JPH03289726A - Time division communication method for mobile object communication - Google Patents

Abstract

PURPOSE:To improve the effective availability of a frequency with the reduction of a transmission output by utilizing the multiple load gain of a signal and to enable economical communication by converting the level of this signal to be used between a radio base means and a mobile radio means based on the difference of the multiple load gain provided for a frequency division multiplex signal. CONSTITUTION:Since the multiple load gain exists even in the time division time compression multiplex signal, the multiple load gain can be concretely calculated by using the various design parameters of a system. By using such a multiple load gain and the multiple load gain provided for the well-known frequency division multiplex signal, the degree of modulation is improved for FM (PM) modulation while keeping interference jamming or the like within an allowable value. Therefore, the transmission output can be reduced and the frequency band can be effectively utilized. Further, since the peak value of an output signal from a transmitter is not increased over a fixed value in the transit amount of the modulation, the obstacle of the system operation can be removed. Thus, a modulator or an amplifier is easily designed and the economical communication is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the effective use of multiple load gain of a time compression multiplex signal, which is a modulation signal, in a time division communication method of a wireless communication channel in mobile communication. More specifically, given a radio channel, one of the many mobile radios in the service area is communicating with an opposing radio base station by setting up a radio link. When another mobile radio starts communicating with another radio base station using the same radio channel, due to the effective use of frequencies or radio wave propagation characteristics, the communication between the mobile radio and the radio At the same time as eliminating any negative effects on communication with the base station, another communication signal is placed in a low frequency band outside the frequency band of the time division multiplexed signal, and the multiple load gain of this signal is also utilized. The purpose of the present invention is to provide a method that improves the effective use of frequencies by reducing the transmission power and enables economical communication.

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

Literature 1. Ito ``Study of mobile phone system - Proposal of time division time compression FM modulation system -'' IEICE technical report RC389-1
1 Literature dated July 1989 2. Ito: Mobile phone system study - Time division time compression F
Theoretical study of M modulation system” IEICE technical report RC389-39
In other words, in Document 1, a transmission signal (baseband signal) is divided into predetermined time intervals and stored in a memory circuit, and when read out, the speed is n times faster than the speed at which it is stored in the memory circuit. It is built into mobile radios and radio base stations in order to be read out in a predetermined time slot at high speed, angle-modulated or amplitude-modulated with the signal accommodated by the time slot, and transmitted and received intermittently over time. a wireless receiving circuit having a receiving mixer that communicates with each other, a wireless transmitting circuit having a transmitting mixer, a synthesizer applying voltage to the receiving mixer of the wireless receiving circuit, and a synthesizer applying voltage to the transmitting mixer of the wireless transmitting circuit. On the other hand, a switch circuit is provided to intermittent the output of each applied synthesizer, and to synchronize this intermittent state for both transmission and reception, and also to synchronize the same intermittent transmission and reception as above with that of the mobile radio device for the radio base station that communicates oppositely. In order to extract only the signals accommodated in the predetermined time slots, the receiving side opens and closes the radio receiving circuit to receive the signals, demodulates the signals, stores the obtained signals in the storage circuit, and An example of a system has been reported in which a system is constructed in which it is possible to reproduce the baseband signal, which is the original signal that has been transmitted, by reading out the signal at a low speed that is 1/n of the speed at which it is stored in this memory circuit. There is.

In addition, Reference 2 examines adjacent channel interference and co-channel interference, which are problems when applying the TCM (time division time compression multiplexing)-FM method described above to small zones. Possibilities of realizing the system have been shown by appropriately selecting parameters.

Furthermore, the multiple load gain of a so-called frequency division multiplexed signal, which is obtained by converting the frequency of an audio signal and multiplexing it so that it does not overlap on the frequency axis, is described in, for example, the following documents 3 and 4.
is shown.

Literature 3. B, D, Ho1brook, J, T, Di
xon: LoadRating Theory for
r Hultichannel Amplifiers
.

BSTJ, 1B, Oct., 1939 Reference 4. C
,B., Feldman et al.”Band Width an
dTransmission Performance
” BSTJ, July 1949490-595
Figure 13 on page 13 was created from Figures 7 of the above-mentioned document 3, and Figure 14 was quoted from page 495 of the above-mentioned document 4, and is substantially the same as that shown in figure 13. It is shown that the same multiple load gain can be obtained.

The reason why multiple load gain can be obtained and its application to wireless angle modulation will be briefly explained below.

The level of an active telephone channel carrying telephone signals varies from person to person, gender, and subscriber line length; There is always a gap. Also, while the other party is talking, the other party does not speak and no signal is added to one direction. Do not speak during exchange connection. Therefore, the individual signal levels are diverse, and the sum ljj of these signals cannot be easily determined. However, clarifying this is the most important and fundamental problem in creating a relay line that maintains distortion, crosstalk, quasi-crosstalk, noise, etc. to satisfactory values. Therefore, it has been studied by many people.

FDM method (33: single 5
The level of the method using ideband is to synthesize such voices, and the probability that each voice overlaps at the same time is rare, and while the number of communication channels N is small, the influence of each voice that fluctuates greatly on the synthesized signal is high. wG, 1 is direct, but as the number of multiplexing increases, the individual effects become less direct and become stochastically averaged.Therefore, the peak value of the composite signal becomes extremely small as the number of channels increases. Increase slowly.

This is B, D, Hotbrook and J, T, Di.
xon (Reference 3 above) statistically calculated flea stories in the United States. According to the results, the change in power of a sine wave having the same peak value as the peak value of the multiplexed signal is as shown in FIG. To show how small the increase in the peak value of multiple telephone signals is, the first
The multi-load gain is as shown in Figure 3. That is, for example, in the 960 channel system, 6 channels are loaded at maximum at the same time, and 95
The peak voltage is the same as if the signal of the 4 communication paths were not loaded.

In the SS-FM system, fluctuations in the voltage of the composite signal result in frequency deviations, so when the peak frequency deviation of the composite signal is set to a certain value and the number N of multiplexed communication channels increases, the voltages of each communication signal will be summed. Compared to the multi-load gain shown in Fig. 13, the modulation index for each channel can be increased, and the S/
It is improved by that much more than N.

[Problem to be solved by the invention] In the system construction examples shown in the above-mentioned documents 1 and 2,
The existence of a multiple load gain in time-division time compression multiplexed signals transmitted from a radio base station to a large number of mobile radios is not disclosed, and this multiple load gain is not utilized.

Therefore, if this multiple load gain is concerned.

Had the analysis been done, many benefits would have been gained in system design, such as the reduction in transmit power level possible by increasing the depth of frequency modulation and the ability to amplify the CM signal. The problem is that it is not possible to concretely realize advantages such as ease of amplifier design, realization of an economical amplifier by expanding the operating level setting range, or economy by relaxing the rating conditions of mixers, resistors, and capacitors. There were issues to be addressed.

What was disclosed in References 3 and 4 clarified the multiple load gain in so-called frequency division multiplexed signals in which audio signals are frequency-converted and multiplexed so that they do not overlap on the frequency axis, and are time-division time multiplexed. It cannot be applied to compression multiplexing (TCM> signals, and the existence of multiple load gain is unknown. Advantages (References 1 and 2 above)
There was a problem to be solved that it was not possible to concretely realize the same in the case of .

Generally speaking, in the case of TCM signals, as a result of time-compressing the original signal, an unused low frequency band is generated, and there remains the problem of how to utilize this effectively.

[Means for solving the problem] TCM (time division time compression multiplexing) Taking the number of multiplexed signals (number of communication paths), the time length of one frame, and the highest frequency of the original signal as parameters, the multiplex load of the TCM signal is calculated. Using the sampling theorem, the gain is clearly derived in relation to the multiple load gain in an FDM (frequency division multiplexed) signal, and the multiple load gain decreases depending on the system parameters, but this can be reduced by using a compressor. This has been prevented and made practical.

Furthermore, by using the amplitude distribution characteristics of the TCM signal, a compressor (
A compressor) was inserted to change the distribution to the desired distribution, and an expander was installed on the receiver side for demodulation. here,
Since a TCM signal that time-compresses the original signal is used, there will be an unused part in the low frequency band, so in order to make effective use of this part, for example, FDM signals can also be transmitted and received. , FDM channel converters were installed in both the radio base station and the mobile radio.

[Operation] Since it has become clear that multiple load gain exists in TCM signals, it has become possible to specifically calculate multiple load gain using various design parameters of the system, and it has become possible to calculate the multiple load gain using various design parameters of the system. By using this together with the multi-load gain possessed by the FM (PM) modulation, it is possible to gradually reduce the transmission output by deepening the modulation depth of FM (PM) modulation while keeping interference within the permissible value, making it possible to effectively utilize the frequency band. I also made it possible to wear it. Since the peak value of the output signal from the transmitter no longer increases beyond a certain value in terms of modulation deviation, it is possible to eliminate system operational obstacles, and as a result, the modulator and It has become easier to design amplifiers, and the rated values of passive circuits such as mixers, resistors, and capacitors can be lowered, allowing economical communication.

Furthermore, the frame length of the signal is 1/2fh (2fh
: Nyquist frequency, fh is longer than the highest frequency of the signal>, and if the multiple load gain is expected to decrease compared to an FDM signal with the same number of multiplexes, use a compressor to equivalently maintain the same multiple load gain. I was able to have it.

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

In FIG. 1A, 10 is a general telephone network, and 20 is a gateway exchange for connecting the telephone network 10 and a wireless system. 30 is a wireless base station and a barrier switch 20
It includes an interface with the mobile radio 11, a circuit that converts the signal speed, a circuit that allocates and selects time slots, a control unit, etc.
100 (100-1 to 100-n) and a wireless transmitting/receiving circuit that transmits and receives wireless signals.

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

FIG. 1B shows a circuit configuration of a mobile radio device 100 that communicates with a radio base station 30.

Received signals such as control signals and call signals received by the antenna section enter a radio reception circuit 135 that includes a reception mixer 136 and a reception section 137, and the communication signal that is the output thereof is sent to a speed restoration circuit 138 and a control section 140. It is input to the clock regenerator 141. The clock regenerator 141 regenerates a clock from the received signal and sends it to the speed recovery circuit 13.
8, the control section 140, and the timing generator 142.

The speed recovery circuit 138 calculates the speed (pitch in the case of an analog signal) of the compressed and segmented communication signal in the received signal.
is restored and input as a continuous signal to telephone section 101 and control section 140.

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

The output of the modulator included in the transmitting section 134 is transmitted to the transmitting mixer 13
3, the signal is converted to a predetermined radio frequency, transmitted from the antenna section, and received by the radio base station 30.

In order for the mobile radio device 100 to send a radio signal to the radio base station 30 using a time slot that is permitted to be used, timing information from the timing generator 142 shown in FIG. 1B is sent to the control unit 140. It is necessary that the information has been obtained through

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

This mobile radio device 100 further includes a synthesizer 121.
-1 and 121-2, and selector switches 122-1, 1
22-2, a transmission/reception intermittent controller 123 and a timing generator 142 that generate signals for switching the changeover switches 122-1 and 122-2, respectively.
Synthesizers 121 - 1 and 121 - 2 , transmission/reception intermittent controller 123 , and timing generator 142 are controlled by control section 140 . Each synthesizer 121-1.1
21-2 is supplied with a reference frequency from a reference crystal oscillator 120.

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

N-channel communication signal 22-1 between barrier exchange [20
22-n are connected to a signal processing unit 31 forming an interface through a transmission path.

Now, the communication signal 22- sent from the barrier switch 20
1 to 22-n are input to the signal processing unit 31 of the wireless base station 30. The signal processing section 31 is equipped with an amplifier for compensating for transmission loss, and also performs so-called 2-wire to 4-wire conversion. That is, the input signal and the output signal are mixed and separated, and the input signal from the barrier switch 20 is sent to the signal speed conversion circuit group 51. Also, signal speed restoration circuit group 3
The output signal from 8 is transmitted to the barrier exchange [20 by the signal processing unit 31 using the same transmission path as the input signal. Among the above input signals from the barrier switch 20, the signal speed conversion circuit group 5 including many signal speed conversion circuits 51-1 to 51-n
1 and undergoes speed (pitch) conversion at predetermined time intervals.

Furthermore, the signal transmitted from the radio base station 30 to the gateway exchange 20 is determined by the output of the radio receiving circuit 35 being transmitted to the signal selection circuit group 39.
is input to the signal speed restoration circuit group 38 via the signal speed (
Pitch> is converted and input to the signal processing section 31.

Now, the control of the radio reception circuit 35 or the output of the call signal is performed by a signal selection circuit 39 that selects a signal for each time slot.
-1 to 39-n is input to the signal selection circuit group 39,
Here, speech signals are separated corresponding to each speech channel 0 day 1 to CHn. This output undergoes signal speed (pitch) restoration in a signal speed restoration circuit group 38 including signal speed restoration circuits 38-1 to 38-n provided for each channel, and then is input to the signal processing section 31. , after undergoing 4-wire to 2-wire conversion, this output is sent to the barrier exchange 1120 as a communication signal 22-1~
22-n.

