JPH0541692A - Time division communication method for movable body communication - Google Patents

Abstract

PURPOSE:To enable the diversity transmission and reception by complex- modulating composite signals for telephone, data or the like with the use of the identical radio carrier in the movable body communication with a time- compressed signal on a frame time slot. CONSTITUTION:With a time slot of a radio channel which is allocated between a mobile radio equipment 100 and a radio base station 30, the amplitude of a telephone signal is compressed by a syllabic compressor to modulate the frequency, and the modulated signal is transmitted and received by compressing the amplitude of the same telephone signal again by the syllabic compressor. A large multiple load gain can be obtained, the transmission power can be reduced without expanding the required band width, the interference to the adjacent radio channel can be prevented in advance, and the service can be improved because of the effective use of the frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio base station for time division communication of a radio communication channel in mobile communication and a mobile radio. More specifically, one of a number of radio channels provided to the system is provided, and one of a number of mobile radios in the service area is used by the radio channel of the opposite radio base station. For example, when another mobile radio device desires to use the same radio channel while communicating with the communication signal by setting a radio line with a telephone signal, the mobile radio device already in communication And the wireless base station, the independent wireless line is set up by using the same wireless channel between the other mobile wireless device and the wireless base station without adversely affecting the communication between the mobile base station and the wireless base station. Etc. The present invention relates to a time division communication system of a radio channel that enables communication of signals such as.

[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 RC
S89-11 July 1989

Reference 2. 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 3. Ito "Elucidation of multiple load gain of time division time compression multiplex telephone signal and its application to FM mobile communication" IEICE Technical Report RCS89-65 Mar. 1990.

Reference 4. Ito “Cirabic Compander-
Of Multiple Load Gain Characteristics of TCM Signals Using
Proceedings of the 1990 Autumn Meeting of the Institute of Electronics, Information and Communication Engineers B-2
70 1990 September

That is, in Reference 1, a transmission signal (baseband signal) is divided into predetermined time interval units and stored in a memory circuit, and when reading this, the speed is n times faster than the speed of storing in the memory 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 in an expected manner, the same method as described above for synchronizing the intermittent transmission and reception with that of the mobile wireless device is used, and the receiving side extracts only the signal accommodated in the predetermined time slot. Therefore, by opening and closing the wireless receiving circuit, receiving and demodulating, the signal obtained 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 that enables reproduction of a transmitted baseband signal, which is an original signal, is constructed has been reported.

Further, in Reference 2, 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 eliminating or reducing this effect. I suggest you do.

Next, in Reference 3, the multiplex load gain, which has been known to exist in the conventional FDM (frequency division multiplex) signal, has a similar multiplex load gain to the FDM signal in the time division time compression multiplex (TCM) system. Reveal that there is, 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.

Further, in Reference 4, the multiple load gain obtained by the TCM signal may not be a desired value depending on the system parameter conditions. In that case, the TCM signal is created on the transmitting side. When this is done, a Syrabic compander (Syrabic compressor) is inserted at an appropriate part in the modulator input section to change the amplitude frequency characteristic of the TCM signal to obtain a substantially larger multiple load gain than before insertion. , And reported that it is possible to reduce the wireless transmission power by determining the modulation level of angle modulation or amplitude modulation based on this gain.

However, regarding the signal transmission of this system, no description has been given regarding measures for eliminating the adverse effects of fading that occurs when transmitting a transmission medium, particularly space, such as transmission diversity. Also, in a system in which a wireless base station and a mobile wireless device facing each other set up a wireless line and communicate using a telephone signal,
The same carrier is subjected to complex modulation such as angle modulation and amplitude modulation (one is angle modulation and the other is amplitude modulation, or one is amplitude modulation and the other is amplitude modulation) by the same signal, and this composite modulation wave is used. No explanation is given for communicating. Furthermore, the application of the Syrabic compander to composite modulated waves has not been made in any literature.

[0012]

A radio base station and a large number of mobile radio units facing each other establish a radio line, and, for example,
When communication is performed using a TCM-converted telephone signal, in order to improve the quality of a transmitted signal, for example, when transmission diversity (assuming a multiplexing number of 2) is performed by a conventional method, the frequency efficiency is as follows. It is disadvantageous in use. That is, with frequency diversity, the frequency used is doubled. Although the frequency used in time diversity (assuming that the number of multiplexing is 2) is the same as before, the time required for transmission is doubled, which means that the frequency utilization efficiency will be halved. Was left.

Further, when the multiplicity of the TCM-converted signal is high or when the distance in the wireless section is large, the wireless transmission output becomes large, and there is a demand for power saving, which should also be solved. It was a challenge.

[0014]

On the other hand, in the modulation method according to the present invention, a composite modulation is used in which the same carrier is angle-modulated by a TCM-converted telephone signal and at the same time amplitude-modulated by the same TCM-converted telephone signal. It is possible to reduce the transmission power required by the system by reducing the transmission power required by the system by increasing the multiplex load gain of the signal by using the syracic compander while simultaneously measuring the effective use of frequency and achieving the diversity effect. is there.

Further, depending on the type of the signal, when the spread of the sideband of the modulated signal may be wider than that of the single modulation of only the angle modulation or the amplitude modulation, a bandpass filter is provided on the output side of the modulated signal. By providing this, it becomes possible to limit the spread of the sideband to a constant spread. Therefore, the spread of the sideband signal of the radio signal is substantially the same as that obtained by angle-modulating or amplitude-modulating with a single signal. It is possible to suppress the spread of sidebands, prevent interference with adjacent wireless channels, and enable effective frequency use.

When a radio base station and a large number of mobile radio devices (n units) facing each other establish radio channels and communicate with each other, a TCM signal transmitted from the radio base station is created as follows. .. That is, after creating a TCM signal from n telephone signals coming from the telephone network to the wireless base station,
This TCM signal is divided into two to create two sets of TCM-converted telephone signals. Angle modulation and amplitude modulation are performed on the same carrier wave using each of these.

However, when the signal to be transmitted has a multiple load gain by converting it into a TCM like a telephone signal, a Syracic compander (syracic compressor) is inserted in front of the input section of the modulator to have an amplitude of the TCM signal. It is possible to reduce the wireless transmission power by obtaining a substantially larger multiple load gain than before the insertion by changing the characteristics and determining the modulation level of the angle modulation or the amplitude modulation based on this gain.

This composite modulated wave is transmitted to many mobile radio devices. On the other hand, a large number of mobile radio units facing each other receive in their own assigned time slots and demodulate by a process reverse to that of the time of modulating the composite modulated signal. Further, regarding the composite modulated signal transmitted from the mobile radio device to the radio base station, the telephone signal is subjected to the same time compression as that performed in the radio base station, and is then divided into two minutes. As described above, the same kind of angle modulation and amplitude modulation as that performed in the radio base station is performed in the time slot allocated to itself for the same carrier wave, and then the signal is transmitted to the radio base station. The system configuration will be described.

