JPH053451A - Time division communication method for mobile object communication - Google Patents

Abstract

PURPOSE:To prevent radio interference by allowing a radio base station and a mobile radio equipment to decide a transmission level of a composite signal based on a multiple load gain to suppress a side band component of a modulation wave within a specified value. CONSTITUTION:Each radio base station 30 forms a service area covering plural zones. Moreover, each of mobile radio equipments 100-1 to 100-n are moved in crossing with plural zones. Then in order to make communication with the radio station 30, a radio channel is employed, in which signals compressed timewise and blocked are superimposed onto a time slot of frame structure. A gate exchange 20 implements communication exchange between the base station 30 and each mobile radio equipment 100. As a result, the signal is modulated by applying emphasis or de-emphasis to a frequency characteristic decided by a maximum frequency of an original signal or the like. The base station 30 and the radio equipment 100 decide the transmission level of the composite signal based on a multiple load gain and radio interference is prevented by suppressing a side band component of a modulation wave within a specified value.

Description

Detailed Description of the Invention

[0001]

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

[0002]

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

Reference 1. Ito "Study on mobile phone systems-Proposal of time division time compression FM modulation system-" IEICE Technical Report RC
S89-11 July 1989

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

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

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

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

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

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

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

[0011]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the example of system construction 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 explanation of multiple load gain is not given. Document 4 describes the multiple load gain related to the signal power of the TCM signal, but the effect of the frequency characteristic of the signal on the sideband of the modulated wave is not clarified, and unsolved in wireless interference. There were challenges left.

[0012]

The number of multiplexed TCM (time division time compression multiplex) signals (the number of channels), the time length of one frame, and the maximum frequency of the original signal are used as parameters, and T
The frequency characteristic of the CM signal is clearly derived by using the same formula as that for deriving the multiplex load gain of the TCM signal, and before the signal is added to the angle modulator or the like, the frequency is de-emphasized by a de-emphasis or pre-emphasis circuit. The characteristics are compensated, the sideband component of the modulated wave is suppressed within a specified value, and it is possible to prevent radio interference to adjacent channels.

[0013]

In addition to the multiple load gain at the average power of the TCM signal, the influence of the frequency characteristics on the modulated signal has been clarified. Therefore, various load parameters such as the multiple load gain and the sideband characteristics are used by using various design parameters of the system. It becomes possible to concretely calculate the characteristics, and it is possible to gradually reduce the transmission output by increasing the modulation degree of FM (PM) modulation while keeping the interference and the like within the allowable value. Therefore, the amplifier can be easily designed, and the rated values of passive circuits such as mixers, resistors, and capacitors can be lowered, and an economical system can be constructed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1, FIG. 2 and FIG. 3 show the system configuration for explaining one embodiment 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,
The mobile wireless device 100 (100-1 to 100-n) has a wireless transmission / reception circuit for exchanging wireless signals.

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

FIG. 2 shows a circuit configuration of the mobile radio 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 speed (pitch in the case of an analog signal) of the compressed and delimited communication signal in the received signal and inputs it to the telephone section 101 and the control section 140 as a continuous signal. ing.

The communication signal output from the telephone unit 101 is divided by the speed conversion circuit 131 at predetermined time intervals, and the speed (pitch in the case of an analog signal) is increased (compressed) and transmitted. Mixer 133 and transmitter 134
And is applied to the wireless transmission circuit 132 including.

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

The timing generator 142 supplies 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 that generate signals for switching each of -2, and the synthesizers 121-1 and 121-2, the transmission / reception gating controller 123, and the timing generator 142 are control units. It is controlled by 140. Each synthesizer 121
The reference frequency is supplied to the -1, 121-2 from the reference crystal oscillator 120.

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, an 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 to make the gateway switch 20.
Sent to. Of the above, the input signal from the gateway switch 20 is input to the signal speed conversion circuit group 51 including many signal speed conversion circuits 51-1 to 51-n, and the speed (pitch) conversion is performed by dividing the signal speed conversion circuit group 51 at predetermined time intervals. receive. As for the signal transmitted from the wireless base station 30 to the gateway switch 20, the output of the wireless receiving circuit 35 is input to the signal speed restoration circuit group 38 via the signal selection circuit group 39, and the speed (pitch) is converted. It is input to the signal processing unit 31.