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

By storing input signals such as audio signals and control signals divided into a certain length of time in a storage circuit, and changing the speed when reading them out, for example, reading them out at a speed 15 times faster than when they were stored, the signal can be read out. It becomes possible to compress the time length. The principle of the signal speed conversion circuit group 51 is the same as when playing back audio recorded by a tape recorder at high speed, and in reality, for example, COD (Char
geCoupled Device), BBD
(Bucket Brigade Device) can be used, and the memory used in television receivers and tape recorders that compress or expand the time axis of conversations can be used (References: Koita et al.
“A tape recorder that compresses/expands the time axis of conversations”
Nikkei Electronics July 26, 1976 92-
Page 133〉.

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

The control or audio signals outputted from the barrier switch 20 via the signal processing section 31 are input to the signal speed conversion circuit group 51, where the signals are assigned to each time slot after speed (pitch) conversion processing is performed. The signal is applied to the signal allocation circuit group 52. This signal allocation circuit group 52 is a buffer memory circuit that stores one segment of high-speed signals output from the signal speed conversion circuit group 51, and outputs the signals according to instructions from the control section 40. The signals in the buffer memory are read out using the timing information provided from the timing generation circuit 42 and transmitted to the wireless transmission circuit 32.As a result, the communication signals do not overlap in time series when viewed in terms of channels. They are arranged in series, and when all of the control signals or speech signals described below are implemented, they appear as if they were continuous signal waves.

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

The output signal of the signal speed conversion circuit group 51 is sent to the signal assignment circuit group 5.
2 and are given time slots in a predetermined order. SDI in Figure 2A(a), 5D2
-, SDn indicate that the speed-converted communication signals are allocated to each time slot.

Here, one time slot accommodates a synchronization signal and a control signal or a call signal as shown in the figure. If the call signal is not implemented, only the synchronization signal is added and the empty slot signal is added to the call signal portion. In this way, as shown in FIG. 2A(a), the wireless transmitting circuit 32
In this case, signals forming one frame are applied to the modulation circuit in time slots SD1 to SDn.

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

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

Figure 3A shows these frequency relationships. In other words, in the figure (a), it is an example of an out-of-band signal, 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. 3A (b) shows an example of an in-band signal, which is used when making and receiving calls.

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

The above was a case of analog signals, but if a digital data signal is used as a control signal, it is also possible to digitally encode the audio signal and time-division multiplex the two to transmit. The circuit configuration of is shown in FIG. 3C. FIG. 3C shows an audio signal digital encoding circuit 9.
This is an example of a case in which the data signal is digitized at 1, multiplexed with a data signal by a multiplex conversion circuit 92, and applied to a modulation circuit included in the wireless transmission circuit 32. However, in digital data signals, there is usually no multiple load gain when multiplexing analog signals, which will be described later, so this point must be kept in mind when designing the system.

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

On the other hand, the signal sent from the mobile radio device 100 is received by the antenna section of the radio base station 30 and input to the radio reception circuit 35. FIG. 2A (b) schematically shows this upstream input signal.

That is, time slot S(,Il,5LI2.・
... SUn indicates a transmission signal addressed to the radio base 830 from the mobile radios 11100-1, 100-2°, . . . , 100-n. In addition, each time slot SU1.5LJ2,
The contents of .

However, depending on the short distance between the radio base 830 and the mobile radio device 100 or the signal speed, the synchronization signal may be omitted. Roughly speaking, the waveform of the radio carrier wave of the above-mentioned uplink radio signal within a time slot is schematically shown as shown in FIG. 2B (C).

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

A timing signal from a timing generation circuit 42 that generates a predetermined timing is applied to the signal selection circuit u39 according to a control signal instruction from the control unit 40, and a synchronization signal and a control signal are applied for each time slot SU1 to Sun. Or the call signal is output separately. Each of these signals is input to the signal speed restoration circuit u3B. This circuit is connected to the mobile radio device 1001 on the transmitting side. : Speed conversion circuit 131 (
It has a function to perform the inverse conversion of FIG. 1B), thereby faithfully reproducing the original signal and transmitting it to the gateway exchange 20.

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

As shown in FIG. 1C, the control signal from the control section 40 is applied to the wireless transmission circuit 32 in parallel with the output of the signal allocation circuit group 52. However, depending on the magnitude of the speed conversion rate, it is also possible to apply the signal to the wireless transmission circuit 32 from the output of the signal allocation circuit group 52 after performing the same processing as the call signal.

Next, as shown in FIG. 1B, the mobile radio device 100 also has a circuit configuration required when the radio base 830 functions as a single communication channel. The frequency distribution on the output side when an original signal, for example, an audio signal (0.3 to 3.0 KHz) passes through the signal speed conversion circuit group 51 (Fig. 1C) is shown in Fig. 3B. In other words, if the audio signal is converted 15 times as shown in the previous example, the frequency distribution of the signal will be as shown in Figure 3B.
This means that it has been expanded to 5KH2 to 45KHz.

Note that although the frequency distribution of the signal has been expanded here, the form of the waveform has simply been stretched (similarly transformed) on the frequency axis, and there is no change other than the similar transformation of the waveform. This is necessary when calculating the value of the multiload gain.

Now, FIG. 3B shows a case where the control signal is simultaneously transmitted using the lower frequency band of the audio signal. Among these signals, the control signal (0,2~4.0KH2>
and the call signal C port 1 (at 4,5-45 KHz, denoted as SDl) is a time slot, e.g.
Suppose that it is housed in l. Other time slot SD
The same applies to the audio signals accommodated in 2 to 3[)n.

That is, time slot sor <r=2°3,
-, n) accommodate a control signal (0,2 to a, oKHz) and a communication signal CHi (4,5 to 45KH2). However, the signals in each time slot are arranged in chronological order, and the signals in multiple time slots are not applied to the wireless transmission circuit 32 at the same time.

In addition, the above control signals are not implemented when a time slot for control signals is provided at the beginning of the frame, and when the lower frequency band is used for other signals, the frequency of the communication signal Near the band 1g1 (4,1 to 4.4 day Z or 46 to 4B, 5kH2) may be provided.

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

f > 2 f H ep On the other hand, in digital signals, audio is usually 64 kb/S
Since the signals are digitized at a certain speed, it is necessary to read the scale on the horizontal axis in FIG. 3B, which describes the case of an analog signal, by raising it by about one digit, but the above relationship also holds true in this case.

Further, the control signal that has entered the radio base M30 from the mobile radio device 100 is input to the radio reception circuit 35, but a part of its output is input to the control unit 40, and the other part is sent via the signal selection circuit group 39. and is sent to the signal speed restoration circuit group 3B. After the latter control signal undergoes a speed conversion (conversion to a low speed signal) that is completely opposite to that at the time of transmission, it becomes the same signal speed as that used in the general telephone network 10 and is transmitted via the signal processing section 31. Sent to barrier exchange 1120.

Other embodiments 100B and 100C of the mobile inorganic device 100 are shown in FIGS. 1D and 1E. The difference with the mobile radio 11100 shown in FIG. 1B is that it performs a compression operation to prevent the peak value of the output signal from the transmitter from increasing beyond a certain value in modulation deviation. A compressor 171 and an expander 172 for expanding the signal compressed by the compressor when it is received.
It is equipped with the following.

Mobile radio! ! 11008 (FIG. 1D), the compressor 171 is connected to the speed conversion circuit 131 and the wireless transmission circuit 1.
32, and the expander 172 is provided between the radio receiving circuit 135 and the speed restoration circuit 138. In the mobile radio m1ooc (FIG. 1E), the compressor 171 is connected to the telephone section 101 and the speed conversion circuit 131.
An example is shown in which the expander 172 is provided between the speed restoration circuit 138 and the telephone unit 101.

FIG. 1 shows another embodiment 100 of a mobile radio 11100.
D is shown. Mobile radio 10 shown in FIG. 1D
The difference from 0B is that FDM channel converters 173, 174 and switches 118-1, 118-2 are added, and these constitute an uncompressed signal communication means. The signal is transferred to FDM channel converter 17
4 and speed restoration circuit 138, and switch 118-2 selects the transmission signal from FDM channel converter 1.
73 and speed conversion circuit 131, it is possible to select whether to transmit/receive using an FDM (frequency division multiplexing) signal or a TCM (time division time compression multiplexing) signal.

FIG. 1G shows the first radio transmitting circuit 1 shown in the figure.
Details of a circuit suitable for 32 are shown.

The digital/analog signal mixer 217 includes a control section 14
0, an analog TCM signal from compressor 171 and FDM channel converter 1.
one of the analog FDM signals from 73,
The three signals are applied and mixed, modulated by a modulator 216, and a transmission output is applied to the antenna section via a transmission mixer 133.

The first diagram shows the radio receiving circuit 13 shown in Figure 1F.
Details of a circuit suitable for 5 are shown.

The received signal from the antenna section is converted into a digital signal via a receive mixer 136° amplifier 2112 and a frequency discriminator 212.
A digital signal is applied to the analog signal separator 213 using the timing signal from the timing generator 142, and is transmitted to the clock regenerator 14] and the control unit 14.
0, the analog TCM and FDM signals are passed through a bandpass filter 214 to an expander 172 and an FDM signal, respectively.
It is applied to the DM channel converter 174.

Unless otherwise specified below, mobile radio equipment 100.10
08.100C and 100D are collectively referred to as the mobile radio device 100.

Other embodiments 30B and 30C of the radio base station 30 are shown in FIG. 11 and FIG. 1J.

The difference from the radio base station 30 shown in FIG. 1C is that the compression operation is performed to prevent the peak value of the output signal from the transmitter from increasing beyond a certain value in terms of modulation deviation. compressor 71 or compressors 71-1 to 71-n
and an expander group 72 including an expander 72 or expanders 72-1 to 72-n for conversely expanding a signal compressed by the compressor when it is received. be.

In the radio base station 30B (FIG. 11), the compressor 71 is provided between the signal allocation circuit group 52 and the radio transmission circuit 32, and the expander 72 is provided between the radio reception circuit 35 and the signal selection circuit group 39. It is provided. In the wireless base station 30C (Fig. 1J), the compressor 71-
The compressor group 71 including 1 to 71-n is connected to the signal processing unit 3.
1 and the signal speed conversion circuit group 51, and includes the expanders 72-1 to 72-n.
A broken example is shown.

First, another embodiment 30D of the wireless base station 30 is shown in the figure. The difference from the radio base station 30B shown in FIG. 1I is that FDM channel converters 73 and 74 are added to the transmitting side and the receiving side, and these constitute uncompressed signal communication means. It operates in the same way as the mobile radio device 100D.

Here, switch 11 used in mobile radio device 100D
The functions 8-1 and 118-2 are performed by the signal processing unit 31 in the wireless base station 30D according to instructions from the control unit 40.

Below, unless otherwise specified, wireless base station 30.30
8.30G and 30D are collectively referred to as the wireless base station 30.

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

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

When the mobile radio device 100 is powered on, the first
In the wireless receiving circuit 135 in Figure B, the downlink (wireless base station 30
→Mobile radio@100) Start capturing the control signal included in the radio channel (channel C port 1). If the system is provided with multiple radio channels, i) the radio channel exhibiting a received input electric field of R; ii)
iii) A radio channel (hereinafter referred to as It enters the receiving state for channel C port 1). This is possible by capturing the synchronization signal within the time slot SDi shown in FIG. 2A(a). In the control unit 140, the synthesizer 121-
The switch 122-1 is also fixed in the position of the synthesizer 121-1.

Therefore, when the receiver of the telephone unit 101 is taken off-hook (starting a call) (S201, FIG. 4A), the synthesizer 121-2 in FIG. 1B generates a local oscillation frequency that enables transmission on the wireless channel CH1. A control signal is received from the control section 140 to cause the control to occur.

Further, the switch 122-2 is also turned toward the synthesizer 121-2 side and becomes fixed. Next, wireless channel C port 1
The call control signal outputted from the telephone unit 101 is sent using the telephone unit 101. This control signal has a frequency band shown in FIG.
It is sent using un.

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

Specifically, the following method is used to capture the time slot Sun. As shown in FIG. 2A (a), the control signal transmitted from the radio base station 30 includes a synchronization signal and a subsequent control signal, and the mobile radio device 100 receives this signal to perform frame synchronization. becomes possible.

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

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

In other systems, there may be no empty slot indication in any of the time slots, in which case the audio multiplex signal SDI that follows.

SD2. ..., it is necessary to search for the presence of SDn one after another and check for empty time slots.

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

Therefore, assuming that the time slot Sun for uplink signals is an empty slot, it is decided to use this empty time slot, and the control signal for calling is sent out, and the necessary timing is extracted from the response signal from the wireless base 430. It is also possible to send out burst-like control signals.

If there is a call from another mobile radio at the same time, the calling signal will not be properly transmitted to the radio base station 30 due to call collision, and the operation will have to be restarted from the beginning, but this probability is When viewed as a system, this value is kept to a sufficiently small value. If call collisions are to be further reduced, the following method may be used.