A plurality of radio base stations having radio transceivers, a radio receiving circuit having a reception mixer for communicating while moving within a service area covered by the plurality of radio base stations, and a radio transmission having a transmission mixer. Circuit and switching receiving means including a synthesizer capable of switching and receiving only the signal of the timing given to itself to the receiving mixer of the wireless receiving circuit, and switching only at the timing given to itself to the transmitting mixer of the wireless transmitting circuit In a mobile radio device including a switching transmission means including a synthesizer capable of transmitting, a transmission signal (composite signal of telephone, fax, etc.) is divided into predetermined time interval units and stored in a storage circuit, and then read. At the time of output, the data is read at a predetermined time slot at a speed n times faster than the speed stored in the memory circuit. Lim slot signals contained by (hereinafter referred to as TCM signal.) Angle modulation or amplitude modulation of the same carrier by TCM of telephone signals,
(However, insert a Syrabic compander, here a Syrabic compressor, in front of the modulator input.)
The obtained signal is further amplitude-modulated or angle-modulated by the same TCM-converted telephone signal (usually, if the former is angle modulation, the latter is amplitude modulation; if the former is amplitude modulation, the latter is angle modulation).
Then, a radio receiving circuit having a reception mixer, which is built in a mobile radio and a radio base station for intermittently transmitting and receiving in time, and which communicates with each other, and a radio transmission circuit having a transmission mixer, A switch circuit is provided for the synthesizer applied to the reception mixer of the wireless reception circuit and the synthesizer applied to the transmission mixer of the wireless transmission circuit, and the output of the applied synthesizer is interrupted, and the interrupted state is synchronized for both transmission and reception, and they are opposed to each other. A mobile wireless device that communicates by using the same method as described above for synchronizing intermittent transmission / reception with that of a wireless base station, and at the receiving side the predetermined time
In order to extract only the signal stored in the slot,
The wireless reception circuit is opened and closed to receive, and the signal obtained by demodulation (however, inserting a Sylabic compander (Sylabic expander) after the output of the demodulator) is stored in the storage circuit by the process exactly opposite to that at the time of transmission. However, when this is read out, it is read out at a low speed of 1 / n of the speed stored in this memory circuit, and in the radio base station, a predetermined time slot is used to set a communication path with a predetermined mobile radio device. By providing the communication path control means, it is possible to reproduce the baseband signal that is the transmitted original signal in the wireless base station and the mobile wireless device, and a gateway switch for connecting a general telephone network and the wireless base station is provided. Built a system that includes.

[0020]

In order to allow a large number of mobile radios to exist in the radio base station and its service area and to communicate with the radio base station by any number of mobile radios, one radio channel is temporally arranged. It is divided into a plurality of time slot series, and one of these time slot series is selected and communication is performed using this. When one mobile radio device is communicating with a radio base station using a composite modulation signal and another mobile radio device desires to communicate with this radio base station,
For a mobile radio device that wishes to communicate using a new composite modulation signal, an unused one of the time slots is given to the radio base station that is already in use to communicate with the radio base station. By enabling communication, it is possible for many communications to execute without interfering with each other and without adversely affecting the transmission power used for own communications. ..

In addition, the gateway exchange has a radio channel used for communication with the mobile radio in the radio base station and its time, as an interface function for connection with another telephone network and a control function for the mobile radio communication network. It has functions such as slot determination and radio wave transmission / reception.

As a result, even if all the radio channels given to the system are in use, if there is an empty time slot not used for communication in each time-divided time slot of each radio channel, It is possible to make a call to a mobile wireless device that has newly requested a call, and it is possible to continue a call to a mobile wireless device that has moved during a call from an adjacent zone. The mobile wireless device in 1 is capable of communicating with another wireless base station in the vicinity while communicating with one wireless base station.

The modulation method used therein is such that the same carrier wave is TCM-converted into a telephone signal to perform angle modulation and at the same time T
The spread of the sideband signal of the radio signal is limited because the spread of the sideband of the modulated signal is limited to a certain spread by the bandpass filter by using the composite modulation in which the same telephone signal converted into the CM is amplitude-modulated. , It becomes possible to suppress the spread degree when the angle modulation or the amplitude modulation is substantially performed by a single signal.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a system to which the present invention is applied, a case where an analog telephone signal is converted into a TCM and used will be described in order to explain the principle thereof.

FIG. 1 shows a system configuration for explaining the concept of the present invention. In FIG. 1, 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 has an interface with the gateway switch 20, a circuit for converting the speed of signals, a circuit for allocating and selecting time slots, a control unit, etc. for setting and releasing a wireless line. , Mobile radio 100 (100-1 to 100-n)
And a wireless transmission / reception circuit for exchanging wireless signals.
Here, between the gateway switch 20 and the wireless base station 30,
There are transmission lines for transmitting the communication signals 22-1 to 22-n including the communication signals of the communication channels CH1 to CHn and the control signals.

FIG. 2 illustrates the principle of the present invention.
The circuit configuration of the mobile wireless device 100 that communicates with the wireless base station 30 is shown. Received signals such as control signals and call signals received by the antenna unit enter the wireless reception circuit 135 including the reception mixer 136 and the reception unit 137, and the output communication signal is the speed restoration circuit 138 and the control unit 140.
Is input to 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 restoration circuit 138 restores the speed (pitch in the case of an analog signal) of the compressed and delimited communication signal in the received signal, and the expander 172 expands the amplitude characteristic as a continuous signal. After receiving it, it is input to the telephone unit 101 and the control unit 140.

The communication signal output from the telephone unit 101 is subjected to compression of the amplitude characteristic by the compressor 171, and then the communication signal is divided at a predetermined time interval by the speed conversion circuit 131 to determine its speed (in the case of analog signal, (Pitch) at high speed (compression), and the transmission mixer 133 and the transmission unit 134
And is applied to the wireless transmission circuit 132 including.

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 send 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.

The timing generator 142 supplies the necessary timing 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 that 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
The reference frequency is supplied to the -1, 121-2 from the reference crystal oscillator 120.

FIG. 3 shows a radio base station 30 for explaining the principle of the present invention. The n-channel communication signals 22-1 to 22-n with the gateway switch 20 are connected to a signal processing unit 31 that forms an interface on a transmission path.

The communication signals 22-1 to 22-n sent from the gateway switch 20 are input to the signal processing section 31 of the radio base station 30. The signal processing unit 31 is provided with an amplifier for compensating for transmission loss, and also performs so-called 2-wire-4 wire conversion. That is, the input signal and the output signal are mixed and separated, and the input signal from the gateway switch 20 is subjected to the compression of the amplitude characteristic by the compressor group 71 including the compressors 71-1 to 71-n, and then the signal speed conversion circuit group. Sent to 51. Further, the signal speed restoration circuit group 38
The output signal from is subjected to expansion of the amplitude characteristic by the expander group 72 including the expanders 72-1 to 72-n, and then the signal processing unit 31 uses the same transmission path as the input signal to the gateway switch 20. Sent. Of the above, the gateway switch 2
The input signal from 0 has many signal speed conversion circuits 51-1.
Is input to the signal speed conversion circuit group 51 including
Velocity (pitch) conversion is performed at predetermined time intervals. As for the signal transmitted from the wireless base station 30 to the gateway switch 20, the output of the wireless receiving circuit 35 is input to the signal speed restoration circuit group 38 via the signal selection circuit group 39, and the speed (pitch) is converted. It is input to the signal processing unit 31.

The control of the radio receiving circuit 35 or the output of the call signal is performed by 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, and the call signals are separated corresponding to each of the call channels CH1 to CHn. This output is received by the signal speed restoration circuit group 38 including the signal speed restoration circuits 38-1 to 38-n provided for each channel. The signal speed (pitch) is restored and the expander group 72 expands the amplitude characteristic. After receiving the signal, the signal is input to the signal processing unit 31 and, after undergoing 4-line to 2-line conversion, this output is sent to the gateway switch 20 as communication signals 22-1 to 22-n.

