JPH0661936A - Time-division communication method for mobile object communication - Google Patents

Abstract

PURPOSE:To provide a mobile object communication system where the electric power of signals are compared with each other between an adjacent frame where the time compression is applied to a time slot of a frame constitution and a frame adjacent to the succeeding adjacent frame and a time one-way telephone signal is not put on the time slot when the difference of electric power between both signals is less than the fixed value. CONSTITUTION:Each radio basic station 30 covers plural zones. A barrier switchboard 20 uses a radio channel where the time one-way signal suppressed down to a level that is compressed and divided in terms of time put on a time slot of a frame constitution for the communication with the station 30 and then switches the communication among the mobile radio equipments 100. Then the electric power of the time one-way telephone signals are compared with each other between an adjacent frame and the succeeding adjacent frame. If the difference of the electric power between both signals is less than the fixed value, no time one-way telephone signal is put on the time slot. Thus the large multilex load gain is acquired. Then the transmission power is reduced and the frequency can be effectively used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system in which a signal having a band characteristic such as a telephone is time-divided / time-compressed and then amplitude-modulated or angle-modulated to reduce the redundancy of the transmitted signal. The power of the signal is reduced, the level of the signal is raised to a value determined by the difference between the reduced level and the power level originally possessed by the signal, and then the depth of modulation applied to the signal by amplitude modulation or angle modulation. By deepening the depth substantially, improving the transmission quality of the signal or reducing the wireless transmission power, and further resulting from the reduction in redundancy, by inserting another signal in the empty signal time, etc., The present invention relates to a method of effectively using frequencies. More specifically, given a radio channel,
Using this, while one of many mobile radios in the service area is setting up a radio line and communicating with the opposite radio base station, other mobile radios use the same radio channel. When communication is started with another wireless base station, it may adversely affect the communication between the mobile wireless device and the wireless base station that are currently communicating due to effective use of frequency or radio wave propagation characteristics. The present invention intends to provide a method for improving the effective utilization of the frequency by gradually reducing the transmission output and an economical system using the method, while eliminating the above.

[0002]

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

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

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

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

Reference 4. Ito "Time division time compression multiplexing (T
CM) Multiple load gain of telephone signal ”IEICE Technical Report SST 91-58 March 1992.

Reference 5. Hayasaka "Introduction to Acoustic Engineering" Published by Nikkan Kogyo Shimbun, March 1978, pages 21-30

Reference 6. Nishimaki "Electroacoustic Vibration" edited by The Institute of Electronics and Communication Engineers, published by Corona, July 1960, 21-22
page

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

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

Further, in Documents 3 and 4, the conventional FDM
The multiple load gain, which is known to be present in (frequency division multiplex) signals, is F even in the time division time compression multiplex (TCM) system.
It is clarified that there is a multiple load gain similar to the DM signal, and its quantification and system operation examples are explained. Then, by using this multiple load gain to deepen the modulation depth of FM, the transmission power can be significantly reduced, and it is expected that the mobile wireless device can achieve significant power saving. Has been reported.

Further, in Document 5, the nature of the voice uttered by a person is described in detail.

FIGS. 12A to 12E show waveforms of vowel sounds a, d, a, o, and u of a voice. The first formant of vowel a in FIG.
z, the second formant is at 2400-3000 Hz. The first formant of vowel d in (b) is 350-55.
0 Hz, the second formant is 1500-2000 Hz,
The third formant is at 2500-3000 Hz, and similarly in the case of the vowel a of (c), 600-800 Hz,
1000-1400Hz, 2700-3100Hz,
In the case of the vowel sound (d), 420 to 500 Hz, 760 to
1000 Hz, 1300 to 2000 Hz, 300 to 480 Hz, 1000 to 1400 H in the case of vowel U of (e)
z, 2000-3000 Hz.

The frequency component that characterizes such a vowel is called a formant. On the other hand, the consonant appears in a transient manner only for a short time, its frequency component is relatively high, and its energy is extremely small. Figure 13 is "CHO"
In the sound waveform of (cho), the part where the amplitude is noticeable is CH
This is the part of the vowel O that follows, and the essential consonant is the fine waveform part that appears at the beginning.

The smallest pronunciational unit that constitutes a word is called a syllable. Most Japanese syllables take the form of (consonant c) + (vowel v), but in foreign languages the structure is complex and typical syllables are (consonant c) + (vowel v) + (consonant c) Such a configuration is adopted. The duration of the syllable is 100-
At 300 ms, the average is 1/8 second and the inter-syllable pause time is 100-200 ms.

Next, the relationship between the energy of voice and the amount of information will be described with reference to FIG. Even if the peak appearing in the waveform of the voice is compressed and removed, the amount of transmitted information does not change much. On the other hand, if the vicinity of 0 of the voice waveform is removed, the amount of information carried will drastically decrease even if a large amplitude area is left as it is. FIG. 14 shows the results of this experiment, in which the horizontal axis represents the amount of removal of the peak or zero portion of the speech waveform, and the vertical axis represents the reduction in word intelligibility caused by such removal.

FIG. 15 clearly shows the removal conditions when the vicinity of 0 and the peak of the experimental data of FIG. 14 are removed. Here, the peak removal amount = 20 log (p ₁ / p ₀ ) (dB) 0 vicinity removal amount = 20 log (p ₂ / p ₀ ) (dB).

Further, Document 6 describes in detail how the level distribution of voice changes with time.

FIG. 16 shows power (sp) when a person speaks a word.
eech power), which varies drastically with time as shown. The following types of power are defined to represent the power of such voice. J _i : Instantaneous speech power (instantaneous power) Power at each moment J _p : peak speech power (peak power) Maximum value of J _i within a certain time J _m : mean speech power (short-time average power) 10 ms
Average value of J _i during the period J _a : average speech power (long-time average power) A value obtained by dividing the energy of speech spoken within a certain time by the time, including the pause time.

The change in voice power (Fletcher) when pronounced "quite" is shown in the figure. The bar graph in the upper part of FIG. 16 shows the instantaneous value J _i , and the lower curve in FIG.
0 ms) shows the change of the average value J _m . The value of J _p is 1
The maximum value of J _m is 40 while it is about 500 μW.
At μW, there is only one tenth of J _p . J _a becomes even smaller. This means that the instantaneous power is much higher than the average power, which is important for the design and adjustment of electroacoustic devices. When voice power flows through the electric circuit, if the meter indicates this, the meter has some inertia, so that the instruction cannot follow the instantaneous power J _i , so only a value close to the average power J _m. Although not shown, microphones, speakers, and ears follow J _i fairly faithfully, so when handling the voice of a word, an unexpectedly larger amount of power is passed than when instructed by a meter, and unexpectedly compared with the case of continuous sound. Give a great feeling.