The control of the radio receiving circuit 35 or the output of a call signal includes a signal selection circuit group 3 including signal selection circuits 39-1 to 39-n for selecting a signal for each time slot.
9, and the call signals are separated corresponding to each of the call channels CH1 to CHn. This output is input to the signal processing unit 31 after being restored in the signal speed (pitch) by the signal speed restoring circuit group 38 including the signal speed restoring circuits 38-1 to 38-n provided for each channel. 4-line-2
After undergoing line conversion, this output is sent to the gateway switch 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. The input signal such as a voice signal or a control signal, which is divided into a certain time length, is stored in a storage circuit, and the speed is changed when reading the input signal, and the read signal is read at a speed of, for example, 15 times that of the storage time. Can be compressed. The principle of the signal speed conversion circuit group 51 is
This is the same as playing back the sound recorded by a tape recorder at high speed. In practice, for example, CCD (Char
ge Coupled Device), BBD (Bucket Brigade Devic)
e) can be used, and a memory used in a television receiver or a tape recorder for compressing or expanding the time axis of conversation can be used (reference: Kosaka et al. “Compress time axis of conversation / Expanding Tape Recorder Nikkei Electronics July 26, 1976
92-133).

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

The control or voice signal output from the gateway switch 20 via the signal processing unit 31 is input to the signal speed conversion circuit group 51, and the speed (pitch) conversion processing is performed, and then the time slot is set. It is applied to a signal allocation circuit 52 which separately allocates signals.

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

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

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

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

In the above examples, tone signals are used. However, by increasing the number of tone signals or by modulating the tones to form subcarrier signals, various types of signals can be transmitted at high speed. Becomes

Although the above is the case of the analog signal, when the digital data signal is used as the control signal, it is also possible to digitally encode the voice signal and time-division multiplex both of them for transmission. FIG. 7 shows the circuit configuration in this case. FIG. 6 shows an example in which the voice signal is digitized by the digital encoding circuit 91, the data signal and the data signal are multiplex-converted by the multiplex conversion circuit 92, and applied to the modulation circuit included in the wireless transmission circuit 32. However, for digital data signals, the analog signal multiple load gain, which will be described later, does not normally exist, so this point must be noted in the system design. Then, if the opposite receiver receives the signal and the demodulation circuit performs the reverse operation to that shown in FIG. 6, the audio signal and the control signal can be separately taken out.

On the other hand, the signal 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 this upstream input signal. That is, the time slots SU1, SU2, ..., SUn represent transmission signals addressed to the radio base station 30 from the mobile radios 100-1, 100-2, ..., 100-n. Further, the details of each of the time slots SU1, SU2, ..., SUn are made up of a call signal and / or a control signal as shown in the lower left of FIG. However, the synchronization signal can be omitted depending on the case where the distance between the mobile wireless device 100 and the wireless base station 30 is small or the signal speed. Further, when the waveform of the radio carrier of the uplink radio signal in the time slot is schematically shown in FIG.
It becomes like (c). Similarly, the transmission waveform from the wireless base station 30 to each mobile wireless device 100 is as shown in FIG.

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

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

The mode of transmitting the signal space in the present invention will be described below with reference to the required transmission band and the relationship between the required transmission band and the adjacent radio channel.

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

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

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

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

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

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 wireless transmission circuit 32 together with the control signal, a required transmission band of at least f _C ± 45 kHz is required. However, f _C is a radio carrier frequency.
If there are a plurality of wireless channels given to the system, the speedup of signals by the signal speed conversion circuit group 51 is limited to a certain value due to the limitation of these frequency intervals. F _rep the frequency intervals of multiple wireless channels
And the maximum signal speed due to the speedup of the above audio signal is f
_{If H} , then the following inequalities must hold between them. f _rep > 2f _H On the other hand, in the case of a digital signal, the voice is usually digitized at a speed of about 64 kb / s. Therefore, it is necessary to read the scale of the horizontal axis in FIG. However, the relation of the above equation holds in this case as well.

