time T due to multiple reflections (-τ1) (τ1 < t < T > er) Signal component S of time slot SDn immediately before time slot SD1 delayed by time τ1 Therefore, the interference signal s which exceeded the guard time and fell into the time slot SDl, (↑To−τ1) (0<t<τ.) Of the above, i) is the echo distortion caused by the current analog FM system. This includes a component that causes echo distortion and a useful signal that differs only in phase from the original signal, but it must be noted that all of ii) are harmful signals.

(5,2) Setting system parameters Since no TCM method has been put into practical use, the number of multiplexes n is set to 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, Tt...frame length, T...time slot length T-...guard time length, n...voice multiplicity To/T...inter-slot overlap rate"O
VR...overlap time length" ALD...below the allowable delay time due to multiplex propagation,...synchronization pulse time length Td...data signal time slot length η...frame efficiency, fo... -Carrier frequency fM...Modulation signal frequency.

Md...Modulation depth Standard modulation deviation flJH: Modulation signal frequency of interference wave.

(5, 3) Example of Calculating the Amount of Interference 1) Change in Amplitude Due to Interference A numerical sieve is performed based on the parameters shown in FIG. 8, and the results are shown in FIG. Here, 'a' in the figure represents the range of amplitude.

2) Phase distortion due to interference When the phase distortion due to the desired wave and the echo wave V is calculated and expressed as S/N, FIG. 10A is obtained. However, system 1
Since this effect hardly appears in the case of 0 and 100, the case of system 1000 was determined.

From the same figure, the size of the reflected wave is about the same as the direct wave (X = 1)
Even if the delay time τ is less than 5 μsec, S/
It can be seen that N is secured at 30 dB or more, but 10 μs
When it exceeds ec, it gradually decreases to 25d at 15μsec.
It will be about B. This means that as the delay time τ between the desired wave and the echo wave V increases, the useful signal components decrease.

When the interference between the D wave and the adjacent time slot wave is calculated as S/N, Figure 10B is obtained. From the same figure, it can be seen that even if an interference wave with the same amplitude as the own signal is superimposed due to delay (Y = 1 >, if the delay time τ is 15 μsec or less, a S/N of 20 dB is secured. .

(5, 4) 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 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.
When the wave moves, the envelope and phase of the received wave fluctuate randomly as shown in FIG. 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 from several tens of meters to at most 100 meters, and at most, the distance is about 1 to 2 μsec when the car is traveling on an automated metropolitan tram. However, in suburban areas, especially in areas with mountains and hills such as basins, 1
Values from 0 to 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 various parameters shown in FIG. 8, system 1000 will be taken as an example.

In this system 1000, the guard time length Tg is 1
Since it is set to 0 μsec, there is no problem with indoor cell phones or car phones in the city. However, from the point of view of effective frequency utilization, it takes too much card time than necessary, and it is necessary to improve the - layer. On the other hand, if a car is driving in a suburban area such as a hilly area, it will be 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 launch pad on the roadside without the aid of a wireless device. In such a system, TCM-F
We will explain how to select M's card time so that it is 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 card 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 set to zero. 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 card 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. 2G 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 card time of the time slots belonging to one group is 1 μsec, and the card time of the time slots belonging to one group is 1 μsec. The guard time of the time slot to which it belongs is set to 5 μsec, and the guard time of the other time slots is 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 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.

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. In order to
A method for implementing slot switching will be explained.

The mobile radio device 100 has a long guard time. It is assumed that communication is in progress using time slot SD1°5tJ1 belonging to group 1, which has a short time slot. At this time, it is assumed that the interference detector 162 of the mobile radio device 100 shown in FIG. 1B detects interference based on multiple wave propagation.

Then, the mobile radio device 100 transmits the card time length to the radio base station 30 using the out-of-band control signal of the call signal. , for example, that a switch 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, in order to make tone signals and digital signals less susceptible to interference, various measures have been taken, such as using low-speed data and implementing error correction and retransmission.

In the unlikely 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 100 in the time slot SD1 in the form of a control signal that can be easily received by the mobile radio t1100. This signal can be easily received by mobile radio 100 even if it is under interference.

Now, the radio base station 30 which has received a control signal notifying the occurrence of interference from the mobile radio device 100 or which has itself recognized the occurrence of radio interference, is in use when the guard time length Tg is in use within the same radio channel. groups longer than those of
For example, when we investigated whether there were any free time slots in group 2, we found that time slot SDI 2. SUl
2 is found to be usable (Fig. 2G (
a).