Since the value of J _a is an average value including the pause time, it is smaller than J _m , and is about 10 μW in a normal conversation. That is, it can be seen that the sound power is extremely small considering that the average power is only about 10 W even if one million people speak at the same time. When a very loud voice, J _a is about 1000 μW, and even a small voice of 0.1 μW can be used, and a whisper of 0.00
The story can be understood with 1 μW. J _p is 5000μ in case of talk
Do not exceed W. Therefore, the speech power is 0.01
˜5000 μW, or 57 dB range. However, the range of normal voice is set to about 40 dB.

[0022]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the system construction example shown in (1), a general description of a mobile communication system using a TCM signal is given, and the system can be constructed by this, but the multiple load gain is not explained. In Documents 3 and 4, the multiple load gain relating to the signal power of the TCM signal is explained, but it is a case where the analog telephone signal is temporally compressed into divided signals and these are all transmitted. The power of the signal is compared with the time-compressed delimited signal to be mounted on the adjacent frame, the next adjacent frame, etc. as in the method of No. 1, and if the value does not exceed a predetermined constant value, The increase of the multiple load gain obtained when the number of frames is not equipped with signals has not been clarified, and has been a problem to be solved.

Further, in Document 5, although the nature of the voice uttered by a human is explained in detail, the telephone signal is divided into time signals, and the power of the signal is set in the adjacent frames as in the method of the present invention. Compare with the temporally compressed delimited signal to be installed in the next adjacent frame, etc., and if the value does not exceed a predetermined fixed value, the signal of the case of not mounting the signal for a fixed number of frames There is an unsolved problem that there is no description about the characteristics, and a method for effectively utilizing the characteristics is not disclosed.

[0024]

[Means for Solving the Problems] An analog telephone signal is transmitted to a TC.
When transmitting with M-FM, the power of the signal is compared with a temporally compressed delimited signal to be mounted in an adjacent frame, a next adjacent frame, etc., and the value does not exceed a predetermined fixed value. Did not install signals for a fixed number of frames. As a result, the power carried by the signal is reduced, which results in an increase in multiple load gain. Further, in order to prevent the peak of the signal from causing an influence such as radio interference with other radio channels, a silabic compressor is added before the amplitude modulator or the angle modulator of the radio transmitter. As a result, it is possible to eliminate the possibility that the time difference telephone signal affects other radio channels such as radio interference. In addition,
A bandpass filter, which functions as a compressor, is inserted in the radio output stage.

Further, as a result of adopting the above method,
The time slot that does not carry the generated signal can be equipped with another signal that is temporally compressed and separated, which also improves the effective frequency utilization rate.

[0026]

12 and 13 show that when the majority of the duration of the telephone signal is divided into short time intervals (for example, 10 ms),
It shows that the same signal is repeated repeatedly. This is a case where a telephone signal is divided into time signals, and when signals are sequentially transmitted in a frame structure, there are many cases where there is almost no change as compared with signals to be mounted in adjacent frames, next adjacent frames, etc. It is expected. Therefore, as described above, the power level of the signal is set to the adjacent frame,
Compared with the signal to be installed in the next adjacent frame, etc., if the value does not exceed a predetermined value, the signal is not installed for a fixed number of frames. Abbreviated as "time transmission method"). As a result, the power of the signal is reduced, resulting in an increase in multiple load gain.

However, since the electric power of the above-mentioned time piece signal has a considerably high level, there is the following problem if the radio carrier wave is angle-modulated using these signals without suppressing the electric power. Will occur.

When the waveform of the signal does not include a steep component, the modulation depth of the angle modulation is increased by the decrease of the signal level, that is, the increase of the multiple load gain. There is no risk of radio interference occurring in the channel, but if the signal contains a steep component, there is a risk of radio interference occurring in the adjacent radio channel at peak time. Therefore, in such a case, it is necessary to remove a steep signal component. It is appropriate to use a Syrabic compander. As a result, we have made it possible to reduce the transmission power by increasing the modulation depth of the angle modulation by using a larger multiple load gain than before, without the possibility of radio interference occurring in the adjacent radio channels. Alternatively, a bandpass filter is inserted in the radio output stage to perform an action equivalent to that of a silabic compressor, and a large multiple load gain can be obtained. The total multiple load gain thus obtained is used to maintain the interference and the like within the allowable value, and the modulation degree of FM (PM) modulation is deepened, whereby the transmission output can be gradually reduced. In addition, the design of the amplifier in the input stage of the modulator becomes easy, and the rated values of passive circuits such as mixers, resistors, and capacitors can be lowered, making it possible to construct an economical system.

Further, as a result of adopting the method as described above, the following two points are possible as a new usage method of the time slot in which the generated signal is not mounted.

At the time of the time slot not carrying the signal, the radio carrier itself is deleted.

In a time slot that does not carry a signal, another signal that is temporally compressed and separated is carried.

Among the above, there is an effect of preventing the occurrence of radio interference. Has made it possible to increase the number of telephone channels that can be used simultaneously in the system, both of which have made it possible to improve the effective utilization rate of frequencies.

[0033]

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

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

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

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

The speed restoration circuit 138 restores the level (pitch in the case of an analog signal) of the communication signal which is the compressed and delimited level-suppressed time difference telephone signal (described in detail later) in the received signal and sets the level. The suppression is released and the signals are input to the telephone unit 101 and the control unit 140 as continuous signals.

In the communication signal output from the telephone unit 101, the speed conversion circuit 131 divides the communication signal into predetermined time intervals to obtain a level-suppressed time difference telephone signal, and its speed (pitch in the case of an analog signal). Faster (compression)
Then, it is applied to the wireless transmission circuit 132 including the transmission mixer 133 and the transmission unit 134.

A part of the signal processed by the speed conversion circuit 131 is input to the signal level measuring device 179, the level of the time-segmented signal is measured, and the level of these signals is measured. Compared and measured. As a result, information such as whether or not the value exceeds a certain value defined by the system is transmitted to the control unit 140. Details of these operations will be described later.

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

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

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

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

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

Next, the function of the signal speed conversion circuit group 51 (FIG. 3) will be described. By storing input signals such as voice signals and control signals, which are time-difference telephone signals divided into fixed time lengths, in a storage circuit, changing the speed at the time of reading this, and reading at a speed of, for example, 15 times that in the case of storing , It becomes possible to compress the time length of the signal. The principle of time compression of the signal speed conversion circuit group 51 is the same as the case of reproducing a voice recorded by a tape recorder at high speed. In practice, for example, a CCD (Charge Coupled Device) is used.
), BBD (Bucket Brigade Device) can be used. Furthermore, it is also possible to use a semiconductor memory capable of repetitive writing and reading whose capacity has been remarkably increased recently.