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

Next, the operation of making and receiving calls 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 the mobile radio device 100 will be described with reference to the flowcharts shown in FIGS. 9 and 10.

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

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

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

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

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

In another system, there is a case where an empty slot is not displayed in any time slot. At this time, the audio multiplexed signals SD1 and SD that follow are displayed.
2, ..., SDn must be searched one after another to check for empty time slots.

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

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

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

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

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

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

This dial tone is transmitted 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 radio base station 30 has already responded to the calling signal from the mobile radio 100, and has set the time
The slot is given, and the signal selection circuit group 39 and the signal allocation circuit group 52 of the radio base station 30 are operated to receive the uplink time slot SU1 and to transmit the downlink time slot SU1.
The state has shifted to transmitting the signal of the slot SD1.
Therefore, the dial signal transmitted from the mobile wireless device 100 is the signal selection circuit 39-1 of the signal selection circuit group 39.
After passing through, it is input to the signal speed restoration circuit group 38, where the original transmission signal is restored and transferred to the gateway switch 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
Is 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 reception is awaited, and it is received by the radio reception circuit 135, 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 unit 101.
Thus, a call is started between the mobile wireless device 100 and the ordinary telephone in the ordinary telephone network 10 (S21).
6).

The telephone call unit 101 of the mobile radio 100 is used for ending the call.
By hooking the handset of the mobile phone (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 terminals of the synthesizers 121-1 and 121-2, respectively.

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

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

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

An incoming call signal from the general telephone network 10 to the mobile radio 100 via the gateway switch 20 is transmitted to the radio base station 30.
Suppose you have arrived. Similar to the voice signal, these control signals pass through the signal speed conversion circuit group 51, and are transmitted to the control unit 40 (FIG. 3) through the signal allocation circuit group 52, similarly to the voice signal. Then, the control unit 40 uses the empty slot of the downlink time slot of the radio channel CH1 addressed to the mobile wireless device 100, for example, SD1, to move the mobile wireless device 10
0 ID signal + incoming call signal display signal + time slot use signal (for example, for transmission from the mobile radio 100, S
Use SU1 corresponding to D1). In the mobile wireless device 100 that receives this signal, the signal is transmitted from the receiving unit 137 of the wireless receiving circuit 135 to the control unit 140. 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 unit 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.

It should be noted that it is theoretically explained in Document 2 that signal transmission is executed in good condition by using this system and does not adversely affect other radio channels in the system. Theoretical proof of multiple load gain in telephone signal and its application are also described in reference 4, so they are omitted and the TCM applied to the present invention is described below.
Theoretically explain the frequency characteristics of the signal, and then
The application will be described.

(3) Frequency characteristics of TCM signal transmitted from radio base station TCM (time division time compression multiplexing)
Expressions for deriving the frequency characteristic of the signal from the already obtained multiplex load gain of the TCM signal (see FIG. 11) and FIG. 11 showing the relationship between the multiplex number of voice signals and the multiple load gain obtained thereby are used. Explain. The signals handled below are telephone signals.

Consider again the average power of FDM (Frequency Division Multiplexing) and TCM signals with the same number of multiplexes. If the same signal source is used as the telephone signal source, both FDM and TCM signals should have the same value if they are measured for a fixed time length and their average power values are taken.
In the case of an FDM signal, it is obvious that it is not necessary to take a time average, and even if the average power in a very short time is taken, it can be regarded as almost the same as the average power in a relatively long time, for example, 1/6000 seconds. , TCM signals require the average power of one frame. However, if the frame time length is 1/6000 seconds or less, it will be the same as that of the FDM signal, as already described in Reference 4, but if it is 1/6000 seconds or more, the multiple load is applied. The value of the average power has changed in consideration of the gain.

