JPH05199165A - Time split communications method for mobile communication - Google Patents

Abstract

PURPOSE:To provide the mobile communication conveying the time-compressed telephone signal with the level suppressed to the time slot in frame configuration. CONSTITUTION:This method uses each radio-base station 30 constituting the service area covering multiple zones and a gate exchange 20 exchanging communications with each mobile radio device 100 using radio channels conveying time-compressed telephone signals with the level suppressed to the time slot in frame construction crossing across zones so as to communicate with the radio base station. Accordingly, the large multiple load gain can be obtained to be used for the increase of modulation displacement in the radio base station and the mobile radio device. Thus, the transmission power can be reduced and an efficient use of the frequency can be made.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system in which a signal having a band characteristic such as that of a telephone is time-divided / time-compressed and then modulated, and the redundancy of the transmission signal is reduced. The present invention relates to an effective use method of frequency and an effective use method of frequency. More specifically, a certain wireless channel is provided, and one of the many mobile wireless devices in the service area is used to set up a wireless channel and communicate with an opposite wireless base station. Among, when the other mobile wireless device starts communication with another wireless base station using the same wireless channel, because of effective use of frequency or radio wave propagation characteristics, respectively, with the mobile wireless device during communication, It is intended to provide a method for improving the effective utilization of frequency by gradually reducing the transmission output while eliminating the adverse effect on the communication with the radio base station, and an economical system using the method. Is.

[0002]

2. Description of the Related Art In mobile communication using voice to which a small zone method is applied, a method using a time division time compression multiplexed signal is described in the following document.

Reference 1. Ito "Study on mobile phone systems-Proposal of time division time compression FM modulation system-" IEICE Technical Report R
CS89-11 July 1989

Reference 2. Ito "Study on mobile phone system-Theoretical study on time-division time-compression FM modulation system"
RCS89-39 October 1989

Reference 3. Ito "Study on mobile phone systems-Study on multipath propagation characteristics of time division time compression multiple FM system-"
IEICE Technical Report RCS89-47 January 1990

Reference 4. Ito "Elucidation of multiple load gain of time division time compression multiple telephone signal and application to FM mobile communication" IEICE Technical Report RCS89-65 March 1990

Reference 5. Ito "On Co-Channel Interference When Time-division Time-compression Multiplexed Telephone Signal is Applied to Small Zone System" IEICE Technical Report RCS90-7 1990
Month

That is, in Reference 1, a transmission signal (baseband signal) is divided into predetermined time interval units and stored in a storage circuit, and when this is read, it is n times faster than the storage speed in the storage circuit. Built in mobile radios and radio base stations to read at a predetermined time slot, angle-modulate or amplitude-modulate a carrier wave with the signal accommodated in this time slot, and to transmit and receive intermittently in time. , A switch for a radio receiving circuit having a receiving mixer that communicates with each other, a radio transmitting circuit having a transmitting mixer, a synthesizer applied to the receiving mixer of the radio receiving circuit, and a synthesizer applying to the transmitting mixer of the radio transmitting circuit A circuit is provided, and the output of the synthesizer applied to each is interrupted, and this interrupted state is transmitted and received. For the wireless base station that communicates with each other for the opposite purpose, the same method as the above is used to synchronize the intermittent transmission and reception with that of the mobile wireless device, and the receiving side extracts only the signal accommodated in the predetermined time slot. Therefore, the signal received by demodulating by receiving and opening the wireless receiving circuit is stored in the memory circuit, and at the time of reading this, by reading at a low speed of 1 / n of the speed stored in this memory circuit, A system example in which a system capable of reproducing a baseband signal which is the transmitted original signal is constructed has been reported.

Next, in Document 2, the above-mentioned TCM is used.
(Time-division time compression multiplexing) -Adjacent channel interference and co-channel interference, which are problems when the FM system is applied to a small zone, are being studied, and the system can be realized by selecting system parameters appropriately. The possibility is shown.

In Reference 3, the effect of multipath fading that a TCM signal receives during transmission in space is examined, and guard time is set between time slots as a measure for removing or reducing this effect. I suggest you do.

Further, in Reference 4, the multiplex load gain, which has been known to exist in the conventional FDM (frequency division multiplex) signal, has a multiplex load gain similar to that of the FDM signal in the time division time compression multiplex (TCM) system. Reveal that, and
It explains the quantification and operation examples of the system. Then, by using this multiple load gain to deepen the modulation depth of the FM, the transmission power can be significantly reduced, and it is expected that the mobile wireless device can achieve a significant power saving. Has been reported.

[0012] Document 5 describes co-channel interference in a radio system using a TCM signal. Among them, when a carrier wave is angle-modulated using a TCM signal, the amount of modulation deviation is increased. , It is described that co-channel interference is reduced to improve the effective utilization of frequencies.

[0013]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the system construction example shown in FIG. 1, a general description of a mobile communication system using a TCM signal is given. Although the system construction is possible by this, it is compressed in time slots of a frame structure. It is a case where all the power of a divided signal is transmitted, and when the power exceeds a level defined by the system, only the signal power obtained by subtracting the value is transmitted is not described.
In Document 4, the multiple load gain relating to the signal power of the TCM signal is explained.
Only the case of transmitting all of the time-compressed delimited signals to slots is disclosed, and when the transmission power exceeds the level set by the system, when the value is suppressed by a certain rule and transmitted. It is possible to increase the multiple load gain of the signal, reduce the wireless transmission power, and improve the effective utilization of frequency, but these cases have not been clarified.