Next, a compander having a main function of the present invention will be described.

A compander is a general term for a combination of a compressor (compressor) and an expander (expander). What is used in analog voice communication is one that operates in accordance with the envelope level of voice, and is also called a syracic compander. Called
Currently widely used.

Generally, in mobile communication, the reception level fluctuates as much as 20 to 30 dB due to fading, so that the reception S / N (signal-to-noise ratio) is greatly deteriorated as compared with the case where there is no fading, and the reception level is considerably high. Even at times, various noises are introduced during communication, resulting in annoying disturbing sound. There are thermal noise, click noise, and random FM noise as noise. In particular, click noise is audible to the ear when there is no call, and even if the line is designed so that the intelligibility of a single note can be sufficiently secured, subjective evaluation is greatly deteriorated. .. The compander has the effect of increasing the voice level in the wireless section during a call and improving the S / N, and greatly suppressing the noise generated in the wireless system when there is no call, and is a very effective technique for improving call quality in mobile communications. It will be a means.

In the present invention, a compander similar to the one described above is used to compress and decompress signals in the vicinity of the peak value of the TCM signal and its level to improve the amplitude characteristic. The specific system configuration and operation will be described below.

2 and 3 respectively show a mobile radio device 1.
00 and the radio base station 30 are companders. In FIG. 3, the compressor group 71 is inserted between the signal processing unit 31 and the signal speed conversion circuit group 51, and the amplitude of the telephone signal is compressed here. An example of the compression characteristic received at this time is shown in FIG.

The compressor characteristic of FIG. 4 gives an output of n ^1/2 with respect to the input signal n, and is therefore called 1/2 compression. That is, when the input level changes by 10 dB, the output level changes by 5 dB. Therefore, the distribution of the amplitude characteristic of the audio signal is 1/2 in decibel. Therefore, when entering the wireless transmission circuit 32,
The distribution of the signal applied to the wireless transmission circuit 32 is 1/2 in decibel as compared with the case where the compressor group 71 does not compress.

Now, it is assumed that the amplitude-compressed signal is transmitted from the wireless base station 30 from the antenna and received by the mobile wireless device 100. The configuration of the mobile wireless device 100 is as shown in FIG. 2, and the time-compressed voice signal of the received signal is
After demodulated by the wireless reception circuit 135, the speed restoration circuit 13
8 and is restored to the original signal speed. Further, it is input to the expander (expander) 172. This input signal will undergo a conversion according to the expander characteristic of FIG. That is, when the input level changes by 5 dB, the output level changes by 10 dB. As a result, as shown in the center of FIG. 4, the overall characteristic is that the voice input change on the transmitting side is 1 dB and the telephone input change on the receiving side is also 1 dB, and the original signal is reproduced faithfully.

The above description has been given of the case where the wireless base station 30 transmits and the mobile wireless device 100 receives, but the same applies to the case where the mobile wireless device 100 transmits and the wireless base station 30 receives. Thus, the user does not feel the presence of the compander at all in both the up and down calls, and the communication quality is improved.

Next, it will be explained that the above-mentioned compander contributes to the increase of the multiple load gain of the analog telephone signal converted into TCM. The multiple load gain of the TCM-converted analog telephone signal is greatly influenced by the average power of the signal within the sampling time interval obtained by sampling at the reciprocal of the Nyquist frequency. That is, if the variation in the average power is large (the distribution of the amplitude of values larger than the average is large), the multiple load gain does not increase (Reference 4). As described in Document 3, in order to reduce the variation in average power, it is necessary to shorten the frame period. However, this is generally difficult, and the present invention uses a compander to solve this problem. As described above, the compressor 1 is provided in front of the modulator on the transmission side.
71, 71 are used. As a result, it acts to suppress a large value among the above variations in the average power. Therefore, the multiple load gain becomes large. Thus, the increased multiple load gain is used to reduce the radio transmission power (Reference 3).
Therefore, it becomes possible to further reduce the transmission power.

Next, the function of the signal speed conversion circuit group 51 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 the signal speed conversion circuit group 51 is tape
This is the same as playing back the sound recorded by the recorder at high speed. In practice, for example, CCD (Charge Coupl
ed Device) and BBD (Bucket Brigade Device) can be used, and the memory used in a television receiver or a tape recorder for compressing or expanding the time axis of conversation can be used (reference: Kosaka et al. "Tape recorder that compresses / expands the time axis of conversation" Nikkei Electronics July 26, 1976 92-1
33).

CCD exemplified by the signal speed conversion circuit group 51
The circuit using the BBD or BBD can be used as it is for the signal speed restoration circuit group 38 as described in the above document. In this case, the clock from the clock generator 41 and the control signal from the control unit 40 are used. By receiving the timing signal from the timing generator 42 that generates the timing, the read speed is set lower than the write speed.

The control or voice signal output from the gateway switch 20 via the signal processing unit 31 is the compressor group 7
In 1, the amplitude characteristic is compressed, input to the signal speed conversion circuit group 51, subjected to speed (pitch) conversion processing, and then applied to the signal allocation circuit 52 that allocates signals 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 communication signals or control 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. S in FIG. 5 (a)
Dn, 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. 5A, 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 that are time-series 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 call in the incoming and outgoing call of the telephone, either in the band of the telephone signal or out of the band is used. It is possible. FIG. 6 shows these frequency relationships. That is, in the figure (a), the out-of-band signal is illustrated, and the low frequency side (250 Hz) or the high frequency side (3850 Hz) can be used. This signal is used, for example, when sending a control signal during a call. FIG. 6B shows an example of the in-band signal, which is used at the time of incoming and outgoing calls. In the above examples, tone signals are used. However, by increasing the number of tone signals or modulating the tones to form subcarrier signals, it is possible to transmit various types of signals at high speed.

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. FIG. 7 shows the circuit configuration in this case. FIG. 7 shows an example in which the voice signal is digitized by the digital encoding circuit 91, and 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. 7, the audio signal and the control signal can be separately taken out.

On the other hand, the signal sent 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. 5B schematically shows this 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. Further, when the contents of each time slot SU1, SU2, ..., SUn are shown in detail,
As shown in the lower left of FIG. 5B, it is composed 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 of FIG. 5B in a time slot is schematically shown, FIG.
It becomes like (c). Similarly, the downlink transmission waveform from the wireless base station 30 to each mobile wireless device 100 in FIG.
As shown in (d).

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 section 40. However, depending on the size of the speed conversion rate, it is 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
In response to an instruction from 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 is sent to the 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 with 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, also in the mobile wireless device 100, as shown in FIG. 2, of the functions of the wireless base station 30, the circuit configuration is required when the communication channel is one channel.

Original signal, eg, voice signal (0.3 kHz-
FIG. 9 shows a frequency distribution on the output side when 3.0 kHz) passes through the signal speed conversion circuit group 51 (FIG. 3) via the compressor group 71. That is, if the audio signal is converted 15 times as described above, the frequency distribution of the signal is 4.5 kHz to 45 kHz as shown in FIG.
It has been expanded to. 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.

Now, FIG. 9 shows a case where the control signal is simultaneously transmitted by 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 simultaneously applied to the wireless transmission circuit 32.

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. F is the frequency interval of a plurality of wireless channels
Let _rep be the maximum signal speed f _H due to the speedup of the audio signal described above, and the following inequality must be established between the two. 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.