CCD exemplified by the signal speed conversion circuit group 51
A circuit using a BBD, a BBD, or a large-capacity semiconductor memory can be directly used for realizing the time extension function of the signal speed restoration circuit group 38. In this case, the clock generator 4 is used.
This can be realized by receiving the timing signal from the timing generator 42 that generates the timing according to the clock from No. 1 and the control signal from the control unit 40, and making the reading speed slower than the writing speed.

A part of the signal processed by the speed conversion circuit group 51 is input to the signal level measuring instrument group 79 including the signal level measuring instruments 79-1 to 79-n, and each of the time-divided telephones. The levels of the signals are measured, and the levels of these signals are compared and measured. as a result,
Information such as whether or not the value exceeds a certain value determined by the system is transmitted to the control unit 40. Details of these operations will be described later.

The control or voice signal output from the gateway switch 20 via the signal processing unit 31 is input to the signal speed conversion circuit group 51, a time difference signal is obtained, a predetermined level is suppressed, and a speed (pitch) is set. Signal allocation circuit group 5 for allocating signals by time slot after conversion processing
2 is applied. This signal allocation circuit group 52 is a buffer
This is a memory circuit, which stores a single segment of high-speed signals output from the signal speed conversion circuit group 51, and uses the timing information from the timing generation circuit 42 given by the instruction of the control unit 40 to determine the signals in the buffer memory. reading,
It is sent to the wireless transmission circuit 32. As a result, when the communication signals are viewed as channels, they are arranged in series without overlap in time series, and when all the control signals or call signals described later are implemented, it is as if they were continuous signal waves. become.

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

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

Regarding the transmission of the control signal between the radio base station 30 and the mobile radio device 100 prior to the call in the incoming and outgoing call of the telephone, whether in the band of the telephone signal or out of the band is used. It is possible to use the low frequency side (250 Hz) or the high frequency side (3850 Hz) of the out-of-band signal. This signal is used, for example, when it is desired to send a control signal during a call. The in-band signal is used when making and receiving calls.

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

Although the above is the case of the analog signal, when the digital data signal is used as the control signal, the voice signal which is the level-difference time difference telephone signal is also digitally encoded and both are time-division multiplexed. It is also possible to convert and transmit the data, and the circuit configuration in this case is shown in FIG. In FIG. 5, a voice signal is digitized by a digital encoding circuit 91 and the data signal and the data signal are multiplexed and converted by a multiple conversion circuit 92.
This is an example of a case where the signal is subjected to multiplex conversion by and applied to the modulation circuit included in the wireless transmission circuit 32. However, for digital data signals, the analog signal multiplex load gain, which will be described later, does not normally exist, and therefore this point must be noted in the system design. Then, if the opposite receiver receives the signal and the demodulation circuit performs an operation opposite to that shown in FIG. 5, the audio signal and the control signal can be separately taken out.

On the other hand, the signal sent from the mobile radio 100 is received by the antenna section of the radio base station 30 and input to the radio receiving circuit 35. FIG. 4B schematically shows the upstream input signal. That is, the time slots SU1, SU2, ..., SUn represent transmission signals addressed to the radio base station 30 from the mobile radios 100-1, 100-2, ..., 100-n. Further, when the contents of each time slot SU1, SU2, ..., SUn are shown in detail, as shown in the lower left part of FIG. 4 (b), a speech signal or (and) control signal which is a level-suppressed time difference telephone signal. Is made up of. However, the synchronization signal can be omitted depending on the case where the distance between the mobile wireless device 100 and the wireless base station 30 is small or the signal speed.

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

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

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

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

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

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

Now, the control signal is simultaneously transmitted by using the lower frequency band of the voice signal which is the time difference telephone signal whose level is suppressed. Of these signals, the control signal (0.2 to 4.0
kHz) and the speech signal CH1 (SD1 at 4.5 to 45 kHz) are contained in a time slot, for example SD1. Other time slots SD2 to SDn
The same applies to the audio signal accommodated in.

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

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

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

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

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

(1) Calling from mobile radio device 100 will be described with reference to the flowcharts shown in FIGS. 6 and 7.

When the power of the mobile wireless device 100 is turned on, in the wireless receiving circuit 135 of FIG. 2, the wireless channel is included in the downlink (wireless base station 30 → mobile wireless device 100) wireless channel (referred to as channel CH1). Start capturing control signals. To this end, the wireless channel (hereinafter referred to as channel CH1) is in the receiving state according to the procedure defined in the system. This is possible by capturing the sync signal in the time slot SDn shown in FIG. 4 (a). The control unit 140 sends a control signal to the synthesizer 121-1 so as to generate a local oscillation frequency that enables reception of the radio channel CH1, and also the switch 122.
-1 is also in a state of being tilted down and fixed to the synthesizer 121-1 side.

Therefore, the telephone receiver of the telephone unit 101 is turned off.
When hooked (start of calling) (S201, FIG. 6), the synthesizer 121-2 of FIG. 2 receives from the control unit 140 a control signal for generating a local oscillation frequency that enables transmission of the radio channel CH1. Also, the switch 122-2 is also tilted to the synthesizer 121-2 side to be in a fixed state.
Next, the call control signal output from the telephone unit 101 is transmitted using the radio channel CH1. This control signal is
It is transmitted, for example, using the time slot SUn.

Now, the call control signal from the mobile radio device 100 is properly received by the radio base station 30, and the mobile radio device 100 is sent.
If the ID (identification number) of is detected (S202),
The control unit 40 searches for a currently empty time slot. As a result, for example, if the time slot SD1 is vacant, the time slot SDn of the radio channel CH1 is used for the mobile wireless device 100 by the downlink control signal (the mobile wireless device 100 →
The wireless base station 30) SU1 and the corresponding downlink (wireless base station 30 → mobile wireless device 100) SD1 are instructed to be used (S203).

In response to this, the mobile radio 100 shifts to the receivable state in the designated time slot SD1 and SU1 which is the time slot for the uplink radio channel corresponding to the downlink time slot SD1.
(See FIG. 4B). Mobile radio 1
In the control unit 140 of 00, the transmission / reception interrupt controller 12
3 to operate the switches 122-1 and 122-2 (S204). At the same time, a slot switching completion report is sent to the radio base station 30 using the upstream time slot SU1 (S205), and a dial tone is waited for (S206).