(see (b)). Then, the mobile radio device 100 is instructed to use this for transmission and reception.

Therefore, the control unit 140 of the mobile radio device 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 CH1 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 SU1,5tJ12°SDl
, SDl 2 are now being transmitted and received in parallel. During this switching transmission/reception period, the radio base checks time slot 5U12 of channel CH1 and confirms that the quality of the same time slot is at a certain level 12 or higher. This continues until station 30 confirms, after which it releases channel CH1 time slot SD1°SUI and channels CH1 time slot SDI2. Communication is continued without momentary interruption only by SUl 2.

The switching frequency f1 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 CH1 is n, and the time interval of one time slot is T1, then it is given by =1 fl -(nT1) x2.

78 to 7E are flow charts showing the flow of operations when switching channels when co-channel interference occurs during a call.

Gateway exchange 20. Radio base station 30 and mobile radio device 10
0 has started operation, the switch group included in the barrier exchange 20 is on, and communication is in progress between the radio base station 30 and the mobile radio device 100. For this communication, time slots sD1 . SU1. Downstream frequency F1 and upstream frequency f1 are used (3451, Figure 7A).

The mobile radio device 100 is constantly connected to the radio base station 30 in communication.
reception status reports from, for example, fading or
If a control signal in each time slot used for communication reports (3452) that reception is not possible due to interference, and interrupts the standards required by the actual system. The radio base station 30 that receives this sends a report from the transmission quality monitoring section 34 within its own station (this has the function of the reception quality monitoring section 158 and the interference detection section 162 of the mobile radio device 100). After comprehensive consideration, decide whether to perform busy zone switching or time slot switching within the same zone. If the reason for the inability to receive is due to a decrease in the received electric field, the process moves to a separately determined busy zone switching operation (S453 YES).

If the cause of the inability to receive is not due to a drop in the received electric field (3453 NO>), check whether it is due to co-channel interference (S454, Figure 7B) and determine that it is necessary to change the time slot within the same channel.5455 ), reports to the radio 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 SU1 (34
56) Then, the control unit 40 of the wireless base station 30 that received this (S457) searches for the presence or absence of an empty time slot, and determines the time slot 5D12.5U12 (3458). The control unit 40 transmits time slot 12 of channel CH1, that is, SDl 2. SUl 2
command to prepare for communication (S459, 7th
Figure C).

This command is sent by a control signal outside the band of time slot SD1, and the mobile radio 100 receives this communication preparation command (5460), channel CH1, time slot SD12. Preparations are made to enable communication by SUL 2, that is, the control unit 140 causes the transmission/reception intermittent controller 123 to start an operation that also uses time slots 5D12 and 5U12 (3461).

On the other hand, the wireless base station 30 also uses time slot SD1.
12. In order to prepare for parallel communication by SU1.12, the signal selection circuits 3B-1, 38-2 of the signal selection circuit group 38,
Signal speed restoration circuit 38-1 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 (34
62).

When the mobile radio device 100 is ready to communicate using the time slots SD12 and 5L112 of the channel CHI, the mobile radio device 100 sends a report of completion of preparation in a timely manner.
A report is made to the wireless base station 3o using a control signal outside the band of slot SU1 (S463). Upon receiving this report, the wireless base station 3° transmits time slot SD12. SUl
The preparation for parallel transmission and reception by 2 is completed (5464), and parallel transmission and reception is started (S465, FIG. 7D). That is, the SDl 2 sends out a communication signal including an ID signal, and the mobile radio device 100 receiving this communication signal (8466
), upon confirming that the signal of time slot 5D12 addressed to radio base station 3o was successfully received (S467),
A confirmation signal is sent by the control signal of time slot 5U12 (3468). When the radio base station 30 receives this report (S469), the radio base station 30 selects time slot 5U12.
The transmission quality is confirmed by the transmission quality monitoring unit 34 (S47
0), time slot SD1.0 between the radio base station 30 and the mobile radio 100; The mobile radio 11100 is commanded to stop the communication that was being performed using SU1 (S471, 7th
Figure E). The mobile radio device 100 that received this (S472
), time slot sD1. Communication by SU1 is turned off (S373). That is, the control section 140 controls the transmission/reception intermittent controller 123 to set the time slot 5D12.
．． .