Further, in Document 5, it is explained that, when communication is performed by using a TCM signal, if the modulation deviation amount is increased, co-channel interference is reduced and the effective utilization of frequency is improved. However, there is an unsolved problem that there is no description about the processing of the transmission power level and a method for effectively using the transmission power level is not disclosed.

[0015]

In a mobile communication system using a TCM (Time Division Time Compression Multiplex) signal, a transmission signal is a time-compressed and delimited signal for transmission in a frame-structured time slot. Usually, the carrier is modulated in addition to the angle modulator, amplified to an appropriate level, and then added to the antenna for transmission.

In order to increase the multiple load gain of the signal, the power of the temporally compressed delimited signal is applied to the angle modulator for transmission in the time slots of the frame structure. If the signal power is below the level specified by the system, and if the signal power exceeds the level specified by the system, the value is suppressed by a certain rule and then added to the angle modulator. As a result, the multiple load gain of the signal can be increased, and as a result, the transmission power can be reduced.

[0017]

In the communication using the TCM signal, a large number of telephone signals are disconnected as transmission signals at fixed time intervals (this is called a time piece signal), and this is, for example, 10 times.
In the case of multiplexing, it is compressed ten times in time and arranged at the position of the time slot number given to each of the 10 time slots prepared in the frame structure.
In the conventional method, all the powers of these compressed signals are sequentially added to an angle modulator for transmission to modulate a carrier wave, which is amplified to an appropriate level and then added to an antenna for transmission. However, once again, if the signal power is below the level set by the system, the power remains as it is.If the signal power rises above the level set by the system, the value is suppressed by a certain rule, and then the angle modulation is performed. I will add it to the bowl.

As a result, the average power of the signal contained within the time 1 / (2f _h ) (f _h is the highest frequency of the telephone signal) of the signal applied to the angle modulator for transmission is reduced. This means that in consideration of the content suggested in Document 4, the radio wave interference of this radio channel with the adjacent radio channel is reduced. Therefore, the signal level applied to the angle modulator may be increased to a level at which the same radio wave interference as before occurs. It is judged that the increase of the signal level applied to the angle modulator is due to the increase of the multiple load gain of the signal, and as a result, the modulation deviation amount is increased. The increase in the amount of modulation deviation brings about an improvement in the signal-to-noise (S / N) ratio, and if the S / N is kept at the conventional value, the transmission power can be reduced accordingly.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1, 2 and 3 show a system configuration for explaining a basic operation example of the present invention.

In FIG. 1, reference numeral 10 is a general telephone network, and 20 is a gateway switch for switching and connecting the telephone network 10 and a wireless system. Reference numeral 30 denotes a wireless base station, which is an interface with the gateway switch 20, a circuit for converting a signal speed, a circuit for allocating and selecting a time slot,
There is a control part etc., besides setting and releasing the wireless line,
It has a wireless transmission / reception circuit for exchanging wireless signals with the mobile wireless device 100 (100-1 to 100-n).

Here, the gateway switch 20 and the radio base station 30
And the communication lines 22-1 to 22-n including the call signals of the call channels CH1 to CHn and the control signals.

FIG. 2 shows a circuit configuration of the mobile radio device 100 which communicates with the radio base station 30. A received signal such as a control signal or a call signal received by the antenna unit is received by the wireless receiving circuit 13 including the receiving mixer 136 and the receiving unit 137.
5, and the output communication signal is the speed restoration circuit 1
38, the control unit 140, and the clock regenerator 141. The clock regenerator 141 regenerates a clock from the received signal and applies it to the speed restoration circuit 138, the control unit 140, and the timing generator 142.

The speed restoring circuit 138 restores the speed (pitch in the case of an analog signal) of the communication signal, which is a compressed and delimited level-suppressed signal (described in detail later) in the received signal to suppress the level. It is released and input as a continuous signal to the telephone unit 101 and the control unit 140.

The communication signal output from the telephone section 101 is divided by the speed conversion circuit 131 at predetermined time intervals to obtain a level-suppressed telephone signal, and the speed (pitch in the case of an analog signal) is determined. It is applied at high speed (compressed) to the wireless transmission circuit 132 including the transmission mixer 133 and the transmission unit 134.

The output of the modulator included in the transmission unit 134 is converted into a predetermined radio frequency in the transmission mixer 133,
The signal is transmitted from the antenna unit and received by the wireless base station 30. In order to transmit a radio signal to the radio base station 30 using the time slot permitted to be used by the mobile radio device 100, the timing information from the timing generator 142 shown in FIG. Must have been obtained by

The timing generator 142 supplies necessary timings to the transmission / reception interrupt controller 123, the speed conversion circuit 131 and the speed restoration circuit 138 by the clock from the clock regenerator 141 and the control signal from the control unit 140. There is.

The mobile radio 100 further includes synthesizers 121-1 and 121-2 and a changeover switch 122.
-1, 122-2 and changeover switches 122-1 and 122
-2 includes a transmission / reception gating controller 123 and a timing generator 142 which generate signals for switching each of -2, and the synthesizers 121-1 and 121-2, the transmission / reception gating controller 123, and the timing generator 142 are control units. It is controlled by 140. Each synthesizer 121
A reference frequency is supplied to the -1, 121-2 from the reference crystal oscillator 120.