Even if the mobile radio device 100 finds an empty time slot in which it can make a call, it does not use the entire time slot, but rather uses only the first half of the time slot for some mobile radio devices and only the second half for other mobile radio devices. This is a method that allows you to use In other words, the portion of the time slot used as a calling signal is divided into several types, and this is used to classify a large number of mobile radios into groups, and each group is assigned a time period within that one time slot. It is a way of giving.

Another method is to create many different frequencies for the control signal,
This is a method of dividing a large number of mobile wireless devices into groups and applying this to each group. According to this method, even if control signals of different frequencies are transmitted simultaneously using the same time slot, no interference will occur at the radio base station 30. The above two methods may be used separately, or when used together, the effects will increase synergistically.

Now, suppose that the calling control signal from the mobile radio m1oo is successfully received by the radio base 830 and the IDC identification number of the mobile radio 1100 is detected (S202>, the control unit 40 determines the time slot in which the room is currently occupied). Search. The time slot given to the mobile radio 100 may be Sun, but just to be sure, perform a search.
In addition to 00, this is also used to respond to simultaneous calls from other mobile radios, and to provide time slots suitable for service types and service classifications.

As a result, if the time slot SDI is vacant, for example, the time slot SD1 of the radio channel CHI is used for the mobile radio 1fi100, and the time slot uplink (mobile radio 100→radio base station 30> SUI.

and instructs to use the corresponding downlink (radio base station 30 → mobile radio device 100) SDl (3203
>.

In response, the mobile radio 11100 transitions to a state in which it can receive data in the instructed time slot SD1, and also changes the time slot 5LJ1 (FIG. 2A), which is the time slot for the uplink radio channel corresponding to the downlink time slot SD1. b) Select ).

At this time, in the control unit 140 of the mobile radio Vs100, the transmission/reception intermittent controller 123 is operated, and the switch 122 is activated.
-1 and 122-2 are started (3204>).

At the same time, a slot switching completion report is sent to the wireless base 1430 using the uplink time slot SUI52.
05), wait for dial tone (5206>).

Time slot SU of the radio carrier of this upstream radio signal
The state of No. 1 is schematically shown in FIG. 2B (C). In addition to time slot SU, the radio base station 30 receives SU as an uplink signal from another mobile radio 14100.
3 Sun is included in one frame and sent.

The radio base station 30 that has received the slot switching completion report (
S207>, a calling signal is sent to the barrier switch 20 (3208), and the barrier switch va20 that receives this detects the ID of the mobile radio device 100 and selects the necessary switch among the switch group included in the barrier switch 20. Turn on (32
09>, send dial tone (3210.4th
Figure B).

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

When transitioning to this state, the telephone unit 1 of the mobile radio [100]
Since a dial tone is heard from the 01 handset, the dial signal begins to be sent. This dial signal is speed-converted by the speed conversion circuit 131 and sent out from the wireless transmission circuit 132 including the transmission section 134 and the transmission mixer 133 using the uplink time slot SU1 (3213>. Thus, the transmitted dial signal is It is received by the radio receiving circuit 35 of the base station 30.

This radio base station 30 already responds to the calling signal from the mobile radio 100, gives the time slot to be used, and operates the signal selection circuit group 39 and signal allocation circuit group 52 of the radio base station 30. So, time for the uphill.
It receives the slots St and l'l and is now in a state of transmitting the signal of the downlink time slot SDI. Therefore, the dial signal transmitted from the mobile radio device 100 passes through the signal selection circuit 39-1 of the signal selection circuit group 39, and then is input to the signal speed restoration circuit group 38, where the original transmission signal is restored. The call signal 2 is transmitted through the signal processing section 31.
It is forwarded to the gateway exchange 20 as 2-1 (3214),
A call path to the telephone network 10 is set (S215>).

On the other hand, input signals from the barrier exchange TFI 20 (initial control signal, call signal when a call is started) are sent to the wireless base station 30.
After being subjected to speed conversion by the signal speed conversion circuit group 51, the time slot SD1 is given by the signal allocation circuit 52-1 of the signal allocation circuit group 52. Then, it is transmitted from the radio transmission circuit 32 to the mobile radio device 100 using the time slot SD1 of the downlink radio channel.

The mobile radio device 100 is on standby for reception at time slot SD1 of radio channel C port 1, and is received by the radio reception circuit 135, the output of which is sent to the speed restoration circuit 13B.
is input. In this circuit, the original signal of the transmission is restored and input to the handset of the telephone section 101. Thus,
A call is started between the mobile radio 100 and a regular telephone within the regular telephone network 10 (3216).

The call is terminated by on-hooking the handset of the telephone unit 101 of the mobile radio 100 (8217), and the end-of-call signal and the on-hook signal from the control unit 140 are transmitted to the speed conversion circuit 1.
31 from the wireless transmission circuit 132 to the wireless base station 30 (3218>), and the control unit 140 stops the operation of the transmission/reception intermittent controller 123 and switches the switches 122-1 and 122-2 to the synthesizer. It is fixed to the output ends of 121-1 and 121-2.

On the other hand, in the control unit 40 of the radio base station 30, the mobile radio device 1
When the call termination signal from 00 is received, the call termination signal is transferred to the barrier exchange 83120 (3219), and the switch group (not shown) is turned off to terminate the call (S220).
>. At the same time, the signal selection circuit group 39 and signal allocation circuit group 52 in the radio base station 30 are opened.

In the above explanation, control signals between the radio base station 30 and the mobile radio device 100 are controlled by the signal speed conversion circuit group 51. Although it was explained that the signal speed restoration circuit group 38 etc. are not passed through,
This is for convenience of explanation, and communication can be carried out without any problem even through the signal speed conversion circuit group 51, signal speed restoration circuit group 3B, control signal speed conversion circuit 48, or signal processing section 31, as with audio signals. .

(2> Incoming call to mobile radio 11100 The mobile radio 100 is on standby with the power turned on. In this case, as explained in the section on making a call from the mobile radio 100, the procedure specified by the system is followed. It is in a state of waiting to receive the downlink control signal of radio channel 0 day 1 according to the following.

Assume that an incoming call signal to the mobile radio device 100 arrives at the radio base station 30 from the general telephone network 10 via the barrier switch 20. These control signals are transmitted as communication signals 22 to the control section 40 via the signal rate conversion circuit group 51 and the signal allocation circuit group 52, similarly to the voice signals. Then, the control unit 40 selects an empty slot among the downlink time slots of the radio channel C port 1 addressed to the mobile radio device 100, for example,
Using Dl, the ID signal of the mobile radio 100, the incoming call signal display signal, and the time slot use signal (the mobile radio 100
For example, for transmission from 0, 5LJ1 corresponding to SDl
). Mobile radio device 1 that received this signal
00 is transmitted from the receiving section 137 of the radio receiving circuit 135 to the control section 140. The control unit 140 confirms that this signal is an incoming call signal to its own mobile radio 100, so it causes the telephone unit 101 to emit a ring tone and at the same time, at the designated time slot SD'l, 5tJ1. The transmission/reception intermittent controller 123 is operated to standby, and the switches 122-1 and 122-2 are started to be turned on and off. In this way, the state has shifted to a state in which calls can be made.

It should be noted that it is theoretically explained in Reference 2 that signal transmission is performed in good condition using this system and does not adversely affect other wireless channels in the system, so it will be omitted here. It will be theoretically explained that the TCM signal applied to the present invention has multiple load gain, and then its application will be described.

(3) Regarding the multiple load gain of the TCM signal transmitted from the wireless base station 30 In order to relate the multiple load gain of the TCM (time division time compression multiplexing) signal to the multiple load gain of the FDM (frequency division multiplexing) signal, first, , ``Each audio signal flowing in each DM channel C-1.C-out 2...CHn is expressed in the form of a function.The FDM signal is obtained by converting the frequency of the audio signal as is well known, and is shown in Fig. 5. As shown, these multiplexed signals are arranged in a line on the frequency axis, and this multiplexed signal is often used in coaxial transmission systems and microwave analog communication systems, and multiple load gain is also incorporated into practical systems and has great effects. Note that the spectrum in Figure 5 has 12 channels.
(0 days 1 to 12) is shown, but general Niha, 12
m(7) and others, 60,120,480.960,1200
．． Many different types are used, including 2,700 pieces.

In the following description, it is assumed that the input audio signal level to the FDM signal or TCM signal is the same. Now, the fifth
Figure Channel C Day 1. C mouth 2.0 mouth 3.・・・・・・
Audio signal flowing to CHn (In the case of wired, the frequency band to be transmitted is 0.3 to 3.4, but for mobile radio signals, it is 0.3 to 3.0, so this value is limited〉 as f (1), -1'2(t3゜......,
Let fn(t). The frequency components of these signals are as follows: Channel C port 1 is 0.3~3.0k)-12°CH2
is 4.3 to 7.0kHz, -・-, CHn is 4×(n-
1> + 0.3 to 4 The signal waveform itself has not changed at all, just shifting to a higher frequency on the axis.This is important in finding the multiload gain, and can be expressed as follows.Known knowledge of FDM signals The multiload gain of is exactly the same as the signal when n voices are arranged on the frequency axis as shown in Figure 5, and the signal when n voices without frequency conversion are simply mixed. Proof: The mixed signal of channel C 1. C port 2..., C day n is expressed by the following equation.

F(t) −fl (t) 10f2 (t) 10−+f
, (t)(1> Specifically, fi(t) is expressed as follows.

kH2 (2) (3) However, I≧2 Further, the mixed signal when frequency conversion is not performed is given by the following equation.

G(t) −Cl3 (j) +g2 (j) ten...
+g, (t) (4) Here, gl(1)-fl(t) kH2 (5) <6> However, i≧2 Next, find the power possessed by the signals of equations (1) and (4). .

First, "The power of (t) is f gi Qj dt=0 (7) On the other hand, the power of G (t) is (8> However, we used the fact that no power is formed between different signals. That is, ffi fj dt=0 (9) However, i-4:j Now, from equations (2> and (3)), df fl(t)di (10> f・2(t) d t (11) However, 1≧2 (10), (11>> From the equations, F(t)''miG(t)2 (12) is obtained.

That is, it has become clear from the above explanation that the power of a signal is not related to frequency conversion.

Next, consider applying the sampling theorem to gi(t). Since the highest frequency fh of Jm is 3KH2, the time interval is 1/(2fh), that is, 1/6000
It is well known that if sampling is performed every second, the original signal can be reproduced later even if only the sampled value (voltage value) is transmitted.

Therefore, f, (1) is calculated at the time interval [1/6000+(1/6000)(i -1)/60
00] seconds (13〉). In the figure, ta=1/6
000 seconds.

t b= (1/6000) x (1/6000)
seconds.

to= (1/6000) X (5999/6000
) seconds.

t d= 1/6000+ (1/6000) x (
3000/6000) seconds.

to=1/6000 seconds.

It is. Hereinafter, in order to explain specifically, the multiplex number n is set to 6.
000.17 The frame length is 1/6000 seconds.

Now, on the horizontal axis of Figure 6A (a), put 600 small bags (diameter 1/6000 x 1/6000 seconds) as shown in Figure 6B (c).
0 pieces, and one large bag with a diameter of 1/6000 second, are arranged as shown in the figure. Then, compare the above sampled values to matchsticks and consider how these matchsticks fit into the bag.

Since the function g1(t) (i = 1, 2..., n) has 6000 matchsticks per second, and they are equally spaced in time, the capacity bag (1), (2),...,(N
), and this operation is repeated for each frame. That is, bag (1) has gl (1/6000) bag (2) has g2 (1/6000+ 1/6000x 1/6
000) Bag (3) contains g3 (1/6000+1/
6000X 2/6000) bag (6000) has C1
(1/6000 + 1/6000000 x 5999 /6000) will be inserted respectively.

Also, in the large bag (Σ6000), the mixed signal G(t
) is included. In this case, the sampling time is 1/6000+1/
6000x3000 /6000. In other words, it is set as the midpoint of one frame. Then, the value of the next matchstick will be stored in the large bag (Σ6000).

The large bag (Σ6000) has G (1/6000+ 1/6000x3000 /6
000) Below, the value of the match stick from bag (1) to (6000), Chi (1/6000) g2 (1/6000+1/6000X1/6000
).

Q 6000 (1/6000+1/6000x 59
The sum of 99/6000) and the value of the matchsticks in the large bag (Σ6000) G (1/6000 + 1/6000X 3000 /
6000) are compared as shown in equations (14) and (15) below.