In addition to operating only time slot SU1.5U12. SDI communication stop report to channel CH1
is sent using time slot 5U12 (S47
4. ). The wireless base station 30 that received this (S475)
, executes similar measures at its own station (S476).

As a result, the channel switching operation period ends, and the mobile radio device 50 is disconnected from the radio base station 30 for an instant.
Communication can be continued without noise (S4
77).

By the way, when changing the time slot during a call as mentioned above, how big is the amount of interference?
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 threshold value for this operation, the already explained FIGS. 10A and 10B 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.

Also, FIG. 10C, which is necessary for the explanation of the next section (6), will be explained. FIG. 10C shows how the S/N changes when the signal modulation depth Δf1 is changed. Here, it is assumed that the delay time τ is 12.5 μsec. Increasing the modulation deviation increases the S/
It specifically shows the amount by which N increases, and can be used for system design. However, the graph in FIG. 10C shows the case where the modulation shift is increased to the value indicated by Δf1 on the horizontal axis of the figure for both the interference wave and the desired wave.

(6) Measures to be taken when neither the measures in paragraphs (4) nor (5) can be implemented A method for dealing with this problem by switching the channel during a call between adjacent wireless base stations 30 has been explained. In addition, in section (4), a method for switching wireless channels or time slots within a certain wireless zone when wireless interference occurs due to other communications during a call within the same zone has been described. Zarani (5)
In this section, we explained countermeasures for removing multiwave propagation distortion.

However, depending on the call traffic situation during operation of the system, the above measures may or may not be implemented.

For example, in the case where the electric field value first decreases, i) the call traffic within the zone of the surrounding wireless base station 30 is congested, and even if you try to perform channel switching according to section (4), there will be an empty channel (time There is no slot).

The next case in which radio interference occurs is ii) The call traffic within the radio base station 30's own zone is congested, making it impossible to shift to a time slot group with a long guard time.

i) The call traffic in the zone of the surrounding wireless base station 30 is congested, and all time slots with long card times are being used, and if this is used at the own station, wireless interference will occur. Therefore, it cannot be used at your own station.

■) If the circumstances mentioned in ii) and 1ii) above are not met, the mobile wireless 1fi owned by a subscriber with a high service class
For IQO, it is necessary to leave time slot groups with long card times open.

As a countermeasure for the above-mentioned case, there is a method of increasing the transmission power of the transmitters of both the radio base station 30 and the mobile radio device 100, which are communicating face to face with respect to the radio base station 30 and the mobile radio device 100 where the input electric field has decreased. This countermeasure can be easily taken for the mobile radio device 100 by increasing the gain of the power amplification section included in the radio transmitting circuit 132 (not shown in FIG. 1B); 30 is not as easy as mobile radio 100. This is because the wireless base station 30 generally communicates with many mobile wireless devices, and in order to increase only the transmission power for a specific mobile wireless device, the first
This is because it is necessary to provide the wireless transmission circuit 32 with a special circuit as shown in FIG. 4A. FIG. 14A will be explained in detail in the next section (7>).

(7) Example of System Construction Capable of Composite Services Above, the case where a single service is provided by the system according to the present invention has been described, or the mobile radio device 100 is a mobile phone terminal and two image terminals.

The system according to the present invention exhibits its characteristics when terminals with different service targets coexist, such as car phone terminals. This will be explained using FIG.

The signal processing unit 31 of the radio base station 30B in FIG.
The gateway switch 20 in Figure A and the communication channels CH'l to CH
Communication signal 22-1 including each call signal of m and a control signal
They are connected by a transmission line that transmits ~22-m.

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 30B. The signal processing unit 31 is equipped with an amplifier to compensate for transmission loss, and in addition to the functions already described, such as performing so-called 2-wire to 4-wire conversion, the following functions are provided in the case of incoming calls. .

Based on the ID signal included in the control signal addressed to the specific mobile radio device 100 from the barrier switch 20, the radio base station 30B
identifies whether the incoming call is addressed to a mobile phone or a car phone, and determines whether to send it to the signal speed conversion circuit group 51a (for mobile phones) or 51b (for car phones) depending on the result. Here, the signal speed conversion circuit groups 51a and 51b are the same as the signal speed conversion circuit group 51 in FIG. 1C.