A radio base station 30 is shown in FIG.
N-channel communication signal 22-1 with the gateway switch 20
22 to 22-n are connected to the signal processing unit 31 that forms an interface on the transmission path. Therefore, the communication signals 22-1 to 22-n sent from the gateway switch 20 are transmitted to the wireless base station 30.
Is input to the signal processing unit 31. The signal processing unit 31 includes an amplifier for compensating for transmission loss,
So-called 2-line to 4-line conversion is performed. That is, the input signal and the output signal are mixed and separated, and the input signal from the gateway switch 20 is sent to the signal speed conversion circuit group 51. Further, the output signal from the signal speed restoration circuit group 38 uses the same transmission line as the input signal in the signal processing unit 31, and the gateway exchange 20
Sent to. The input signal from the gateway switch 20 is input to the signal speed conversion circuit group 51 including many signal speed conversion circuits 51-1 to 51-n, is subjected to level suppression and is divided at predetermined time intervals, Receives (pitch) conversion. As for the signal transmitted from the wireless base station 30 to the gateway switch 20, the output of the wireless reception circuit 35 is input to the signal speed restoration circuit group 38 via the signal selection circuit group 39,
The speed (pitch) is converted, the level suppression is released, the original telephone signal is restored, and the signal is input to the signal processing unit 31.

The control of the radio receiving circuit 35 or the output of the call signal includes the signal selection circuit group 3 including the signal selection circuits 39-1 to 39-n for selecting the signal for each time slot.
9 is input, and the call signal is separated corresponding to each call channel CH1 to CHn. This output is restored by the signal speed restoration circuit group 38 including the signal speed restoration circuits 38-1 to 38-n provided for each channel to restore the signal speed (pitch) of the level-suppressed telephone signal. Is input to the signal processing unit 31 and is subjected to 4-line to 2-line conversion, and this output is transmitted to the gateway switch 20 as a communication signal 22-.
1 to 22-n.

Next, the function of the signal speed conversion circuit group 51 (FIG. 3) will be described. The input signal such as a voice signal or a control signal, which is divided into a certain time length, is stored in a storage circuit, and the speed is changed when reading the input signal, and the read signal is read at a speed of, for example, 15 times that of the storage time. Can be compressed. The principle of time compression of the signal speed conversion circuit group 51 is the same as the case of reproducing a voice recorded by a tape recorder at a high speed.
CD (Charge Coupled Device), BBD (Bucket Bri
gade Device) can be used, and the memory used in a television receiver or a tape recorder that compresses or expands the time axis of conversation can be used (reference: Kosaka et al. “Compressing the time axis of conversation. / Expanding tape recorder "Nikkei Electronics 1976 7
26th month, pp. 92-133).

CCD exemplified by the signal speed conversion circuit group 51
As described in the above-mentioned document, the circuit using BBD or BBD can be used as it is for realizing the time extension function of the signal speed restoration circuit group 38. In this case, the clock and control from the clock generator 41 are used. This can be realized by receiving a timing signal from a timing generator 42 that generates timing according to a control signal from the unit 40 and setting the reading speed to be slower than the writing speed.

The control or voice signal output from the gateway switch 20 via the signal processing unit 31 is input to the signal speed conversion circuit group 51, and is subjected to speed (pitch) conversion and predetermined level suppression processing. Then, it is applied to a signal allocation circuit 52 which allocates a signal for each time slot.

The signal allocating circuit 52 is a buffer memory circuit, which outputs 1 signal output from the signal speed converting circuit group 51.
A high-speed signal corresponding to a delimiter is stored in memory, the signal in the buffer memory is read out by the timing information from the timing generation circuit 42 given by the instruction of the control unit 40, and the signal is sent to the wireless transmission circuit 32. As a result, when the communication signals are viewed as channels, they are arranged in series without overlap in time series, and when all the control signals or call signals described later are implemented, it is as if they were continuous signal waves. become.

The above signals are sent to the wireless transmission circuit 32. The state of this compressed signal will be described with reference to FIG.

The output signals of the signal speed conversion circuit group 51 are input to the signal allocation circuit 52 and given time slots in a predetermined order. SD in Figure 4 (a)
, SD2, ..., SDn indicate that the speed-converted communication signals are assigned to each time slot. Here, in one time slot, a synchronizing signal and a call signal or / and a control signal are accommodated as shown in the figure. When the call signal is not installed, an empty slot signal is added to the call signal portion only with the synchronization signal, or in some systems, no signal including the carrier wave is transmitted. In this way, as shown in FIG. 4A, in the wireless transmission circuit 32, a signal forming one frame in the time slots SD1 to SDn is added to the modulation circuit. The multiplex signals time-serialized to be transmitted are angle-modulated in the wireless transmission circuit 32, and then transmitted to the space from the antenna section.

Regarding the transmission of the control signal between the radio base station 30 and the mobile radio 100 prior to the telephone call when making or receiving a telephone call, whether the telephone signal is in-band or out-of-band is used. It is possible. FIG. 5 shows these frequency relationships. That is, in the figure (a), an example of the out-of-band signal is shown, and as shown in the figure, the low frequency side (250 Hz) or the high frequency side (3850 Hz) can be used. This signal is used, for example, when it is desired to send a control signal during a call. FIG. 5B shows an example of the in-band signal, which is used at the time of making and receiving calls.

Although the above-mentioned examples are all for tone signals, it is possible to transmit various kinds of signals at high speed by increasing the number of tone signals or by modulating the tones to form subcarrier signals. Becomes

Although the above is the case of the analog signal, when the digital data signal is used as the control signal, it is also possible to digitally encode the voice signal and time-division multiplex both of them for transmission. A circuit configuration in this case is shown in FIG. FIG. 6 shows an example in which the voice signal is digitized by the digital encoding circuit 91, the data signal and the data signal are multiplex-converted by the multiplex conversion circuit 92, and applied to the modulation circuit included in the wireless transmission circuit 32. However, for digital data signals, the analog signal multiple load gain, which will be described later, does not normally exist, so this point must be noted in the system design. Then, if the opposite receiver receives the signal and the demodulation circuit performs the reverse operation to that shown in FIG. 6, the audio signal and the control signal can be separately taken out.