That is, if the multiple load gain is not considered in the system design, the frame length may be sufficiently longer than 1/6000 seconds, and the average power of the TCM signal in one frame is equal to that of the FDM signal. It is natural to be. However, from the viewpoint of multiple load gain, when one frame is longer than 1/6000 seconds, subframes are configured every 1/6000 seconds, and the average power for each is calculated, and the average of the largest subframes is calculated. The power value had an effect on the determination of the multiple load gain. For example,
A TCM signal having a multiplexing number of 6000 and one frame time of 1/3000 seconds must be considered to have an FDM conversion multiplexing number of 3000 as compared with a TCM signal having a multiplexing number of 6000 and one frame time of 1/6000 seconds.

Therefore, the multiplex load gain is 49.7 dB, which is 3 dB lower than the value when the multiplex number is 6000. When the 1 frame time length is changed to 1/1500 seconds, 1/400 seconds, ..., 1 second, the multiple load gain is obtained by using Reference 4 or FIG. 11, and is as shown in FIG. FIG. 12 shows the number of voice multiplex n.
3 shows the relationship among the multiplex load gain X, the one-frame time length t _e , the number of multiplexes n ′ in FDM conversion, and the multiplex load gain Y in FDM conversion obtained in the TCM signal.
That is, when the one-frame time length t _e is 1/6000 seconds, the TCM signal has the same multiplex load gain X = Y as that of the FDM signal, but when the one-frame time length becomes as large as 1 second, the FDM conversion is completely performed. It will not have a load gain Y.

The above matters will be examined with respect to the frequency characteristic of the TCM signal. First, a human speech spectrum will be described.

As is known, the speech spectrum of human speech is
It concentrates on the low frequency band. FIG. 13 shows an example of the average value of the speech spectrum of a person and the unbiased variance square root σ. Here, the solid line shows the frequency distribution of a female voice (average of 5 people) and the broken line shows the frequency distribution of a male voice (average of 2 people).
The long-term effective value (dB) per 1 Hz is the frequency (kH
It can be seen that the focus is on the low part of z). Therefore, the frequency characteristic of the telephone signal also exhibits the frequency characteristic when the low frequency band of 0.3 kHz or less and the high frequency band of 3 kHz or more are cut off. Therefore, it can be seen that the telephone signal spectrum is also concentrated in the low frequency band and is lowered by about 25 dB in the vicinity of the high frequency of 3 kHz as compared with that in the vicinity of 0.3 kHz. Let us consider what happens to this when the telephone signal is a TCM signal. In the graph shown in FIG. 13, an unbiased variance square root σ is shown, for example, in a line segment vertically written in the vicinity of 0.3 kHz of a woman, and the degree of variation in the conversational speech spectrum in the vicinity of 0.3 kHz ( ± 3 to 5 dB) can be known.

What has an important effect in the present invention is the value of the unbiased variance square root σ near the highest frequency of the telephone signal. This value is related to the modulation shift amount of frequency modulation. That is, it is the power and modulation shift amount in the vicinity of the highest frequency of the modulation signal that have a large effect on the spread of the sidebands of the modulation wave. For example, when frequency-modulating a signal of one channel of a telephone like a cordless telephone, if the level near the highest frequency of the telephone signal is high, the value of the unbiased square root σ of that neighborhood is considered and the signal level becomes the highest. It becomes necessary to determine the magnitude of the amount of modulation deviation so that the amount of modulation deviation of the frequency modulation does not adversely affect the adjacent radio channel. And, depending on the person, the conversation speech spectrum of 3 kHz
There is variation in the signal level near z, and in addition, the value of the unbiased square root σ of the signal near 3 kHz varies from person to person. Therefore, when performing frequency modulation, assuming that the value of the unbiased square root σ is a fairly large value, most people must determine the magnitude of the modulation deviation so that it becomes less than that value.

The spread of the modulated wave when frequency-modulating the TCM signal of the present invention will be examined below with reference to FIG.