As an ID identification method, for example, a simple method is to identify a mobile phone if the last digit of the phone number is an even number, and a car phone if the last digit is an odd number. A slightly more complicated method is to use one of the four digit numbers.
Those in the 5000s and 6000s are identified as mobile phones, and the others are identified as car phones. Furthermore, there are various methods such as identifying a mobile phone if the last two digits are 40 or less, and identifying it as a car phone if the last two digits are less than 40.

By identifying as described above, the input signal from the barrier exchange 20 is sent to the signal speed conversion circuit group 51a, 51b, and subsequent processing of the signal follows the process described above. However, what should be kept in mind here is that
The signal speed conversion circuit group 51a and the 5° 1b have different speeds in speed conversion. That is, mobile phones have faster signal conversion speeds and shorter guard times than car phones.

The reason for doing the above is that, as described in Document 3, the method for removing adverse effects differs depending on the difference in multiwave propagation characteristics.

On the other hand, the output from the radio receiving circuit 35 includes a signal from a mobile phone or a car phone, and the former is input to the signal selection circuit group 39a, and the latter to 39b, where it is subjected to the signal processing described above. become. Here, the signal selection circuit groups 39a and 39b are respectively the same as the signal selection circuit group 39 in FIG. 1C.

The signal speeds of the signals from the mobile telephones and car telephones selected by the signal selection circuit groups 39a and 39b, respectively, are restored by the signal speed restoration circuit groups 38a and 38b, respectively. Here, the signal speed restoration circuit groups 38a and 38b are respectively the same as the signal speed restoration circuit group 38 in FIG. 1C. The signals that have undergone speed restoration processing are transmitted to the barrier exchange 20 by the signal processing unit 3 using the same transmission paths as those for the corresponding input signals.

The frame structure of the above composite signal is shown in FIG. 2H. FIG. 3(a) shows an output signal of the wireless transmission circuit 32 of the wireless base station 30B, and the structure of one frame is divided into subframes a and b. Subframe a is the mobile radio device 100
It shows the time slot sequence for mobile phones,
Subframe b shows a car phone. The time width and guard time of the time slot of subframe a are smaller than those of subframe b because
This is because the multiple load gain, which will be described later, is large and is less susceptible to the effects of multi-distorted wave propagation. The synchronization signal is shown as an example in which the last time slot of each subframe is used, or depending on the system, only one synchronization signal is used in one frame.

Note that Figure 2H shows a case where there is a subframe space within one frame that can be used for another purpose, which will be described later. In the case of the zone method, when used for transmission signals from adjacent wireless base stations, the effective frequency utilization rate improves.

The calling/receiving operations for the composite service shown in FIGS. 1A, 1B, and 1F are not much different from those already explained in FIGS. 4A and 4B.

However, the type of terminal is ID-identified depending on whether it is a mobile phone or a car phone, and the speed conversion or restoration speed of each signal is different, and the transmission output of the wireless base station 30B is also significantly different. To explain the transmission output of the wireless base station 30B, it is 5CPC (Sinc+le Channel
Per Carrier> system, that is, the transmission power for a normal cordless phone is 10 mW, and for a car phone it is 5W. Therefore, it can be seen that the car phone must provide 500 times higher transmission power than the mobile phone (5W/10mW=500), that is, unless the difference in multiload gain, which will be described later, is not taken into consideration. In reality, since the multiple load gains of each signal are also different, the above-mentioned significant difference in transmission power level does not necessarily occur.

If the system design is improved, it is possible to reduce the level difference.

In the following, a method will be described in which subsystems having different transmission powers can coexist in one system as described above, and also be highly resistant to the adverse effects of multiple wave propagation.

FIG. 1G shows a detailed configuration of the signal speed conversion circuit group 51a shown in FIG. 1F. In FIG. 1G, switch 81-1.
82-1.81-2.82-2゜...,...,81
-m and 82-m are each controlled by a control signal from the control unit 40, and normally each switch is turned to the a side, and the low frequency pass filter 83-1.
．． ..., 83-m is not controlled to be turned on.

