JPH04343537A - Time division communication method for communication of mobile body - Google Patents

Abstract

PURPOSE:To attain the transmission/reception of composite signals by the same radio carrier by modulating the frequency of a telephone signal by means of one time slot in a radio channel allocated between a mobile radio set and a radio base station and then modulating the amplitude of the Modulated telephone signal by a facsimile signal to transmit/receive the amplitude-modulated signal. CONSTITUTION:When many mobile radio sets 100-1 to 100-n exist in the service area of the radio base station 30, one radio channel is time-divided into plural time slot sequences in order to attain communication between the optional number of radio sets and the base station. Then one of the sequences is selected to execute communication. When a certain radio set is being communicated with the base station 30 by means of a composite signal, a radio set newly requiring communication by means of a composite signal is allowed to communicate with the base station 30 by applying one of unused sequences to the using radio channel. Thus the mutual interference of many communication cases can be prevented and bad influence to self communication can be suppressed.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is directed to ISDN (Integr.
ated Services Digital Net
This invention relates to radio base stations and mobile radios for time-division communication of radio communication channels in modern mobile communications. More specifically, given a radio channel among many radio channels given to the system, one of the many mobile radios in the service area can use it to communicate with the opposing radio base station. For example, while setting up a wireless line and communicating using a communication signal using a combination of telephone and telephone or telephone and fax signals,
When another mobile radio device wishes to communicate using the same radio channel, the communication between the other mobile radio device and the radio base station can be performed without adversely affecting the communication between the mobile radio device and the radio base station that are already communicating. The present invention relates to a time-division communication system using the same radio channel that enables communication of composite signals including telephone, fax, data, and image signals by setting up an independent radio line with a base station using the same radio channel.

0002

2. Description of the Related Art A system employing time division time compression multiplexed signals in mobile communication using voice using a small zone system is described in the following literature.

[0003] Literature 1. Ito “Studying mobile phone systems-
Proposal of time-division time compression FM modulation method -” IEICE technical report
RCS89-11 July 1989

[0004] Literature 2. Ito “Studying mobile phone systems-
Study of multiple wave propagation characteristics of time division time compression multiplexing FM system -
“IEICE Technical Report RCS89-47 January 1990

00
05] Literature 3. Ito “Elucidation of the multiple load gain of time division time compression multiplexed telephone signals and its application to FM mobile communications”
IEICE Technical Report RCS89-65 March 1990

0
[006] In other words, in Document 1, a transmission signal (baseband signal) is divided into predetermined time intervals and stored in a memory circuit, and when read out, the signal is read out at a predetermined speed n times faster than the speed at which it is stored in the memory circuit. The time of
read out at a time slot and angle or amplitude modulate the carrier wave with the signal accommodated by this time slot;
A radio receiving circuit having a receiving mixer that communicates with each other, a radio transmitting circuit having a transmitting mixer, and a radio receiving circuit, which are built into a mobile radio device and a radio base station for temporally intermittent transmission and reception. A switch circuit is provided for the synthesizer that applies voltage to the receiving mixer of the wireless transmitter circuit and the synthesizer that applies voltage to the transmitting mixer of the wireless transmitting circuit, and the output of the synthesizer applied to each is intermittent, and this intermittent state is synchronized for both transmission and reception, and communication is performed oppositely. The same method of synchronizing intermittent transmission and reception as described above with that of mobile radio equipment is used for radio base stations that use
In order to extract only the signal contained in the slot,
The signal is received by opening and closing the radio receiving circuit, and the signal obtained by demodulation is stored in a storage circuit, and when it is read out, it is read out at a low speed that is 1/n of the speed at which it is stored in this storage circuit. An example of a system has been reported in which a system is constructed that enables the reproduction of the baseband signal, which is the original signal.

[0007] Furthermore, in Document 2, the influence of multipath fading that TCM signals receive while transmitting in space is studied, and as a measure to eliminate or reduce this influence, a guard time is set between time slots. I am proposing to do so.

[0008] Furthermore, in Document 3, the multiple load gain, which was known to exist in conventional FDM (frequency division multiplexing) signals, has been found to exist in the time division time compression multiplexing (TCM) system as well. It clarifies the above, and explains its quantification and system operation examples. By using this multiload gain to increase the depth of FM modulation, it is possible to significantly reduce the transmission power, and we have obtained the prospect that it will be possible to significantly reduce power consumption in mobile radio equipment. has been reported.

However, with the arrival of the ISDN era, opposing radio base stations and mobile radios have set up radio links, and
In a system that simultaneously uses multiple communication signals, such as telephone and telephone and telephone and fax, which are one of the signal formats in the SDN era, the same carrier wave is modulated by angle modulation and angle modulation by two independent signals, respectively. Or, no literature describes the case where composite modulation such as angle modulation and amplitude modulation is performed and a composite signal is transmitted and received using this composite modulated wave.

0010

[Problem to be Solved by the Invention] When an opposing wireless base station and a large number of mobile wireless devices establish a wireless line, for example,
When communicating using multiple communication signals (hereinafter referred to as composite signals.Composite signals consisting of three or more signals will be described later), such as telephone and telephone and telephone and fax, which are converted into commercials, conventional In angle or amplitude modulation in which the carrier wave is modulated by a TCM composite signal as in the method, increasing the signal compression ratio increases the highest frequency of the TCM signal; However, if TCM is implemented without using TCM, the time slot length will become longer, and therefore the frame length will become longer.In both cases, the expected effect in terms of effective frequency utilization cannot be obtained, which is a problem that remains to be solved.

[0011]

[Means for solving the problem] When a large number of mobile radio devices (n pieces) facing a radio base station each set up a radio line and communicate using composite signals, the radio base station transmits The TCM signal to be used is created as follows. That is, a TCM signal is created in which n telephone signals and n telephone or facsimile signals constituting a composite signal are separated, and each of these signals is used to perform angle modulation or amplitude modulation on the same carrier wave. This complex modulated wave is transmitted to multiple mobile radios. On the other hand, a large number of opposing mobile radio devices receive the signal in their own assigned time slots, and demodulate the composite signal using a process reverse to that used when modulating the composite signal. In addition, for composite signals sent from mobile radios to radio base stations, telephone signals and telephone signals, or telephone signals and fax signals, are subjected to the same time compression as is performed at radio base stations, and then The system was configured to perform the same type of angle modulation or amplitude modulation as is performed at wireless base stations on the carrier wave. The system configuration will be explained below.

[0012] A plurality of radio base stations equipped with radio transceivers, a radio reception circuit having a reception mixer that communicates while moving within the service area covered by the plurality of radio base stations, and a radio transmission having a transmission mixer. a switching receiving means including a synthesizer capable of applying two frequencies to the receiving mixer of the wireless receiving circuit to switch and receive signals of two channels, and a transmitting mixer of the wireless transmitting circuit.
In a mobile radio device that includes a switching transmission means including a synthesizer that can switch and transmit signals of two channels by applying two frequencies, transmission signals (composite signals such as telephone and fax signals) are transmitted at predetermined time intervals. It is divided into units and stored in a memory circuit, and when read out, it is read out in a predetermined time slot at a speed n times faster than the speed at which it is stored in the memory circuit, and the signal accommodated by this time slot (hereinafter referred to as TCM signal ), the same carrier wave is angle-modulated or amplitude-modulated by a TCM-converted telephone signal, and then angle-modulated or amplitude-modulated by a TCM-converted fax signal to transmit and receive data intermittently over time. A radio reception circuit that has reception mixers facing each other and communicates, a radio transmission circuit that has a transmission mixer, built in the base station, a synthesizer that applies voltage to the reception mixer of the radio reception circuit, and a transmission mixer of the radio transmission circuit. A switch circuit is provided for the synthesizer that applies the voltage, and the output of the synthesizer that is applied is intermittent, and this intermittent state is synchronized for both transmission and reception, and the same intermittent transmission and reception as described above is applied to the mobile radio that communicates with the radio base station. On the receiving side, in order to extract only the signal accommodated in the predetermined time slot, the receiving side opens and closes the radio receiving circuit to receive the signal, and then demodulates the signal using a process that is completely opposite to that used when transmitting. The obtained signal is stored in a memory circuit, and when it is read out, it is read out at a low speed of 1/n of the speed at which it is stored in this memory circuit. By providing a communication path control means for setting a communication path with the radio base station, it is possible to reproduce the baseband signal, which is the original signal transmitted, at the radio base station and mobile radio equipment, and it is possible to reproduce the baseband signal, which is the original signal transmitted, at the radio base station and mobile radio equipment, and to connect the general telephone network and the radio base station. A system including a barrier switch was constructed to connect the two.