The radio base station 30 has a time slot S
In addition to U1, SU3 and SUn are included in one frame and transmitted as an upstream signal from another mobile radio 100. Upon receiving the slot switching completion report (S207), the wireless base station 30 sends a calling signal together with the ID of the mobile wireless device 100 to the gateway switch 20 (S20).
8). On the other hand, in the gateway switch 20, the mobile radio 10
The ID of 0 is detected, and a necessary switch of the switch group included in the gateway switch 20 is turned on (S209),
The dial tone is transmitted to the wireless base station 30 (S21).
0, FIG. 7).

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

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

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

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

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

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

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

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

(2) Incoming Call to Mobile Radio Device 100 The mobile radio device 100 is in a standby state with the power turned on.
In this case, as described in the section of calling from the mobile radio 100, the downlink control signal of the radio channel CH1 according to the procedure defined by the system is in the standby state.

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

Note that the fact that signal transmission is executed in a good state using this system and that it does not adversely affect other radio channels in the system is theoretically explained in Reference 2, and is therefore omitted. Then, a specific system construction method in the case of applying the "transmission method at the time of level change" according to the present invention will be described below, in which the reduction amount of power of a signal (increase amount of multiple load gain) and the effective frequency Explain the improvement of usage.

(3) Concrete system construction method of "transmission method at level change" Hereinafter, a concrete system construction method of "transmission method at level change" applied to a TCM telephone signal will be described with reference to FIGS. 8 (a) and 8 (b). And (c). However, for convenience of description, the waveform of the signal is schematically represented, and the number of samples given to one time piece signal is four, which is one digit or more smaller than the actual number.

(3.1) Generation of Time-Slot Signal FIG. 8A shows the waveform of one telephone signal input to the signal speed conversion circuit group 51 of the radio base station 30 shown in FIG. In FIG. 6A, the horizontal axis represents time and the vertical axis represents voltage. Numbers 1 to 20 on the vertical axis (only odd numbers are shown) are signals at equal intervals (assuming that the maximum frequency of the signal is f _h , the time interval is 1/2 f _h or less) t ₁ to t ₂₀ The vertical line at each position indicates the voltage values p _{1 to} p ₂₀ of the signal, that is, the value (sample value) of the sample signal shown in FIG. Although the actual signal is much longer in time than shown in FIG. 8, it is set to t _{1 to} t _{20 in} FIG. 8 for convenience.

The signal waveform shown in FIG. 8A is cut at a constant time interval T (T is equal to the frame length of the system) and stored in the storage circuit. Next, the time piece signal stored in the storage circuit is read out and the following processing is performed.

The signal level measurement is performed for each time piece signal.

The comparison (difference value comparison) of the measured values of the power (FIG. 8 (c)) level of the signal is performed for each adjacent time piece signal. Δ _i = Σp _i -Σp _j becomes the value Δ _i (1,2,3,4,5) are obtained. Here, Σ of the first term on the right side represents the sum total from i = 1 to 4, and Σ of the second term also represents the total sum from j = 5 to 8. Since the above equation is complicated, it will be simply referred to as Δ ₁ = L ₂ −L ₁ below. However, L ₁ , L ₂ , L ₃ , and L ₄ represent the level of each time piece signal (see FIG. 8B).

The magnitude of the difference value Δ _i of is compared (with a constant value d), and the following processing is performed according to the magnitude.

(3.2) Determining Whether to Transmit the Time Piece Signal Based on the Size of the Difference Signal Each time piece signal transmitted by the following process (in the case of FIG. 8, L ₁ , L ₂ , L ₃ , L ₄ ,…) is decided.

[0091] i) L ₂ when -L ₁ ≧ d In this case, FIG. 8 (L _1, L ₂ shown in b), L _1, L ₂ representing the average amplitude power level of the period T of ... etc., Is transmitted as the time piece signal of FIG. Therefore, these time piece signals are D / A converted and subjected to the time compression described in (3.3). Note that the time piece signal length in this case is T. ii) When d ≧ L ₂ −L ₁ At this time, since the time piece signal L ₂ has a small amplitude, it is ignored and deleted from the transmission signal, and the level of the next adjacent time piece signal L ₃ is measured. As a result, L ₃ when L ₃ -L ₁ ≧ d is transmitted. However, when d> L ₃ −L ₁ , the time piece signal L ₃ is deleted from the transmission signal, and the next adjacent time piece signal L ₄ is transmitted. For this L ₄ , the level difference with L ₁ is not measured, and it is transmitted after waiting for the timing of L ₄ to be transmitted. The reason why L ₄ is unconditionally transmitted without measuring the level difference from L ₁ is as follows.

Even if the level difference of each of L ₁ , L ₂ , L ₃ , and L ₄ is d or less, these level differences are sequentially added. Therefore, the level difference between L ₁ and L ₄ is d or more. There is a possibility that

When the level difference comparison is continuously performed with an excessively large number of time piece signals, the signal delay time increases accordingly.

(3.3) Description of Actual System Operation Hereinafter, the specific system operation of the “transmission method at the time of level change” according to the present invention will be transmitted by the uplink (the mobile radio 100 transmits) by using the above system model. Then, the wireless base station 30 receives the signal).

In FIG. 2, in the mobile radio 100, the telephone signal output from the telephone unit 101 is the speed conversion circuit 13
At 1, the signal is first time-divided. A part of this output is input to the signal level measuring device 179, and the rest is input to the time compression circuit included in the speed conversion circuit 131, and is transmitted to the mobile wireless device 100 through the process described above. However, depending on the conditions described below, a time piece signal that is not transmitted to the mobile wireless device 100 is also generated.

Now, the time piece signal L ₁ input to the signal level measuring unit 179 of the mobile radio 100 (this L ₁ is automatically transmitted without undergoing the processing described below) is The level is measured respectively. Next, the level difference (difference values Δ ₁ and Δ ₂ ) is measured from these values, and the incoming time piece signals L ₂ , L ₃ and L are successively measured.
The level of _{4 is} also measured similarly. Δ ₁ = L ₁ −L ₂ Δ ₂ = L ₁ −L ₃ is obtained. These values of Δ ₁ and Δ ₂ are compared with a constant value d (for example, d = 3 dB) defined by the system, and as a result, the cases described in (3.2) i) and ii) occur. , The corresponding “transmission method at level change” is applied. However, in the actual system operation, the control unit 140 is not notified immediately after the determination of the magnitude of Δ _{1 that} the time piece signal L ₂ should be transmitted for the reason described below.
_When Δ ₁ is larger than d for the first time after the magnitude determination of ₂ , the control unit 140 transmits the information for transmitting the time piece signal L _2.
To send to. Moreover, at this time, the signal level measuring device 1
At 79, the information including whether or not the time piece signal L ₃ should be transmitted is also notified.