However, due to the influence of multiple wave propagation, for example, Fig. 2H (
Suppose that the quality of the signal in time slot 5Da-1 shown in a> has deteriorated. This deterioration is caused by the transmission quality monitoring section 34 (first
Fig. F> is detected and immediately transmitted to the control unit 40. If the control unit 40 wants to transfer the signal of time slot 5Da-1 to subframe b etc. with a large guard time, or if it is found that this is not possible due to the congestion of call traffic, the control unit 40 transfers the signal of time slot 5Da-1 to subframe b etc. with a large guard time, Among the signals, it is decided to insert a signal input to the signal speed conversion circuit 51a (regarding the low frequency pass filter 83-1 (for example, 0.3 to 2.5 kHz). Then, the switch 81-1.82
A control signal is sent to -1 to cause the terminal to move from the a side to the b side. At the same time, the signal speed conversion circuit 51a-1
The time compression rate is lower than the conventional 1/n (1/n) x 2
．． 5/ Instruct to increase by 3.0 times. As a result, the time length of time slot 5Da-1 is reduced by 2.5/3.0 times, or about 83%, from the conventional value.

The guard time between time slot 5Da-1 and the immediately preceding time slot increases significantly as shown in the numerical example below, and the time slot 5Da due to multiple wave propagation increases.
-1 radio interference will be significantly reduced. In addition, if even this level of value is insufficient, the high cutoff frequency of the aforementioned low frequency pass filters 83-1 to 83-m can be changed to the aforementioned 2.
．． If you lower it from 5kH2 to 2kH7 or 1.5kH2, you can get even more guard time.
It becomes possible to greatly reduce interference due to multiple wave propagation. However, if the high-frequency components of the signal are cut off too much, the quality will deteriorate significantly, so it is necessary to keep it at an appropriate value. In FIG. 11, which will be described later, the frequency band of the telephone signal (
0.3~3.0kH2) respectively 0.3~1.5kH
Two examples are shown where z is scaled down from 0.3 to 2.5 kHz.

The above explains how interference from adjacent time slots is removed or reduced by increasing the guard time.
In the present invention, as explained below, the increase in multiple load gain is used to increase the amount of modulation deviation, and the time
We would like to clarify that the transmission quality of slot 5Da-1 can be further improved. According to document 4, the frame length T
t is T > 1/(2fh) However, fh is the highest frequency of the audio signal, and when the number of multiplexes is n, the multiple load gain is determined by the value n'-nxl-'(2fhTt) (1) It is assumed that the value is equal to the multiple load gain of a frequency division multiplexed signal having a multiplex number.

However, the above formula (1) assumes that the density of the CM signals in the frame is constant, and as shown in Figure 2H, the time slot width, card time length, or maximum signal In the case of a time slot arrangement with different frequencies, the density of the TCM signal is not uniform, so simply substitute the total number of time slots, frame length, and Nyquist frequency into equation (1) to find the FDM equivalent multiplex number. , even if the value of the multiload gain is obtained from this, it will lack accuracy.

Below, we will derive a mathematical formula that gives an accurate multiple load gain 1q even when the time slot density is not uniform as shown in FIG. 2H, and then we will derive the case where the highest frequency of the signal is different. To derive the former equation, divide the frame into several subframes, and if the signal density (time slot density) is constant within each subframe, then the multiple load gain within this subframe is It will show the correct value. , g', that is, the frame length Tt is subframe T1. T2, . . . , T, and the number of multiplexing in each subframe is nl.

n2. ..., nk, and assuming that all the signals are telephone signals, the multiload gain of CM (No. 3) existing in each subframe can be found by thinking as follows.For example, if the DM conversion gain in subframe T1 is The multiplex number is
It is assumed that only T1 is multiplexed within the frame length, and the number of multiplexes can be set to O at other times. That is, -n1 x1/(2fhT1) +Qx 1 / (2fh(Tt = n1x1/ (2fhT1) >(1-1>) Similarly, for n, n3..., nk, '2'
= n2 x 1 / (2fh T2 ) (1-2> n k = n k X 1 / 2 f h T k (
It is equal to the multiple load gain of a frequency division multiplex signal having a multiplex number determined by the value 1-k>.

Next, the subframe is divided into several sub-subframes, and the highest frequencies of signals are made equal within the divided sub-subframes.