000 10CJ 2 (1/6000+1/6000X 1/
6000) 10g3 (1/6000+1/6000x
2/6000) +... +g7 (1/6000+1/6000x(i-1)
/6000)+ g6ooo(1/6000+ 1/6
000X 5999 /6000) (14) G (1/6000+1/6000x3000/600
0 ) = g1 (1/6000+1/6000x
3000/6000) 10g2 (1/6000+1
/6000x3000/6000)+... 1+-go(1/6000+1/6000x3000/
6000 ) (15) As a result of comparing equations (14) and (15), if (16) is true and the average value converges to O every time Δ is sampled at 1/6000 second intervals, then This proves that the multiload gain in the FDM signal is similar and has the same value in the TCM signal. This is because 6000 bags placed on the horizontal axis have a capacity of 1 bag.
It represents a time slot, the sum of the bags is one frame, and the match sticks inside the bags are used for each signal q, c+,
, Q can be considered to be a signal subjected to time compression multiplexing (TCM>) at time 1 2 """ n times, and T
This is because the CM signal is well mixed, like the large bag (Σ6000) in FIG. 6B (C), and can be regarded as one FDM signal. Therefore, in this example, even though it is a TCM signal, there is no particular need for time compression, and the degree of compression is 1.

In addition, in Fig. 6B (C), the position of the bag on the horizontal axis (axis between 11!) and bag (1) is as follows: 1/6000≦t<1/6000+1/6000
x 1/6000 bag (2) is 1/6000+ 1/600() x 1/6000≦t
<1/80D.

11/6000x 2/6000 Bag (i) is 1/6000+t/6000x (i-1)/6000
≦t < 1/6000, + 1/6000x i/6
000 bags (6000) is ? /6000+1/6000x 5999/6000≦
t < 1/600 (>+1/6000x6000/8
000 is shown. On the other hand, the audio signal J(i), C20(j),..., J
(t) ,...g6000("), each sampling time is 1/600
0. 1/6000+1/6000x 1/6000.
......, 1/6000+ 1/6000
x 1-1)/6000. ......, 1/
Since the setting is 6000+1/6000x5999/6000, each matchstick will enter the book bag while touching the side of the bag. This is done for convenience; if you want to put a matchstick in the center of the bag, for example, change the time t of Cl1(t) to t = 1/6000 + 1/6000x (i + 0.5
) /6000. However, even with this selection, the conclusion of this proof does not change.

Now, compare the corresponding terms on the right sides of equations (14> and (15>).

Δi=Q・ (1/6000+ 1/6000x (i
-1)/6000)-gi (1/6000+1
/6000
(1/6000+3000/60002) represents the difference in signal magnitude between seconds. This difference is like the error value of random noise, and the channel (
CH+ > i = 1, 2. --------, n may take a positive value, a negative value, or occasionally O, but generally it varies left and right around O, and the variation is normally distributed. It will be.

The above was about a certain time t ''' to.The next sampling is performed 1/6000 seconds later.

The next one is delayed by another 1/6000 second. This sampling is performed, for example, 6000 times per second, so the average value of equation (17) for one second will be (18〉), that is, close to O. This means that even more time is required. If you multiply the time, it will become clearer, and if you take the average over 10 seconds or 30 seconds, you can think that equation (18) becomes O.

As described above, FDM and T with the same multiplicity (6000)
Although it has been revealed that the average power level of each CM signal is the same, the amplitude distributions of the two types of multiplexed signals will now be explained.

Here, the message flowing through Telephone 1 channel @'r(x)(/
=1.2,3. Assume that the mean value and variance of ...> are as follows.

Average value E[f(1riko=O) Dispersion E[f(ff)]=σ2 First, as the average value and variance of N multiplexed FDM signals are well known, the average value is The above function gi (i=1.2°...
. . , n) is similarly obtained. The average value is: The variance is Next, the average value and variance of the TCM signal used in the present invention are determined. In this case, the integral number fH(n+k
) is renamed according to the following relationship.

f i (n+k) = f (kN+n+1-1) Now, find the average value.

The variance is [-1 E [f(n)]=eim1/L:XX f(n)→
oo n=0 For simplicity, let = rN, then E [f(n)]=4'im(1/rN)r-+■ r-I N 1Σ 1/N ff1llll(1/r )1=1
r→prison-1 =E [fH(t)] =O Next, find the variance.

[→oo n=0 For simplicity, let L=rN, then E [f(n) 2]=eim(1/rN)r−+(3
) 1:1 r-+(3) =σ2 This revealed that the dispersion has the same amplitude distribution as the one channel of the audio signal.

Depending on how the system parameters are taken, when transmitting a TCM signal, if the signal has a large peak value, which increases the modulation deviation of FM modulation and may cause interference to adjacent channels, it is necessary to set σ in advance. For example, a circuit for compressing to σ1/2, that is, 1/2 compression (1/2 in decibel value)
/2〉The compressor 171 having the function of
It is necessary to insert it as shown in Figure 1F and then add it to the transmitter. On the receiving side, it is necessary to reproduce the original sound after using a circuit that performs an expansion operation, that is, an expander 172 as shown in FIGS. 1D to 1F.

The above means that the multiple load gain obtained with FDM is
This is nothing but showing that it can be obtained even with M.

However, the value of the multiple load gain quoted from the above-mentioned document 3 is that the frequency band of the audio signal is 0.3 to 3.4 KH2, whereas It was assumed that the same value could be obtained in the transmission band of 0, 3 to 3.0 KH2. This assumption can be accepted with virtually no error.

In addition, in the case of a TCM signal, since the signal is time compressed,
The frequency component it has increases by the degree of compression, but this is because only the frequency component has been changed as mentioned above, and the signal waveform itself has just undergone a similarity transformation to extend it on the frequency axis, so the multiload gain amount There is no change in
Below, we will prove it strictly using mathematical formulas.

The TCM signal is expressed as follows using equations (5) and (6).

3, 0KHz (19) Tatashi, ffT≦t≦T/n+NT h, (t) =0 Tatashi, 1/n<ffT<t<T-11! TZ=1.
2, 3. ......T is the time length of one frame. Therefore, the time-compressed CM signal is This is because only 1/n of the time is transmitted.If we want to express this in terms of voltage, it would be n times the power). Now, when we calculate the power in equation (20) for the time T of one frame, we get the following equations (7) and (8) as well, as in equations (7) and (8). 2dt (21) Therefore, if time is taken as an integer multiple of the frame, the power possessed by signal port (1) and G (t) is
It was found that t)2 (22>).

Next, the frame length of the audio n-channel multiplexed TCM signal is 1.
/ (The multiple load gain when shorter than 2fh> will be explained.

In this case, as above, FDM of audio n-channel multiplexing
It can be easily proven that it has a value equivalent to the multiload gain in the signal.

For example, assume that the frame length is 1/8000 seconds. Then, the sampling frequency is changed from the aforementioned 6000roZ to aoooday2, and each audio signal Q1 (j), g
2(1), . . . , Qo(t), and also sample the mixed audio signal G (t) at 8000H2, and compare these two. In other words, by simply changing the horizontal axes in Figures 6A (a), (b) and 6B (C) from 1/6000 to 1/8000,
All of the above explanations apply.

Briefly, we will explain what happens to the multiple load gain when the frame length becomes longer than 1/(2fh). In conclusion, the multiple load gain generally decreases, and its specific value is determined below. As a concrete value, the number of multiplexes is 6000, which is the same as the previous example, and the frame length is 1/3000.
This will be explained by taking as an example a case in which the number of seconds is reached. The size of the bags arranged on the time axis increases as the frame length increases (as shown in Figure 6B (d)).To be exact, the diameter of the bags is 1/6000 x 1/3000 seconds. Then, if we add up all the diameters of n bags, we get 1/3000
seconds. Also, the diameter of the large bag (Σ6000) is 1/30
00 seconds.

Now, as above, the sampling frequency is 17600.
Consider putting the Matsutchi stick sampled at 0 seconds into a container. In this case, if the frame length is set to 1/6000 seconds as described above, the following inconvenience will occur. That is, FIG. 6B (d
) As shown in 1/6000 seconds, the bag is (1) ~
(3000), while Matsushibo has 6000.
Since I have books, I can put two books in each bag.

That is, as shown in FIG. 6B (d), the bag (1) receives the audio signal g1(t) and the audio signal g2(1), and the bag (2) receives the audio signal q2(1).
) and 03 (t), bag (3) has q3 (t) and Q4
(j) ,..., hereafter, bag (3000) has Q 30
0(>(t)) and g3001 (t), each matchstick (signal value) is placed. Note that gl(j) is placed in a bag (6000) which is the previous sampling time. On the other hand, bags (3001) to (6000) do not contain any Matsushi sticks sampled within this time, and the next sampling time of 1/60
Each Matsushi stick sampled within 00 seconds is 2
It will be sent to the book.

On the other hand, for the large bag (Σ6000'), there are 2
Since you will own a book of matchsticks, two matchsticks, that is, G (1/6000+1/6000x3000/600
0) and G (1/6000+1/6000x9000
/6000) is inserted (however, G (1/6000+ 1/6000x 9000/
6000) is the matchstick (signal) sampled within the next 1/6000 second, as described above.

What does the above 3B involve?

The fact that two matchsticks are placed in the bags (1) to (3000) means that two channels of audio J(t) and ``i+1(t) are mixed in each time slot of the TCM signal. To do this technically, it is necessary to enter 2 channels (0 ports) - DM.
and the total of 3000 slots is 2 (0 slots) x 30
00 = 6000 (Cth) TCM signal should be generated. And these and a large bag (Σ6000
) will be compared in size with the previous match stick in the same way as described above.

Although this is also a method, it is not a TCM signal in the original sense. Therefore, in order to include only one audio signal in each time slot, the following must be done. 6000 audio signals are divided into two groups, one group can be placed in bags (1) to (3000), and the other groups can be placed in bags (3001) to (6000).

This operation will be explained using FIG. 6D (f).

There are bags (1) to (6000) and large bags (Σ600).
0) are prepared. Now, in the bags (1) to (6000) written at the top, there are Matsushibo Qi,
G3.

q ,...-"5999 are each addressed to one bottle.The large bag (Σ6000) contains G1 (1/6000+1/6000x3000/6
000) is displayed. On the other hand, the bags (1) to (6000) written at the bottom have 12 and G4. , G6.

...One bottle of 2g6ooo is placed in each bottle, and a large bag (Σ6000) contains G2 (1/6000+1
/6000X 9000/6000) is displayed.

By doing as shown in this figure, two match sticks will not be mixed in the same bag, and with the same proof as when the length of one frame is 1/6000 seconds, which was already explained, FDM
It can be seen that the multiplexing gain of the signal (in this case, 3000 multiplexes) is the same as that of the TCM signal.

The above explanation can be expressed as follows.

n voices expressed by equation (4) (in this case, mouth = 600
0 > is divided into two and expressed as follows.

G1(t) =C11(t) +g3(t)+...
10" 5999 (t) (4'> G2 (i) =Q2 (j) +Q4 (j) +"
・+Q6000(i)(4”) zoshi・The above-mentioned proof can be performed for each of the above equations. However, the sampling timing shall be performed under exactly the same conditions as above.

In the above explanation, it has become clear that there is a need for grouping in order to obtain the multiple load gain, but it will be explained below that the TCM signal requires signal compression.

In Figure 6D (f), the upper bag group (1) to (6000) and the lower bag group (1) to (6000) contain only one matchstick, but the TCM signal Considering this, there is still some dissatisfaction. That is, the upper bag group and the lower bag group are simultaneous in time, so within one time slot of the TCM signal,
Still gl and 02゜g3 and 04・"'" 59
99 and g6000 are supposed to coexist and become 0゛.

Signal compression removes this, and the following method may be used. That is, gl, G3. ...,"599
Regarding 9, there are two bags (1) and (3001), (2
) and (3002), ..., (3000) and (600
0), respectively, to the previous bags (1), (2),...
, (3000), and as for CJ, Q,,Q, the same 24°"6000 is stored in the later bags (3001), (3002),...
, (6000).

To do this, for example, regarding Ql, the following composite signal may be created. That is, it is sufficient to create the sum of signals obtained at two adjacent sampling times. Technically, the audio signal is stored in a memory circuit and read out in a time-division manner at twice the speed (duty ratio 50%), and the signal obtained by sampling this read signal at a sampling rate of 1/3000 seconds is It is desired. However, in this case, the TCM signal value (voltage value) of the instantaneous value of the sampling time is
It is impossible to faithfully reproduce the original signal, and it is necessary to transmit a signal with a fixed time width (time slot length).

If the above operation is viewed from the viewpoint of multiple load gain, it will be as follows.

If the frame length is longer than the sampling time interval of 1/6000 seconds, even if the multiplex number n is 6000,
It is not possible to obtain a multiple load gain in FDM with 0C multiplexing, and if the frame length is 1/3000 seconds, the multiple load gain is equivalent to that of an FDM signal of 30,000 days.

The multiple load gain is calculated when the frame length is roughly 1 second and the multiplex number n = 6000.

An explanatory diagram in this case is shown in FIG. 6C (e). To explain the figure, one frame is one second, and n = 6
000, the diameter is 1/600 on the horizontal time axis.
There are 6,000 0-second bags, which form one frame. In this case g1(t),...
Q Think about where you can put the sampled matchsticks of 6000 (t). If the sampling timing is the same as in the case where the frame length is 176,000 seconds, then bags (1), (2), (3)
.