Further, 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 it is sent to the gateway exchange 20 via the signal processing unit 31.

Next, the various operations of the system according to the present invention will be described in the following order, and it will be theoretically proved that the present invention is highly practical. (1) Call origination and termination operations (2) Theoretical explanation of the present invention (a) Mathematical expression of modulated wave (b) Sideband spread of modulated wave (c) Calculation of frequency effective utilization rate (3) Composite signal System configuration

(1) Calling and Receiving Operations Calling operations will be described with reference to the flowcharts shown in FIGS.

When the power supply of the mobile radio device 100 is turned on, in the radio reception 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 possible by capturing the sync signal in the time slot SDn shown in FIG. 5 (a). In the control unit 140, the synthesizer 121-1
To the switch 1 so as to generate a local oscillation frequency that enables reception of the radio channel CH1.
22-1 is also in a state of being tilted down and fixed to the synthesizer 121-1 side.

Therefore, the telephone of the telephone section 101 is turned off.
When a hook (call origination) is made (S201, FIG. 10), FIG.
The synthesizer 121-2 of receives the control signal from the control unit 140 so as to generate the local oscillation frequency that enables the transmission of the radio channel CH1. Further, 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 transmitted by the frequency band shown in FIG. 9 using, for example, the time slot SUn.

This control signal is transmitted in the 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. 5A, the control signal transmitted from the radio base station 30 includes a synchronization signal and a control signal that follows the synchronization signal. The mobile radio 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, there is a case where an empty slot is not displayed in any time slot, and at this time, the following audio multiplexed signals SD1, SD2, ..., SD
It is necessary to search for the presence of n 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 in 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, the 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 100 is properly received by the radio base station 30, and the mobile radio 100
If the ID (identification number) 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 and the time slot ascending (the mobile radio device 10) by the downlink control signal.
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 shown in FIG. 8 (c). In addition to the time slot SU1, the radio base station 30 receives SU as an uplink signal from another mobile radio 100.
3 and SUn are sent in one frame. In the wireless base station 30 that has received the slot switching completion report (S207), the mobile wireless device 100 is addressed to the gateway switch 20.
The calling signal is sent out together with the ID of (S208). On the other hand, the gateway exchange 20 detects the ID of the mobile wireless device 100, turns on a necessary switch in the switch group included in the gateway exchange 20 (S209), and dials
The tone is transmitted to the radio base station 30 (S210, FIG. 1).
1). This dial tone is transferred to the mobile wireless device 100 by the wireless base station 30 (S211), and the mobile wireless device 100 confirms that the communication path has been set (S2).
212).

When this state is entered, the mobile wireless device 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 sent to the speed conversion circuit 131 via the compressor 171.
The speed is converted by the transmission unit 134 and the transmission mixer 1.
The signal is transmitted from the wireless transmission circuit 132 including 33 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 radio base station 30 has already responded to the calling signal from the mobile radio 100, and has 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 uplink time slot SU1 and to transmit the downlink 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 the signal speed restoration circuit group 38, the original transmission signal is restored via the expander group 72 and transferred to the gateway exchange 20 as the call signal 22-1 via the signal processing unit 31 ( (S214), a call path to the telephone network 10 is set (S215).

On the other hand, an input signal (initial 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 via the compressor group 71 in the wireless base station 30. Then, the signal allocation circuit 52-1 of the signal allocation circuit group 52 causes the time slot S
D1 is given. Then, the data is transmitted from the wireless transmission circuit 32 to the mobile wireless device 100 using the time slot SD1 of the downstream wireless channel. The state of the time slot SD1 of the downlink radio carrier is shown in FIG. 8 (d).

In the mobile radio 100, the radio channel CH
In the time slot SD1 of No. 1, the reception is awaited, and it is received by the radio reception circuit 135, and its output is input to the speed restoration circuit 138. The original signal on the transmission side is restored in this circuit, and the telephone unit 1 is transmitted via the expander 172.
01 is input to the receiver. Thus, a call is started between the mobile wireless device 100 and the ordinary telephone in the ordinary telephone network 10 (S216).

The end of the call is the telephone section 101 of the mobile radio 100.
By hooking the telephone included in (S2
17), the call end signal and the on-hook signal from the control unit 140 are the compressor 171 and the speed conversion circuit 131.
Via the wireless transmission circuit 132 to the wireless base station 30 (S218), the control unit 140 stops the operation of the transmission / reception gating controller 123, and causes the switches 122-1 and 122-2 to switch to the synthesizer, respectively. 1
It is fixed to the output terminals of 21-1 and 121-2.

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, control signals are exchanged between the radio base station 30 and the mobile radio 100 through the compressor group 71, the signal conversion circuit group 51, the expander group 72, the signal speed restoration circuit group 38 and the like. I explained that there is no
This is for convenience of explanation, and communication can be performed without any trouble through the compressor group 71, the signal speed conversion circuit group 51, the signal speed restoration circuit group 38, the expander group 72, and the signal processing unit 31, like the audio signal. Is.

Next, the operation of receiving a call to the mobile wireless device 100 will be described. The mobile wireless device 100 is in a standby state with the power turned on. In this case, as described in the calling operation 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. These control signals pass through the compressor group 71, the signal speed conversion circuit group 51, and the signal allocation circuit group 52 to the control unit 40 (FIG. 3) as the communication signal 22 similarly to the voice signal. Then, the control unit 40 uses an empty slot of the downlink time slots of the radio channel CH1 addressed to the mobile radio 100, for example, SD1 to output the ID signal of the mobile radio 100 + the incoming signal display signal +
A time slot use signal (for transmission from mobile radio 100, SU1 corresponding to SD1, for example, is used) is transmitted. In the mobile wireless device 100 that receives this signal, the signal is transmitted from the receiving unit 137 of the wireless receiving circuit 135 to the control unit 140. The control unit 140 confirms that this signal is an incoming call signal to the mobile wireless device 100 of its own, so that the telephone unit 101 sounds a ringing tone and at the same time waits at the instructed time slot SD1, SU1. The transmission / reception gating controller 123 is operated as described above, and the switches 122-1 and 122-2 are turned on and off.
Thus, the call is ready to be made.

(2) Theoretical explanation of the present invention

(A) Mathematical Expression of Modulated Wave First, a description will be given of the case of single angle modulation in which compound modulation by angle modulation or amplitude modulation is not performed, and then the effect of compound modulation according to the present invention is theoretically explained. explain.

The data or telephone signal (for analog or digital format signals) which is the output signal (or control signal) of the telephone section 101 of FIG. 2 can be expressed as follows.

Μ (t) = Σa _i cos (ω _i t + θ _i ) (1) Here, Σ means summing i = 1 to m. The control signal existing outside the band is μ _c (t) = Σa _i cos (ω _i t + θ _i ) (2) where Σ means the sum of i = m + 1 to n, and a _i Is the magnitude of the amplitude, ω _i is the angular frequency of the signal θ _i is t
Represents the phase when = 0. m and n represent positive integers.

Next, the case of frequency modulation will be described.
The invention applies equally to phase modulation and amplitude modulation. Expression (1) or Expression (1) and Expression (2) I = I ₀ sin∫ (ω + μ (t)) dt = I ₀ sin (ωt + s (t)) (3) or I = I ₀ sin∫ (ω + μ) _{(t) + μ c (t} )) dt = I 0 sin (ωt + s (t) + s c (t)) and becomes (4).