In other words, sub-frame T1 is changed to sub-sub-frame T11.
．． T12. ..., Tlpl, and the highest frequency of the signal in each divided sub-subframe is fhll, f, ..., fold, 1, and the number of multiplexes is n.
11. n12. . . , n1p1, and similar division is performed for other subframes T2, T3, . . . , Tk. The multiple load gain of the TCM signal present in subframe T1 can be determined from the number of multiplexed FDM exchanges described below by introducing the same concept as described above.

n11' = n11X 1 X (2f hll T
11) (11-1>n12' = n12X 1 X (2T112 T12
) n1p1=r11p1X 1 X (2fhlpl”
lpl) (1-1-pl) Subframes T2, T3 . ..., Tk is also obtained in the same manner as above. However, this is extremely troublesome, so the following concept of instantaneous FDM conversion multiplex number is introduced.

n' = ρX 1/ (2fh>(1'
) where ρ=n/T (2)(
In equation 1'), ρ is the ratio of the number of multiplexes n included in the minute subframe near the considered time slot to the number of subframes, that is, it can be considered from the concept of signal density, and fh is the highest frequency of the signal contained in the time slot of interest.

By introducing the above concept, the time slot configuration within a frame and the multiple load gain of TCM signals having different maximum frequencies of signals vary from moment to moment. However, if this change is not significant, it can be counted as an average multiple load gain using the FDM conversion type as shown in the following equation.

n''' =nx 1/ (2fhHTH) (1'') However, 1 /f (1/n > hH= ×(1/fh11+1/fh12+...+1/f
hK, k) 1/TM = 1/n x (1/T11+ 1/T12+...+1/TK
pk) where n is the time slot 5Da-1 whose result has already been explained, which is greater than or equal to the total number of time slots in the frame.
It is clear that the multiload gain increases when applied to FM modulation, and therefore, if the increase in the multiload gain is used to increase the modulation deviation of FM modulation, it can contribute to improving the signal-to-noise ratio. It will be easy to understand that.

The multiple load gain of each subframe of a composite TCM signal is determined using a specific system example, and a construction example for realizing this will be described below.

In Fig. 2H, if the system parameters of each subframe are assumed as shown in Fig. 12, the multiple load gain of the TCM signal of each subframe is calculated based on the conditions of Fig. 11 with reference to Fig. 13. is given as shown in the multiload gain column. Here, FIG. 13 is a diagram showing the multiple load gain obtained with reference to Document 4.

Using the multiload gain thus obtained, the required transmission power for each subframe a and b can be determined by the following equation.

Subframe a 10 log [10mWx 500] -30=7
dBm i.e. 5 mW subframe b 10 loQ [5W x50] -13=11dBW
That is, the value of the above required transmission power of 12.5W is also shown in FIG. However, the required transmission power at 5 cpc was set to 10 mW for a mobile phone and a button for a car phone.

Next, the communication quality of the signal in the time slot belonging to subframe a deteriorates due to the influence of multiple wave propagation, and for the reasons mentioned above, the guard signal in subframe b etc.
If it is not possible to shift to a time slot with a wider time slot, the signal frequency band of the telephone signal is
Reduce high frequency range. The effect at that time will be specifically explained using FIG. 11.

In FIG. 11, the frequency range of the telephone signal in time slot 5Da-1 is 0.3 to 1.5 kHz and 0.3 to 1.5 kHz.
The two cases compressed to 3 to 2.5 kHz are blown out in the normal case (SDa-2 to 5 Da-nu).

Frequency range of time slot 5Da-1 0.3-1.
In the case of 5kHz2, the frequency band of the signal is 1/2 of the normal frequency band, so it is possible to increase the signal compression rate to twice that of the normal case. Therefore, the time slot time length is 0.9 μsec, and the guard time (SD
The time interval between a-1 and the immediately preceding time slot> is 0.2+0.9=11 μsec, which is more than five times the normal value. In addition, the number of FDM conversion type multiplexes is doubled to 66, and the multiplex load gain is increased by 5 dB to 35 dB. As a result, the depth of FM modulation can be increased by 5 dB compared to usual, and as shown in FIG. 10C, an improvement in S/H of approximately 5 dB or more can be expected depending on the operating conditions.

Frequency range of time slot 5Da-1 0.3-2.
In the case of 5k)-12, similar calculations yield results as shown in FIG. However, in FIG. 11, calculations are made for subframe a and subframe b, and are not calculated for other subframes. Note that the actual compression rate of the telephone signal in subframe a or subframe b is related to the frame length.
0 m sec, the compression ratio of the telephone signal in time slots 5Da-2 to 3[)a-500 of subframe a is: 0.1x (11500) = 115000 Also, in subframe bk:#, 0 .1xl 150=11500.