[0013]

[Operation] A wireless base station and a large number of mobile wireless devices exist within its service area, and in order for any number of mobile wireless devices to be able to communicate with the wireless base station, one wireless channel is It is divided into a plurality of time slot series, and one of these time slot series is selected and used for communication. If one mobile radio device is communicating with a radio base station using a composite signal and another mobile radio device requests communication with this radio base station, the mobile radio device that newly requests communication using the composite signal By giving the machine one unused time slot sequence on a radio channel that is already in use and allowing it to communicate with the radio base station, many communications can be made. It has become possible to communicate without interfering with each other and without adversely affecting one's own communication.

Furthermore, while one radio base station and mobile radio are communicating using one time slot within one channel (one time slot of the old channel), communication In order to maintain and improve quality, one time slot within the same or another channel (one time slot of a new channel) is (slot) to communicate. In addition, the gateway switch has an interface function for connection with other telephone networks and a control function for the mobile radio communication network, and has the function of determining the radio channel used for communication with mobile radio equipment at the radio base station and its time slot. , equipped with a function to stop emitting radio waves, etc.

As a result, even if all the wireless channels given to the system are in use, if there is an empty time slot that is not used for communication within each time-divided time slot of each wireless channel, It is now possible to make a call to a mobile radio that has requested a new call, it is also possible to continue a call to a mobile radio that has moved from an adjacent zone during a call, and one radio base It has become possible for a mobile radio device communicating with a station to perform diversity communication with other nearby radio base stations.

The modulation method used is to angle modulate the same carrier wave with TCM telephone signals and simultaneously
Composite modulation in which angle modulation or amplitude modulation is performed using other telephone signals or fax signals converted into commercials is used, and the spread of sidebands of the modulated signal is limited to a certain range by a bandpass filter. The degree of spread when the spread of a sideband signal is angle-modulated or amplitude-modulated by a substantially single signal (the sideband when a telephone signal or a fax signal is angle-modulated or amplitude-modulated by a signal with a higher frequency) It became possible to suppress the spread of the wave signal.

[0017]

[Example] The system to which the invention is applied is ISDN (Integrat), which is expected to be introduced worldwide in the future.
ed Services Digital Netwo
rk comprehensive service digital network). ISD
Communication terminals for the N system include not only telephones but also non-telephone terminals such as fax, image, and data terminals.

Therefore, in order to explain the principle of the system to which the present invention is applied, analog telephone signals are
The case where it is converted into M and used will be explained.

FIG. 1 shows a system configuration for explaining the concept of the present invention. In FIG. 1, 10 is a general telephone network, and 20 is a gateway exchange for connecting the telephone network 10 and a wireless system. 30 is a wireless base station, which includes an interface with the gateway exchange 20, a circuit for converting signal speeds, a circuit for allocating and selecting time slots, a control unit, etc., and is responsible for setting and canceling wireless lines. , mobile radio equipment 100 (100-1 to 100-n)
It has a wireless transmitting/receiving circuit that sends and receives wireless signals. Here, between the barrier switch 20 and the wireless base station 30,
There are transmission lines for transmitting communication signals 22-1 to 22-n including communication signals of communication channels CH1 to CHn and control signals.

In order to explain the principle of the present invention, FIG.
A circuit configuration of a mobile radio device 100 that communicates with a radio base station 30 is shown. Received signals such as control signals and call signals received by the antenna section enter a wireless reception circuit 135 including a reception mixer 136 and a reception section 137, and the communication signal output from the radio reception circuit 135 is sent to a speed restoration circuit 138 and a control section 140.
is input to the clock regenerator 141. The clock regenerator 141 regenerates a clock from the received signal and applies it to the speed recovery circuit 138, the control section 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 segmented 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 transmitted by a speed conversion circuit 131 which divides the communication signal into predetermined time intervals, increases the speed (pitch in the case of an analog signal) (compresses), and transmits the signal. The signal is applied to a wireless transmission circuit 132 including a mixer 133 and a transmitter 134.

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

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

The mobile radio 100 further includes synthesizers 121-1 and 121-2, and a changeover switch 122.
-1, 122-2 and selector switch 122-1, 122
-2, the transmitter/receiver intermittent controller 123 and timing generator 142 are included, and the synthesizer 121-1, 121-2, the transmitter/receiver intermittent controller 123, and the timing generator 142 are the control unit. 140. Each synthesizer 121
-1 and 121-2 are supplied with a reference frequency from the reference crystal oscillator 120.

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

Now, the communication signals 22-1 to 22-n sent from the barrier exchange 20 are input to the signal processing section 31 of the radio base station 30. The signal processing section 31 is equipped with an amplifier for compensating for transmission loss, and also performs so-called 2-wire to 4-wire conversion. That is, the input signal and the output signal are mixed and separated, and the input signal from the barrier switch 20 is sent to the signal speed conversion circuit group 51. Further, the output signal from the signal speed restoration circuit group 38 is transmitted to the barrier exchange 20 by the signal processing section 31 using the same transmission path as the input signal. Among 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 speed (pitch) conversion is performed at predetermined time intervals. receive. Also, the signal transmitted from the wireless base station 30 to the barrier switch 20 is transmitted to the wireless receiving circuit 3.
The output of No. 5 is inputted to the signal speed restoration circuit group 38 via the signal selection circuit group 39, speed (pitch) converted, and inputted to the signal processing section 31.

Now, the control of the radio reception circuit 35 or the output of the call signal is performed by the signal selection circuit group 3 including signal selection circuits 39-1 to 39-n that select signals for each time slot.
9, where the speech signals are separated corresponding to each speech channel CH1 to CHn. This output undergoes signal speed (pitch) restoration in a signal speed restoration circuit group 38 including signal speed restoration circuits 38-1 to 38-n provided for each channel, and then is input to the signal processing section 31. , 4 line-2
After undergoing line conversion, this output is sent to the barrier switch 20 as communication signals 22-1 to 22-n.

Next, the functions of the signal speed conversion circuit group 51 will be explained. By storing input signals such as audio signals and control signals divided into fixed time lengths in a memory circuit, and reading them out at a speed that is 15 times faster than when they were stored, the time length of the signal can be changed. It becomes possible to compress. The principle of the signal speed conversion circuit group 51 is that
This is the same as playing back audio recorded by a recorder at high speed, and in reality, for example, a CCD (Charge
Coupled Device), BBD (Buc
ket Brigade Device) can be used, and the memory used in television receivers and tape recorders that compress or expand the time axis of conversation can be used (References: Kosaka et al. Compressing/expanding tape recorder” Nikkei Electronics July 26, 1976 92
~133 pages).

CCD exemplified in signal speed conversion circuit group 51
As described in the above-mentioned document, a circuit using a BBD can also be used as it is for the signal speed restoration circuit group 38, and in this case, the clock from the clock generator 41 and the control signal from the control section 40 can be used as is. Upon receiving a timing signal from a timing generator 42 that generates timing,
This can be achieved by making the reading speed slower than the writing speed.