... (6000), one matchstick indicating each audio signal will be inserted into each one.

On the other hand, the large bag (Σ6000) has 6000 matchsticks (having values sampled at each sampling period) indicating G (t). This means that
This means that 6000 audio channels are mixed and input into each time slot of the TCM signal. The technology that makes this possible is FDM, but this does not allow for the TC
It can only be applied to M signals. Therefore, in order to have only one audio signal in each time slot,
The 6,000 audio signals must be divided into 6,000 groups, and each group (in this case, one channel) must be input.

This shows that the multiple load gain in this case is O, which is not obtained at all. Further, the signal compression degree of the CM signal in this case is 6000.

As is clear from the above explanation, we have shown that the multiple load gain decreases when the time length of one frame becomes longer than the sampling period required to faithfully reproduce the audio signal. Expressed in terms, the frame length t is t
When e > 1/(2fh) and the number of multiplexes is n, the multiple load gain is n' = nx1/(2fh t
o) The value is equal to the multiple load gain of a frequency division multiplexed signal having a multiplex number determined by (23>).

According to the above-mentioned documents 1 and 2, the practical range of frame length t and multiplexing number n is as follows: frame length t: 0.1 seconds≧te≧0.000
The 5-second multiplex number n is approximately 3000≧n≧2, and as long as it is within the above range, it will be clear from the above example that equation (23>) always holds true.

In addition, in order to address one match stick in the bag as a TCM signal, in other words, to input one original audio signal, the time length t8 of one frame must be longer than 1/2fh. , the signal must be compressed, and the compression ratio ψ is given by φ=t8/(1/2fh>).

The meaning of the multiple load gain obtained from equation (23) is shown in FIG. 15. The frame length of the TCM signal is plotted on the horizontal axis, and the peak power within the frame (1/600
0 second average) changes as shown by the polygonal line A'APBC'. Now, assuming that the frame length of the TCM signal is t8 (the number of multiplexing is n>), the peak power within the frame at this time is given by point P. Then,
The multiple load gain at this time is given by line segment PP', where a perpendicular line is drawn from point P to the extension of line segment C'B and the intersection point is P'. As can be seen from FIG. 15, the multiple load gain of the TCM signal increases as to becomes smaller, but becomes constant after a certain value. Conversely, when 1e becomes larger than a certain level, there is no gain at all. Both critical points are related to the multiplexing number n, ie, the number of time slots.

(4> Regarding the multiple load gain of TCM signals received at the radio base station 30 The radio base station 30 receives TCM signals transmitted from a large number of mobile radios 100, but the received waves have Let us consider the multiple load gain.To conclude, as will be described later, from the mobile radio device 100, the wireless base station 3
Assuming that exactly the same multiple load gain as when transmitting from 0 can be obtained, it is understood that transmission may be performed with a deeper modulation factor.

However, if the compressor (group) 71 is used in the radio base station 30 as shown in FIG. 11 or 1,
It is also necessary to insert a compressor 171 in front of the wireless transmission circuit 132 on the mobile radio device 100 side, as shown in FIGS. 1D to 1F.

As a specific example, 1 frame length is set to 1 sampling time interval.
/6000 seconds and the number of multiplexes is 6000. Wireless base station 3
0 is assumed to be communicating simultaneously with 6000 mobile radio devices 100 using the same carrier wave and using all the time slots 60001 of one frame.

The positions of the mobile radio devices 100 are arranged at equal intervals on the same circumference when viewed from the radio base station 30, and the receiving antenna of the radio base station 30 is omnidirectional, and the transmitting antenna of the mobile radio device 100 is also omnidirectional. And the magnitude of the transmission power from each mobile radio m"+oo is all the same, and each mobile radio
It is assumed that the carrier waves used to transmit 00 are phase-synchronized with each other. Furthermore, the radio wave propagation characteristics between the mobile radio device 100 and the radio base station 30 are
00 and wireless base 7fi30 are the same. Under the above assumption, the transmitted signals of each mobile radio l1100 entering the radio base station 30 will be received exactly the same. Therefore, the appearance of the received signal within one frame in this case can be considered to be exactly the same as when it is transmitted from the wireless base station 30. Conversely, even though each mobile radio@100 transmits only a single voice channel in the time slot given to it, it is assumed that a multiplex load sequence 1q can be obtained by multiplexing the number of multiplexes of 6000. This indicates that transmission may be performed using a modulation depth that takes into account load gain.

Although ideal conditions have been set above, consider the actual system operating conditions. In this case, the positions of the mobile radios 11100 are randomly scattered, and the radio wave propagation state changes in various ways, so the received power of the radio base station 30 varies for each time slot. Furthermore, the carrier waves from each mobile radio 1100 are not necessarily phase-synchronized. Therefore, if the depth of modulation is large in a time slot with a high reception level, it is expected that the adjacent time slots will be adversely affected due to the influence of multiplex radio wave propagation. However, this can be alleviated by taking other measures such as increasing the guard time.

In addition, in the case of the small zone method, as co-channel interference,
There is no need to worry too much about the possibility that the transmitted waves of one mobile radio 11100 may cause interference to other radio base stations 30 that are located in different locations; on the contrary, it may be possible to use this to gradually reduce the number of repeated zones. . This is because multiple load gain is used as FM (PM) modulation, and as a result of deep modulation, wideband gain can be obtained and resistance to co-channel interference is increased.

Taking all of the above into consideration, the system design assumes that substantially the same multiple load gain can be obtained when the mobile radio device 100 transmits and when the radio base station 30 receives, as when transmitting from the radio base station 30. It became clear that it could be done.

(5> Specific utilization method of multiple load gain The multiple load gain is calculated in the case where one frame length is 1 m5ec and the number of TCM (time division time compression multiplexing) is 500, and an example of its utilization will be explained.

First, S CP C (Single Channel
Per Carrier.

Find the signal S to noise N ratio of analog FM (in which the signal of one telephone channel is modulated on one carrier wave), and calculate this and TC
Compare with M. The level (voltage value) of the input signal to the receiver is C, the FM modulation index is mf, and the noise level (voltage value) per unit frequency is n.

Assuming that the bandwidth of the low frequency amplifier in the discriminator output stage is Fa and the highest modulation frequency f8 of the modulated wave is equal to 8, the signal-to-noise ratio is given by the following formula.

S/N-3172m C(2F)-172f
a (24) This formula was quoted from the following literature.

Edited by Sugawara "FM Radio Engineering" Nikkan Kogyo Shimbun Co., Ltd., 1960, p. 401 (13, 25) Formula Next, the TCM signal with multiplexing number Q is FM radio under the following conditions.
The S/difference in this case is given by the following formula.

(S/interval>, oH= 31/2mfQCQ(2Fao>-1/2(25>) However, Fao=QFa m(Qm Qm((25'>no=Qn In other words, in the TCM signal, the frequency of the original signal is Since the bandwidth of the low frequency amplifier is multiplied by Q, the modulation depth (modulation index) is also multiplied by Q, and therefore the noise level is also multiplied by Q, so (25 ' ) is appropriate.

Next, TCM received signal level 3 "2" rQ so that S/ on the left side of equations (23) and (24> take the same value)
cQ (2FaQ) - ""(26> From the formula (26), we obtain Co=Q" C (27>. In other words, the reception level is 017 in voltage.
2 times, which means that Q times the power level is required. Therefore, the transmission power needs to be increased by Q times from 5CPC.

Next, find the multiple load gain of the TCM signal in the above example.

As already explained in (3), in this case FDM
The equivalent multiplex number is n' = 500x1/6000 (sec > ÷ (
1/1000 (sec)) = 500X1/6 = 8
3 CH Therefore, it can be seen from FIG. 13 that the multiple load gain is an intermediate value between 28.6 dB for 60 channel multiplexing and 32.6 dB for 120 channel multiplexing.

If you create the graph shown in Figure 12 based on Figure 13 and estimate it, you will get 5% 306B@ for each multiple load.Therefore, deepen the modulation depth (deviation) and gradually reduce the transmission power. Use this multiload gain to 5cp without CM
c, that is, the transmission power of a 1-channel analog FM signal is iomw at the cordless telephone level.The required transmission power in this case is calculated by multiplying by 500 using the formula (27) and then subtracting the multiple load gain, and iolog (10mW x 500) -30dB=7d
Bm(28> In other words, 5.0 mW is obtained. This means that TCM requires less power.

Next, the physical meaning of multiple load gain in TCM signals will be explained, and points to be noted when using this as a system will be described.

The TCM signal has a long frame period of 1 second or more (multiplexing number 6).
000), no multiload gain can be obtained; however, in this case, the FM of the TCM signal
The modulation index has a constant value defined by the system. For example, the modulation index of the original signal (0.3 to 3.0 KH2) is 1.75 KHz (1 KH2 tone signal with standard modulation deviation), and this is multiplexed with 500 TCs.
The signal band in the case of M is 150 to 1500KH21, and the standard modulation deviation is 875Kt (Z) (when a tone signal of 500KH2 is modulated as standard). However, if the frame length is 1m5ec, as mentioned above, the multiple load gain A gain of 30 dB was obtained, and this multiple load gain was used to increase the depth of modulation, but we will explain what the actual modulated wave looks like.

First, consider an all-channel implementation, ie, a telephone signal is flowing in all time slots. In this case, the effect that a multiple load gain of 30 dB has on the increase in modulation deviation is that, considering from Figure 14, the multiple load gain is the value obtained by subtracting approximately +8 dB as the relative power of sine waves with equal peak values. It can be seen that it is equal to the modulation shift of the signal when only one time slot is used in a TCM signal having an arbitrary frame length.

Next, consider the case where the load is gradually reduced from all time slot implementation. That is, the question is what will happen to the modulation shift of the signal when some percentage of the time slots are used for actual audio signal transmission and the rest are not used as empty time slots.

In this case, since the number of implemented channels is reduced, the multiple load gain is naturally reduced as well. For example, 1/2 25
In the case of 0 implementation, the multiple load gain is n' = 250X1/6000÷(1/10DO)= from equation (23).
250X1/6 = 42 (Cth) Therefore, the first
It can be seen from Figure 2 that the multiple load gain is 24.5 dB. However, since the load is 172, the power level of the modulated signal is lowered by 3 dB. Therefore, the geometric multiple load gain in this case is 27.5d13, and T
Although the effective modulation depth of CM-FM is slightly larger, this is considered to have no effect on system operation.

Find the effective modulation shift when the number of implementations is reduced and only one time slot is used. The multiple load gain for one channel is OdB, but the signal load is reduced by 11500, ie, 27 dB, compared to when it is fully implemented. Therefore, the apparent multiple load gain is 27 dB, and even if the modulator is operated with this gain set to 30 dB, it may be assumed that there is no effect on system operation. In addition, at the input stage of the modulation circuit of an actual radio, IDC (In5t
Antaneous Deviation Contr
ot instantaneous modulation deviation amount suppression) circuit is provided, and is provided with a function of limiting the modulation depth to a certain value or less. Therefore, the effective modulation deviation of the modulator output is kept below a certain value, regardless of the implementation state of the TCM telephone signal.

As explained above, by using the multiple load gain of the TCM signal to increase the modulation deviation of the FM signal,
It has become clear that the transmission output can be significantly reduced. Technically, this means that it has a very large effect on power saving.

In other words, 10mW continuous transmission wireless at 5CPC! 1 is operated at a time rate of 11,500 times, that is, 0.2%, and its output is only 10 mW, or 172 times, 5,111 W, so it is obvious that the power saving effect is large.

Next, a system comparison is shown in FIG. 7 when the frequency bands of cordless telephones currently used in our country are used in the TCM system, and the present invention will be explained in detail.

In FIG. 7, various characteristics of cordless telephones and FDM systems as well as various TCM systems are listed for comparison. Here, the abbreviations of each specification will be explained.

fo...Carrier frequency NCH'...Number of required wireless channels n...Number of possible calls (calls) N...Maximum number of calls as a system max fw...Frequency band of modulated signal vl...Modulator input Maximum voltage at stage (1/6000
q'...Multiple load gain (estimated from Figure 10) Maximum voltage at the modulator input means when adding vq1 multiload gain (1/6000 second average) Md...Modulation depth (
Standard modulation) P□...Transmission power A,...Service area (distance from wireless base station)
te...One frame length N□,...Number of time slots in one frame n'.
...FDM conversion multiplex number ((calculated from formula 23) In Fig. 7, the 70M system systems 1A, IB, 2.
In 3, the maximum number of calls N as a system is the frequency band 12 given to the one-way station max of the cordless telephone, and if day Z is used as a TCM-FM signal with one carrier wave on 5k days ZX89CH = 112°5. , from Reference 1, 148 multiplexes, that is, 148 in terms of cordless telephones.
It can be seen that up to the channel (Cth) can be used. The frequency band fw of the modulation signal of the FDM system in the figure was calculated as 444 and 2 for system comparison. Also TC
The multiple load gain q' of the M system 1B is OdB when calculated from equation (23), but for comparison with the system 2, it is calculated as the number in parentheses.