Next, the radio base station 30B shown in FIG.
A specific method for obtaining transmission signals required for transmission of each subframe a and b in the figure will be explained. However, the Haku subframe within the frame was omitted. Therefore, the detailed configuration of the wireless transmission circuit 32 shown in FIG. 1F will be explained using FIG. 14A.

In FIG. 14A, from the left side, the signal assignment circuit group 52a (
signal group included in subframe a) or the output of the signal allocation circuit group 52b (signal group included in subframe b), or intra-frame variable amplification baseband amplifier 3
21.

As its name suggests, the intra-frame variable amplification baseband amplifier 321 changes the amplification (output level) from the timing generation circuit 42 for each subframe (further subdivided and for each time slot) of the signal constituting the frame. It can be made variable by timing information, and techniques for varying the amplification degree are well known.

FIG. 14B shows an example of a change in amplification degree. In this case, the amplification degree changes between subframe a and subframe b as shown in the figure. Furthermore, time slot 5Da-1
As already explained, the amplification increases only when the adverse effects of multiple wave propagation occur. However, this change in amplification degree will be repeated periodically over time.

Thus, the operating conditions for the intra-frame variable amplification baseband amplifier 321 placed before the FM modulator 322 are set to 3Q dB in subframe a (however, the amplification is 31 dfs only for time slot 5Da-1).
(or 35 dB)) If subframe b is set to give 13 dB (FIG. 11), it is possible to obtain the required value as the amount of modulation shift. However, it is assumed that the input level of the intraframe variable amplification baseband amplifier 321 is the same for both subframes a and b.

Next, on the output side of the FM modulator 322, an intra-frame amplification variable high frequency amplifier 323 is installed again, and this operating condition is set to an output level of 7 dBm in subframe a.
(5mW>, same for subframe b<116B
When set so that w (12,5W > is obtained,
A system that satisfies the design parameters will be constructed. Note that in the period in one frame shown in FIG. 148, amplification and modulation determined by the nature of the signal contained therein are performed during the time that does not yield to either subframe a or subframe b. Of course.

The above is a case where the radio base station 30B transmits, but a case where the mobile radio device 100 transmits will be explained. The transmission signal of mobile radio 100 is simpler than that transmitted by radio base station 30B. This is because the mobile radio device 100 is configured for each purpose, such as a mobile phone or a car phone, and the required transmission power and modulation shift amount are determined for each subsystem. Among these, the transmission power differs in each system due to the transmission antenna gain and the loss of the feeding system, but the modulation deviation amount of the FM modulator is the same as that of the corresponding signal transmitted from the wireless base station 30B. The transfer quantity is given in the same way as when constructing a normal system. To be more precise, the descent (
(transmitted by the wireless base station 30B and received by the mobile wireless device 100)
The frequency bandwidth given to the line and the upstream (mobile radio 1
This is because if the frequency bandwidth given to the line (transmitted by 00 and received by radio base station 30B) is the same, frequency efficiency is highest when the system is operated under the above conditions.

However, in the mobile radio device 100 where the signal quality is degraded due to the influence of multiple wave propagation even in the same subframe, the signal dividing circuit 13 whose detailed configuration is shown in FIG.
9, the switches 181 and 182 are connected to the control unit 140.
The low frequency pass filter 18 is operated by a control signal from the low frequency pass filter 18.
3 side, and the same operation as the wireless base station 30 is performed.

As mentioned above, as a result, the frequency band of the telephone signal is reduced, the compression ratio of the signal is increased, the multiple load gain is increased, and the amount of modulation shift is increased.

The example described here is a case of system construction that includes two subsystems with different service targets: a mobile phone carried by a person and a car phone used in a car, which provide the same service content of telephone calls. In addition to this, cases involving different service contents such as telephone and image communication, or cases involving three or more types of services,
The degree of signal compression, multiple load gain, signal amplification, or required transmission output level is different for each, and the measures to be taken in the event that any of these signals suffers from signal quality deterioration due to multiwave propagation are also as explained above. It is also possible.

[Effects of the Invention] As is clear from the above explanation, the time division time compression multiplex signal is composed of composite signals such as many types of signals and signals that enable many types of services, which have not been clearly shown in the past. As a result of quantitatively clarifying the multiple load gain of the composite signal for each basic signal group that makes up the composite signal, and k for each time slot unit signal group that makes up the composite signal, we found that each basic signal Even if the depth (deviation) of angle modulation is increased by the amount of multiload gain for each signal group, roughly speaking, for each time slot, the effect on other radio channels can be minimized compared to conventional designs. In addition, it is possible to reduce the transmission output level per wireless channel compared to conventional systems, which not only helps in reducing power consumption, but also improves amplifier design and passive element ratings. Since it has become possible to design rationally and economically, up to the point of determining the method, the effect on communication systems, especially wireless systems, is extremely large.