On the other hand, the signal transmitted from the mobile radio 100 is received by the antenna section of the radio base station 30 and input to the radio receiving circuit 35. FIG. 4B schematically shows the upstream input signal. That is, the time slots SU1, SU2, ..., SUn represent transmission signals addressed to the radio base station 30 from the mobile radios 100-1, 100-2, ..., 100-n. The contents of each of the time slots SU1, SU2, ..., SUn are shown in detail in the lower left of FIG. 4 (b) and consist of a call signal and / or a control signal. However, the synchronization signal can be omitted depending on the case where the distance between the mobile wireless device 100 and the wireless base station 30 is small or the signal speed. Further, when the waveform of the radio carrier of the uplink radio signal in the time slot is schematically shown in FIG.
It becomes like (c). Similarly, the transmission waveform from the wireless base station 30 to each mobile wireless device 100 is as shown in FIG.

The control signal of the input signals arriving at the radio base station 30 is immediately added from the radio receiving circuit 35 to the control unit 40. However, depending on the size of the speed conversion rate, it is also possible to add the signal from the output of the signal speed restoration circuit group 38 to the control unit 40 after performing the same processing as the call signal. The call signal is applied to the signal selection circuit 39. The signal selection circuit group 39 includes a control unit 4
According to the instruction of the control signal from 0, a timing signal from a timing generation circuit 42 that generates a predetermined timing is applied, and a synchronization signal, a call signal or a control signal is separately output for each time slot SU1 to SUn.

Each of these signals has a signal speed restoration circuit 38.
Is input to. This circuit has a function of performing inverse conversion of the speed conversion circuit 131 (FIG. 2) in the mobile radio device 100 on the transmission side, whereby the original signal is faithfully reproduced and transmitted to the gateway exchange 20. Become.

Hereinafter, an aspect of transmitting the signal space according to the present invention will be described with reference to the required transmission band and the relationship between the transmission band and the adjacent radio channel.

As shown in FIG. 3, the control signal from the control unit 40 is applied to the radio transmission circuit 32 in parallel with the output of the signal allocation circuit 52. However, depending on the size of the speed conversion rate, after the same processing as the call signal is performed, the signal allocation circuit 5
It is also possible to add from the output of 2 to the wireless transmission circuit 32.

Next, in the mobile wireless device 100, as shown in FIG.
As shown in FIG. 5, the circuit configuration is required when the communication path among the functions of the wireless base station 30 is one channel.

Original signal, eg voice signal (0.3 kHz-
The frequency distribution on the output side when 3.0 kHz) passes through the signal speed conversion circuit group 51 (FIG. 3) is as shown in FIG. That is, if the audio signal is converted 15 times as described above, the frequency distribution of the signal is as shown in FIG.
It means that the frequency is expanded to 4.5 kHz to 45 kHz. Although the frequency distribution of the signal is expanded here, it should be noted that the shape of the waveform simply undergoes a similarity transformation in which the frequency axis is stretched, and the waveform itself does not change. This is necessary when determining the value of the multiple load gain.

Now, FIG. 8 shows a case where the control signal is simultaneously transmitted using the lower frequency band of the audio signal. Of these signals, control signals (0.2 to 4.0)
kHz) and the speech signal CH1 (represented as SD1 at 4.5-45 kHz) are contained in a time slot, for example SD1. The same applies to audio signals accommodated in the other time slots SD2 to SDn.

That is, the time slot SDi (i =
2, 3, ..., N) is a control signal (0.2 to 4.0 kH)
z) and the communication signal CHi (4.5 to 45 kHz). However, the signals in each time slot are arranged in time series, and the signals in a plurality of time slots are not added to the wireless transmission circuit 32 at the same time.

The above control signal is not implemented when a time slot for the control signal is provided at the beginning of the frame, and when the lower frequency band is used for another signal, the communication signal is not used. Near the frequency band of (4.1 to 4,4
KHz or 46-46.5 kHz).

When these call signals are applied to the angle modulator included in the radio transmission circuit 32 together with the control signal, a required transmission band of at least f _C ± 45 kHz is required. However, f _C is a radio carrier frequency. If there are a plurality of wireless channels given to the system, the speedup of signals by the signal speed conversion circuit group 51 is limited to a certain value due to the limitation of these frequency intervals. The frequency interval of a plurality of wireless channels is f
Let _rep be the maximum signal speed due to the speedup of the above-mentioned audio signal be f _H, and the following inequality must be established between them. f _rep > 2f _H On the other hand, in the case of a digital signal, the voice is usually digitized at a speed of about 64 kb / s. Therefore, it is necessary to read the scale of the horizontal axis in FIG. However, the relation of the above equation holds in this case as well.

In addition, from the mobile radio 100 to the radio base station 3
The control signal input to 0 is input to the wireless reception circuit 35, part of its output is input to the control unit 40, and the other is sent to the signal speed restoration circuit group 38 via the signal selection circuit 39. . The latter control signal undergoes speed conversion (conversion to a low speed signal) completely opposite to that at the time of transmission, and then the general telephone network 10
The signal speed is the same as that used in the above, and is sent to the gateway exchange 20 via the signal processing unit 31.

Next, the operation of making and receiving a call in the basic operation of the system according to the present invention will be described by taking the case of a voice signal as an example.

(1) Calling from mobile radio device 100 will be described with reference to the flowcharts shown in FIGS. 9 and 10.

