JPS63233623A - Mobile body communication system and its radio channel switching method - Google Patents

Abstract

PURPOSE:To improve communication quality, by controlling a system so that the communication of a pair of transmission/reception parts is monitored, and a period when transmission/reception can be performed simultaneously between another radio base station which supplies the best call quality to another pair of transmission/reception parts is given when the call quality is lowered less than a prescribed value. CONSTITUTION:By providing two pairs of first and second transmission/reception parts, the system is constituted so that the radio base station in which the call quality is guaranteed can be obtained by the second transmission/reception parts 31-2 and 33-2 as continuing the communication by the first transmission/ reception parts 31-1 and 33-1 by using an old channel when the communication quality is lowered. After obtaining such radio base station(new channel), the communication is continued by switching the channel from the old one to the new one in the first transmitter/receiver. In such a way, it is possible to prevent the momentary disconnection of the communication due to the switching of the channel from being generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wireless communication channel switching method and system in mobile communication. More specifically, in mobile communication using a small zone configuration, when the communication quality with the fixed wireless station that is communicating with the opposite station deteriorates due to the movement of the mobile terminal that is communicating, The present invention also relates to a so-called communication (talk) channel switching method and system for setting up a new communication channel with another fixed wireless station that satisfies communication quality and canceling the previous communication channel.

[Prior Art] This type of conventional technology is employed, for example, in the car telephone system of NTT (Nippon Telegraph and Telephone ■), which is currently in commercial service. In this case, self! The mobile radio installed in the Pli moves away from the radio base station of the other party's communication station as the car travels, for example, from 5 to 7 minutes away from the radio base station.
If the value exceeds this value, the reception input electric field value of the radio wave decreases, resulting in deterioration of call quality. Therefore, in a small zone configuration,
Wireless base stations within a service area are 10 to 12-
Therefore, in the above case, there is always another wireless base station near the current location of the car (within 5 to 6 points), and another wireless base station is installed between this new wireless base station and the mobile wireless device. A wireless channel is used to continue the call. NTT
In this system, a radio line control station is installed to control a large number of radio base stations and mobile radios, and the radio line control station controls the setting and cancellation of calls on the radio line. When deterioration occurs, multiple radio base stations around the mobile radio receive the radio waves transmitted by the mobile radio, and a specific radio base station among them sets up a new radio channel with the mobile radio. When it is determined that the desired call quality can be maintained by doing so, a new channel is set between the mobile radio and the radio base station.

FIG. 6 shows a conceptual diagram of the configuration of a conventional system that operates as described above, and will be explained using this diagram.

In Figure 6, the radius surrounded by four circles is 5 to 7 KIn.
Zones 14A, 14B, 14G, and 14D are designated as the service area of the car telephone, and the mobile radio device 15 installed in the car is connected to the radio base station 13 in zone 14A.
Suppose that you are communicating with A.

Since the automobile is traveling from zone 14A to zone 14G, the relative distance between radio base station 13A and mobile radio 15 is increasing.

Assuming that the communication is continuing and the car moves from zone 14A to zone 14C, the distance between the wireless base station 13A and the mobile radio 1115 will be 5 to 7KI11 or more, and the input electric field value of the mutually received radio waves will be This results in a drop in transmission quality below a certain level. This state of quality deterioration is constantly monitored by the radio network control station 12, and when the quality drops below a certain standard, the radio Base station 13A and mobile radio I! 115 to measure the quality of the wireless channel in use (assumed to be channel CH1). Wireless base station 13 that received this request
B, 13C and 13D each transmit their own radio channel search reception 1m (not shown) to channel C1-(1
The radio network control station 12 receives the signal and reports its status to the radio network control station 12. Radio network control station 1 that received this report
2, the received input electric field EB of the radio base stations 13B, 13C, and 13D.

Compare the values of Eo and ED, Eo>EB, E. >E
o, and when the EC confirms that a certain level of quality is ensured from the perspective of transmission quality, the wireless line control I
Station 12 assumes that it has moved from zone 14A to zone 14C, disconnects the wireless channel CH1 used in zone 14A, and instead uses one of the wireless channels available at wireless base station 13G in zone 14G. A procedure for using an unused channel (assuming channel CH10), ie, channel switching during a call, is started.