[Brief explanation of the drawing]

FIG. 1A is a block diagram showing the configuration of a gateway exchange provided in the system of the present invention and its connection relationship with a telephone network and a radio base station; FIG. 1B is a circuit diagram of a mobile radio device used in the system of the present invention; FIG. 1C is a circuit configuration diagram of an embodiment of a wireless base station used in the system of the present invention, FIGS. 1D and 1E are specific circuit configuration diagrams of a wireless transmission circuit, and FIG. A circuit configuration diagram of another embodiment of the wireless base station used in the system; Figure 1G is a detailed circuit diagram of a signal speed conversion circuit group that is a component of Figure 1E; Figure 1H is Figure 1B. Figure 2A is a time slot structure diagram for explaining the time slots used for transmitting time division time compression multiplexed signals, and Figure 2B is a time slot structure diagram for explaining the time slots used for transmitting time division time compression multiplexed signals.・A waveform diagram showing the radio signal waveform of the slot; FIGS. 2C and 2D are time slot structure diagrams for explaining channel switching in the system of the present invention; FIGS. 2E (a') and (b) are FIGS. 2F and 2G are spectral diagrams and circuit configuration diagrams for explaining configuration examples of control signals used in the invention, and time slots for explaining time slots used when interference occurs in the system of the present invention. A slot structure diagram; FIG. 2H is a time slot structure diagram for explaining the frame structure of a composite signal used in the system of the present invention; FIGS. 3A and 3B are spectra showing spectra of speech signals and control signals. Figures 4A and 4B are flowcharts showing the flow of the calling operation of the system according to the present invention, Figures 5A, 5B, 5C and 5D.
6A, 6B, 6C, 6D, and 6E are flowcharts showing the flow of channel switching operations between adjacent wireless zones in this system.
7A, 7B, and 7C are flowcharts showing an example of the operation flow of time slot switching for dealing with interference during a call in a system according to the present invention.
7D and 7E are flowcharts illustrating other examples of the operational flow of time slot switching to deal with interference during a call in the system according to the present invention,
Figure 8 is a parameter numerical diagram showing examples of various parameters used in a time division time compression multiplex communication system, Figure 9 is an amplitude change diagram showing changes in amplitude due to multiple wave propagation, Figures 10A and 10B are S/ due to multiwave propagation distortion
Figure 10C is an S/N diagram showing S/to due to changes in the modulation depth of the signal, and Figure 11 shows the multiload gain when the present invention is applied to a composite signal. Figure 12 is a multiple load gain diagram showing the relationship between the multiple load gain of a frequency multiplexed signal and the number of communication paths, quoted from a known document. Figure 13 is a multiple load gain diagram of a time division time compression multiplexed signal. Figure 14A is a diagram showing the relationship between the number of audio signals and the number of multiplexed audio signals.
FIG. 148 is a circuit configuration diagram showing the internal configuration of the radio transmitting circuit which is a component of the figure. FIG. 148 is an amplification characteristic diagram of the variable amplification amplifier of the radio transmitting circuit shown in FIG. 14A. 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 to 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 81.82...
- Switch 83...Low frequency pass filter 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 1
21-1, 121-3...Synthesizer 122-1.
122-2...Switch] 23...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 141.
... Clock regenerator 158 ... Reception quality monitoring section 159 ... Power amplifier 161 ... FM modulator 1
62...Interference detector 167...Local oscillator 168...Gain control unit 169...Modulation deviation amount control unit, 181°182...Switch 183...Low frequency pass filter 184... ...Amplifier] 85...2 branch circuit.

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 during communication detects deterioration in communication quality due to mixing of time slots adjacent to the time slot in use, the communication quality deteriorates. The maximum frequency of the delimited signal associated with the time slot in use is decreased, and the time compression ratio of the delimited signal is increased accordingly to increase the guard frequency between the adjacent time slots. A time division communication system for mobile communication in which the modulation shift of a transmission signal is increased in accordance with an increase in multiple load gain obtained by increasing the time compression ratio.