The control or audio signals outputted from the barrier exchange 20 via the signal processing section 31 are input to the signal speed conversion circuit group 51, and after speed (pitch) conversion processing is performed, the control or audio signals are converted into time slots. It is applied to a signal allocation circuit 52 that allocates signals separately.

This signal allocation circuit 52 is a buffer memory circuit, and the signal speed conversion circuit group 51 outputs 1
The delimited high-speed signals are stored in memory, and the signals in the buffer memory are read out using timing information from the timing generation circuit 42 given in accordance with instructions from the control section 40, and sent to the wireless transmission circuit 32. As a result, when communication signals are viewed in terms of channels, they are arranged in series without overlapping in chronological order, and when all of the control signals or communication signals described below are implemented, they appear as if they were continuous signal waves. become.

The above-mentioned signals are sent to the wireless transmission circuit 32. The state of this compressed signal is shown in FIG. 4 and will be explained.

The output signals of the signal rate conversion circuit group 51 are input to a signal allocation circuit 52, and time slots are assigned in a predetermined order. SD of Figure 4(a)
1, SD2, . . . , SDn indicate that the speed-converted communication signals are allocated to each time slot. Here, one time slot accommodates a synchronization signal and a control signal or/and a communication signal as shown in the figure. If a speech signal is not implemented, only a synchronization signal is used and an empty slot signal is added to the speech signal portion, or depending on the system, no signal is transmitted at all, including the carrier wave. In this way, Figure 4
As shown in (a), in the wireless transmission circuit 32,
A signal forming one frame is applied to the modulation circuit in time slots SD1 to SDn. The time-series multiplexed signal to be transmitted is angularly modulated in the radio transmission circuit 32, and then sent out into space from the antenna section.

Regarding the transmission of control signals between the radio base station 30 and the mobile radio device 100 prior to the telephone call when making or receiving a telephone call, it may be carried out within the telephone signal band or outside the telephone signal band. It is possible. FIG. 5 shows these frequency relationships. That is, in FIG. 4A, an example of an out-of-band signal is shown, and a low frequency side (250 Hz) or a high frequency side (3850 Hz) can be used. This signal is used, for example, when it is desired to send a control signal during a call. FIG. 5B shows an example of an in-band signal, which is used when making and receiving calls. The above examples were all tone signals, but by increasing the number of tone signals or modulating the tone to create a subcarrier signal, it is possible to transmit many types of signals at high speed.

[0036] The above was a case of analog signals, but if a digital data signal is used as a control signal, it is also possible to digitally encode the audio signal and time-division multiplex the two for transmission. , the circuit configuration in this case is shown in FIG. FIG. 6 shows an example of a case in which an audio signal is digitized by a digital encoding circuit 91, a multiplex conversion circuit 92 converts the audio signal and a data signal, and the resulting signal is applied to a modulation circuit included in the wireless transmission circuit 32. However, for digital data signals, analog signal multiload gain, which will be described later, usually does not exist, so this point must be taken into account when designing the system. The audio signal and the control signal can be extracted separately by receiving the signal with the opposing receiver and performing the operation opposite to that shown in FIG. 6 in the demodulation circuit.

On the other hand, the signal sent from the mobile radio device 100 is received by the antenna section of the radio base station 30 and input to the radio reception circuit 35. FIG. 4(b) schematically shows this upstream input signal. That is, time slots SU1, SU2, . Furthermore, the details of each time slot SU1, SU2,..., SUn are as follows:
As shown in the lower left part of FIG. 4(b), it consists of a call signal and/or a control signal. However, if the distance between mobile radio device 100 and radio base station 30 is small or depending on the signal speed, it is possible to omit the synchronization signal. Furthermore, when the waveform within the time slot of the radio carrier wave of the upstream radio signal in FIG. 4(b) is schematically shown, FIG.
c). Similarly, each mobile radio device 1 in FIG. 4(a)
The downlink transmission waveform from the radio base station 30 to 00 is shown in FIG.
d).

Now, among the input signals that have arrived at the radio base station 30, the control signal is immediately applied to the control section 40 from the radio reception circuit 35. However, depending on the magnitude of the speed conversion rate, it is also possible to apply the signal to the control unit 40 from the output of the signal speed restoration circuit group 38 after performing the same processing as the call signal. Further, a call signal is applied to a signal selection circuit 39. The signal selection circuit group 39 includes a control section 4
A timing signal from a timing generation circuit 42 that generates a predetermined timing is applied in response to an instruction from a control signal from 0, and a synchronization signal, a speech signal, or a control signal is separated and output for each time slot SU1 to SUn.

Each of these signals is processed by a signal speed restoration circuit 38.
is input to. This circuit has the function of inversely converting the speed conversion circuit 131 (FIG. 2) in the mobile radio device 100 on the transmitting side, and as a result, the original signal is faithfully reproduced and transmitted to the gateway exchange 20. Become.

[0040] Hereinafter, the manner in which signals are transmitted in a signal space according to the present invention will be explained using the required transmission band and the relationship between this and adjacent radio channels.

As shown in FIG. 3, the control signal from the control section 40 is applied to the wireless transmission circuit 32 in parallel with the output of the signal allocation circuit 52. However, depending on the size of the speed conversion rate, the signal allocation circuit 5
It is also possible to add the output of 2 to the wireless transmission circuit 32. Next, as shown in FIG. 2, the mobile radio device 100 also has a circuit configuration required when one of the functions of the radio base station 30 is a communication path.

Original signal, for example, an audio signal (0.3 kHz
~3.0kHz) is the signal speed conversion circuit group 51 (Figure 3)
The frequency distribution on the output side when passing through is shown in FIG. That is, if the audio signal is converted 15 times as described above, the frequency distribution of the signal will be expanded to 4.5 kHz to 45 kHz, as shown in FIG. Although the frequency distribution of the signal is expanded here, it must be noted that the waveform form is simply subjected to a similarity transformation in which the frequency axis is stretched, and the waveform itself remains unchanged.

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

That is, time slot SDi (i=
2, 3,...,n) are control signals (0.2 to 4.0kHz
) and a communication signal CHi (4.5 to 45 kHz) are accommodated. However, the signals in each time slot are arranged in chronological order, and the signals in multiple time slots are never applied to the wireless transmission circuit 32 at the same time.

[0045] When these communication signals are applied to the angle modulation section included in the radio transmitting circuit 32 together with the control signal, a required transmission band of at least fC ±45 kHz is required. where fC is the radio carrier frequency. If there are a plurality of wireless channels given to the system, the speed-up of the signal by the signal speed conversion circuit group 51 is limited to a certain value due to restrictions on these frequency intervals. The frequency interval of multiple wireless channels is f
rep and the maximum signal speed due to the above-mentioned speed increase of the audio signal is fH, then the following inequality must hold between the two. frep>2fH On the other hand, in digital signals, audio is usually digitized at a speed of about 64 kb/s, so it is necessary to read the scale on the horizontal axis in Figure 8, which explains the case of analog signals, by raising it by about one digit. However, the relationship in the above equation also holds true in this case.

[0046] Furthermore, the mobile radio device 100
0 is input to the radio reception circuit 35, a part of its output is input to the control unit 40, and the rest is sent to the signal speed restoration circuit group 38 via the signal selection circuit 39. . After the latter control signal undergoes a speed conversion (conversion to a low speed signal) that is completely opposite to that at the time of transmission, it is transmitted to the general telephone network 10.
The signal speed is the same as that used in , and is sent to the barrier exchange 20 via the signal processing section 31 .

Next, various operations of the system according to the present invention will be explained in the following order, and the high practicality of the present invention will be theoretically proven. (1) Call origination and call reception operations (2) Theoretical explanation of the present invention (a) Mathematical expression of modulated waves (b) Spread of sideband waves of modulated waves (c) Calculation of frequency effective utilization rate (3) Composite signal System configuration for

(1) Call origination and call reception operations FIGS. 9 and 1
The calling operation will be explained using the flowchart shown in FIG.