The following is a reference to the literature "Car telephone radio line control system research practical application report Vo 1.26 of Nippon Telegraph Telephone Telecommunications Research Institute"
．． No. 7 This will be explained with reference to page 1885.

(1) The channel switching signal uses a control line included in each transmission path 16 between the radio network control station 12 and each radio base station 13, and between each radio base station 13 and mobile radio device 15. This is a wireless communication channel.

(2) A channel switching signal is sent to the mobile radio 15 from the radio base station 13A with which communication was previously performed, and a radio continuity test tone is sent from the radio base station 13C, which is currently communicating with the mobile radio. It is sent to the mobile radio device 15.

(3) When the mobile radio device 15 cannot receive a call to the radio continuity test 1, it returns to the old communication channel set with the radio base station 13A and continues the communication.

The above (1) to (3) are the channel switching methods currently used by NTT during a call, but as is clear from these explanations, it is clear that the caller, i.e., the caller himself! PI Tun telephone users will experience the following noises mixed into their calls. That is, (a) the control signal for switching according to (1) above (in this case, a 300 bit/sec digital signal) is inserted after the call is disconnected, so the call is disconnected.

(b) During the call test described in (2) above, there is no noise, but there is no sound, and during this period, the other party's voice is not transmitted to you, and your own voice is not transmitted to the other party (call disconnection).

The duration of call interruption due to (a) and (b) above is 0.7
It is said to be ~0.8 seconds. On the other hand, the radio network control station 12
Then, the wireless base station 13G is instructed to start a conversation with the mobile wireless device 15 using, for example, channel CHIO through the transmission path 16C between the two. Since this instruction is also carried out at the same time as the continuity test described above, from this moment on, the radio base station 13A ends communication with the mobile radio device 15, and the radio base station 13C instead communicates with the mobile radio device 15. Start communication. Further, the radio network control station 12 is connected to the telephone network 1
0 is requested to switch the channel switch SW in the exchange 11 for connecting each radio base station 13 to the telephone network 10 from the radio base station 13A to 13C. That is, the A-4 switch is turned off (indicated by a blank triangle) using the communication path switch SW in FIG. 5), and the C-4 switch is turned on (indicated by a black triangle). With the above operation, the mobile radio 15 is used in the car to connect the telephone network 10.
Any telephone in zone 14A, 14B,
The call will continue no matter where you move to 14C or 14D.

In this way, the user (caller) is given a technical guarantee that he or she can make a call anytime and anywhere within the service area while the car is in motion. That service is good.

[Problems to be Solved by the Invention] However, in the above-mentioned call channel switching method implemented by NTT, the call is temporarily disconnected (for 0.7 to 0.8 seconds) when the wireless channel is switched. However, since a control signal (300 bits/second) other than the call signal is inserted, it has the disadvantage of being unpleasant to the ears. If there is a temporary interruption in the call line or noise, it is not a big problem because it can be compensated for by listening again when the content of the call is voice, but it is not a big problem. When a facsimile terminal is installed and used for sending and receiving, there is a drawback that if a channel is switched during operation, a black line (or white line) appears on the facsimile output, significantly deteriorating the received image quality. Furthermore, in the case of data communications, errors in the data signal occurred, necessitating procedures such as retransmission.

In order to remove the harsh noise, there are methods to turn off the sound during channel switching or to use an out-of-band signal, but although the purpose of removing the harsh noise can be achieved, the time when the line is disconnected is The problem remains that, since it still exists, it is completely ineffective in eliminating the negative influence on facsimile and data signals.

[Means for solving the problem] A plurality of wireless base stations equipped with wireless transceivers and a first set of wireless transmitters and receivers that communicate while moving within a service area covered by the plurality of wireless base stations. In a system including a mobile radio terminal having a radio base station and a second set of radio transmitter/receivers, if the communication quality falls below a certain value during communication with one radio base station, the mobile radio terminal's second radio base station A pair of wireless transmitter/receivers uses another wireless channel to find a wireless base station that satisfies a certain communication quality among other wireless base stations, and finds a satisfying tlA-free base station (if For example, the first set of transmitting/receiving units of the mobile radio terminal disconnects the communicating channel (old channel), and the second set of transmitting/receiving units switches to the obtained communication channel (IJ'i channel). to allow communication to continue.