Upon receiving this signal, the control section 140 controls the transmission / reception intermittent controller 123 to be turned on, and transmits the compressed time piece signal L ₂ from the wireless transmission circuit 132. At this time, the time piece signal L ₃ is also transmitted as a control signal including information indicating whether or not the time piece signal L ₃ should be transmitted (this information is transmitted to the radio base station 30).
Therefore, it is possible to effectively utilize "time slots without signals" in the uplink, which will be described later).

If Δ ₁ is smaller than d, the control unit 140 is notified that the time piece signal should not be transmitted. In this case as well, the signal level measuring instrument 179 notifies the information including whether or not the time piece signal L ₃ should be transmitted. Upon receiving this signal, the control unit 140 controls the transmission / reception gating controller 123 to turn off the compressed time piece signal L.
₂ is prevented from being transmitted from the wireless transmission circuit 132 (in this case, it may be prevented from being transmitted including a wireless carrier wave depending on the system).

Similarly, the signal levels of the next time piece signal L ₃ are also compared, the result is reported to the control unit 140, and the control unit 140 receiving this information determines whether or not to transmit the radio signal. decide. Next time piece signal L
₄ informs the control unit 140 that the signal should be transmitted regardless of its signal level (the time piece signal L ₄ corresponds to L ₁ described above in the next cycle). Upon receipt of this signal, the control unit 140 controls the transmission / reception interrupt controller 123 to turn on the compressed time piece signal L ₄ to the wireless transmission circuit 1.
Send from 32.

This completes one cycle of the system operation on the signal transmitting side, which has been described focusing on the measurement of the signal level, and the next time piece signal L ₅ or the subsequent time piece signals L ₆ and L ₆ .
_{For 7} , the operation of contacting and controlling the signal level measuring device 179 and the control unit 140 and the like are repeatedly repeated.

Now, the operation of the receiving side to which the above signal is sent will be described below. In the radio base station 30 which has received the telephone and control signals having the above contents from the mobile radio 100, the radio reception circuit 35 demodulates them, and then the control signal is sent to the control unit 40 and the telephone signal component is sent to the signal selection circuit group 39. Is input to the signal selection circuit 39-1. Here, after the above-described signal processing is performed, it is input to the signal speed restoration circuit group 38. Here, the same signal processing as in the case of the mobile wireless device 100 is performed, but since a part of the telephone signal component is not transmitted, the telephone signal that is simply restored becomes a toothless state in terms of time. There is.

FIG. 9A shows this state, in which the signal SU1 carried in the time slot 1 of frame number 1 is loaded.
1, the signal SU41 mounted in the time slot 1 of the frame number 4, the signal SU61 mounted in the time slot 1 of the frame number 6, the signal SU71 mounted in the time slot 1 of the frame number 7, The signals SU91 carried in the time slot 1 of the frame number 9 are shown, respectively, but the other frame numbers 2, 3, 5 and 8 show that no signal was included. Incidentally, the temporal relative positions of these transmitted time piece signals are obtained by decoding the control signal, so the positions are not erroneous. Further, in FIG. 9A, the time slots SU11, SU41, signals SU61, SU7.
The broken line connecting 1 and SU91 indicates the original signal on the transmission side.

Now, if the restoration signal in the missing tooth state shown in FIG. 9A is used as it is, the noise is large and difficult to hear. Therefore, a method of suppressing the noise will be described. There is a method for filling the empty time slots (shown by diagonal lines) shown in FIG. 9B with adjacent signals. That is, FIG. 9B shows empty time slots SU21 and S21.
U31 is filled with the dummy signal of SU11, empty time slot SU51 is filled with the dummy signal of SU41, and empty time slot SU81 is filled with the dummy signal of SU71. As a result, the missing tooth state is removed, and although some noise components are mixed in, the original signal can be almost restored.

The above is the example of the system operation in the uplink (the mobile radio 100 transmits, the radio base station 30 receives), but in the downlink (the radio base station 30 transmits, the mobile radio 100 receives) Is also the same. The outline will be described with reference to FIG. 3. The signal level measuring instrument group 79 of FIG. 3 corresponds to the signal level measuring instrument 179 of the mobile wireless device 100 described above. The specific system operation of the “transmission method at level change” according to the present invention is similar to that of the mobile radio 100. However, the information indicating whether or not the time piece signal L ₃ that is performed by the mobile wireless device 100 should be transmitted from the wireless base station 30 to the mobile wireless device 1.
Notifying 00 is not always necessary and may be omitted.

(3.4) Time length of time piece signal close to actual system and degree of improvement of redundancy Below, a value close to an actual system parameter is used as a TCM system to improve the redundancy of a telephone signal. The degree and the value of the signal delay amount are obtained to explain the high practicality.

(3.4.1) System parameters of TCM system Frequency band of telephone signal: 0.3 to 3.0 kHz
z TCM system frame length: T = 10 ms Multiplicity: n = 50 From the above system parameters Time length of time piece signal: T = 10 ms Number of samples of time piece signal: g = 0.01 ms /
(1/6000 ms) = 60 is obtained.

(3.4.2) Calculation of Redundancy Reduction Amount As described above, the magnitude of the differential signal Δ is set to d, and the redundancy of the transmission signal when d = 3 dB is set. Calculate the amount of reduction.

Assume an occurrence rate when adjacent time piece signals are transmitted together.

The occurrence rate is estimated to be 1/10 or less from FIGS. 12 (a), 12 (b) and FIG. That is, if adjacent time-series signals are transmitted together, then 1/10
It will be estimated as follows. Using this assumption and the model described in (3.2) (which is a fairly high-fidelity transmission modem), the reduction amount of redundancy and the like are obtained as follows.

That is, all the probabilities P of each event occurring in the model of (3.2) i) and ii) are obtained, and this is multiplied by the reduction amount of the redundancy when this event occurs, and all of these are multiplied. You can add them together. When L ₂ −L ₁ ≧ d and L ₃ −L ₁ ≧ d, P ₁ = (1/10) × (1/10) = 1/100 L ₂ −L ₁ ≧ d, d> L ₃ −L _{When 1} , P ₂ = (1/10) × (9/10) = 9/100 d> L ₂ −L ₁ , L ₃ −L ₁ ≧ d, P ₃ = (9/10) × ( 1/10) = 9/100 When d> L ₂ −L ₁ and d> L ₃ −L ₁ , P ₄ = (9/10) × (9/10) = 81/100 When calculating the redundancy reduction amount A,
It becomes as follows. A = (P ₁ × 1) + (P ₂ × 1/3) + (P ₃ × 1/3) + (P ₄ × 2/3) = 0.61 That is, it is reduced to 61%, This means that the occupied frequency bandwidth is reduced to 3 kHz × 0.61 = 1.83 kHz in terms of baseband signal. Alternatively, it can be said that this value means that the effective frequency utilization is improved to 1 / 0.61 = 1.64 times.