When the power supply of the mobile radio device 100 is turned on, in the radio receiving circuit 135 of FIG. 2, it is included in the downlink (radio base station 30 → mobile radio device 100) radio channel (referred to as channel CH1). Start capturing control signals. If the system is provided with multiple radio channels, i) the radio channel showing the maximum received input field ii) the radio channel indicated by the control signals contained in the radio channel iii) Within the radio channel , The wireless channel (hereinafter referred to as channel CH1) is being received according to the procedure defined in the system, such as the channel having an empty time slot. This is the time shown in Fig. 4 (a).
This is possible by capturing the sync signal in the slot SDn. The control unit 140 sends a control signal to the synthesizer 121-1 so as to generate a local oscillation frequency that enables reception of the radio channel CH1, and also switches 12
2-1 is also in a state of being tilted and fixed to the synthesizer 121-1 side.

Therefore, turn off the handset of the telephone unit 101.
When hooked (start of calling) (S201, FIG. 9), the synthesizer 121-2 of FIG. 2 receives from the control unit 140 a control signal for generating a local oscillation frequency that enables transmission of the radio channel CH1. Also, the switch 122-2 is also tilted to the synthesizer 121-2 side to be in a fixed state.
Next, the call control signal output from the telephone unit 101 is transmitted using the radio channel CH1. This control signal is
This is transmitted by means of the frequency band shown in FIG. 5, for example using the time slot SUn.

This control signal is transmitted in time slot S
It is limited to only Un and is sent in bursts and no signal is sent in other time zones, so that it does not adversely affect other communications. However, if the speed of the control signal is relatively low, or if the amount of information in the signal is large and cannot be accommodated in one time slot, the same time of one frame later or the next frame Sent using slots.

To capture the time slot SUn,
Specifically, the following method is used. As shown in FIG. 4A, the control signal transmitted from the wireless base station 30 includes a synchronization signal and a control signal that follows it. The mobile wireless device 100 receives the synchronization signal and the frame synchronization. It will be possible. In addition, this control signal contains the currently used time slots and the unused time slots (empty time slots).
Control information such as slot display) is included. Depending on the system, time slot SDi (i = 1, 2,
..., n) is being used by another communication,
Sometimes it only contains sync and call signals,
Even in such a case, the unused time slot normally contains a synchronization signal and a control signal, and by receiving this control signal, the mobile radio 100 uses which time slot to issue a call signal. Can be sent.

When all the time slots are in use, it is impossible to make a call on this radio channel and it is necessary to sweep and search another radio channel.

In another system, an empty slot may not be displayed in any of the time slots. At this time, the audio multiplexed signals SD1 and SD following it may be displayed.
2, ..., SDn must be searched one after another to check for empty time slots.

Now, returning to the present discussion, the mobile radio 100, which has received the control information sent from the radio base station 30 by any of the above methods, sends out the call control signal at which time slot. Whether or not it should be possible can be determined by including the transmission timing.

Then, the time slot SU for the upstream signal
Assuming that n is an empty slot, this empty time slot is used, a call-out control signal is transmitted, a required timing is extracted from a response signal from the radio base station 30, and a burst-like control signal is generated. Can be sent out.

If another mobile radio device makes a call at the same time, a call signal is not properly transmitted to the radio base station 30 due to a call collision, and it is necessary to restart the operation from the beginning. However, this probability is suppressed to a sufficiently small value when viewed as a system. If it is desired to reduce call collisions further, the following measures are taken. If mobile radio 100 finds an empty time slot that it can make a call, it does not use all of that time slot, but only the first half for some mobile radios and only the second half for some mobile radios. This is the method to use. That is, as a calling signal, the used portion of the time slot is divided into several types, and using this, a large number of mobile radio devices are grouped, and each group is assigned a time zone within that one time slot. How to give. Another method is to create various types of frequencies that the control signal has, and to assign this frequency to each group by grouping a large number of mobile radio devices. According to this method, even if control signals having different frequencies are simultaneously transmitted using the same time slot, interference does not occur in the radio base station 30. The above two methods may be used separately, or if they are used together, the effect is synergistically increased.

Now, the call control signal from the mobile radio device 100 is properly received by the radio base station 30, and the mobile radio device 100 is received.
If the ID (identification number) of is detected (S202),
The control unit 40 searches for a currently empty time slot. The time slot given to the mobile radio 100 may be SUn, but a search is performed just in case. This is because, in addition to the mobile wireless device 100, it is possible to handle simultaneous calls from other mobile wireless devices and to provide time slots suitable for the service type and service classification.

As a result, for example, time slot SD
1 is available, the time slot SDn of the radio channel CH1 is used for the mobile radio device 100 by the downlink control signal (time slot uplink (mobile radio device 10)).
0 → Radio base station 30) SU1, and the corresponding downlink (radio base station 30 → mobile radio 100) SD1 is instructed to be used (S203). In response to this, the mobile wireless device 100 shifts to a state in which it can be received at the instructed time slot SD1 and SU1 which is a time slot for the uplink radio channel corresponding to the downlink time slot SD1 (see FIG. Select b)). At this time, in the control unit 140 of the mobile wireless device 100, the transmission / reception gating controller 123 is operated to turn on the switch 122-1.
And 122-2 are started to operate (S204). At the same time, a slot switching completion report is sent to the radio base station 30 using the uplink time slot SU1 (S205),
Wait for dial tone (S20)
6).

The time of the wireless carrier of this upstream wireless signal
The state of the slot SU1 is schematically shown in FIG. 7 (c). The radio base station 30 has a time slot SU
In addition to No. 1, SU3 and SUn are included in one frame and transmitted as an upstream signal from another mobile radio device 100. Upon receiving the slot switching completion report (S207), the wireless base station 30 sends a calling signal together with the ID of the mobile wireless device 100 to the gateway switch 20 (S20).
8). On the other hand, in the gateway switch 20, the mobile radio 10
The ID of 0 is detected, and a necessary switch of the switch group included in the gateway switch 20 is turned on (S209),
The dial tone is transmitted to the wireless base station 30 (S21).
0, FIG. 10).