When the power of the mobile radio device 100 is turned on, the radio reception circuit 135 in FIG. Start capturing control signals. If the system is provided with multiple radio channels, i) the radio channel exhibiting the highest received input field ii)
(iii) A wireless channel instructed by a control signal included in the wireless channel (iii) A channel with an empty time slot among the time slots in the wireless channel, etc. CH1) is in the receiving state. This is possible by capturing the synchronization signal within time slot SDn shown in FIG. 4(a). In the control unit 140, the synthesizer 121-1
A control signal is sent to switch 1 to generate a local frequency that enables reception of wireless channel CH1.
22-1 is also tilted and fixed to the synthesizer 121-1 side.

Therefore, the telephone in the telephone section 101 is turned off.
When hooking (starting a call) (S201, FIG. 9), the synthesizer 121-2 of FIG. 2 receives a control signal from the control unit 140 to generate a local oscillation frequency that enables transmission of the wireless channel CH1. Further, the switch 122-2 is also turned toward the synthesizer 121-2 side and becomes fixed. Next, the calling control signal output from the telephone unit 101 is sent out using the wireless channel CH1. This control signal is
With the frequency band shown in FIG. 8, this is transmitted, for example, using time slots SUn.

This control signal is sent in time slot S.
Since the signal is limited to Un and is sent in bursts and no signals are sent during other time periods, it does not adversely affect other communications. However, if the speed of the control signal is relatively slow or the amount of information in the signal is large and cannot be accommodated in one time slot, the control signal may be transmitted at the same time in one frame later or in the next frame. Sent using slots.

To capture time slot SUn,
Specifically, the following method is used. As shown in FIG. 4(a), the control signal transmitted from the radio base station 30 includes a synchronization signal and a subsequent control signal, and the mobile radio device 100 receives this signal to perform frame synchronization. It becomes possible. Additionally, this control signal includes information on currently used time slots and unused time slots (empty time slots).
Contains control information such as slot display). In some systems, time slots SDi (i=1, 2,
..., n) is used by other communications,
In some cases, it only contains a synchronization signal and a call signal;
Even in such a case, the unused time slots usually contain a synchronization signal and a control signal, and by receiving these control signals, the mobile radio 100 determines which time slot to use to send the calling signal. It is possible to know whether to send a .

Note that if all time slots are in use, it is impossible to make a call on this radio channel, and it is necessary to sweep and search for another radio channel. In other systems, empty slots may not be displayed in any of the time slots, and in this case, the following audio multiplex signals SD1, SD2, ..., SDn
It is necessary to search for the presence of empty time slots one after another and check for empty time slots.

Now, returning to the main topic, the mobile radio device 100, which has received the control information sent from the radio base station 30 by one of the above methods, determines in which time slot it sends out the call control signal. It is possible to judge whether the transmission should be sent or not, including the timing of the transmission.

[0055] Therefore, the time slot SU for uplink signals
Assuming that n is an empty slot, we will use this empty time slot, send out a call control signal, extract the necessary timing from the response signal from the wireless base station 30, and send a burst control signal. Can be sent.

[0056] If a call is made from another mobile radio at the same time, the calling signal will not be transmitted properly to the radio base station 30 due to call collision, and it will be necessary to start operation from the beginning again. However, this probability is kept to a sufficiently small value when viewed as a system. If call collisions are to be further reduced, the following method may be used. If the mobile radio device 100 finds an empty time slot in which it can make a call, it does not use the entire time slot, but rather uses only the first half of the time slot for some mobile radio devices and only the second half for other mobile radio devices. This is a method that allows you to use it. In other words, the portion of the time slot used as a calling signal is divided into several types, and this is used to classify a large number of mobile radios into groups, and each group is assigned a time period within that one time slot. It is a way of giving. Another method is to create a variety of frequencies for control signals, and to divide a large number of mobile wireless devices into groups and give these frequencies to each group. According to this method, even if control signals of different frequencies are transmitted simultaneously using the same time slot, no interference will occur at the radio base station 30. The above two methods may be used separately, or when used together, the effects will increase synergistically.

Now, the call control signal from the mobile radio device 100 is successfully received by the radio base station 30, and the mobile radio device 100
Suppose that the ID (identification number) of is detected (S202),
The control unit 40 searches for a currently vacant time slot. The time slot given to the mobile radio device 100 may be SUn, but a search is performed just to be sure. This is to accommodate simultaneous calls from other mobile radios in addition to the mobile radio 100, and to provide time slots suitable for service types and service classifications.

As a result, for example, time slot SD
1 is vacant, the time slot SDn of the radio channel CH1 is used for the mobile radio device 100, and the time slot upstream (mobile radio device 10
0→radio base station 30) SU1, and the corresponding downlink (radio base station 30→mobile radio device 100) SD1 are instructed to be used (S203). In response, the mobile radio device 100 transitions to a state in which it can receive data in the instructed time slot SD1, and at the same time, the mobile radio device 100 shifts to a state in which it can receive data in the instructed time slot SD1, and also transmits the time slot SU1 (FIG. 4), which is the time slot for the uplink radio channel corresponding to the downlink time slot SD1. b) Select ). At this time, in the control unit 140 of the mobile radio device 100, the transmission/reception intermittent controller 123 is operated, and the switch 122-1 is activated.
and 122-2 to start operating (S204). At the same time, a slot switching completion report is sent to the wireless base station 30 using uplink time slot SU1 (S205);
Wait for dial tone to be sent (S206)
.

[0059] The radio carrier wave time of this upstream radio signal
The state of slot SU1 is shown in FIG. 7(c). In addition to the time slot SU1, the radio base station 30 also receives SU as an uplink signal from another mobile radio device 100.
3 and SUn are included in one frame and sent. Upon receiving the slot switching completion report (S207), the wireless base station 30 sends the mobile wireless device 100 to the gateway switch 20.
A calling signal is sent together with the ID (S208). On the other hand, the gateway switch 20 detects the ID of the mobile radio 100, turns on the necessary switches among the switch groups included in the barrier switch 20 (S209), and dials the
Sends a tone to the wireless base station 30 (S210, FIG. 10
). This dial tone is transferred by the wireless base station 30 to the mobile wireless device 100 (S211), and the mobile wireless device 100 confirms that the communication path has been set (S2
12).

[0060] When transitioning to this state, the mobile radio device 100
Since a dial tone is heard from the handset of the telephone section 101, transmission of a dial signal begins. This dial signal is speed-converted by a speed conversion circuit 131, and a wireless transmission circuit 13 including a transmission section 134 and a transmission mixer 133
2, it is transmitted using the upstream time slot SU1 (S213). Thus, the transmitted dial signal is received by the radio receiving circuit 35 of the radio base station 30.

[0061] This radio base station 30 has already responded to the calling signal from the mobile radio device 100 and has determined the time and date to be used.
At the same time, the signal selection circuit group 39 and signal allocation circuit group 52 of the wireless base station 30 are operated to receive the uplink time slot SU1 and to receive the downlink time slot SU1.
The state has shifted to the state where the signal of slot SD1 is transmitted. Therefore, the dial signal transmitted from the mobile radio device 100 is transmitted to the signal selection circuit 39-1 of the signal selection circuit group 39.
After passing through the signal speed restoration circuit group 38, the original transmission signal is restored and transferred to the gateway exchange 20 as a call signal 22-1 via the signal processing unit 31 (S21
4) A call path to the telephone network 10 is set (S215)
.

On the other hand, the input signal (initial control signal, call signal when a call is started) from the barrier switch 20 undergoes speed conversion at the signal speed conversion circuit group 51 in the wireless base station 30, and then is sent to the signal allocation circuit. Signal assignment circuit 52-1 of group 52
gives time slot SD1. Then, the time signal of the wireless channel downstream from the wireless transmission circuit 32 is
It is transmitted to mobile radio device 100 using slot SD1. The state of time slot SD1 of this downlink radio carrier wave is shown in FIG. 7(d).