[Operation] By providing two sets of first and second transmitter/receivers in a mobile radio terminal, when the communication quality deteriorates,
While continuing communication through the old channel in the first transmitter/receiver,
The second transmitting/receiving unit searches for a wireless base station that can guarantee call quality, and selects such a wireless base station (new channel).
After this is requested, the first transceiver also switches from the old channel to the new channel and continues communication, so there is no longer a momentary interruption in communication due to channel switching.

[Embodiment] FIG. 1 shows a system configuration for explaining an embodiment of the present invention. A mobile radio 50 is shown, which is typically installed within a motor vehicle. The mobile vJ radio 50 includes one antenna unit and two sets of transmitter/receiver units, that is, a transmitter unit 51-1.
and 51-2. There are receiving sections 53-15 and 53-2, and a control section 58 controls one or both of them to perform predetermined operations. Synthesizer 55-
16 and 55-2 are the transmitting section 51-1, 51-2 and the receiving section 53, respectively, according to the control signal from the control section 58.
-1.Create the necessary transmitting and receiving frequencies for 53-2. In addition, two sets of transmitting and receiving sections 51-1.53-1.51-2.53-
2 and the telephone unit 59 are wired to enable parallel transmission and reception. The control section 58 functions to receive the output from one of the receiving sections, determine the receiving state, and perform control operations.

In the center of FIG. 1, wireless base stations 30-1 and 30-2 are shown.
It is shown. The wireless base station 30 is normally equipped with a plurality of transmitting/receiving sections 31 and 33, but since it is not necessary for the detailed explanation of the present invention, the transmitting section 3 is shown in the drawing.
1-1.31-2 and one receiving section 33-1.33-2 are shown. Furthermore, the configuration of the wireless system control device 20 is shown on the left. The radio system control device 20 includes a communication control section 21 that controls each radio base station 30 and mobile radio device 5.
It has the function of specifying the wireless line used with 0, installing and canceling the line, and switching the line (channel) during communication. Further, when it becomes necessary to change the communication path for monitoring the line quality of the communication line or switching channels during a communication, a switch group 23 is provided for changing the communication path. The communication control unit 21 also controls this switch group 23.

The operation will be described when mobile radio device 50 switches the speech (communication) channel from communicating with radio base station 30-1 to communicating with radio base station 30-2 as the vehicle moves. In addition, the feature of the present invention, which is that there is no instantaneous interruption due to channel switching, will also be explained.

The mobile radio device 50 includes a transmitting section 51-1 and a receiving section 53-
It is assumed that communication is in progress using communication channel CH1 with radio base station 30-1 using communication channel CH1. It is assumed that the mobile radio@50 moves away from the radio base [30-1] and approaches the radio base 830-2, as explained in FIG. Then, as the relative distance between the mobile radio device 50 and the radio base station 30-1 increases, the call quality begins to deteriorate, so the radio system control device 20 in FIG. The quality deterioration of the transmitted signal from the mobile radio device 50
/N Monitoring unit 22 (indicates that the level has decreased to 1 or less)
To detect. Note that even at level L1, the line is set to exceed the required value φ. All nearby wireless base stations 30 are requested to measure the quality of the transmitted signal of the mobile wireless device 50.

In response to this request, each radio base station 30 sends the measured value to the radio system control device 20, so that the S/O of the radio system control device 20
The N monitoring unit 22 starts comparison with level L2 of the communication quality standard. As a result of the comparison, the measurement result of the wireless base station 30-2 has the best value, and it is the product I! If it is confirmed that L2>11 is satisfied, the mobile radio device 50 determines that it has moved to the communication zone (Zone 2) of the radio base station 30-2, and switches channels. decide to have it done. Then, as a result of investigating available communication channels in zone 2, it is learned that channel Cl-12 is usable. Therefore, using the downlink communication channel CH1 that is currently in use, the vJ radio 50 is transferred by a control signal.
On the other hand, the transmitter 51-2 and the receiver 53-2 that are inactive
to perform transmission and reception on communication channel CH2.