This dial tone corresponds to the radio base station 30.
Is transferred to the mobile wireless device 100 (S211), and the mobile wireless device 100 confirms that the communication path has been set (S212).

When this state is entered, the mobile radio 100
Since a dial tone is heard from the handset of the telephone section 101, the transmission of the dial signal is started. This dial signal is subjected to speed conversion by the speed conversion circuit 131, and the wireless transmission circuit 13 including the transmission unit 134 and the transmission mixer 133.
From 2, the data is transmitted using the upstream time slot SU1 (S213). Thus, the transmitted dial signal is received by the wireless reception circuit 35 of the wireless base station 30.

The wireless base station 30 has already responded to the call signal from the mobile wireless device 100 and set the time
The slot is given, and the signal selection circuit group 39 and the signal allocation circuit group 52 of the radio base station 30 are operated to receive the upstream time slot SU1 and receive the downstream time slot SU1.
The state has shifted to transmitting the signal of the slot SD1.
Therefore, the dial signal transmitted from the mobile wireless device 100 is the signal selection circuit 39-1 of the signal selection circuit group 39.
After passing through, it is input to the signal speed restoration circuit group 38, where the original transmission signal is restored and transferred to the gateway exchange 20 as the call signal 22-1 via the signal processing unit 31 (S21).
4) The call path to the telephone network 10 is set (S21).
5).

On the other hand, an input signal (initially a control signal, a call signal if a call is started) from the gateway switch 20 is subjected to speed conversion by the signal speed conversion circuit group 51 in the radio base station 30, and then the signal allocation circuit. Signal allocation circuit 52-1 of group 52
Has given a time slot SD1. Then, the time of the downlink radio channel from the radio transmission circuit 32
It is transmitted to the mobile wireless device 100 using the slot SD1.

In the mobile radio 100, the radio channel CH
In the time slot SD1 of No. 1, the wireless communication circuit 135 is on standby for reception, and its output is input to the speed restoration circuit 138. In this circuit, the original signal on the transmitting side is restored and input to the handset of the telephone section 101.
Thus, a call is started between the mobile wireless device 100 and the ordinary telephone in the ordinary telephone network 10 (S21).
6).

The telephone call unit 101 of the mobile radio 100 is used for ending the call.
By hooking the handset of the device on (S217),
The end signal and the on-hook signal from the control unit 140
The signal is transmitted from the wireless transmission circuit 132 to the wireless base station 30 via the speed conversion circuit 131 (S218), the control unit 140 stops the operation of the transmission / reception interrupt controller 123, and the switches 122-1 and 122- 2 is fixed to the output ends of the synthesizers 121-1 and 121-2, respectively.

On the other hand, in the control unit 40 of the radio base station 30,
When the call end signal from the mobile wireless device 100 is received, the call end signal is transferred to the gateway switch 20 (S219), the switches of the switch group (not shown) are turned off to end the call (S).
220). At the same time, the signal selection circuit group 3 in the radio base station 30
9 and the signal allocation circuit group 52 are opened.

In the above description, the control signals are exchanged between the radio base station 30 and the mobile radio 100 without passing through the signal conversion circuit group 51, the signal speed restoration circuit group 38, etc., but this is explained. For the sake of convenience, the signal speed conversion circuit group 51 and the signal speed restoration circuit group 38 are the same as those for the audio signal.
Communication can be performed without any trouble through the signal processing unit 31 and the signal processing unit 31.

(2) Incoming Call to Mobile Wireless Device 100 It is assumed that the mobile wireless device 100 is on standby while the power is on.
In this case, as described in the section of calling from the mobile radio 100, the downlink control signal of the radio channel CH1 according to the procedure defined by the system is in the standby state.

An incoming call signal from the general telephone network 10 to the mobile radio 100 via the gateway switch 20 is transmitted to the radio base station 30.
Suppose you have arrived. Similar to the voice signal, these control signals pass through the signal speed conversion circuit group 51 and are transmitted to the control unit 40 (FIG. 3) through the signal allocation circuit group 52, similarly to the voice signal. Then, the control unit 40 uses the empty slot of the downlink time slot of the radio channel CH1 addressed to the mobile wireless device 100, for example, SD1, to move the mobile wireless device 10
0 ID signal + incoming call signal display signal + time slot use signal (for transmission from the mobile radio 100, for example, S
(Use SU1 corresponding to D1). In the mobile wireless device 100 that has received this signal, it is transmitted from the receiving unit 137 of the wireless receiving circuit 135 to the control unit 140. Control unit 1
At 40, since it is confirmed that this signal is an incoming signal to the mobile radio device 100 of its own, at the same time as making a ringing tone from the telephone unit 101, it waits at the instructed time slot SD1, SU1. Transmission / reception intermittent controller 1
23, and switches 122-1 and 12
Turn on and off 2-2. Thus, the call is ready to be made.

It is theoretically explained in Document 2 that signal transmission is performed in good condition using this system and does not adversely affect other radio channels in the system. , The theoretical proof of multiple load gain in telephone signals, and its application are also described in document 4, so the description thereof will be omitted and the TC applied to the present invention will be described below.
When the signal power level of the M signal exceeds a certain value defined by the system, the effect of suppressing that value according to a predetermined rule will be described.