[0063] In the mobile radio device 100, the radio channel CH
1 time slot SD1, it is on standby for reception and 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 T included in the terminal section 102. Thus, a call is started between the mobile radio device 100 and a regular telephone within the regular telephone network 10 (S216).

[0064] The end of the call is at the terminal section 102 of the mobile radio device 100.
By on-hooking the handset of the telephone T included in the telephone (S217), the end-of-call signal and the on-hook signal from the control unit 140 are transmitted from the wireless transmission circuit 132 to the wireless base station via the speed conversion circuit 131. 30 (S218), and the control unit 140 sends it to the transmission/reception intermittent controller 1.
23 is stopped, and switches 122-1 and 122-2 are fixed to the output ends of synthesizers 121-1 and 121-2, respectively.

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

In the above explanation, it has been explained that control signals are exchanged between the radio base station 30 and the mobile radio device 100 without passing through the signal conversion circuit group 51, the signal speed restoration circuit group 38, etc.; For the convenience of
Communication can be carried out without any problem even through the signal processing section 31 or the signal processing section 31.

Next, the operation of receiving a call to the mobile radio device 100 will be explained. It is assumed that the mobile radio device 100 is on standby with the power turned on. In this case, as explained in the call originating operation from the mobile radio 100, the mobile radio 100 is in a waiting state to receive a downlink control signal of the radio channel CH1 according to the procedure defined by the system.

An incoming call signal from the general telephone network 10 to the mobile radio device 100 via the barrier switch 20 is transmitted to the radio base station 30.
Suppose you arrive at These control signals are transmitted as communication signals 22 to the control section 40 (FIG. 3) via the signal speed conversion circuit group 51 and the signal allocation circuit group 52, similarly to the voice signal. Then, the control unit 40 uses an empty slot among the downlink time slots of the radio channel CH1 addressed to the mobile radio device 100, for example, SD1, to control the mobile radio device 100.
ID signal + incoming call signal display signal + time slot usage signal (for example, SD
1) is sent. In the mobile radio device 100 that receives this signal, it is transmitted from the receiving section 137 of the radio receiving circuit 135 to the control section 140. Control unit 14
0 confirms that this signal is an incoming call signal to its own mobile radio 100, so the telephone unit 101 makes a ring tone and at the same time waits at the designated time slots SD1 and SU1. Transmission/reception intermittent controller 12
3, and the switches 122-1, 122
-2 starts turning on and off. In this way, the state has shifted to a state in which calls can be made.

(2) Theoretical explanation of the present invention

[0070](
a) Mathematical expression of modulated wave First, a case will be explained in which only angle modulation is performed without complex modulation by angle modulation or amplitude modulation, and then the effect of complex modulation according to the present invention will be theoretically explained.

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

μ(t)=Σai cos(ωit+θi)

(1) Here, Σ means the sum of i=1 to m. In addition, the control signal that exists outside the band is
μc(t)=Σai cos(ωit+θi)

(2) Here, Σ means the sum of i=m+1 to n, ai is the amplitude, and ωi is the angular frequency of the signal θi is the phase when t=0. m and n represent positive integers.

Next, the case of frequency modulation will be explained.
The present invention is similarly applicable to phase modulation and amplitude modulation. When the carrier wave is modulated using equation (1) or equation (1) and equation (2), the resulting modulated wave is:
I=I0 sin∫(ω+μ(t))dt
=I0 sin(ωt+s(t))

(3) Or, I=I0 sin∫(ω+μ(t) +μc(
t) )dt =I0 sin(ωt+s(
t) +sc(t))
(4) becomes.

[0074] However, s(t)=Σmi sin(ωit+θi) where Σ represents the sum from i=1 to m, and sc (t)=Σm
i sin(ωit+θi) where Σ represents the sum from i=m+1 to n, and mi=ai/ωi(i=1,
2, 3,..., n), and s(t) shown in equation (4)
+sc(t) will represent the general form of the transmission signal.

Now, using equation (3) or equation (4), the radio signal sent from the antenna of mobile radio device 100 is expressed by the following equation. I=(I01/n) {1+2Σφ−1 sin
φ cosmpt}sin θ1 (5) Here, φ=mπ/n, θ1 =Ω1t+s1(t)+sc1(t), and n
is the number of slots (equally spaced) in one frame, p
is the switching angular frequency, m is a positive odd number, and Σ is from m=1 to ∞
It represents the total up to.

Equation (5) assumes that the transmission signal from the mobile radio device 100 using the same radio channel is in one of n slots in one frame, but if all slots are implemented with signals, state, that is, n mobile radio devices 1
When 00 is communicating using the same wireless channel, the expression of the signals included in the wireless channel is as follows.

I=I1+I2+I3+…+In

(6), I1=(I01/n) {1+2Σφ−1 si
n φ cosmpt }sin θ1 I2
=(I02/n) {1+2Σφ−1 sin φ co
smpt2}sin θ2 I3=(I03/
n) {1+2Σφ−1 sin φ cosmpt3}
sin θ3 …… In=(I0n/n) {1+2Σφ−1 si
n φ cosmptn}sin θn However, Σ is m
= represents the sum from 1 to ∞.

Furthermore, t2=t-2π/(np) t3=t-4π/(np) ... tn=t-2(n-1)π/(np), and θ1=Ω1t+s1(t)+sc1 (t) θ2=Ω2t
+s2(t)+sc2(t)θ3=Ω3t+s3(t)
+sc3(t)... θn=Ωnt+sn(t)+scn(t), where p is the switching angular frequency, m is a positive odd number, and the switching times for n input waves are equally spaced.

Hereinafter, equation (6) will be modified as it will be necessary to investigate the influence of adjacent channel interference, which will be described later. The right side of equation (6) is expanded as shown below.

I=(I01/n)C1+(I02/n)C2
+...+(I0n/n)Cn


(7) Here, C1= sinθ10+b11 sinφ1+
b13 sinφ3+b15 sinφ5+...
C2= sinθ20+b21 sinφ1+b
23 sinφ3+b25 sinφ5+...
... Cn= sinθn0+bn1 sinφ1+
bn3 sinφ3+bn5 sinφ5+...

[0081] Also, b11=φ1-1(sinθ11p + sinθ1
1n)b13=φ3-1(sinθ13p+s
inθ13n)b15=φ5-1(sinθ15p
+ sinθ15n)...b21=φ1-1(sinθ21p+sinθ21
n)b23=φ3-1(sinθ23p+sin
θ23n)b25=φ5-1(sinθ25p+
sinθ25n)...... bn1=φ1-1(sinθn1p+ sinθn1
n)bn3=φ3-1(sinθn3p+sin
θn3n)bn5=φ5-1(sinθn5p+
sinθn5n)...

[0082] Also, φ1 = π/n, φ3 = 3π/n, φ5 = 5π/n
,... is.

[0083] Also, θ10=Ω1t+s1(t)+sc1(t)θ20=Ω
2t+s2(t)+sc2(t)... θn0=Ωnt+sn(t)+scn(t).