However, s (t) = Σm _i sin (ω _i t + θ _i ) where Σ represents the sum from i = 1 to m, and s _c (t) = Σm _i sin (ω _i t + θ _i ) Where Σ represents the sum from i = m + 1 to n, and m _i
= A _i / ω _i (i = 1,2,3, ..., n), and s (t) + s _c (t) shown in the equation (4) represents a transmission signal of a general form. Become.

By using the equation (3) or the equation (4), the radio signal transmitted from the antenna of the mobile radio 100 is expressed by the following equation. I = (I ₀₁ / n) {1 + 2Σφ ⁻¹ sin φ cosmppt} sin θ ₁ (5) where φ = mπ / n, θ ₁ = Ω ₁ t + s ₁ (t) + s _c1 (t), and n Is the number of slots (equal time intervals) in one frame, Ω ₁ is the carrier angular frequency, p is the switching angular frequency, m
Is a positive odd number, and Σ represents the sum from m = 1 to ∞.

Expression (5) is the case where the transmission signal from the mobile radio 100 using the same radio channel is one of the n slots in one frame, but all slots are implemented by signals. State, that is, n mobile radios 1
When 00 is in communication using the same wireless channel, the display of the signal included in the wireless channel by the mathematical expression is as follows.

I = I ₁ + I ₂ + I ₃ + ... + I _n (6), and I ₁ = (I ₀₁ / n) {1 + 2Σφ ⁻¹ sin φ cosmpt} sin θ ₁ I ₂ = (I ₀₂ / n) {1 + 2Σφ ⁻¹ sin φ cosmpt ₂ } sin θ ₂ I ₃ = (I ₀₃ / n) {1 + 2Σφ ⁻¹ sin φ cosmpt ₃ } sin θ ₃ …… I _n = (I _0n / n) {1 + 2Σφ ^-1 sin φ cosmpt _n } sin θ _n where Σ represents the sum from m = 1 to ∞.

Furthermore, t ₂ = t−2π / (np) t ₃ = t−4π / (np) ... t _n = t−2 (n−1) π / (np), and θ ₁ = Ω ₁ t + s ₁ (t) + s _c1 (t) θ ₂ = Ω ₂ t + s ₂ (t) + s _c2 (t) θ ₃ = Ω ₃ t + s ₃ (t) + s _c3 (t) …… θ _n = Ω _n t + s _n (t) + s _cn (t), p is the switching angular frequency, m is a positive odd number, and the switching times for the n input waves are at equal intervals.

In the following, the equation (6) is modified because it is necessary for examining the influence of adjacent channel interference, which will be described later. The right side of the equation (6) is expanded as the following equation.

I = (I ₀₁ / n) C ₁ + (I ₀₂ / n) C ₂ + ... + (I _0n / n) C _n (7) where C ₁ = sinθ ₁₀ + b ₁₁ sinφ ₁ + b ₁₃ sinφ ₃ + b ₁₅ sinφ ₅ + …… C ₂ = sinθ ₂₀ + b ₂₁ sinφ ₁ + b ₂₃ sinφ ₃ + b ₂₅ sinφ ₅ + ………… C _n = sinθ _n0 + b _n1 sinφ ₁ + b _n3 sinφ ₃ + b _n5 sinφ ₅ + ...... is.

Also, b ₁₁ = φ ₁ ^-1 (sin θ _11p + sin θ _11n ) b ₁₃ = φ ₃ ^-1 (sin θ _13p + sin θ _13n ) b ₁₅ = φ ₅ ^-1 (sin θ _15p + sin θ _15n ) ... b ₂₁ = φ ₁ ^-1 (sin θ _21p + sin θ _21n ) b ₂₃ = φ ₃ ^-1 (sin θ _23p + sin θ _23n ) b ₂₅ = φ ₅ ^-1 (sin θ _25p + sin θ _25n ) _{………………} b _n1 = φ ₁ ^-1 (sin θ _n1p + sin θ _n1n ) b _n3 = φ ₃ ^-1 (sin θ _n3p + sin θ _n3n ) b _n5 = φ ₅ ^-1 (sin θ _n5p + sin θ _n5n ) ...

Further, φ ₁ = π / n, φ ₃ = 3π / n, φ ₅ = 5π / n, ...

Further, θ ₁₀ = Ω ₁ t + s ₁ (t) + s _c1 (t) θ ₂₀ = Ω ₂ t + s ₂ (t) + s _c2 (t) ... θ _n0 = Ω _n t + s _n (t) + s _cn ( t).

Further, θ _11p = (Ω ₁ + p) t + s ₁ (t) + s _c1 (t) θ _11n = (Ω ₁ −p) t + s ₁ (t) + s _c1 (t) θ _13p = (Ω ₁ + 3p) t + s ₁ (t) + s _c1 (t) − (6π / n) (n−1) θ _13n = (Ω ₁ −3p) t + s ₁ (t) + s _c1 (t) + (6π / n) (n−1) ) Θ _15p = (Ω ₁ + 5p) t + s ₁ (t) + s _c1 (t)-(10π / n) (n-1) θ _15n = (Ω ₁ -5p) t + s ₁ (t) + s _c1 (t) + (10π / n) (n-1) ... θ _21p = (Ω ₂ + p) t + s ₂ (t) + s _c2 (t) θ _21n = (Ω ₂ −p) t + s ₂ (t) + s _c2 (t) θ _23p = (Ω ₂ + 3p) t + s ₂ (t) + s _c2 (t)-(6π / n) (n-1) θ _23n = (Ω ₂ -3p) t + s ₂ (t) + s _c2 (t) + (6π / N) (n-1) θ _25p = (Ω ₂ + 5p) t + s ₂ (t) + s _c2 (t)-(10π / n) (n-1) θ _25n = (Ω ₂ -5p) t + s ₂ (t _{) + s c2 (t) +} (10π n) (n-1) ...... θ n1p = (Ω n + p) t + s n (t) + s cn (t) - (2π / n) (n-1) θ n1n = (Ω n -p) t + s n ( _{t) + s cn (t)} + (2π / n) (n-1) θ n3p = (Ω n + 3p) t + s n (t) + s cn (t) - (6π / n) (n-1) θ n3n = _{(Ω n -3p) t + s} n (t) + s cn (t) + (6π / n) (n-1) θ n5p = (Ω n + 5p) t + s n (t) + s cn (t) - (10π / n _{) (n-1) θ n5n} = (Ω n -5p) t + s n (t) + s cn (t) + (10π / n) (n-1) is ....

Here, it can be seen from the expression (7) that many carriers are combined. The above is n in FIG.
Although it was a radio signal transmitted from each mobile radio device 100, when the signal transmitted from the radio base station 30 to each mobile radio device 100 is described, this is also obtained in the same manner. It can be seen that the angular frequency can be set as Ω ₁ = Ω ₂ …… = Ω _n (8).

The mobile radio 100 communicating with the radio base station 30 in the face-to-face relation with each other uses only the signals necessary for itself in the equation (6) by the timing generator 142 and the transmission / reception gating controller 123 shown in FIG. It will be used for selective reception. Now, assuming that this is the time slot SD1 shown in FIG. 5 for the mobile wireless device 100-1, the signal becomes the signal represented by the first term on the right side of the equation (6), that is, I ₁ . When the expression (5) passes through the amplitude controller included in the receiving unit 137 of FIG. 2, it has the form as shown in the following expression. I = A sin (Ω ₁ t + s ₁ (t) + s _c1 (t)) (9) However, A is amplitude and is not related to frequency or time. When Equation (9) passes through the frequency discriminator included in the receiving unit 137, the demodulation output is e (t) = μ (t) + μ _c (t). Then, this output is used as the speed restoration circuit 131 of FIG.
If it passes through, the original signal is reproduced.