(3) Level Suppression Effect of TCM Signal at Input to Angle Modulator Hereinafter, a transmission signal from the radio base station 30 will be taken as an example. f
The _h as the highest frequency included in the telephone signal, consider the relationship between the multiplicity n, power and multiplexed load gain possessed by the TCM phased signal having a frame interval 1 / (2f _h).
The power of the telephone signal is measured at a time interval 1 / (2f _h ) (measurement value p) and its change is considered. Clearly the measured value p is
It changes every moment. According to Reference 4, the maximum value of the average power of a TCM-converted telephone signal having a multiplicity of n and a frame interval of 1 / (2f _h ) is equal to the (long-time) average power of an FDM telephone signal of a multiplicity of n. It has been shown to match. From this, therefore, the TCM-converted telephone signal having the multiplicity n and the frame interval 1 / (2f _h ) has the multiple load gain, and its value may be equal to that of the FDM telephone signal having the multiplicity n. It is explained.

A method for obtaining a larger multiple load gain will be considered using the above results. If the maximum value of the average power of a TCM-converted telephone signal having a multiplicity of n and a frame interval of 1 / (2f _h ) can be lowered,
The TCM-converted telephone signal can obtain a larger multiple load gain.

FIG. 11 shows the level suppression characteristic (a) and the characteristic (b) when the level suppression and the compressor or the level suppression cancellation and the expander are used together.
The characteristic shown in FIG. 11A can be realized by the level suppression circuit. In fact, the existence of such circuits is well known and readily available or available.

FIG. 11A shows the input / output characteristic of the level suppressing circuit. The input / output characteristic has a direct proportional (linear) relationship unless the input signal level exceeds a constant value p _o . However, when the input signal level exceeds a certain value p _o , the output suppression characteristic appears and the maximum input level p _m
In the case where this circuit is not provided, the output P _m in the characteristic indicated by the broken line aob is suppressed to P _m ′, and when the suppression ratio is λ, it is suppressed by λ = P _m ′ / P _m . The suppression ratio λ can be set arbitrarily, but is usually selected to be about 5 to 10 dB. It is possible to set λ to a larger value, but the degree of dependence on the stability of the suppression circuit increases, and when canceling suppression at the receiver, it also depends on the stability of the suppression cancellation circuit. The error may increase.

Now, when the level suppression circuit having the suppression ratio described above is installed on the input side of the angle modulator, the TCM
The maximum value of the average power of the encrypted telephone signal will be reduced by 10 dB. Therefore, the (equivalent) multiple load gain of this signal may be obtained by adding 10 dB to the multiple load gain value when the signal is not suppressed.

The above is an example of a transmission signal from the radio base station 30, but the same applies to the case of transmission from the mobile radio 100.

Further, as the modulation method, not only the angle modulation but also the amplitude modulation can be applied. That is TC
This is because the average power of the M-converted telephone signal is lowered, and therefore even if the modulation rate of the amplitude modulation is substantially increased, the overmodulation does not occur.

Now, the level suppression circuit, the level cancellation suppression circuit and the peripheral circuits installed in the mobile radio 100 of FIG. 2 will be described.

12A and 12B show the internal structures of the speed conversion circuit 131 and the speed restoration circuit 138 having these functions, respectively. In FIG. 12A, the telephone signal from the telephone unit 101 is input to the level suppression circuit LC1. Here, the telephone signal from the telephone unit 101 is subjected to level suppression as described with reference to FIG. This output is divided into two by the switch SW31, and the memory circuit M
It is sent to E1-1 or ME1-2. The level-suppressed telephone signal is temporarily stored in the memory circuit ME1-1 or ME1-2, and the signal compression circuit SC1-1 or SC1-.
2 and compressed for 2 hours. This output is switch SW3
2 are alternately taken out and sent to the transmission unit 134.
Switch SW31 or switch SW3 in FIG.
2 is controlled by a signal from the control unit 140 and is turned on / off at an appropriate timing.

As a result of the above operation, the transmitting section 134 transmits the time-compressed telephone signal, which has been subjected to the level suppression, to the radio base station 30 as an angle modulated wave at an appropriate modulation level.

Next, the received signal to the mobile wireless device 100 will be described focusing on the level cancellation suppressing circuit. 12
In (b), the demodulated signal from the receiving unit 137 is input to the switch SW33, is divided into two, and is expanded by the signal expansion circuit SE.
The received signals time-compressed in 1-1 or SE1-2 are time-expanded. These outputs are the memory circuit ME
2-1 or ME2-2. The time-extended telephone signal is temporarily stored in the memory circuit ME2-1 or ME2-2 and sent to the switch SW34, and its output is alternately taken out and input to the level suppression canceling circuit LR1. The telephone signal whose level is suppressed here is shown in FIG.
The level suppression received at the transmitting side is canceled by the operation (the polygonal line aod) which is completely opposite to the level suppression as described in (a), and the level of the telephone signal above a certain level is restored (the straight line and the broken line). aoy). This output is sent to the telephone unit 101. The switch SW33 or the switch SW34 in FIG. 12B is controlled by a signal from the control unit 140, and is turned on / off at an appropriate timing.

Regarding the radio base station 30 that communicates opposite to the mobile radio 100, the level suppression circuit is installed in the signal speed conversion circuit group 51, and the level release suppression circuit is installed in the signal speed restoration circuit group 38, and their operation is performed. Is a mobile radio 1
It is the same as that described in No. 00.