[0084] Also, θ11p=(Ω1+p)t+s1(t)+sc
1(t) θ11n=(Ω1-p)t+s1(
t)+sc1(t) θ13p=(Ω1+3p)
t+s1(t)+sc1(t)-(6π/n)(n-1
) θ13n=(Ω1-3p)t+s1(t)+
sc1(t)+(6π/n)(n-1) θ15
p=(Ω1+5p)t+s1(t)+sc1(t)−(
10π/n)(n-1) θ15n=(Ω1-5
p) t+s1(t)+sc1(t)+(10π/n)(
n-1) ... θ21p=(Ω2+p)t+s2(t)+sc
2(t) θ21n=(Ω2-p)t+s2(
t)+sc2(t) θ23p=(Ω2+3p)
t+s2(t)+sc2(t)-(6π/n)(n-1
) θ23n=(Ω2-3p)t+s2(t)+
sc2(t)+(6π/n)(n-1) θ25
p=(Ω2+5p)t+s2(t)+sc2(t)−(
10π/n) (n-1) θ25n=(Ω2-5
p) t+s2(t)+sc2(t)+(10π/n)(
n-1) ... θn1p=(Ωn+p)t+sn(t)+sc
n(t)-(2π/n)(n-1) θn1n=
(Ωn-p)t+sn(t)+scn(t)+(2π/
n) (n-1) θn3p=(Ωn+3p)t+
sn(t)+scn(t)-(6π/n)(n-1)
θn3n=(Ωn-3p)t+sn(t)+sc
n(t)+(6π/n)(n-1) θn5p=
(Ωn+5p)t+sn(t)+scn(t)-(10
π/n) (n-1) θn5n=(Ωn-5p)
t+sn(t)+scn(t)+(10π/n)(n-
1) …….

Looking at equation (7), it can be seen that it is a combination of many carrier waves. The above was a radio signal transmitted from the radio base station 30 in FIG. In, Ω1 = Ω2 ...=Ωn

It can be seen that it is sufficient to set (8).

The mobile radio device 100 communicating with the radio base station 30 uses the timing generator 142 and the transmission/reception intermittent controller 123 shown in FIG. This will be used for selective reception. Now, if this is the time slot SD1 shown in FIG. 4 for the mobile radio device 100-1, the signal will be the first term on the right side of equation (6), that is, I1. Formula (5)
When the signal passes through the amplitude controller included in the receiving section 137 in FIG. 2, it takes the form shown in the following equation. I=A sin(Ω1t+s1(t)+sc1
(t))
(9) However, A is amplitude and is not related to frequency or time. Equation (9) passes through the frequency discriminator included in the receiving section 137, and the demodulated output is obtained as e(t)=μ(t)+μc(t). Then, this output is sent to the speed restoration circuit 131 in FIG.
The original signal is reproduced by passing it through.

Below, we will quantitatively evaluate the spread of sidebands of radio modulated waves, which is a problem in system construction, and explain that the system according to the present invention can be operated without any problems in practice.

(b) Sideband spread equation of radio modulated wave (7
) presents a fairly complicated mathematical formula, but if you look at the content of the formula, you will find the following.

(i) When modulating the original carrier wave with the TCM signal, the switching angular frequency p of each time piece signal constituting the TCM signal causes a large number of subcarriers (±p, ± around the carrier angular frequency Ω). 3p, ±5p, ...) exist. However, this effect is noticeable when transmitting using only one time slot, such as when transmitting from the mobile radio 100 to the radio base station 30.
If 0 is transmitting, this effect will gradually decrease as the number of time slots used increases, and will not be present at all if all time slots are used to transmit.

(ii) The original carrier wave and a number of subcarriers (±p, ±3p, ±5p around the carrier angular frequency Ω)
.

[0091] Therefore, the signal bandwidth of the radio signal represented by equation (7) becomes extremely large because the sidebands are greatly expanded. If the signal is sent out into the air as it is, there is a possibility that it will cause radio wave interference to adjacent channels. One countermeasure is to limit the spread of sideband waves to a certain range by inserting a bandpass filter on the input side of the modulated wave, and then add the sideband to the modulator. Another countermeasure that has been put into practice is to limit the spread of sideband waves to a certain range by inserting a bandpass filter on the output side of the modulated wave. These are used not only in the case of TCM signals but also in wireless systems in general, where the modulated signal is then converted to a defined carrier frequency (not shown),
After increasing the power (not shown), this signal is sent into space towards the opposing communicating mobile radio 100. However, if the characteristics of the bandpass filter are too severe to restrict the spread of sidebands, distortion noise will occur. Therefore, a trade-off between the two is necessary, but in the microwave analog radio relay system that uses FDM (a signal obtained by frequency-dividing and multiplexing telephone signals), which has been put into practical use, a band-pass filter with the following bandwidth is used. is used. That is, if the highest frequency of the FDM telephone signal (baseband signal) is Fh, the passband width of the bandpass filter is ±(1.3 to 1.5) F around the carrier angular frequency Ω.
It is about h.

On the other hand, in the case of a TCM-converted telephone signal, regarding the passband width of a bandpass filter that generates less distortion noise and reduces the possibility of causing radio wave interference to adjacent channels, there are known documents. No, but a) T
In the case of a CM telephone signal, the baseband signal has a significantly wider band, similar to the FDM signal. b) In addition to a), since only one channel of the telephone signal is widened, distortion noise is generated less even if the band is narrowed compared to an FDM signal. Therefore, the limited bandwidth of a practical wireless signal that does not generate large distortion noise is defined as ±(1.1 ~1.5) ωH (Here, it is assumed to be 1.5 ωH for convenience of calculation, but a practical value of 1.2 to 1.33 is assumed). Therefore, taking into consideration the existence of the switching angular frequency p of each time piece signal that constitutes the TCM signal, the overall passband width of the bandpass filter is 1.5 (ωm +p)×2

It is expressed as (10).

FIG. 11(a) shows the spectrum of the radio signal expressed by equation (5). Regarding the spread of sideband waves when this signal is amplitude-modulated with a modulation depth of 100% using another TCM telephone signal (lowest frequency ωL, highest frequency ωH) having the spectrum shown in FIG. 11(b). explain. Note that FIG. 11 is a schematic illustration in which the energy of a signal wave is expressed by power, and the sideband characteristics of the modulated wave are flat, and the energy is constant over an angular frequency of 0 to ωH. And so. In FIG. 11(a), only the first sideband waves a and b of the frequency modulated wave are shown.

In this case, equation (5) is expressed as follows. I=(I01/n)H(t) sin Ω1t
{1+2Σφm-1 sinφm cos mpt}2


(11) Here, H(t) =1+k(h(t)+hc(t))φm=
mπ/n, where k is a parameter indicating the depth of amplitude modulation and 0<k
≦1, h(t) is the fax signal, and hc(t) is its control signal.

Equation (11) has a very complicated expression, but it becomes easier to understand if you consider the following. That is,
Equation (11) is an expansion of Equation (5) to each of the right sides of Equation (7), for example, the following equation a1=(I01/n)[sin{(Ω1+p
)t+s1(t)+sc1(t)} is amplitude-modulated, so the spread of the sidebands of the complex-modulated radio signal appears to be even larger in addition to the spread in equation (7). However, in reality, the spread of the sideband does not increase and is almost the same as the spread of the sideband of a single modulated radio signal.

This will be explained theoretically below. First, let us assume that the right side of equation (11) is expanded and expressed as the following equation. I=(1+a+b)(c+d)sin Ω1
t (1
2) However, a: Upper sideband of the amplitude modulated wave b: Lower sideband of the amplitude modulated wave c: Upper sideband of the frequency modulated wave d: Lower sideband of the frequency modulated wave sin Ω1 t: Radio carrier wave Now, if we expand the right side of equation (12), we get I=(
c+d) sin Ω1 t+(a+b)(c+d)si
n Ω1 t (13) The first term on the right side of equation (13) represents the frequency modulated wave itself, and it can be seen from this term alone that no spread of sideband waves occurs. Next, the second term on the right side of equation (13) is further expanded as r=ac+ad+bc+bd

(14) However, in equation (14), the term of the radio carrier wave is omitted.

The angular frequency distribution of each term on the right side of equation (14) is examined. As is clear from FIGS. 11(a) and 11(b), since these are the products of two sideband waves, the distribution yields results similar to "convolution" in statistics.