Multiplexing number of TCM system 2 in Figure 7 (number of time slots in one frame NT8) 14B, frame length te
Find the multiple load gain of the TCM signal of =1 mSeC. (
As shown in Equation 23, the FDM equivalent number of multiplexes in this case is 24.6 C ports. Therefore, from FIG.
We know that it will be an intermediate value of 2.6d13.

Estimating from Fig. 12, we get 21 dB@. Therefore, this is used to deepen the modulation depth (deviation) Md and reduce the transmission power P. TCM is not available CP C
(Single Channel Per Carri
er), that is, the transmission output of a 1-channel analog M signal is 10 mW, which is the level of a cordless telephone.The required transmission power in this case can be found by multiplying by 148 using equation (27) and then subtracting the multiple load gain. .

That is, 101og (10mWx 14B) -21dB=11
．． Obtains 7dBm. Time rate of TCM is 1/14B
The transmission time will be approximately the same, and the transmission power itself will be approximately the same. However, 1 at the transmitter input stage.
It seems that there are many examples of systems that suppress peak output by installing a compressor 71.171 of about /2 compression, but details are available at (
This will be explained in Section 8.

The 70M system shown in Fig. 7 cannot obtain a large multiple load gain q' like the FDM system, so it is inferior to the FDM system in terms of gradual reduction of the transmission power P.
Since the mobile radio station 100 of the 0M system uses intermittent transmission using time slots, its average power is FD
It will be on the same level as the M system. In addition, taking into account that the hardware configuration of the mobile radio 11100 of the 70M system is much simpler and cheaper than that of the mobile radio of the FDM system, the 70M system is much simpler and cheaper than the mobile radio of the current cordless telephone. It has become clear that this system has higher frequency utilization efficiency and is more economical than the FDM and FDM systems.

Note that in a 70M system, the shorter 8 is in one frame length, the greater the multiple load gain can be obtained, but it cannot be made too short. This is because if the one frame length te of an audio signal is short, the number of samples cannot be increased, making it difficult to faithfully reproduce the original sound. Practically, one frame length to is about 1 to 5 m5ec.

(6) Physical meaning and considerations of multiple load gain in TCM signal Let us compare the 70M system shown in FIG. 7 again. system 1
In A, each time slot S is
The signal of 1 second of audio is compressed to 1/148 second,
``After M, it is sent out into space, whereas in Figure 8 (b
) system 2, the audio signal of 1/1000 seconds is roughly multiplied by 1/148, subjected to FM, and then sent out into space. Hereinafter, we will consider the physical reason why in System 1A, the modulation depth Md must be maintained at 1.75 rad rms, similar to a cordless telephone, whereas in System 2, this can be made as deep as 21 dB.

First, in system 1A, a comparison is made between system 1B and system 2, in which the transmission power P1 is lowered by 21 dB than the value shown in FIG. 7, and the modulation shift keying depth Md is increased by 11.2 times (21 dB). think of. However, ID
C (instantaneous modulation deviation amount suppression) circuit and compressor 171.
Expander 172 supports system 1B and system 2.
Assume that it is not used in both systems.

If the influence of radio wave propagation characteristics such as multiple wave propagation on communication is not taken into account, and if other design specifications are taken into consideration, both systems will Both should be able to be received with the same reception quality.

Next, we examine the influence on adjacent wireless channels. System I
In B, it is often the case that a voice signal, for example 'a', is transmitted at a high level for 1 second, and therefore TCM
Even after 1/148 seconds, the modulation deviation is, for example, 1.
Sending the modulated wave into space by making it 11.2 times larger than 75 rad rms reduces the transmission power to 11.7 m-
It will be demonstrated below that even if the signal is reduced to 1, it will cause significant interference to adjacent channels or other communications.

Quantitatively determine how large the system is compared to System 2. For this purpose, the signal power of system IB and system 2 existing within a certain period of time may be compared. However, if the time for this is set too long, the comparison becomes meaningless, so here it is set to 17148 seconds. Then, in system 1B, a high level signal (voltage value ■□ × 1 second)
lasts for 1/148 seconds, so the total electric power E1 is: El = 1/2Vm" x 1/14B (29) It should be noted that .about.8148 corresponds to the case where all peak voltage values are used (however, as will be described later, this is in a severe direction).

On the other hand, in system 2, a high level signal (voltage value
I/100 seconds> how many of the 148 multiplex signals are there?
Calculate how many medium or low level signals there are. In other words, if Vi is the voltage of each time slot, the total power E2 is: E2 = 1/2ΣVi Xi/148 (30) The total power IE2 can be estimated to be more approximate than the value in Fig. 11, and this Therefore, if we calculate the ratio between equation (29) and equation (30), r=201og148-0.15=28(dB)(3
1) From the above, the power of the signal input to the modulator of system IB within a fixed time of 1/148 seconds is
It was found that the modulated wave is 28 dB higher compared to The difference of 28 dB should actually be exactly equal to the multiple load gain of 21 dB.If the comparison time and peak power amount are selected accurately, it is possible to multiplex 1 audio channel and 148 audio channels (FDM conversion 424.6 channels). This is because there is a difference in load gain.

A brief explanation of the above results is as follows. System FB stores high-level audio signals for as long as 1 second, compresses the time, and sends them into space as M signals within 1/148 seconds, whereas System 2 stores high-level audio signals for only 171,000 seconds. This is stored in memory and compressed to 1/148.Similar processing is performed on the other 137 time slots within one frame, and high-level audio, medium-level audio, or , various signals such as mostly silent voices are arranged in chronological order and sent out into space as FM signals.

As a result, the input signal level of the modulator within one frame of system 2, and thus the amount of modulation deviation (modulation depth Md), is lower by the multiple load gain (21 dB>) compared to system 1B. , the amount of interference to adjacent channels is also reduced by the amount of modulation deviation.Of course, the amount of modulation deviation of system IB does not cause interference if the audio signal within one time slot is silent. It is clear that since the time of one frame is shortened in system 2, the average power within a frame is always low, whereas in system 1B, this average power is not constant and fluctuates greatly.

This is the problem.

(7) Countermeasures against peak modulation deviation of the CM-FM signal As explained above, it is clear that if the multiple load gain of the TCM system is used to increase the amount of modulation deviation, the transmission power can be significantly reduced. Now, we will explain countermeasures against peak deviation (peak modulation deviation).

Although it is small in terms of time probability, peak deviation (peak modulation deviation) also occurs in TCM-FM signals (system 2 described above), and it is denied that this may cause adjacent channel interference. Can not.

First, as used in mobile communications in general, the input stage of the modulation circuit of a radio is equipped with an IDC (In5tantane).
003 DeViatiOn Control (instantaneous modulation deviation amount suppression) circuit may be provided to provide a function to limit the modulation depth to a certain value or less. If this is used, the modulator output will be regardless of the TCM telephone signal condition.
This means that the maximum modulation shift is kept below a certain level.

In addition, as another countermeasure, microwave analog (FDM-1
800C etc.) experience with the method will be helpful. In the microwave analog system, a bandpass filter is inserted into the transmitter output (antenna feed line input) to remove the high-order sidebands of the M signal.
Prevents interference with adjacent channels. A method exactly similar to this may be adopted for the CMFM.

(8) TC with one frame length longer than (1/6000 seconds)
Regarding the method of increasing the multiple load gain of the M signal using a compander, the frame length of the TCM signal is related to the number of multiplexes and the time length for time-dividing the audio signal, and is an important system parameter. In the case of a mobile radio system, a short frame length may cause adjacent channel interference as described in the above-mentioned document 2, so it cannot be made too small. Also, when performing time-division processing of audio signals, if the time length is too short (for example, 0.1 m 5ec), the size of the overlapping signals accompanying this time length will be the same, which will reduce transmission efficiency and effective frequency utilization. rate decreases. Therefore,
Practically speaking, a time of about 0.001 to 0.01 seconds is convenient.
However, considering the above points, the frame length of the TCM signal is equal to the sampling interval (1/6000 seconds).
Although it has already been explained that the multiload gain of this signal decreases as the signal becomes longer, a method of not reducing the multiload gain will be described below.

Let us consider again the average power of FDM and CM signals having the same multiplexing number. FDM if the same signal source is used as the telephone signal source.

If both TCM signals are measured over a fixed time length and their average power values are taken, they should have the same value.

In the case of FDM (g@), there is no need to take a time average, and it is clear that even if you take the average power over a very short period of time, it can be considered the same as the average power over a relatively long period of time, for example, 1/6000 seconds. However, in the TCM signal, it is necessary to take the average power of one frame. However, as mentioned above, if this frame time length is 1/6000 seconds or less, it will be the same as that of the FDM signal. However, when the time exceeds 1/6000 seconds, the average power value becomes different in consideration of multiple load gain.

In other words, if multiple load gain is not considered, no matter how long the frame length is, the TCM within one frame is
It follows that the average power of the signal will be equal to that of the FDM signal. However, from the point of view of multiload gain, if one frame is longer than 1/6000 seconds,
Subframes are constructed every 6000 seconds, and the average power for each is determined, and the average power value of the largest subframe has an influence on determining the multiple load gain.

Therefore, if the average power of each TCM signal divided every 1/6000 seconds is kept low by some method, and therefore it is higher than the FDM conversion multiplex number or more precisely, the multiplex number before division is If it has a multiload gain equal to , it can be considered to be substantially equivalent to an FDM signal. Therefore, each telephone signal, which is a signal group from which a CM signal is created, is subjected to the following conversion by a certain conversion circuit. In other words, it is a circuit that reduces the average power by an amount commensurate with the desired multiple load gain compared to the original level, even though it is unavoidable that the amplitude distribution is compressed. This will be explained below using specific system parameters.

To explain using the example shown in FIG. 6D, when the number of multiplexes is 6000, 1
A TCM signal with a frame time of 1/3000 seconds has a multiplex number of 6000.1. Compared to a TCM signal with a frame time of 1/6000 seconds, the FDM equivalent number of multiplexes must be considered to be 3000. Divided 3000 multiplex TCM
A level conversion circuit is added to each signal to reduce the signal level so that the average power measured at 1/6000 second intervals can be considered to be equivalent to that of 6000 multiplexed signals. Calculate how much level reduction is required using Figure 10.

In Figure 10, the number of multiplexed CM signals is kept constant, and the number of multiplexed CM signals is kept constant.
The FDM-converted multiplex number n obtained from equation (23) when changing the frame length of the M signal from 1/6000 seconds to 1 second
′ is calculated and the corresponding multiple load gain is shown.

Here, each symbol used in FIG. 10 is as follows: n...Multiplex number FDM converted multiple load gain obtained from the formula There is.

From Figure 10, the multiplex number n' in FDM conversion is 6000 and 3.
000, the multiple load gain Y is 52.7d, respectively.
B, 49.7 dB is obtained, so the average power level to be reduced is: X-Y=52.7-49.7=3, or 3 dB.

This 3dB equivalent multiple load gain is 4! ? In order to obtain X-Y, it is not necessary to simultaneously apply 3 dB level conversion (suppression) to both partial frames obtained by dividing one frame of the CM signal into two. Also, it is not necessary to apply level conversion to all the signals in the time slots included in one partial frame, but it is only necessary to apply level conversion to signals in a small number of time slots that have high power. Therefore, the time rate for providing level conversion (suppression) is a small value. The level of the peak portion of the signal in the time slot subjected to suppression may be suppressed by 3 dB or more.

In an actual system, a suppression level of about 2 dB is sufficient for this TCM signal.

As explained below, this result is operated assuming that this CM signal also has the same value of 52.7 dB as the multiple load gain Y of the FDM signal with the DM conversion multiplex number n' of 6000 in FIG. There will be absolutely no problem in letting him do so.

Next, an actual circuit that provides the above level conversion will be explained. This circuit is widely known as a compressor and is used in mobile communications transmitters. On the other hand, in the receiver, an expander is used as a circuit paired with the compressor, and both are collectively called a compander.

A compander is a compressor (compressor) and an expander (
This is a general term for combinations of expanders (expanders), and those used in analog voice communications operate in response to the envelope level of the voice, and are also called syllabic companders, which are currently widely used.

In general, in mobile communications, the reception level fluctuates greatly by 20 to 30 dB due to fading, so the reception S/N (
The signal-to-noise ratio is greatly degraded compared to the case without fading, and even when the reception level is quite high, various noises enter during a call, resulting in disturbing noise. Noise includes thermal noise, click noise, and random FMI sound, but click noise is especially noticeable when there is no call, and even if the line is designed to ensure sufficient single-tone intelligibility,
This will greatly deteriorate subjective evaluation. A compander increases the audio level in the wireless section during a call and improves the S/N.
It also has the effect of greatly suppressing the noise generated in the wireless system when there is no call, making it a very effective means of improving call quality in mobile communications.

In the present invention, a funpanda similar to the one described above is used to compress the peak value of the TCM signal.