The present invention can be used in combination with the above-described level suppressing circuit and level canceling suppressing circuit as well as a silabic compander. Syrabic compander is a known technique, and the circuit is commercially available. This is used by one set of a compressor and an expander. The compressor is inserted in the front stage of the angle modulator on the transmission side, and the expander is used in the output stage of the demodulator on the reception side. The installation locations suitable for the present invention of these circuits will be described with reference to FIG.
Regarding the compressor, between the output side of the level suppression circuit LC1 of FIG. 12 (a) and the switch SW31, and regarding the expander, between the output side of the switch SW34 of FIG. 12 (b) and the level suppression canceling circuit LR1. , Each is best installed. Comparing the functions of the level suppression circuit LC1 and the compressor, the former is mainly for level suppression and the average power of the telephone signal is also reduced, whereas the latter has the same average power and the level distribution of the signal has Change (lower high level, increase lower level)
It has a function for. Further, the level suppression canceling circuit LR1
The comparison between the expander and the expander is opposite to the relationship between the level suppression circuit and the compressor described above.

FIG. 11B shows the characteristics when two types of circuits, a level suppressing circuit and a compressor, and a level suppressing canceling circuit and an expander, are used together. In FIG. 11B, the polygonal line AOB represents the input characteristic of the angle modulator when the level suppressing circuit and the compressor are used together on the transmitting side. The input level p _o is the center of the operation, and when the signal power is below this level, the level is increased, and when it exceeds this level, large level suppression is received from both the level suppression circuit LC1 and the compressor.

By inserting such a circuit, not only the multiple load gain of the present invention can be increased, but also the adverse effect of a signal when it is transmitted through a spatial medium is significantly reduced.

Next, the polygonal line COD in FIG. 11 (b) is the characteristic when the level suppression canceling circuit LR1 inserted into the output side of the frequency discriminator of the receiver and the expander are used together.
Below the input level p _o , the level is suppressed, and above this level, a large level up is received from both the level suppression canceling circuit LR1 and the expander. As a result, the transmission / reception comprehensive characteristic is the straight line XOY shown by the broken line,
This is the same as the total transmission / reception characteristics in the case where the four circuits of the transmission side level suppression circuit LC1 and the compressor and the reception side level suppression release circuit LR1 and the expander do not exist.

[0092]

As is clear from the above description, the TCM
By suppressing the high power of the signal on the transmission side of the converted telephone signal, it is possible to increase the multiple load gain of the TCM signal, which increases the modulation deviation of the angle modulation (modulation rate of the amplitude modulation). When used, the S / N (signal-to-noise ratio) can be improved, which can also be used to reduce the transmission power, and the power can be saved, so that the frequency can be effectively used. Therefore, the effect of the present invention is extremely large.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram showing a concept of a system of the present invention.

FIG. 2 is a circuit configuration diagram for explaining a basic operation of a mobile wireless device used in the system of the present invention.

FIG. 3 is a circuit configuration diagram for explaining a basic operation of a radio base station used in the system of the present invention.

FIG. 4 is a time slot structure diagram for explaining a basic operation used in the system of the present invention.

FIG. 5 is a spectrum diagram showing spectra of a call signal and a control signal.

FIG. 6 is a circuit configuration diagram for multiplexing a voice signal and a data signal.

FIG. 7 is a waveform diagram showing a radio signal waveform of a time slot.

FIG. 8 is a spectrum diagram showing spectra of a call signal and a control signal.

FIG. 9 is a flow chart showing a basic operation flow of the system according to the present invention.

10 is a flow chart showing a flow of basic operation of the system according to the present invention together with FIG. 9.

FIG. 11 is a characteristic diagram showing a level suppression characteristic (a) and a characteristic (b) when the level suppression and the compressor are used together or when the level is released and the expander is used together.

FIG. 12 is a circuit configuration diagram of a specific example of the speed conversion circuit (a) and the speed restoration circuit which are the constituent elements of FIG. 2;

[Explanation of symbols]

10 Telephone Network 20 Gateway Switch 22-1 to 22-n Communication Signal 30 Radio Base Station 31 Signal Processing Unit 32 Radio Transmission Circuit 35 Radio Reception Circuit 38 Signal Speed Restoration Circuit Group 38-1 to 38-n Signal Speed Restoration Circuit 39 Signal Selection circuit group 39-1 to 39-n Signal selection circuit group 40 Control unit 41 Clock generator 42 Timing generation circuit 51 Signal speed conversion circuit group 51-1 to 51-n Signal speed conversion circuit 52 Signal allocation circuit group 52-1 .About.52-n signal allocation circuit 91 digital encoding circuit 92 multiplex conversion circuit 100, 100-1 to 100-n mobile radio device 101 telephone unit 120 reference crystal oscillator 121-1, 121-2 synthesizer 122-1, 122-2 Switch 123 Transmission / reception gating controller 131 Speed conversion circuit 132 Wireless transmission circuit 133 Transmission mixer 134 Transmission unit 135 Radio reception circuit 136 Reception mixer 137 Reception unit 138 Speed restoration circuit 141 Clock regenerator LC1 level suppression circuit LR1 level suppression cancellation circuit ME1-1, ME1-2, ME2-1, ME2-2 Memory circuit SC1-1, SC1-2 signal compression circuit SE1-1, SE1-2 signal expansion circuit SW31 to SW34 switch

Claims (1)

[Claims] 1. A radio base means (30), each of which covers a plurality of zones to form a service area, and a frame structure for moving across the plurality of zones and communicating with the radio base means. Mobile communication using barrier switching means (20) for exchanging communication with each mobile radio means (100) using radio channels carrying time-compressed delimited signals in time slots In the time division communication method of, when the power level of the temporally compressed delimited signal exceeds a predetermined level, the excess level is suppressed and transmitted to obtain an increase in multiple load gain,
A time division communication method for mobile communication, wherein an increase in the multiple load gain is used to increase a modulation deviation to reduce a transmission level.