Next, the value of the signal delay amount is obtained. this is,
More easily requested. That is, since the time piece signal L ₂ is kept waiting until the time piece signal L ₄ , the maximum value of the signal delay amount = 10 ms × 2 = 20 ms. However, since this signal delay amount is one-way,
In telephone communication, it is necessary to take a round trip value. Therefore, 2
It is 40 ms, which is twice 0 ms.

If it is desired to reduce the delay amount, the frame length may be shortened. For example, if the frame length is set to 5 ms, which is half of 10 ms, the signal delay amount is 20 ms even in a round trip. However, if the frame length is too short, the efficiency of the time piece signal generation / reproduction of the original signal decreases, so there is a limit to the shortening. The limit is 1-5ms
Is assumed. Also, if it is desired to further improve the effective frequency utilization, the deterioration of the signal quality gradually increases,
It suffices to increase the difference value d described in (3.2) and increase the transmission cycle of the time piece signal that is transmitted without measuring the level difference.

(3.4.3) Calculation of Total Information Transmission Amount Required as System The reduction rate of the occupied frequency of the telephone signal is clarified by the calculation of the redundancy reduction amount obtained in (3.4.2). However, it is necessary to separately calculate the total amount of information transmission required for the system. This is because it is necessary to transmit the comparison information of the magnitude between the difference value Δ and d of the time piece signal described in (3.2) and (3.3) as a control signal to the communication partner.

Hereinafter, the amount of information will be calculated. Since the time length of the time piece signal is 10 ms, the number of time piece signals existing in one second is 100. Therefore, as the control signal, it is necessary to transmit to the communication partner whether or not these 100 time piece signals have been transmitted. Therefore, 100
Since the bit information must be sent within 1 second, the total information transmission amount necessary for the system is 1.83 kHz as a telephone signal and 100 bps as a control signal. The control signals described above are sent in the following various ways.

Lower sideband of the compressed time piece signal Sub-time slot dedicated to control signal provided in time series in each time slot Dedicated control signal common to each telephone signal assigned to the frame Time slot

A method of using the lower sideband of the compressed time piece signal of the above will be described. Other methods can be similarly designed. In this case, the following band exists as the lower sideband. Frequency band 0 to 15 kHz However, since the time width is 1/50 = 20 ms, control signals must be sent intermittently. Since the number of frames existing in one second is 50, the control signal to be transmitted in each time slot has an average of 2 bits. However,
A control signal must be mounted on the non-transmitted time piece signal. Therefore, the maximum is 2 bits × 3 = 6 bits.

Now, is it possible to transmit the above information amount as a control signal? That is, does the control signal transmission line have a sufficient transmission capacity? This examination will be conducted below.

Since the frequency band is 0 to 15 kHz,
It can be seen that about 10 kbps (10 kilobits per second) can be transmitted as a binary digital signal. Therefore, in a time width of 20 ms, 10 kbps × 1 / 50s = 200b, that is, a maximum of about 200 bits. Therefore,
It can be seen that the control signal transmission line has sufficient transmission capability.

It is to be noted that about 6 bits of information is 0 to 15k.
It is easy to transmit in the Hz band and need not necessarily be in digital form. For example, six tone signals having the following frequencies 10, 10.5, 11, 11.5, 12, 1
It suffices to prepare 2.5 (kHz), create a control signal by a combination of ON / OFF of these tone signals, and transmit the control signal to the communication partner.

There is also a method of transmitting the control signal using the upper sideband of the telephone signal, and as a merit, there is no band limitation, so that a lot of information can be transmitted. However, it is necessary to design in consideration of the fact that the sideband of the FM wave spreads vertically.

(3.5) Effective Utilization of Time Slots without Signals As described above, when the level difference between adjacent time piece signals is within a fixed value (3 dB), the time piece signals are not transmitted. is what happened. Therefore, this time slot has no signal and is empty.
The effective use of this will be described below using the model described above.

(3.5.1) Effective Utilization of Downlink First, the downlink (transmitted by the wireless base station 30 and transmitted by the mobile wireless device 100).
If it is a receiving line, effective use can be easily achieved. It does not systematically provide 50 time slots in one frame to be mounted on one radio channel systematically for telephone signals, and dynamic time slot assignment may be executed for each frame. It will be.
For that purpose, the control capability of the control unit 40 of the radio base station 30 may be exerted. That is, as the control operation of the control unit 40, the telephone signal allocation of the 50 time slots accommodated in each frame is made for each frame, and the time slot # 1 of the frame number 1 is the telephone signal channel 1
The time slot # 1 of the next frame 2 is the time slot # 1 of the telephone signal channel 5, and the time slot # 1 of the next frame 3 is
Slot # 1 is allowed to be dynamically assigned to telephone signaling channel 6, and so on. As a result, it is possible to effectively utilize the time slot without the signal.

(3.5.2) Effective Utilization of Uplink Channel Next, uplink (mobile radio device 100 transmits, radio base station 3
The method of effectively using the line will be described. In this case, unlike the downlink, system control is somewhat difficult. This is because the "transmission method at the time of level change" of the telephone signal transmitted from the mobile wireless device 100 is different for each mobile wireless device 100 and cannot be controlled by the wireless base station 30. However, if an uplink control line as described below is used to cause each mobile wireless device 100 to previously send information as to whether or not to use the time slot of the next frame by a control signal, the downlink line The same effective use will be achieved.

[0124] In the method, when the control signal is transmitted from the mobile wireless device 100 by the "level change transmission method" described above, information indicating whether or not the "next time piece signal" is not transmitted is previously transmitted by radio. It may be added to the base station and transmitted. Therefore, as described above, the mobile wireless device 100 does not immediately transmit the measured time piece signal, but
It is necessary to measure the level difference between the "next time piece signal" level and the "previous time piece signal" and wait for the result.

(4) Calculation of increase amount of multiple load gain The increase amount of multiple load gain can be easily obtained from the reduction amount of redundancy of 0.61 in the telephone signal obtained in (3.4.2). That is, the signal power of the telephone signal is 0.6
Since it has decreased to 1, the increase amount of the multiple load gain is −20log 0.61 = 4.3 (dB), that is, it is increased by 4.3 dB. Therefore, if this increase amount of the multiple load gain is used to reduce the transmission power, the transmission power may be reduced by 4.3 dB. This is a fairly large amount from a system perspective.