First, consider the case where the frame time length t _e is 1 second. This is the case where the number of multiplexed FDM equivalents n '= 1, that is, there is no multiple load gain Y equivalent to FDM. At this time, what kind of characteristic the frequency characteristic of the TCM signal has is examined. It is n '= 1
As can be seen from the above, it should be considered as a single telephone signal, and thus the frequency characteristic should be considered the same as that of a single telephone signal. However, what should be noted here is spread of the signal frequency, for example, a TCM with a compression ratio of 100 times.
As the frequency characteristics of the signal, (0.3 to 3.0 kHz) ×
100 = (30 to 300 kHz), that is, 30 kHz
from z to 300 kHz. This point is the same in the following description.

Now, consider the case where the frame time length t _e is 1/6 second. This is n ′ = 6, that is, the FDM-converted multiple load gain Y is the same as that of the six-multiplex FDM signal. At this time, the frequency characteristic of the TCM signal should be considered to be a convolution of six frequency characteristics of a single telephone signal, as can be seen from n '= 6. That is, the variation in the frequency characteristics when six telephone signals are folded is wide. To be more precise, the signal magnitude (voltage value) at a certain frequency of the six convoluted telephone signals is the arithmetic sum of the voltage values of the six telephone signals (arithmetic mean if normalized). That is, the signal variation (unbiased square root σ) becomes a value (6 ^1/2 σ) obtained by multiplying the value of a single telephone signal by 6 ^1/2 .

The frequency characteristics when the frame time length is t _e will be described below. In this case, the following equation n '= n (2f _h
T) ^-1 is used to determine n'and the unbiased square root of the frequency characteristic σ
Is the value of a single telephone signal multiplied by (n ') ^1/2 (n
^1/2 σ). Here, f _h is the highest frequency that the signal has, and T is the time of one frame.

The above results show that in the case of a telephone signal,
Since the high-frequency signal component is as low as 20 dB or less as compared with the low-frequency signal component, it is considered that there is no practical problem when n'is 10 or less. However, when n'is about 100, even in the case of a telephone signal, the high frequency signal component may become a problem. That is, the unbiased variance square root σ of a single telephone signal is ± 3 dB.
Then, when n ′ = 100, the unbiased variance square root σ of the TCM signal becomes ± 30 dB and cannot be ignored. However, even in this case, if the time rate is used, the signal level is 30%.
It is very low in dB, and is unlikely to cause a systematic problem.

However, in the case of a TCM signal using an analog telephone signal, since there is a multiple load gain X as described in Document 4, the signal level is raised by this amount. In this case, It is necessary to use the de-emphasis circuit of. As a system, spectrum inversion (replacement of low-frequency signal component and high-frequency signal component) for analog telephone signals is a secret
It becomes very severe due to adjacent channel interference.

As is clear from FIG. 13,
The power of the telephone signal around 0.3 kHz is much higher than that near 3 kHz, so if the spectrum is inverted, it will be 3 kHz.
This is because the signal power near z increases. Therefore, since this is actually a system problem, the present invention uses the de-emphasis circuit described below.

The de-emphasis circuit has been conventionally used in analog microwave circuits and is a known technique. That is, it has a function of suppressing the level of the high frequency component of the frequency characteristic of the input signal to the modulator. For example, with reference to 1 kHz of a telephone signal (0.3 to 3.0 kHz), 3.0 dB linearly in decibels
When a de-emphasis circuit that suppresses 10 dB at z is used, it is possible to suppress the level of the high frequency component of the TCM signal at +30 dB to +20 dB when the multiplexing number n ′ in FDM is 100. become.

After the signal passes through the de-emphasis circuit described above, the signal speed is converted and added to the modulator as described later. The modulated signal wave is transmitted from the antenna. This radio signal is received by the receiver, demodulated and then sent to the telephone, after using the emphasis circuit. The emphasis circuit is a circuit that performs an operation which is completely opposite to that of the de-emphasis circuit. For example, 1 dB of a telephone signal (0.3 to 3.0 kHz) is used as a reference and linearly 10 dB at 3.0 kHz in decibels. When the emphasis circuit of (1) is used, the frequency characteristic of the original telephone signal is reproduced.