The following will quantitatively evaluate the spread of the sidebands of the radio modulated wave, which is a problem in constructing the system, and explain that the system according to the present invention can be practically operated without any trouble.

(B) Spreading of Sideband of Modulated Wave Expression (7) is a fairly complicated mathematical expression, and the following can be understood by observing the contents of the expression.

(I) When the original carrier wave is modulated with the TCM signal, the switching angular frequency p of each time piece signal constituting the TCM signal causes a large number of subcarriers (± p, ± p centering on the carrier angular frequency Ω). 3p, ± 5p, ...) are present. However,
This effect is remarkable when transmitting using only one time slot, such as when transmitting from the mobile wireless device 100 to the wireless base station 30.
, The effect gradually diminishes as the number of time slots used increases, and does not appear at all when transmitting using all time slots.

(Ii) The original carrier wave and a large number of subcarriers (± p, ± 3p, ± 5p, centering on the carrier angular frequency Ω,
There are a number of sideband signals that occur when each of these is frequency-modulated by TCM.

Therefore, the band width of the signal included in the radio signal represented by the equation (7) becomes extremely large because the sideband spreads greatly. If it is sent to the space as it is, there is a possibility of causing radio wave interference to adjacent channels. Therefore, one countermeasure is to insert a bandpass filter on the input side of the modulated wave so as to limit the spread of the sideband to a certain spread and then add it to the modulator. As another countermeasure, a method of limiting the spread of the sideband to a certain spread by inserting a bandpass filter on the output side of the modulated wave is also in practical use. These are used not only in the case of TCM signals but also in wireless systems in general, and the modulated signal is then converted to a defined carrier frequency (not shown) or the output is increased (not shown), This signal is sent to the space toward the mobile radio 100 that communicates with the other side. However, if the characteristics of the bandpass filter are so strict that the spread of the sideband is limited, distortion noise occurs. So there is a trade-off between the two,
In a microwave analog wireless relay system using a practically used FDM (a signal obtained by frequency division and multiplexing a telephone signal), a band pass filter having the following bandwidth is used. That is, assuming that the maximum frequency of the FDM telephone signal (baseband signal) is F _h , the pass band width of the band pass filter is ± (1.3 to 1.5) F centering on the carrier angular frequency Ω.
It is about _h .

On the other hand, in the case of a TCM-converted telephone signal, there is little distortion noise, and the pass band width of the band pass filter that reduces the possibility of causing radio wave interference to adjacent channels is known. However, a) In the case of a TCM-converted telephone signal, the baseband signal has a large band, as in the FDM signal. b) In addition to a), only one channel of the telephone signal has a wide band, and therefore, even if the band is narrowed, distortion noise is less likely to occur. As a result, the practical limited bandwidth of a radio signal that does not generate a large distortion noise is ± (1.1 around the carrier angular frequency Ω, where ω _L and ω _H are the minimum and maximum frequencies of the TCM-converted telephone signal, respectively. ~ 1.5) ω _H (about 1.5 ω _H for convenience of calculation here, but 1.2 ~ 1.33 is suitable as a practical value). Therefore, in consideration of the existence of the switching angular frequency p of each time piece signal which constitutes the TCM signal, the pass band width of the band pass filter is comprehensively expressed by 1.5 (ω _m + p) × 2 (10). It

FIG. 12 (a) shows the spectrum of the radio signal represented by equation (5). This signal is further amplitude-modulated by a telephone signal (lowest frequency ω _L , highest frequency ω _H ) having the same TCM-converted spectrum as shown in FIG. 12B, with the depth of modulation being k (0 <k ≦ 1). The spread of the sideband in the case of doing will be described. Note that FIG. 12 is schematically shown, in which the energy of the signal wave is represented by electric power, the sideband characteristics of the modulated wave are flat, and the energy is constant over an angular frequency range of 0 to ω _H. There is. FIG. 12A shows only the first sidebands a and b of the frequency modulation wave.

In this case, the equation (5) is expressed as follows. I = (I ₀₁ / n) H (t) {1 + 2Σφ _m ^-1 sinφ _m cos mpt} sin θ ₁ (11) where H (t) = 1 + k (μ (t) + μ _c (t)) φ _m = mπ / n, where μ (t) is a telephone signal and μ _c (t) is its control signal. is there.

Expression (11) has a very complicated expression, but it will be easier to understand if it is considered as follows. That is, the formula (11) has the following formula a ₁ = (I ₀₁ / n) [sin {(Ω ₁ + p) t + s ₁ (t)) on each of the right sides of the formula (7) obtained by expanding the formula (5). Since + s _c1 (t)} is amplitude-modulated, the spread of the sidebands included in the composite-modulated radio signal appears to be larger in addition to the spread of equation (7). However, actually, the spread of the sideband does not become large, and is almost the same as the spread of the sideband included in the single-modulated radio signal.

This will be theoretically described below. First, it is assumed that the right side of Expression (11) is expanded with some approximation, and is expressed as the following expression. I = (1 + a + b) (c + d) sin Ω ₁ t (12) where a: upper band of amplitude modulation wave b: lower band of amplitude modulation wave c: upper band of frequency modulation wave d: frequency Lower side wave of modulated wave sin Ω ₁ t: wireless carrier Now, expanding the right side of formula (12), I = (c + d) sin Ω ₁ t + (a + b) (c + d) sin Ω ₁ t (13) Formula (13) The first term on the right-hand side of 13) represents the frequency-modulated wave itself, and it can be seen from this term only that the spread of the sideband does not occur. Next, when the second term on the right side of the equation (13) is further expanded, r = ac + ad + bc + bd (14) However, the term of the wireless carrier wave is omitted in the equation (14).

The angular frequency distribution of each term on the right side of the equation (14) is examined. As is clear from FIGS. 12 (a) and 12 (b), these are the products of two sidebands, so that the distribution has the same result as the "convolution" in statistics.

In FIG. 13, various sidebands a, b,
c and d are (a-1) to (d-1), (a-2) to (d-
In 2), the products ac, ad, bc, bd of the sidebands are (a
-3) to (d-3). Here, it is assumed that the sidebands of the amplitude modulation wave also exist flat between −ω _{H and} ω _H. From FIG. 13, products of sidebands ac, ad, bc, bd
It can be seen that each signal component of is as follows. ac: upper part of carrier angular frequency Ω ₁ (= Ω ₁ ) to 2ω _H
Has a main signal component (a-3). ad: lower −ω _H , upper ω across carrier angular frequency Ω _1.
There is a major signal component in _H (b-3). bc: lower-ω _H , upper ω with carrier angular frequency Ω ₁
There is a major signal component in _H (c-3). bd: Lower part of carrier angular frequency Ω ₁ (= Ω ₁ ) to 2ω _H
Has a main signal component at (d-3). As a result, the distribution of the composite modulated wave on the right side of Expression (12) becomes as shown in FIG. Here, the solid line shows the various sidebands shown in FIG. 13 and their products, and the broken line shows the distribution of the sidebands of the complex modulated wave existing around the carrier angular frequency Ω ₁ .