(5) Peak Suppression Effect of Time Fragment Signal by Syrabic Compressor It has become clear that the system in which the "transmission method at level change" is applied to the TCM method described in (3) has many merits. However, the signal level of the time piece signal is in a state in which there is no change from a system to which the “transmission method at level change” is not applied. Therefore, if the multiple load gain increase amount obtained in (4) is used as it is to increase the angle modulation deviation, when the signal level of the time piece signal shows a peak, the modulation deviation amount becomes excessive, May cause radio interference in adjacent radio channels.

The above problem can be eliminated by a silabic compressor (compressor), which is inserted in the preceding stage of the amplitude modulator or the angle modulator of the radio transmitter to which the time piece telephone signal is applied. This makes it possible to achieve the purpose.

The operation of the Syrabic compressor will be described below. It is widely used in mobile communication transmitters. On the other hand, the receiver uses a Syrabic expander as a circuit that makes a pair with the compressor, and both are called a Syrabic compander.

Syrabic compander is a general term for a combination of a compressor (compressor) and an expander (expander). What is used in analog voice communication is one that operates in accordance with the envelope level of voice, and is currently widely used. Used (Hereinafter, the word syracic is omitted).

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

FIG. 10 shows an embodiment in which a compander is applied to the mobile radio device 100. The internal configuration of the speed conversion circuit 131 is shown at the bottom of FIG. 10, and the telephone signal output from the transmission circuit 107 of the telephone unit 101 is the switch 175.
Thus, the telephone signal is input and stored in the telephone signal storage circuit 171-1 or 171-2 for each frame. The timing of switching the terminals a and b of the switch 175 is performed by a signal from the timing generator 142. The signal stored here is read out and the switch 17
Switching of terminals a and b of 6-1 or 176-2 (this timing also depends on the signal from the timing generator 142)
Is input to the difference signal generating circuit 172-1 or 172-2, where the telephone signal is subtracted from the telephone signal of the immediately preceding frame (converted) and converted into a time piece telephone signal. This converted hourly phone signal is then
It is applied to the compressors 174-1 and 174-2, where the amplitude of the time piece telephone signal is compressed. An example of the compression characteristic received at this time is shown in FIG.

The compressor characteristic of FIG. 11 gives an output of n ^1/2 with respect to the input signal n, and is therefore called 1/2 compression. That is, when the input level changes by 10 dB, the output level changes by 5 dB. Therefore, the distribution of the amplitude characteristic of the audio signal is 1/2 in decibels. Therefore, when coming into the wireless transmission circuit 132, the signal distribution is 1/2 in decibel as compared with the case where the compression is not performed by the compressors 174-1 and 174-2. The outputs of the compressors 174-1 and 174-2 are input to the time compression circuit 173-1 or 173-2. Then, by switching between the terminals a and b of the switch 177 (this timing also depends on the signal from the timing generator 142), one time slot (TCM) of the TCM signal (TCM).
1 is given for each frame unit)
32.

In the radio transmission circuit 132 (FIG. 2), the signal is frequency-modulated at the signal level considering the multiple load gain, and then sent to the transmission mixer 133. The TCM-converted telephone signal frequency-modulated by the transmission mixer 133 becomes one modulated signal wave having a designated carrier frequency, and is transmitted from the antenna to the radio base station 30.

Now, it is assumed that a signal whose amplitude is compressed is transmitted from the radio base station 30 from the antenna and is received by the mobile radio 100. In FIG. 10, the compressed one-sided telephone signal from the wireless reception circuit 135 is input from the right side.
This input signal is input to and stored in the telephone signal storage circuit 161-1 or 161-2 by the switch 165 for each time slot (one for each TCM frame). The timing of switching the terminals a and b of the switch 165 is performed by a signal from the timing generator 142. The signal stored here is then read out,
The time extension circuit 162-1 or 162-2 restores the original telephone signal rate. This restored telephone signal is then still in the form of a time piece telephone signal, and the switch 1
It is input to the expanders 164-1 and 164-2 by switching the terminals a and b of 66-1 or 166-2 (this timing also depends on the signal from the timing generator 142). This input signal will undergo conversion according to the expander characteristics of FIG. That is, the input level is 5
When the dB changes, the output level changes by 10 dB. As a result, as shown in the center of FIG. 11, the overall characteristic is that the change in the voice input on the transmitting side is 1 dB, and the change on the telephone input on the receiving side is also 1 dB, so that the original signal is reproduced faithfully. The outputs of the expanders 164-1 and 164-2 are telephone signal reproduction circuits 1
63-1 or 163-2. Here, the time piece telephone signal is added to the signal in the time slot of the immediately preceding frame, and the original telephone signal for one frame is reproduced. Then, the terminals a and b of the switch 167
The output of the telephone signal reproducing circuit 163-1 or 163-2 is alternately taken out by switching (the timing is also based on the signal from the timing generator 142) of the telephone unit 1
01 to the receiving circuit 106.

The left side of FIG. 10 shows the internal construction of the telephone section 101, which includes a control section 140 and a telephone control circuit 105.
Control signals are exchanged between the two. Also, the receiving circuit 1
06 and the transmission circuit 107 operate by receiving a signal from the clock regenerator 141.

Although the above description has been given of the case where the wireless base station 30 transmits and the mobile wireless device 100 receives, the same applies to the case where the mobile wireless device 100 transmits and the wireless base station 30 receives. That is, also in the wireless base station 30, a compander similar to that included in the mobile wireless device 100 shown in FIG. 10 is installed at a position corresponding to the insertion position in the mobile wireless device 100.

By applying the compander described above, it is possible to eliminate or reduce the possibility that the amplitude of a time piece telephone signal having a large signal level is compressed and adversely affects other radio channels such as radio interference. .

As described with reference to FIGS. 14 and 15, it is also known that even if the peak level signal component of the telephone signal is removed, the effect on the intelligibility of the signal is considerably small. Therefore, the compression degree of the compander is large, and its characteristics change over time,
Even if the reproduction of the peak-level signal component becomes unsatisfactory, the influence on the signal is considerably reduced. This is advantageous in increasing the substantial multiple load gain due to the use of companders. That is, it is estimated that an increase in multiple load gain of 10 dB or more can be expected with 1/2 compression, and 15 dB or more can be expected with 1/4 compression, and it is more advantageous to increase the compression degree.

(6) Peak Suppression Effect of Time-Sone Telephone Signal by Band-Pass Filter Although the peak suppression effect of the time-simple telephone signal by the compander has been described in (5), the same effect is obtained by the signal It will be explained below that it can also be obtained by a bandpass filter inserted in the output stage. As an example, a TCM signal obtained by multiplexing 10 analog telephone signals converted into hourly telephone signals is taken. In this case, the frequency band of the signal is 3 kHz to 30 kHz (the frequency band of the hourly telephone signal is the same). Further, it is assumed that carrier frequencies of 10 waves are arranged at intervals of 125 kHz.