FIG. 14A shows a de-emphasis circuit 81 as a prevention method when the high frequency components of the TCM signal described above affect the sidebands of the modulated signal wave.
An example at the transmitting side of the wireless base station 30 when using is shown. This figure shows 5 of the signal speed conversion circuit groups 51.
1 is a diagram showing an internal configuration of 1-1, in which a telephone signal from a signal processing unit 31 passes through a de-emphasis circuit 81 before being subjected to speed conversion by a signal speed conversion circuit 82, where high frequency components Is suppressed.

FIG. 14B shows an embodiment in which the emphasis circuit 182 is applied to the mobile radio 100 on the reception side when the de-emphasis circuit 81 is used for the radio base station 30 on the transmission side. The figure shows the internal configuration of the receiving unit 137, and the output signal from the receiving mixer 136 is input to the receiving circuit 181 from the left. The signal is demodulated here and then input to the emphasis circuit 182.
As a result, the high frequency components of the signal are emphasized and the signal is output to the speed restoration circuit 138.

In the above description, an example in which the de-emphasis circuit is used on the transmitting side has been described, but when the system parameter of the TCM signal, for example, n ', is relatively small, it is possible to use the emphasis circuit on the transmitting side. .. If you want to use the emphasis circuit on the transmitting side, in the case of frequency modulation,
This is because high frequency components are weak to noise due to so-called triangular noise, and it is desired to prevent this. In this case, the de-emphasis circuit is used on the receiving side.

[0090]

As is apparent from the above description, the frequency characteristic of the time division time compression multiplex signal, which has not been clearly shown in the past, is quantitatively clarified by using the system parameter. Even if the modulation depth (shift amount) is deepened by the amount of the multiple load gain using the theory disclosed in Document 4, and transmitted by applying a de-emphasis circuit or an emphasis circuit. It is possible to suppress the influence on the value within the conventional design value, and it is possible to gradually reduce the transmission output level per radio channel as compared with the conventional system. Therefore, the effect of the present invention is extremely large.

[Brief description of drawings]

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

FIG. 2 is a circuit configuration diagram of an embodiment of a mobile wireless device used in the system of the present invention.

FIG. 3 is a circuit configuration diagram of an embodiment of a radio base station used in the system of the present invention.

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

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

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

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

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

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

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

FIG. 11 is a diagram showing the relationship between the multiple load gain of a time division time compression multiplex signal and the number of multiplexed voice signals.

FIG. 12 is a diagram showing a load multiplex of a time division time compression multiplex signal,
It is a figure which shows the multiple load gain of a frequency multiplex signal, and the relationship of 1 frame time length.

FIG. 13 is a spectrum diagram showing a spectrum of human conversation voice.

FIG. 14 is a circuit configuration diagram showing a circuit configuration of a signal speed conversion circuit and a receiving unit.

[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 -52-n signal allocation circuit 81 de-emphasis circuit 82 signal speed conversion circuit 91 digital encoding circuit 92 multiplex conversion circuit 100,100-1 to 100-n mobile radio 101 telephone unit 120 reference crystal oscillator 121-1,121- 2 Synthesizers 122-1 and 122-2 Switches 123 Transmission / reception interrupt controller 131 Speed conversion times 132 radio transmission circuit 133 transmits the mixer 134 transmission unit 135 radio reception circuit 136 receives the mixer 137 receiving section 138 time expansion circuit 141 clock regenerator 181 receiving circuit 182 emphasis circuit

Claims (1)

Claim: What is claimed is: 1. A radio base means (30) that covers a plurality of zones to form a service area, and a radio base means that moves across the plurality of zones and communicates with the radio base means. Barrier exchange means (20) for exchanging communication with each mobile radio means (100) using a radio channel carrying time-compressed and delimited signals in a time slot of a frame structure for communication. In a time division communication method of mobile communication using and, before modulating the temporally compressed delimited signal, the frequency characteristic of the original signal before the temporally compressed and delimited is a predetermined frequency. A time division communication method for mobile communication, in which compensation is performed to obtain characteristics (81, 182) and the sideband component after modulation is suppressed within a prescribed value.