[0114] -2ω signal components of Figure 14 _H ~ω _H, -ω
_It is divided into _H ~ ω _H and ω _H ~ 2ω _H , and a) −ω _H ~ ω.
_The signal component existing in _H is 50% of the power of the carrier wave and 42% of the power of the sideband. B) The signal component existing other than -ω _{H to} ω _H is 8% because it is the rest of the a).

From this result, it is found that even if the upper limit (ω _H ) of the primary sideband in the case of a single modulated wave is set as the cutoff frequency of the bandpass filter, the power of 92% of the complex modulated wave is included. Became clear.

Next, when the cutoff frequency of the band-pass filter is increased to make it possible to transmit up to 1.5 ω _H , which is 1.5 times the above, the signal component existing within 1.5 (−ω _{H to} ω _H ) is calculated. , The result gets 98%. Therefore, the other signal components existed at 2%, and as a result, it was revealed that most of the signal components existed within 1.5 (-ω _{H to} ω _H ).

The above calculation was made on the assumption that the sideband characteristics of the modulated wave were flat. However, as is well known, the human speech spectrum is concentrated in a low frequency band.

FIG. 15 shows an example of a conversation voice spectrum of a person. Here, the solid line shows the female voice, the broken line shows the male voice, and the dash-dotted line shows the average frequency distribution.
The long-term effective value (dB) per 1 Hz is the frequency (H
It can be seen that the focus is on the low part of z). Therefore, the frequency characteristic of the telephone signal also exhibits the frequency characteristic when the low frequency band of 0.3 kHz or less and the high frequency band of 3 kHz or more in FIG. 15 are cut off. Therefore, the telephone signal spectrum is also concentrated in the low frequency band, and near the high frequency of 3 kHz.
It can be seen that it is about 25 dB lower than that near 0.3 kHz. This also applies to a signal obtained by converting a telephone signal into TCM. When the same calculation as the above is performed using the sideband wave characteristic shown in FIG. 15, the following result is obtained. c) When the signal components existing in the transmission band 1.5 (-ω _{H to} ω _H ) are obtained, the result is 99.9% or more. d) The signal components existing outside the transmission band of 1.5 (-ω _{H to} ω _H ) are the rest of c) and are 0.1%.

Further, 99% or more is obtained even within the transmission band 1.33 (-ω _{H to} ω _H ). That is, it has been shown that it is sufficient to set B _fm-am = 1.33ω _H (15) as the required transmission bandwidth of the composite modulated wave.

This result also means that there is no need to insert a bandpass filter. Alternatively, it is shown that even if a bandpass filter having a narrower band characteristic is inserted to avoid adjacent channel interference, the transmission characteristic is not so badly affected.

The above results show that the TCM is transmitted from the radio base station 30.
It was a case of sending out a telephone signal. It will be described that when the TCM telephone signal is transmitted from the mobile wireless device 100, the modulated signal is further concentrated near the carrier wave. In this case, for example, (I ₀₁ / n) C of the first term on the right side of Expression (7) is used.
Only the signal indicated by ₁ will be transmitted to the radio base station 30. As is clear from the first term on the right side of the equation (7), it can be seen that the TCM-converted telephone signal spreads widely on the frequency axis. That is, a number of subcarriers equivalent to the switching angular frequency p of the time piece signal constituting the TCM signal (± p, ± 3 around the carrier angular frequency Ω ₁ are equivalent).
, p) ± 5p, ..., and the TCM-converted telephone signal spreads widely on the frequency axis due to the large number of subcarriers. For example, p is 50Hz
(= 2π × 50), the first subcarrier has an amplitude of ⅓ of the main carrier on both sides of the carrier angular frequency Ω ₁ of ± 2π × 50, and is mainly on ± 3p, ± 5p, ... 1 / of carrier wave
It has an amplitude of 5, 1/7, ..., 1 in the vicinity of ± 3 kHz.
It will have an amplitude of / 120. However, in an actual radio circuit, when modulating a carrier wave by a TCM telephone signal, a harmonic component is removed in advance through a band pass filter and a fundamental component is amplified. Therefore, the energy of the modulated signal is extremely small in the vicinity of ± 3 kHz and is concentrated in the vicinity of the carrier wave.

(C) Calculation of Effective Frequency Utilization Rate Next, the spread of sidebands in the case of performing the above-mentioned single modulation without using the complex modulation as in the present invention will be described and both will be compared.

A case where the carrier wave is frequency-modulated by two TCM-converted telephone signals will be described. The highest frequency of the signal included in the TCM composite signal is 1.33 (ω _H + p). Therefore, as the required bandwidth of the modulated wave, B _2fm = 1.33 (2ω _H + p) (16)

The equations (15) and (16) are compared.
Since p is smaller than ω _H and is ignored, the equation (15) is obviously smaller than the equation (16) and is about half the size. That is, the frequency effective utilization rate of the present invention is about twice as large as that of the conventional method.

From the above, it was proved that the present invention generally has a higher frequency effective utilization rate than the conventional method. Next,
Further, if TCM is used without increasing the signal compression ratio, the time slot length is lengthened and the amount of information that can be transmitted is reduced. Therefore,
If the information amount of the person who performs the complex modulation is reduced, the result becomes exactly the same as the comparison between the equations (15) and (16). Therefore, also in this case, it is proved that the present invention has a higher frequency effective utilization rate than the conventional method.

The complex modulation described above is a combination of frequency modulation and amplitude modulation. For complex modulation, a combination of frequency modulation and frequency modulation, or amplitude modulation and amplitude modulation is also possible. However, in this case, it is necessary to pay attention so that the frequency bands of the signals do not overlap each other.

(3) System configuration in the case of composite signal Next, the system configuration and its operation in the case of using a composite modulation signal in which a carrier wave is amplitude and frequency modulated by a telephone signal will be described.

16 to 18 show a receiver 137 (FIG. 16) included in the mobile radio 100 (FIG. 2) and the radio base station 30 (FIG. 3) for explaining an embodiment of the present invention.
(A)), the wireless reception circuit 35 (FIG. 16B), the wireless transmission circuit 32 (FIG. 17) and the wireless transmission circuit 32B (FIG. 1).
8 shows a detailed configuration of 8).

FIG. 16A shows a detailed circuit configuration of the receiving section 137 of the mobile wireless device 100. The wireless composite modulation signal received by the antenna unit is applied to the reception unit 137 via the reception mixer 136 and is divided into two parts, and a part of the amplitude modulation signal reception unit 161 operates by receiving the timing signal from the timing generator 142. The other part is input to the frequency modulation signal receiving section 162 which also operates by receiving the timing signal from the timing generator 142.
Then, these output signals are input to the mixing circuit 163. The mixing circuit 163 receives the quality of the input signal (SN ratio).
And select only good signals, or SN
It has a function of mixing both signals according to the ratio. The output of the mixing circuit 163 is divided into two, part of which is input to the speed restoration circuit 138 and the other part of which is input to the clock regenerator 141 (see FIG. 2).

FIG. 16B shows the detailed structure of the radio receiving circuit 35 of the radio base station 30.
After passing through the reception mixer 61, the signal received by the antenna part is divided into two parts, which are input to the amplitude modulation signal receiving part 62 and the other part to the frequency modulation signal receiving part 63. Then, these output signals are input to the mixing circuit 64. The mixing circuit 64 has a function of measuring the quality (SN ratio) of the input signal and selecting only a good signal, or mixing both signals according to the SN ratio. Mixing circuit 6
The output of No. 4 is divided into two, and one part is input to the signal selection circuit group 39 and the other part is input to the control unit 40 (see FIG. 3).