At the same time, it also instructs the radio base station 30-2 to perform transmission and reception on channel CH2.

After issuing these instructions, the radio system control device 20 simultaneously turns on switches SW1 and SW2 of the switch group 23, and also sets the radio base station 30-2 to the same state as the radio base station 30-1. start sending out call signals.

In order to realize the transmission of this control signal, specifically, when the control signal is an analog signal, as shown in Figure 2 (a), a low frequency outside the communication channel band of 0.3 to 3.0 KHz is used. fDo (e.g. about 100Hz) or higher frequency fD1= fD2= f[)3”” f08 (e.g. 4.5KHz in O, lKH2 intervals from 3.8KH2
(up to 8 waves) are used.

Also, 1I1111! When a digital data signal is used as the signal, it is also possible to digitally encode the audio signal and time-division multiplex the two for transmission.
This is shown in FIG. 2(b). FIG. 2(b) shows an example of a case where an audio signal is digitized by a digital encoding circuit 91, and the audio signal is multiplexed with a data signal by a multiplex conversion circuit 92, and then applied to the modulation circuit of the transmitter 31.

FIG. 3 shows a timing chart of the system shown in FIG.

As shown in FIG. 3, the call signal is transmitted to the radio base station 30-1
From the radio base station 30-2, communication is performed using the downlink communication channel CHI to one set of the transmitter 51-1 and the receiver 53-1 of the mobile radio 1150, and from the radio base station 30-2, the mobile radio 5
This is executed for one set of transmitters 51-2 and 53-2 of No. 0, respectively, using downlink communication channel CH2.

Therefore, there is no need to temporarily interrupt the call signal as in the NTT system described above. Receiving section 53-2
The transmission signal received from the radio base 830-2 includes an identification code indicating that the transmission signal from the radio base 82 is outside the band, etc., as explained in FIG. The control unit 58 of the mobile radio device 50 confirms that the call signal is being sent through the call channel determined by the radio control device 20 and that the line quality satisfies the standards. Here, the mobile radio 415 is transmitted from the radio system control bag !20 to the radio base station 30-1.
The difference in length between the transmission path from the radio system control device 20 to the mobile radio device 50 via the radio base station 30-2 is at most 10 inches; If the speed of light is 3 x 105 touches/second, the delay time difference will be 107/3 x 10"k - 0.03 msec, so
A time difference of this magnitude does not cause problems with speech signals when switching channels.

On the other hand, the mobile radio device 50 uses the transmitter 51-2 to transmit the communication channel CH2 instructed by the radio system control '@ station 20.
A signal including the identification number of the mobile radio device 50, the communication channel number, etc., using a communication signal and an out-of-band signal is transmitted to the radio base station 30-2.

The radio base station 30-2 receives the signal sent from the mobile radio 50, and after confirming that the line quality satisfies standards, transfers the signal to the radio system control device 20. In the wireless system control device 20, the transfer! Confirm that the signal was transmitted on the communication channel CH2 as instructed by the Pl radio [50]. By checking the new channels in both the uplink and downlink directions during the parallel reception period, it is confirmed that there will be no problem even if the communication channel is switched to the new channel.

Therefore, wireless system control! At 1120, the wireless base station 30-
1 and mobile radio device 50 to stop using the old channel (in this case, channel CH1 from radio base station 30-1). That is, the wireless base station 30-1 is instructed to stop transmitting and receiving channel CH1 using a control signal. Furthermore, for the mobile radio device 50, a new channel of the radio base station 30-2 (in this case, the new channel of the radio base station 30-2)
Using the channel CH2> from 0-2, the transmitter 51-1
Then, a control signal is sent to stop the operation of the receiving section 53-1. Since this control signal also uses an out-of-band signal as shown in FIG. 2, it does not affect the call signal at all.

When this signal is received by the receiving section 53-2 of the mobile radio device 50 and sent to the control section 58, the control section 58 decodes the meaning of the control signal, and the transmitting section 51-1... The operation of the receiving section 53-1 is stopped. In this manner, the call channel switching operation is completed, and the call continues through channel CH2.