The specific system configuration and operation will be explained below.

FIG. 1D and FIG.
and radio base jt! This is an embodiment in which a compander is applied to the I station 30. In FIG. 1, a compressor 71 is inserted between the signal allocation circuit group 52 and the wireless transmission circuit 32, and compresses the amplitude of the time compression multiplexed signal. An example of the compression characteristics experienced at this time is shown in FIG. 9A.

The compressor characteristics in FIG. 9A are n1 for input signal n.
Since it gives an output of /2, it is called 1/2 compression. In other words, when the input level changes by 10 (1B), the output level changes by 5 dB. Therefore, the distribution of the amplitude characteristics of the audio signal becomes 1/2 in decibels. When the compressor 71 compresses the data, the wireless transmission circuit 32
The amplitude distribution of the signal applied to the signal is 1/2 in decibels.

On the other hand, in the case of an FDM signal, the amplitude distribution is proportional to the number of multiplexes, n1/2, as described above, so the TCM signal that has passed through the compressor 71 is considerably suppressed compared to the FDM signal. It will have an amplitude distribution.

Now, assume that an amplitude-compressed signal is transmitted from the radio base station 30B from the antenna and received by the mobile radio device 100B. As shown in FIG. 1D, the configuration of the mobile radio device 100B is such that the time-compressed audio signal of the received signal is input to an expander 172 inserted on the output side of the receiving section 137. Ru. This input signal is the 9th A
It will undergo transformation according to the expander characteristics shown in the figure.

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. 9A, the overall characteristic is that for every 1 dB voice input change on the transmitting side, the receiving side telephone input change is also 1 dB, and the original signal is faithfully reproduced.

The above explanation is transmitted by the radio base station 30B and transmitted by the mobile radio device 1.
Although we have explained the case where 00B is received, mobile radio 1110
The same applies to the case where 0B transmits and the wireless base station 30B receives. Thus up.

In the case of downlink calls, the user will hardly notice the presence of the compander, and it is expected that the call quality will be improved.

Figure 10 shows the multi-load gain (X-Y) equivalently obtained when using a compressor, and also shows the compression ratio 2/(X-Y> of the compressor used at that time, in FDM conversion) This shows that even if the multiple load gain Y of It has become clear that it is possible to make a significant contribution to reducing power consumption and, ultimately, power saving.

Below is a detailed explanation of how to set the operating level of the compressor.
This will be explained using figures. The meanings of the symbols used in FIG. 11 are the same as those shown in FIG. 10, and the system names refer to the TCM systems 1A and 18.1G shown in FIG. TCM with multiplex number of 148° and 1 frame length of 1m5ec
System system configuration. In this case, the FD in Figure 11
The multiplex number n' of M paralysis is equivalent to 24.6, and the FDM converted multiple load gain Y is 21 dB, but FDM148
Let us consider an operation to obtain a multiple load gain X of 33.6 dB@. For that, 33.6
-21=12.6, i.e. TCM signal (7) 1/60
This means that the highest average power of the partial frames measured at intervals of 00 seconds should be lowered by 12.6 dB. In this case, the number of partial frames is 0.001 (seconds〉÷(1/6000 seconds〉=6), that is, there are 6 partial frames, and among these, 3 to 4 partial frames have an average power that is equal to the average power of an FDM signal with a multiplex number of 148. It should show almost the same level, one or two other subframes will be higher than this, and one or two other subframes will be lower than this.However, even if it is a partial frame that shows a high value, it is only 12 dB. Considering the temporal probabilities, the number of partial frames that degrade the signal is small, and most of the time, the input signal whose level has been increased to match the 33.6 dB value of the multiple load gain X of the FDM signal is added to the modulator. However, the number of partial frames that require large level conversion (suppression) remains small.

A compressor may be used as the circuit for level suppression. That is, by inserting a compressor into the modulator input on the transmitting side, the difference from the FDM-equivalent multiple load gain Y of FDM148 multiplexing of 21 dB is 33.6-21=
12.6 (dB) may be suppressed by a compressor, and the modulation deviation is increased by 33.6 dB before transmission.

Then, an expander with characteristics opposite to those of the demodulator output side of the receiver is inserted to expand the signal by 12.6 dB.

Such a system configuration will be explained using the mobile radio device 100 and radio base station 30 shown in FIG. 1D and FIG. In FIG. 1, the compressor 71 is inserted between the signal allocation circuit group 52 and the wireless transmission circuit 32,
Here, the amplitude of the time compression multiplexed signal is compressed.

Explain how much compression is appropriate.

If the system parameters of system 1A in FIG. 11 are taken, X-Y=12.6 dB will be compressed to a fraction. This amount varies depending on system design, but
For example, suppose you want to compress it to about 2 dB. This is the normal 30 )) C (Single Channel Pe
This is a reasonable value considering the example of the Cordless Telephone (Carrier). This is because cordless telephones allow an increase in modulation deviation of 3 dB more than standard modulation, and even if the deviation increases by more than that, an instantaneous modulation deviation suppression circuit (I
A protection circuit is added to suppress the noise by DC). T.C.
Assuming that similar system parameters and protection circuits are used for the M signal, the compressor compression ratio 2/ (X-Y) will be 2/12.6 (1 dB is a design margin) or less. , compression ratio 2/1 at the modulator input
By inserting a 2.6 compressor and removing the peak value using an instantaneous modulation deviation suppression circuit (IDC),
It will be briefly explained that even if the modulation shift (modulation depth Md) of the modulated wave is increased by the above-mentioned 12.6 dB from the TCM system 1A, a modulated wave without interference in adjacent channels can be obtained.

The characteristics of compressors CA, CB and C6 used in TCM systems 1A, 1B and IC of FIG. 7, respectively, are shown in FIG. 9B. In FIG. 9B, the horizontal axis shows compressor input in various systems.

OdB on the horizontal axis is the average input power of the FDM signal system (referred to as system F) or system IA in Figure 7.
Or it shows the average power of one frame of IB. The same <12.6 dB is the partial frame (1/6
Similarly, 23.6 dB shows the level of the partial frame of system 1B (1/6000 second interval) that showed high average power. . 33.6 dB is 1*q) for each multiple load of system F, and this value is 45! qIA, qIB, qIC (in Fig. Since Y in system 1C is O, qlo is also O, and q
lo is not shown in FIG. 9B) and the equivalent multiple load gain q obtained by compressors CA, CB, CC. A.

qCB= qcc (qcc is also O for the same reason as qIC
, which are not shown in FIG. 9B.

46.2 dB on the horizontal axis is the level 12.6 dB of the partial frames of the system FA that showed high average power added to the above 33.6 dB level, which is also 56
．． 2 dB is the level 23.6 dB of the partial frames of system IB that showed high average power.
．． Added to the 6dB level, also system 1C
The level of 33.6 dB of the partial frame showing high average power is added to the level of 33.6 dB, and it shows the relative input level to the compressors CA, C, C6. .

In other words, if systems 18, 1B, and 1C are operated at each point of 12, 6, 23, 6, and 33.6 dB on the horizontal axis, there is no need to use a compressor, but this would result in multiple load gain or less modulation. Since the amount of deviation cannot be increased much, the level is increased to 46.2.56.2.67.2 dB. At this time, if there was no compressor, the modulator would overmodulate as described above, but this does not occur due to the action of the compressor.

That is, as shown in FIG. 9B, system 18.

The horizontal axis 33 is the center point of each operation of 1B and 1C,
A modulator input level of 33.6 dB (relative level) is given at the 6 dB point, and the operating points of the partial frames with higher average levels are 46.2° and 56.6 dB, respectively.
It is expected that the point will be 2.67.2 dB, but as the characteristics of each compressor, the compressor CA (
Compression rate 2/12.6>, CB (compression rate 2/23
．． 6).

co (compression ratio 2/33.6) is inserted at the modulator input side, so the compressor output has a 33.6 dB
This is because only an output of 35.6 dB, which is 2 dB higher, appears.

As a result of the above, a level-up signal corresponding to the multiload gain of 33.6 dB is added to the low level signal at the modulator input, and a large modulation shift is given.

Now, for example, three wireless base stations having the above characteristics.
A TCM signal whose level has been suppressed from 0C is transmitted via an antenna to mobile radio m1o.

Suppose that it is received at C. The configuration of the mobile radio 1100C is shown in FIG. 1E, in which the received signal is input to the expander 172 after passing through the speed restoration circuit 138. Here, the received signal has compander characteristics CA and CB shown in FIG. 9B.
, co. As a result, the original signal will be faithfully reproduced.

The above explanation is transmitted by the radio base station 30G, and
Although the case where 00C receives data has been explained, the mobile radio device 100
The same applies to the case where C transmits and the wireless base station 30C receives. Thus up.

In the case of downlink calls, the user will not feel the presence of Funpanda at all, and it is expected that the call quality will be improved.

Although the compander described above has exactly the same principle of operation as the currently commercially available audio compander, the required characteristics are different from those for audio (0.3 to 3 kHz), and require advanced characteristics. become.

This is because, as is clear from the above explanation, the frequency range of the input signal to the compressors 71, 171 is extremely wide because the audio is time compressed and multiplexed. For example, in the case of the 148 multiplex in the previous example, the frequency range is 0.3kHz2-3, 148 times day 2, 44.4kHz
kHz to 444kl-1z, and as explained above, the signal level fluctuation is determined by the deviation σ of the amplitude of one audio channel around the average power value, as well as the increase in the level fluctuation of the multiplexed signal (approximately 45 dB). must be assumed.

Further, the expanders 72 and 172 used in the receiver must also have performance that satisfies the above operating conditions.

Therefore, the compander used in the TCM-FM system requires more advanced technology than the companders for cordless telephones and car telephones that are currently widely used.

The above is a so-called ideal compander required for TCM-FM, but below, an example will be described in which a practical and economical compander is applied. For this purpose, consider the application of currently commercially available companders to the present invention.

1E and 1J show the mobile radio device 10 in this case.
The configuration of 0C and wireless base station 30G is shown. In the configuration of FIG. 1J, the compressor group (signal compression circuit group) 71 is as follows:
It is inserted between the signal processing section 31 and the signal speed conversion circuit group 51, and the audio signal is compressed here. For example, in compressor 7]-1, the audio signal undergoes level conversion as shown in the compressor characteristics of FIG. 9B. therefore,
The n audio signals pass through a group of compressors 71 with a compression ratio of Z, and then pass through a group of signal speed conversion circuits 51 . When entering the wireless transmission circuit 32 via the signal allocation circuit group 52, the compressor group 7
Compared to a signal that is applied to the wireless transmission circuit 32 without passing through 1, the amplitude distribution is 1/Z in decibels.

The compression ratio of commercially available compressors is 1/2.1/3, L/
There are various types such as 4, so by combining several of these, an arbitrary value of compression ratio can be obtained.

In the above explanation, an example was shown in which the compression ratio of the output level by the compressor was kept within 2 dB, but the system
Depending on the parameters, there may be cases where 3 dB is allowed, or cases where only 2 dBJ and below are allowed. In the case of the system 1C shown in FIG. 11, which allows only about 1.5 dB and requires a large compression ratio, the requirements for the compressor characteristics may be severe. In this case, if the output level at the center of the compressor's operation is lowered by 2 dB to 31.6 (dB) from 33.6, the multiple load gain will decrease slightly, but the compression ratio of the compressor, 2/(X-Y), will decrease. 1.
5/33.6 color 3.5/33.6, which would make it easier to design as a compressor. On the other hand, depending on how the system parameters are taken, the operation level 33 described above may be reached.
．． It is also possible to set the level higher than 6 dB.

However, in this case, it is essential to use a compander with good characteristics, and you will not be able to obtain any effects by increasing the level.

The time modulation deviation suppressor (IDC) will be briefly explained. Generally, in analog mobile communication using 5 cpc, an IDC is inserted into the modulator input to suppress the modulation deviation amount from increasing beyond a certain value, but when applying the compressor of the present invention, this is not necessary. gender becomes smaller. This is because the insertion of a compressor with a high compression ratio serves as a substitute for the IDC. Also IDC
Even in the case of adding , the characteristics required for this may be extremely loose. Furthermore, a transmission filter is usually inserted on the transmission output side, and this also sufficiently removes overmodulation deviation. FIG. 9B shows the case where an IDC is added that suppresses at a modulator input relative level of 36.6 dB.

Next, we apply multiload gain to the amplifier design. In this case, the level of the multiplexed voice converted into TCM may be considered to be lower than the level conventionally considered by the amount of the multiplex load gain. Therefore, even if the amplification factor can be increased accordingly, or the output level can be made higher than the conventional one by the multiple load gain, the distortion factor and the like will remain at the values conventionally assumed.