FIG. 17 shows the internal structure of the radio transmission circuit 32. The carrier frequency source 37 is on the left side, and the carrier wave from this is input to the frequency modulator 36. On the other hand, the signal from the signal allocation circuit group 52 is input to the frequency modulator 36 that operates under the control of the control unit 40, and the carrier wave becomes a frequency modulated wave. Next, the frequency modulated wave is input to the amplitude modulator 34 which operates under the control of the control unit 40. Here, the signal from the signal allocation circuit group 52 is input, and the frequency modulation wave is amplitude-modulated. Thus, the composite frequency-amplitude modulation is performed. And
This wireless composite modulated wave is input to the transmission mixer 33. Then, after being amplified by a power amplifier (not shown), it is transmitted from the antenna section to a large number of mobile radio devices 100.

FIG. 18 shows another embodiment 32B of the internal structure of the radio transmission circuit 32. Two carrier frequency sources 37-1 and 37-2 are provided on the left side, and the angular frequency Ω _a ,
Outputting carrier wave of Ω _b . This carrier frequency source 37-
The carrier wave from 1 is input to the frequency modulator 36 that operates under the control of the control unit 40, and is frequency-modulated by the signal from the signal allocation circuit group 52. On the other hand, the carrier frequency source 37
The carrier wave from -2 is input to the amplitude modulator 34 which operates under the control of the control unit 40, and is amplitude-modulated by the signal from the signal allocation circuit group 52. The outputs of the above two modulators are input to the transmission mixer 33, where the output frequency is converted into Ω ₁ = Ω _a + Ω _b , and at the same time, the composite modulation wave that has undergone frequency modulation and amplitude modulation is output. ..

Although the above description is concerned with the composite modulation performed by the radio base station 30, the radio transmitter circuit 132 of the mobile radio 100 also performs the composite modulation of the telephone signal and transmits it to the radio base station 30. Will be done.

In the transmission diversity described above, the phase of the TCM-converted telephone signal is not taken into consideration when performing the composite modulation. However, the effect of signal deterioration that occurs when a radio signal propagates in space is
They may be equivalent depending on the system parameters. In this case, it is possible to expect a time diversity effect (about 5 to 10 dB) by delaying either one of the amplitude modulation signal and the angle modulation signal using a delay circuit for about 10 to 100 msec. ..

In the transmission diversity described above, the modulation sideband characteristic of the composite modulation wave applied to the transmission antenna may be wider than the sideband characteristic of the single modulation wave depending on the system parameters. In this case, after obtaining the composite modulated wave, by the bandpass filter,
Adjacent radio channel by transmitting after reducing the sideband characteristic to the extent that it has a modulation sideband characteristic equivalent to the case where amplitude modulation or angle modulation is performed on one carrier with the same modulation signal It is possible to make the increase of radio wave interference to the system negligible.

Furthermore, since the previously described Sylavic compander is inserted in the appropriate part of the preceding stage of the modulator on the transmitting side, this value can be increased when the transmitted signal has multiple load gains. This is possible, and if this value is used to reduce the wireless transmission power, the transmission power can be significantly reduced.

[0137]

As is apparent from the above description, in the modulation method according to the present invention, the same carrier is angle-modulated by the TCM-converted telephone signal, and at the same time, amplitude modulation is performed by the same TCM-converted telephone signal. By using it, it becomes possible to obtain the diversity effect at the same time while measuring the effective use of the frequency. At the same time, it becomes possible to increase the multiple load gain of the signal by using a Syrabic compander, and this value can be used to reduce the wireless transmission power to significantly reduce the transmission power.

Further, depending on the type of signal, if the spread of the sideband of the modulated signal may be wider than that of the single modulation, a bandpass filter is provided on the output side of the modulated signal to spread the sideband. Can be suppressed to substantially the same extent of sideband spread as in the case where angle modulation or amplitude modulation is performed by a single signal, interference with adjacent radio channels can be prevented, and 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 of an embodiment of a mobile wireless device for explaining the principle of the present invention.

FIG. 3 is a circuit configuration diagram of an embodiment of a radio base station for explaining the principle of the present invention.

FIG. 4 is a characteristic diagram showing input / output characteristics of a compander.

FIG. 5 is a time slot structure diagram for explaining time slots used in the system of FIGS. 1 to 3;

FIG. 6 is a spectrum diagram showing spectra of a call signal and a control signal.

FIG. 7 is a circuit configuration diagram for multiplexing a voice signal and a data signal.

FIG. 8 is a waveform diagram showing a radio signal waveform of a time slot.

FIG. 9 is a spectrum diagram showing spectra of a time-compressed speech signal and control signal.

FIG. 10 is a flow chart showing a flow of a calling operation of the system of FIGS. 1 to 3.

FIG. 11 is a flow chart showing a flow of a calling operation of the system of FIGS. 1 to 3 together with FIG. 10.

FIG. 12 is a spectrum diagram showing spread of sidebands of a radio signal.

FIG. 13 is a spectrum diagram showing products of various signal components in a radio signal and sidebands thereof.

FIG. 14 is a spectrum diagram showing a distribution of a composite modulated wave in a wireless signal.

FIG. 15 is a spectrum diagram showing a spectrum of human conversation voice.

16 is a detailed circuit configuration diagram of a receiving unit which is a component of the mobile wireless device shown in FIG. 2 and a wireless receiving circuit which is a component of the wireless base station shown in FIG.

FIG. 17 is a detailed circuit configuration diagram of a wireless transmission circuit which is a component of the wireless base station shown in FIG.

FIG. 18 is a detailed circuit configuration diagram of another embodiment of the wireless transmission circuit which is a component of the wireless base station shown in FIG.

[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 33 Transmission Mixer 34 Amplitude Modulator 35 Radio Reception Circuit 36 Frequency Modulator 37 Carrier Frequency Source 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 to 52-n signal allocation circuit 61 reception mixer 62 amplitude modulation signal reception unit 63 frequency modulation signal reception unit 64 mixing circuit 91 digital encoding circuit 92 multiplex conversion circuit 100 , 100-1 to 100-n Mobile radio 101 Telephone section 120 Reference crystal oscillator 121- , 121-2 Synthesizer 122-1 and 122-2 Switch 123 Transmission / reception gating controller 131 Speed conversion circuit 132 Radio transmission circuit 133 Transmission mixer 134 Transmission section 135 Radio reception circuit 136 Reception mixer 137 Reception section 138 Speed restoration circuit 141 Clock regenerator 142 Timing Generator 161 Amplitude Modulation Signal Reception Unit 162 Frequency Modulation Signal Reception Unit 163 Mixing Circuit

Claims (2)

[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, the amplitude characteristic of the communication signal that is temporally compressed and delimited is adjusted by the silabic compander, and based on the substantial multiple load gain obtained by using the signal whose amplitude characteristic is adjusted. A time division communication method for mobile communication, in which a modulation level is determined by using a signal whose amplitude characteristic is adjusted, and one carrier is subjected to angle modulation and amplitude modulation. 2. A signal whose amplitude characteristic is adjusted, which is used when performing the angle modulation and the amplitude modulation, is divided into two and divided into two.
The mobile body according to claim 2, wherein one signal is obtained, one of the two signals is delayed to provide a time difference, and the two signals provided with the time difference are subjected to the angle modulation and the amplitude modulation for transmission. Time division communication method of communication.