In FIG. 12, various sideband waves a, b, c
, d are (a-1) to (d-1), (a-2) to (d-2
), the products of the sideband waves ac, ad, bc, bd are (a-
3) to (d-3). Here, it is assumed that the sideband waves of the amplitude modulated wave also exist flatly between -ωH and ωH. From Figure 12, the products of sideband waves ac, ad, bc, b
It can be seen that each signal component of d is as follows. ac: Upper part of carrier wave angular frequency Ω1 0 (=Ω1) to 2
There is a main signal component at ωH (a-3). ad: There are main signal components in the lower part -ωH and the upper part ωH with the carrier wave angular frequency Ω1 in between (b-3). bc: There are main signal components in the lower part -ωH and the upper part ωH with the carrier wave angular frequency Ω1 in between (c-3). bd: Lower part of carrier wave angular frequency Ω1 0 (=Ω1) to 2
There is a main signal component at ωH (d-3). As a result of the above, the distribution of the complex modulated wave on the right side of equation (12) becomes as shown in FIG. 13. Here, the solid lines indicate the various sideband waves shown in FIG. 12 and their products, and the broken line indicates the distribution of the sideband waves of the composite modulated wave existing around the carrier angular frequency Ω1.

The signal components in FIG. 13 are -2ωH to ωH,
-ωH to ωH and ωH to 2ωH, and calculate the proportion of power for each. a) Signal components existing between −ωH and ωH are carrier wave power 50% and sideband power 42% b) Signal components existing other than −ωH and ωH are:
Since it is the remainder of a), it is 8%.

From this result, it can be seen that even if the upper limit (ωH) of the primary sideband in the case of a single modulated wave is taken as the cutoff frequency of the bandpass filter, 92% of the power of the composite modulated wave is included. It became clear.

[0101] Next, when the cutoff frequency of the bandpass filter is increased to make it possible to transmit up to 1.5 ωH, which is 1.5 times the above-mentioned value, the signal component existing within 1.5 (-ωH to ωH) The result is 98%. Therefore, the remaining signal components are 2%, and as a result, most of the signal components are 1.5 (-ωH ~ ωH
) was found to exist within

The above calculations were performed on the assumption that the sideband characteristics of the modulated wave were flat. However, as is well known, the human speech spectrum is concentrated in low frequency bands.

FIG. 14 shows an example of a human conversation voice spectrum. Here, the solid line shows the female voice, the dashed line shows the male voice, and the dashed line shows the average frequency distribution.
The long-term effective value (dB) per 1Hz is the frequency (Hz
) can be seen to be concentrated in the low part. Therefore, the frequency characteristics of the telephone signal will also exhibit the frequency characteristics shown in FIG. 14 when the low range of 0.3 kHz or less and the high range 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 the high frequency near 3 kHz is about 25 db lower than near 0.3 kHz. This also applies to signals obtained by converting telephone signals into TCM. When calculations similar to those above are performed using the sideband characteristics shown in FIG. 14, the following results are obtained. c) When determining the signal components existing within the transmission band 1.5 (-ωH to ωH), the result is 99.9% or more. d) The signal components existing outside the transmission band 1.5 (-ωH to ωH) are the remainder of c) and are 0.1%.

[0104] Furthermore, the transmission band is 1.33 (-ωH ~ ωH
), 99% or more is obtained. That is, as the required transmission bandwidth of the complex modulated wave, Bfm-am=1.33ωH

It was shown that (15) is sufficient.

This result also means that there is no need to insert a bandpass filter. Alternatively, it has been shown that inserting a bandpass filter having narrower band characteristics in order to avoid adjacent channel interference does not have much of a negative effect on the transmission characteristics.

[0106] The above results indicate that the TCM
This was a case of transmitting telephone signals. It will be explained that when transmitting a TCM telephone signal from mobile radio device 100, the modulated signal is further concentrated near the carrier wave. In this case, on the right side of equation (7), for example, the first term (I01 /n
) Only the signal shown in C1 will be transmitted toward the wireless base station 30. As is clear from the first term on the right side of equation (7), it can be seen that the TCM-converted telephone signal spreads widely on the frequency axis. That is, TCM
Depending on the switching angular frequency p of the time piece signal that constitutes the signal, there are equivalently a large number of subcarriers (with the carrier angular frequency Ω1 at the center ±
p, ±3p, ±5p, . . .), and these many subcarriers cause the TCM-converted telephone signal to spread widely on the frequency axis. For example, if p is 50Hz (=2π×50), the first subcarrier is 1/1/2 of the main carrier at ±2π×50 on both sides of the carrier angular frequency Ω1.
Hereinafter, it has an amplitude of 1/5, 1/7, ... of the main carrier wave at ±3p, ±5p, ..., and an amplitude of 1/120 around ±3kHz. Become. However, in an actual radio circuit, when modulating a carrier wave with a TCM telephone signal, harmonic components are removed through a bandpass filter in advance and the fundamental wave component is amplified. Therefore, the energy of the modulated signal becomes extremely small near ±3 kHz, and is concentrated near the carrier wave.

(c) Calculation of effective frequency utilization rate Next, the spread of sideband waves when the above-described single modulation is performed instead of composite modulation as in the present invention will be explained, and the two will be compared.

[0108] The case where a carrier wave is frequency modulated with two TCM-converted telephone signals will be explained. The highest frequency of the TCM composite signal is 1.33(ωH +p
). Therefore, as the required bandwidth of the modulated wave,
B2fm=1.33(2ωH+p)

(16)

A comparison will be made between equation (15) and equation (16). Assuming that p is ignored because it is smaller than ωH, equation (15) is clearly smaller than equation (16), about half as large. That is, the effective frequency utilization rate of the present invention is approximately twice as large as that of the conventional method.

From the above, it has been proven that, in general, the frequency effective utilization rate of the present invention is higher than that of the conventional method. next,
Furthermore, if the signal is converted to TCM without increasing the compression ratio, the time slot length will become longer and the amount of information that can be transmitted will decrease, so comparisons cannot be made as is. Therefore,
If we reduce the amount of information on the side that performs complex modulation, we end up with the formula (
15) and equation (16). Therefore, in this case as well, it has been proven that the frequency effective utilization rate of the present invention is higher than that of the conventional method.

The composite modulation described above was a combination of frequency modulation and amplitude modulation. For composite modulation, a combination of frequency modulation and frequency modulation, or combination of amplitude modulation and amplitude modulation is also possible. However, in this case, care must be taken to ensure that the frequency bands of the signals do not overlap with each other.

Finally, the case of a composite signal composed of three or more signals, such as a TCM telephone signal, a facsimile signal, and a data signal, will be explained. One way to implement composite modulation is to further modulate a doubly modulated radio signal. Another method is that if the highest frequency of the data is ωq, then ωm = ωn
+ωq, there is a method of first modulating with a TCM telephone signal and then further modulating with a composite signal of a fax signal and a data signal. In this method, the same carrier wave is only subjected to complex modulation twice, so it can be put to practical use, and the effective frequency utilization ratio is only slightly reduced.

(3) System configuration for composite signals The above explanation was for the case of telephone signals as ISDN signals. The system configuration and its operation in the case of composite signals such as telephone and fax signals will be described below.

FIGS. 15 and 16 show a mobile radio device 100B and a radio base station 30 for explaining an embodiment of the present invention.
The configuration of B is shown. Regarding FIGS. 15 and 16,
The explanation will focus on the points that are different from the corresponding FIGS. 2 and 3.

FIG. 15 shows a circuit configuration of a mobile radio device 100B that communicates with a radio base station 30B. The wireless composite signal received by the antenna section enters a wireless receiving circuit 135 including a receiving mixer 136 and a receiving section 137, where the composite modulated signal is demodulated, and the output composite signal is:
Speed restoration circuits 138a and 138b, a control section 140,
It is input to the clock regenerator 141. That is, of the speed restoration circuits 138a and 138b, the telephone signal is input to the speed restoration circuit 138a, and the fax signal is input to the speed restoration circuit 138b, respectively, and the compressed and segmented telephone signal or fax signal is restored to its speed and converted into a continuous signal. The received signal is input to the control section 140 and the telephone section 101 or the facsimile terminal section 103.