Multiload gain is applied not only to active circuits as described above, but also to
It is also applicable to passive circuits as described below. That is, when applied to a mixer circuit, even if the rated output is increased by the amount of the multiple load gain, it is possible to operate in the conventionally assumed operating state. When applied to a wireless transmitter, this has the following benefits. For example, the first
Inserting a power amplifier into the output of the transmission mixer 133 in Figure B is often used to increase the reach of radio waves. In this case, by introducing a multiple load gain, it is possible to increase the transmission output level higher than the conventionally assumed level by an amount indicated by the multiple load gain. Alternatively, if the same transmission level as the conventional one is sufficient, the rated output of the amplifier can be made with a lower level output than the conventional one by the amount of the multiple load gain.

The above concept of rated power can be applied not only to transmitting tubes but also to resistors, capacitors, inductances, etc.

(9) Use of TCM signals outside the exclusive frequency band As explained above, when a communication signal is time compressed, the exclusive frequency band moves to a higher frequency band. For example, the exclusive frequency band of a signal time compression multiplexed to put 148 channels of audio signals on one carrier wave is 44.4k.
HZ ~ 444 k HZ, and an unused frequency band occurs from O ~ 44.4 until day 2. The utilization of this will be explained using FIG. 2C and FIG. 3D.

FIG. 2C is an embodiment showing the frame structure of a system to which the present invention is applied. The difference from the example shown in FIG. 2A already described is that the synchronization signals inserted in each time slot are combined into independent 1ij 1st period signal time slot SCD, S
This is because the CU was installed.

By doing this, the communication time slot (SD)
~SDn, 5IJ1~SU "1) will only be equipped with communication signals, except for the control a signal that is required at the start or end of communication, when switching between zones, etc. The exclusive frequency band of the frame configuration in Figure 2C is the third
The result will be as shown in Figure D. That is, the Ding CM call signal, control signal (SD1 to 5Dn) and synchronization signal (SCD) exist in the frequency range of 44.4 to 444kHz, and the frequency is 44.4K.
If it is less than 2 days, it will not exist.

Therefore, we are considering implementing other signals in this band to make effective use of the frequency.

Channel C ports 1 to 11 in FIG. 3D show one example, in which the telephone call g]1 channel is implemented as an FDM signal. Next, the hardware configuration of the system will be explained using the first figure and the first figure.

FIG. 1F shows an example of the configuration of a mobile radio 11100D, and it will be explained below that in the case of the same figure, it is possible to transmit and receive a telephone signal carried on an FDM signal as well as a CM signal. 1st
The receiving section 137 receives the incoming call signal transmitted from the wireless base station 30D shown in FIG. The control signal for the incoming call signal instructs the transmission method, and either operates the expander 172, which is a circuit for receiving TCM (time division time compression multiplexing) signals, or the speed restoration circuit 138, or suspends them. Accordingly, the control unit 140 operates the FDM channel converter 174.
Operate the circuit as instructed.

Hereinafter, when transmitting and receiving FDM (frequency division multiplexed) signals, the FDM channel converter 174 is operated and at the same time, switches 11B-1 and 118-2 are turned on to the FDM channel converters 174 and 173 side. Next, from the radio base station 30D, "DM channel converter 173, 174
Since an instruction is sent as to which communication path (channel C 1 to 11 in Figure 3D) to use, the control unit 140 sets the F so that transmission and reception can be performed on the specified communication path (Channel C port).
The DM channel converters 173 and 174 are instructed to operate.

On the other hand, the wireless base 130D decides to operate the FDM channel converters 73 and 74 for the mobile wireless device 100D among the circuits in its own device, and
The state is changed to using the same communication path (channel C port) given to 0D.

As a result of the above, the wireless base station 30D and the mobile wireless device 100
D is now in a state where it is possible to communicate using FDM signals (uncompressed signal communication), and communication is started in the same manner as in the case of the TCM signal described above.

By the way, depending on the mobile radio l1100, for economical reasons and to simplify the equipment configuration, only CM signal transmission and reception, or FD
It is also possible to have a configuration in which only the transmission and reception of the M signal is possible.

Further, the multiplexed load 1q of the composite signal having the signal components shown in FIG. 3D will be explained. As already explained, the multiple load gain of the TCM signal is 21 dB when the frame time is 0.001 seconds, and 1
A single channel FDM signal also has a multiple load gain of about 14 dB, as shown in FIG. Therefore, the wireless transmitter circuit 32, 132 of FIG. 1F or FIG. 1K
The amount of modulation deviation given to the modulator provided in
It can be seen that even if the depth is increased by 21 dB, there is no interference in the adjacent channels. However, the influence on the modulation deviation of the synchronous signal @SCD shown in FIG. 3D was ignored. Even in a practical system, the energy of the control signal relative to the total signal energy is extremely small, so it can be ignored.

The frequency characteristics of the allowable increase in modulation deviation of the above modulator are:
Shown in FIGS. 2D (a) and (b).

(a) shows a case where a flat characteristic of 14 dB is given to the FDM signal and a flat characteristic of 21 dB is given to the TCM signal. In contrast, (b) shows the case where emphasis is given to the high frequency band. The effect of emphasis is well known, and since FM waves are susceptible to so-called triangular noise, a large modulation shift is applied to signals in high frequency bands to cope with this problem. It is natural to apply de-emphasis when demodulating at the receiver.

Next, detailed operations of the radio transmitting circuit 132 and the radio receiving circuit 135, which play an important role in the configuration of the mobile radio device 100D using the above TCM and FDM composite signals, will be explained with reference to FIGS. 1G and 10. .

In FIG. 1G, digital/analog signal mixer 2
17 is a control signal from the control section 140.

The signal after being compressed by the compressor 171 or F
One or two of the output signals from the DM channel converter 173 are applied simultaneously, mixed here, and then input to the modulator 216.

A predetermined modulation shift is given by the modulator 216, the signal becomes an FM signal, is added to the transmission mixer 133, and is transmitted from the antenna section as a predetermined radio frequency.

On the other hand, the signal sent from the wireless base station 30D is received by the wireless receiving circuit 135 of the mobile wireless device 100D.
In the reception mixer 136 shown in Figure 1 showing this detailed configuration, the reception signal from the antenna section is converted into a predetermined intermediate frequency, amplified to an appropriate level by the amplifier 211, and then input to the frequency discriminator 212. Ru. This output is separated by a digital/analog signal separator 213, the digital signal is sent to a clock regenerator 141 and a control unit 140, and the TCM signal and FDM signal are sent to an expander 172 via a bandpass filter 214, respectively. The signal is sent to the FDM channel converter 174. Here, the amplifier 211 is unnecessary if the signal from the receive mixer 136 is sufficiently large.

The above was an example of the operation of the mobile radio device 100D, but the radio base station 30D also has functions similar to those described above. The wireless transmitter circuit 32 is equipped with the wireless transmitter circuit 32 . Note that the control unit 40 of the radio base station 30 in this case exchanges control signals with the signal processing unit 31, unlike in FIG. Which of the communication signals is T?
This is because the signal processing unit 31 itself cannot determine whether it should be processed as a CM signal or an FDM signal. Control unit 40
Then, decide whether to use TCM or "DM low signal" by considering the capabilities of the communicating mobile radio 11100D, that is, whether it can send and receive only TCM signals or whether it can also send and receive FDM signals, and the communication traffic condition at that time. I will do it.

In the above explanation, the FDM transmitter is mounted on the lower frequency band of the exclusive band of the TCM signal, but in reality, the FDM
It is not limited to signals. In other words, it is possible to implement any signal such as a data signal 1 image (analog) signal.Of course,
A TCM signal in which 11 channels of audio signals are multiplexed may be used. However, depending on the signal, there are some signals for which multiple load gain cannot be obtained, and in that case, the modulation shift amount must be used without increasing.

[Effects of the Invention] As is clear from the above explanation, the multiple load gain of a time division time compression multiplexed (DCM) signal, which has not been clearly shown in the past, can be clarified stationarily using system parameters. As a result, for example, the depth of angular modulation (deviation amount)
Even if the transmission is deepened by the amount of multiload gain, the influence on other wireless channels can be suppressed within the conventional design value, and the transmission output level per wireless channel can be reduced to a level lower than that of the conventional system. It became possible to further reduce the amount.

Furthermore, depending on the design parameters of the CM signal, the multiple load gain may be reduced compared to the DM low signal of the same multiplex number, but in such cases, inserting a compressor at the input side of the modulator can effectively reduce the Since it has become possible to increase the multi-load benefit to 1q, which is equivalent to FDM, the effect of contributing to the relaxation of design conditions is extremely large.

[Brief explanation of drawings]

Figure 1A is a conceptual block diagram showing the concept of the system of the present invention, Figure 1B is a circuit diagram of a mobile radio used in the system of the present invention, and Figure 1C is a wireless radio used in the system of the present invention. The circuit configuration diagram of the base station, FIG. 1D, FIG. 1E, and FIG. 1F are circuit configuration diagrams showing other embodiments of the mobile radio device used in the system of the present invention, and FIG. 1G is shown in FIG. Figure 1 is a detailed circuit diagram of a radio transmitter circuit which is a component of the circuit shown in Figure 1F, and Figure 11 is a detailed circuit diagram of a radio receiver circuit which is a component of the circuit shown in Figure 1F. 1 and 1K are circuit configuration diagrams showing other embodiments of the wireless base station used in the system of the present invention, and FIG. 2A is a time slot diagram for explaining the time slots used in the system of the present invention. A slot structure diagram; FIG. 2B is a diagram showing a radio signal waveform of a time slot; FIG. 2C is a time slot structure diagram for explaining another embodiment of a time slot used in the system of the present invention; FIG. 2D is a permissible increase amount diagram showing the permissible increase amount of modulation deviation used in the system of the present invention, FIGS. 3A and 3B are spectral diagrams showing the spectra of speech signals and control signals, and FIG. 3C is FIG. 3D is a spectrum diagram showing the spectrum of the TCM signal and FDM signal; FIG. 48 and FIG. 4B are flow diagrams showing the operation flow of the system according to the present invention; Figure 5 is a spectrum diagram of a frequency division multiplexed signal, Figure 6A is an amplitude diagram showing changes in amplitude of a time division time compression multiplexed signal, Figures 6B, 6C and 6D are a spectrum diagram of a time division time compression multiplexed signal. A sampling diagram showing the state of signal sampling, Figure 7 is a specification diagram showing the specifications of various systems, and Figure 8 is a time slot diagram to explain the time slots used by the system shown in Figure 7. Slot structure diagram, Figures 9A and 9B are characteristic diagrams showing the input/output characteristics of the compander, Figures 10 and 11 are the multiple load gains of the time-division B8 compression multiplexed signal and frequency multiplexed signal, and the compression ratio of the compressor. Figure 12 is a diagram showing the relationship between the multiplex load gain of the time division time compression multiplexed signal and the number of multiplexed audio signals, Figure 13 and Figure 1
Figure 4 is a multiple load gain diagram showing the relationship between the multiple load gain of a frequency division multiplexed signal and the number of communication paths, quoted from a known document, and Figure 15 is a multiple load diagram showing the relationship between the frame length of a TCM signal and multiple load gain. This is a gain diagram. 10... Telephone network 20... Gateway switchboard 22
-1 to 22-n...Communication signal 30...Radio base station 31...Signal processing section 32
...Wireless transmission circuit 35...Wireless reception circuit 38.
-Signal speed restoration circuit group 38-1 to 38-n...Transmission speed restoration circuit 39...
Signal selection circuit group 39-1 to 39-n...Signal selection circuit 40...Control unit 41...Clock generator 42...Timing generation circuit 51...Signal speed conversion circuit group 51-1... 51-n...Signal speed conversion circuit 52...
Signal assignment circuit group 52-1 to 52-n...Signal assignment circuit 71...Compressor (group) 72...Expander (group) 73.74...FDM channel converter 91...Digital Encoding circuit 92...Multiple conversion circuit 100.100-1 to 10O-n-...Mobile radio device 10
1...Telephone unit 11B-1, 118-2...Switch 120...Reference crystal oscillator 121-1, 121-2...Synthesizer 122-1
, 122-2...Switch 123...Transmission/reception intermittent controller 3 13 3 3 3 7 7 1 1 1 1 1...Speed conversion circuit 2...Wireless transmission circuit 133...Transmission mixer 4...
・Transmitter 135...Radio receiving circuit 6...Receive mixer 137...Receiver 8...Speed recovery circuit 141...Clock regenerator 1...Compressor
172...Expander 3.174...FDM channel converter 1...Amplifier 212...Frequency discriminator 3.
...Digital/analog signal separator 4...Bandpass filter 216...Modulator 7...Digital/analog signal mixer.

Claims (1)

[Claims] Each radio base means (30), each covering a plurality of zones to constitute a service area, and time slots of a frame for moving across said plurality of zones and communicating with said radio base means. In a mobile communication method using a barrier exchange means (20) for exchanging communication between each mobile radio means (100) using a radio channel in which compressed separated signals are multiplexed, the radio base means based on the difference between the multiple load gain obtained by the compressed and separated signals and the multiple load gain of the frequency division multiplexed signal having the same multiplicity as the multiplexed signal; A time division communication method for mobile communication in which a signal used for communication with the mobile radio means is level-converted, modulated, and transmitted.