This TCM signal is FM, and its modulation deviation amount is 1.75 × 5 = 8.75 rad. (Rms, 10 kHz
For sine waves). In the above formula, × 5 is
This is because the power reduction of the signal due to the conversion into the hourly telephone signal is utilized for increasing the modulation shift amount. as a result,
As described above, the frequency shift of the FM-modulated modulated signal becomes extremely large in the high-level time piece telephone signal. In terms of specific numerical values, of the effective signal components included in the sidebands of the modulated wave, the approximate maximum frequency f _p is f _p = 30 + 100 = 130 (kHz). Etc. will be adversely affected. To prevent this, a band pass filter may be inserted in the output stage of the wireless modulated wave. The required pass band width B of the band pass filter would then be B = ± 50 kHz.

As a result of inserting the band pass filter, the peak-time signal component of the one-sided telephone signal is suppressed. However, as described above, even if the peak level signal component of the telephone signal is removed,
Since the influence on the intelligibility of the signal is small, there is no problem.

It should be noted that a so-called SCPC (Sing) in which one analog telephone signal is carried on one working carrier frequency is used.
In the le Channel Per Carrier (IDC) method, an IDC (Instanteneous Deviation Control) is inserted before the FM of the signal. This is because when the signal input to the modulator has an excessive level, the level is suppressed to prevent adverse effects such as radio interference on adjacent radio channels. However, since the application of IDC causes distortion noise in the signal, a method such as the method of the present invention for reducing the power level of the signal by generating the time piece telephone signal is desirable. Then a compander or bandpass filter should be applied. Of course, these applications also cause distortion noise in the signal, but since the occurrence probabilities of the peak level of the signal are greatly different, the influence on the signal is reduced, and the superiority of the present invention becomes clear.
Of course, the application of IDC is also possible in the present invention.

[0143]

As is apparent from the above description, in the TCM system using the telephone signal, the multiple load gain of the TCM signal can be further increased by using the time piece telephone signal detailed in the text. Therefore, when this is used to reduce the wireless transmission power, the power consumption is reduced and the frequency can be effectively used. Therefore, the effect of the present invention is extremely large.

[Brief description of drawings]

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

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

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

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

FIG. 5 is a circuit configuration diagram for multiplexing a voice signal and a data signal.

FIG. 6 is a flow chart showing a flow of basic operation of the system according to the present invention.

7 is a flow chart showing a flow of basic operation of the system according to the present invention together with FIG. 6;

FIG. 8 is a waveform diagram showing a process of sampling (b) a signal waveform (a) and obtaining an average power in the present invention.

FIG. 9 is a waveform diagram showing a restored signal from a received signal and a waveform of the restored signal after processing the same in the present invention.

10 is a circuit configuration diagram showing an operation principle of a speed restoration circuit, a telephone unit, and a speed conversion circuit which are the constituent elements of FIG.

11 is a characteristic diagram showing the input / output characteristics of the compressor and expander that are the constituent elements of FIG.

FIG. 12 is a waveform diagram of a vowel.

FIG. 13 is a waveform diagram of consonant + vowel (cho).

FIG. 14 is a characteristic diagram showing information transmission amount characteristics when peaks are removed from a telephone signal and when the vicinity of 0 is removed.

FIG. 15 is a waveform diagram showing waveforms in the case of removing peaks and the case of removing near zero in FIG.

FIG. 16 is a graph showing changes in audio power shown in the cited document.

[Explanation of symbols]

 10 telephone network 20 barrier exchange 22-1 to 22-n communication signal 30 radio base station 31 signal processing unit 32 radio transmission circuit 35 radio reception circuit 38 signal speed restoration circuit group 38-1 to 38-n signal speed restoration circuit 39 signal Selection circuit group 39-1 to 39-n Signal selection circuit group 40 Control unit 41 Clock generator 42 Timing generation circuit 51 Signal speed conversion circuit group 51-1 to 51-n Signal speed conversion circuit 52 Signal allocation circuit group 52-1 To 52-n signal allocation circuit 79 signal level measuring instrument group 79-1 to 79-n signal level measuring instrument 91 digital encoding circuit 92 multiplex conversion circuit 100, 100-1 to 100-n mobile radio device 101 telephone unit 120 standard Crystal oscillator 121-1, 121-2 Synthesizer 122-1, 122-2 Switch 123 Transmission / reception interrupt controller 1 1 speed conversion circuit 132 radio transmission circuit 133 transmission mixer 134 transmission unit 135 radio reception circuit 136 reception mixer 137 reception unit 138 speed restoration circuit 141 clock regenerator 161-1, 161-2 telephone signal storage circuit 162-1, 162-2 Time expansion circuit 163-1, 163-2 Telephone signal reproduction circuit 164-1, 164-2 Expander 165, 166-1, 166-2, 167 Switch 171-1, 171-2 Telephone signal storage circuit 172-1 172-2 Difference signal creating circuit 173-1, 173-2 Time compression circuit 174-1, 174-2 Compressor 175, 176-1, 176-2, 177 Switch 179 Signal level measuring instrument

Claims (4)

[Claims] 1. A radio base means (30) each of which covers a plurality of zones to form a service area, and a frame structure for moving across the plurality of zones and communicating with the radio base means. Mobile communications using barrier exchange means (20) for exchanging communications with each mobile radio means (100) using radio channels carrying time-compressed delimited signals in time slots. In the time division communication method, if the temporally compressed delimited signal is an analog telephone signal, it is compared with the power of the temporally compressed delimited signal to be mounted in the adjacent frame and the next adjacent frame, Time division communication of mobile communication in which the signal sent from the transmitting side to the receiving side is not mounted as long as the number of frames is constant if the signal power difference does not exceed a certain value in advance. Law. 2. The mobile communication according to claim 1, wherein, when the power difference between the signals does not exceed a predetermined constant value, the level unchanged information is transmitted to a communication partner as a control signal. Time division communication method. 3. A time slot in which a signal is not mounted for a fixed number of frames, which occurs when the power difference between the signals does not exceed a predetermined fixed value, includes a time slot between the transmitting side and the receiving side. The time division communication method for mobile communication according to claim 1, wherein a signal for communication different from the communication for (1) is mounted on a time-compressed divided signal. 4. When the information of the level unchanged is transmitted as a control signal to a communication partner, the information of the level unchanged is provided in a control signal time slot and each time slot commonly set in each frame. 3. The time division communication method for mobile communication according to claim 2, wherein the transmission is performed using one of the dedicated frequency bands for the control signals installed.