The telephone signal output from the telephone section 101 is divided into sections at predetermined time intervals by a speed conversion circuit 131a, and the speed thereof is increased to a high speed.
and a transmitting section 134 . Similarly, the fax signal is transferred to the speed conversion circuit 131.
In b, the fax signal is divided into predetermined time intervals, its speed is increased, and the signal is applied to the wireless transmission circuit 132 including the transmission mixer 133 and the transmission section 134.

[0117] FIG. 16 shows a radio base station 30B. Composite signal 22-1 sent from barrier switch 20
~22-n are input to the signal processing unit 31 of the wireless base station 30B. The signal processing section 31 performs 2-wire to 4-wire switching operations and also identifies telephone signals or facsimile signals. The input telephone signal is sent to the signal speed conversion circuit 51a, and the fax signal is sent to the signal speed conversion circuit 51b, and after undergoing speed conversion, the telephone signal is sent to the signal allocation circuit group 52a.
The fax signals are sent to the signal allocation circuit group 52b, and the time and fax signals are sent to the signal allocation circuit group 52b, and time and
The slot is assigned and sent to the wireless transmission circuit 132;
Here it undergoes complex modulation. The signal is then transmitted from the antenna to a large number of mobile radio devices 100B.

[0118] The composite signal sent to the gateway exchange 20 is a composite signal sent from a large number of mobile radio devices 100B to the radio receiving circuit 3.
5, and as outputs, the telephone signal is sent to the signal selection circuit group 39a and the fax signal is sent to the signal selection circuit group 39b, where the signals are selected for each time slot and composited corresponding to each channel CH1 to CHn. The signals are separated. This output is input to a signal speed restoration circuit group 38a for telephone signals for each channel, and to a signal speed restoration circuit group 38b for fax signals, and after each signal speed is restored, the signal speed is restored. The signals are sent to the exchange 20 as composite communication signals 22-1 to 22-n.

Of the above explanations, the wireless transmission circuit 32 which plays a major role in the present invention will be explained with reference to FIG. FIG. 17 shows the internal configuration of the radio transmitting circuit 32, with a carrier frequency source 37 on the left, and a carrier wave from this source being input to the frequency modulator 36. On the other hand, a signal from the signal assignment circuit group 52a is input to the frequency modulator 36,
The carrier wave becomes a frequency modulated wave. Next, this frequency modulated wave is input to the amplitude modulator 34. Here, a signal from the signal assignment circuit group 52b is input, and the frequency modulated wave is amplitude modulated. In this way, complex modulation of frequency and amplitude has been performed. This wireless composite modulated wave is then input to the transmission mixer 33. Thereafter, after being amplified by a power amplifier (not shown), the signal is transmitted from the antenna to a large number of mobile radio devices 100B.

FIG. 18 shows another embodiment 32B of the internal configuration of the radio transmitting circuit 32, in which there are two carrier frequency sources 37-1 and 37-2 on the left, each with an angular frequency Ωa.
, Ωb is output. The carrier wave from this carrier frequency source 37-1 is input to the frequency modulator 36,
Frequency modulation is performed by the signal from the signal allocation circuit group 52a. On the other hand, the carrier wave from the carrier frequency source 37-2 is input to the amplitude modulator 34, and is amplitude-modulated by the signal from the signal assignment circuit group 52b. The above two modulator outputs are input to the transmission mixer 33, where the output frequency is converted to Ω1=Ωa + Ωb, and at the same time, a complex modulated wave that has undergone frequency modulation and amplitude modulation is output.

[0121] The above explanation was about composite modulation performed at the radio base station 30B, but similarly, the mobile radio device 100
The wireless transmission circuit 132 of B also performs composite modulation of the telephone signal and the fax signal, and transmits the signal to the wireless base station 30B.

[0122]

[Effects of the Invention] As is clear from the above explanation, if the present invention is applied to a system that includes non-telephone terminals such as telephones, faxes, images, data, etc. as communication terminals in the ISDN era, which is expected to be introduced worldwide in the future. For example, they can be used simultaneously using the same communication line. In this case, the effect of the present invention is extremely large because the frequency can be used effectively.

[Brief explanation of drawings]

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

FIG. 2 is a circuit configuration diagram of a mobile radio device for explaining the principle of the present invention.

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

FIG. 4 is a time slot structure diagram for explaining time slots used in the systems of FIGS. 1 to 3;

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

FIG. 6 is a circuit configuration diagram for multiplexing audio signals and data signals.

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

FIG. 8 is a spectrum diagram showing spectra of time-compressed speech signals and control signals.

FIG. 9 is a flow chart showing the flow of operation of the system of FIGS. 1 to 3;

10 is a flow chart showing the operation flow of the system of FIGS. 1 to 3 together with FIG. 9;

FIG. 11 is a spectrum diagram showing the spread of sidebands of a wireless signal.

FIG. 12 is a spectrum diagram showing the products of various signal components and their sidebands in a wireless signal.

FIG. 13 is a spectrum diagram showing the distribution of complex modulated waves in a wireless signal.

FIG. 14 is a spectrum diagram showing the spectrum of human conversational speech.

FIG. 15 is a circuit configuration diagram of an embodiment of a mobile radio device used in the system of the present invention.

FIG. 16 is a circuit configuration diagram of an embodiment of a wireless base station used in the system of the present invention.

17 is a detailed circuit configuration diagram of a wireless transmission circuit that is a component of the circuit shown in FIG. 16. FIG.

18 is a detailed circuit configuration diagram of another embodiment of a wireless transmitter circuit that is a component of the circuit shown in FIG. 16. FIG.

[Explanation of symbols]

10 Telephone network 20 Gateway exchanges 22-1 to 22-n Communication signal 30 Radio base station 31 Signal processing section 32 Radio transmission circuit 33 Transmission mixer 34 Amplitude modulator 35 Radio reception circuit 36 Frequency modulator 37 Carrier frequency source 38 Signal speed restoration Circuit group 38-1 to 38-n Signal speed restoration circuit 39 Signal selection circuit group 39-1 to 39-n Signal selection circuit group 40 Control section 41 Clock generator 42 Timing generation circuit 51 Signal speed conversion circuit group 51-1 to 51-n Signal speed conversion circuit 52 Signal assignment circuit group 52-1 to 52-n Signal assignment circuit 79-1 to 79-n Low-pass filter 91 Digital encoding circuit 92 Multiplex conversion circuit 100, 100-1 to 100 -n Mobile radio device 101
Telephone section 103 Fax terminal section 120 Reference crystal oscillator 121-1, 121-2 Synthesizer 122-1,
122-2 Switch 123 Transmission/reception intermittent controller 131 Speed conversion circuit 132 Wireless transmission circuit 133 Transmission mixer 134 Transmission section 135 Wireless reception circuit 136 Reception mixer 137 Receiving section 138 Speed recovery circuit 141 Clock regenerator

Claims (1)

[Claims] 1. Each wireless base means (30) each covering a plurality of zones to form a service area;
each mobile radio means (100) using a radio channel carrying temporally compressed delimited signals in time slots of a frame structure for moving across said plurality of zones and communicating with said radio base means; In a time division communication method for mobile communication using a barrier exchange means (20) for exchanging communication between A first modulated signal is obtained by performing one of angle modulation and amplitude modulation on the signal, and a second communication signal of the plurality of types of communication signals is obtained by using the first modulated signal as a modulated signal. A time division communication method for mobile communication in which a second modulated signal is obtained by performing one of angle modulation and amplitude modulation.