In the operation shown in FIG. 3, only the downlink communication channel is shown. As is clear from the figure, initially, the call signal flows toward the mobile radio 50 only through the channel CHI of the radio base station 30-1, and in the next phase, the communication signal flows through the channel CH1 of the radio base station 30-1. and channel CH2 of the radio base station 30-2 are connected to the mobile radio 50 in parallel.
At the next point in time, the transmission of the radio base station 30-1 is stopped, and communication is performed only on the channel CH2 of the radio base station 30-2.

As is clear from this, according to the present invention, there is no noise caused by momentary line interruptions due to channel switching during a call and noises caused by control signals that are input at momentary interruptions, as described above, and can be eliminated.

The downlink communication signal is sent to the mobile radio device 50 shown in FIG.
The signals are mixed in the telephone section 59 and sent to the caller.

The call quality when parallel reception is performed (1) by both channels is that the outputs of the receiving sections 53-1 and 53-2 are at level L.
1 and L2, but if a circuit is used that reduces the output of the receiving section 53-1 and increases the output of the receiving section 53-2 for mixing, it can be obtained in a better state close to level L2. Reception is possible.

In FIG. 3, the state of transmission from the radio base station 30 and reception by the mobile radio device 50 has been explained, but the same applies to
This is also possible on the radio base station 30 side that receives uplink signals.

In this case, the mobile radio 6150 transmits, and the radio base station 30-
Parallel reception is similarly performed in the receiving sections 33-1 and 33-2 of 1 and 30-2, and these are mixed in the radio system control device 20, so the output of the one with the better quality of the received signal is All you have to do is increase the amount and mix.

48-4D, a flow chart of the system shown in FIG. 1 is shown.

Wireless system control a device 20. The radio base station 30'1.30-2 and the mobile radio 50 start operating, the switch SW2 of the switch group 23 included in the radio system control Il device 20 is on, and the radio base station 30-1 and the mobile radio Communication is in progress with aircraft 50. For this communication, channel C is instructed by the communication control section 21 included in the radio system control device 20.
H1, the downstream frequency F1 and the upstream frequency f1 are used (S101, FIG. 4A).

The wireless base station 30-1 in communication constantly issues a reception status report from the mobile wireless device 50 (8102), and the S/N monitoring unit 22 of the wireless system control device 20 receives the report and checks the call quality It is monitored whether or not it has deteriorated below level L1 (S103). If the call quality has deteriorated below level L1 (3103YES), the communication control unit 2
1 to wireless base station 3 in the vicinity of wireless base station 30-1.
0 to monitor and receive the signal at the upstream frequency f1 used for communication between the radio base station 30-1 and the mobile radio 50 (3104).

Each surrounding wireless base station 30 that has received an instruction to monitor reception (for example, in 30-2>, monitor reception of the signal of frequency f1 3105), and sends the result to the S/W of the wireless system controller 20.
Report to the N monitoring unit 22 (5106), each wireless base station 30
For example, it is detected that the call quality of the wireless base station 30-2 is better than a certain standard level L2 and is the best (S107YES).
.

Therefore, the communication control unit 21 determines that the mobile radio device 50 has moved from the zone covered by the radio base station 30-1 to the zone covered by the radio base station 30-2 (8108).
4th BIK>, in order to switch to communication with the wireless base station 30-2, search for an empty channel that can be used by the wireless base station 30-2 (3109), and as a result, determine channel CH2 (8110) . The communication control unit 21 is a transmitter 51-2 and a receiver 53- of the mobile radio 11150.
2 to prepare for communication on channel CH2 (3111).

A communication preparation command for using channel CH2 is sent to radio base station 30-2, and preparations for communication using channel CH2 are made (3112). This command is simultaneously sent from the wireless base station 30-1 through channel CH1 (81
13). The mobile wireless device 50 receives the communication preparation command on channel CH2 (5114), and
In other words, the control unit 58 instructs the synthesizer 55-2 to receive frequency F2 and transmit at frequency f2, and the synthesizer 55-2 receives the signal from the receiving unit 53-2. 2, the transmitting unit 51-
2, a signal of a frequency that enables uplink frequency f2 to be transmitted is applied (3115, FIG. 4C).

When ready to communicate using channel CH2, mobile radio device 50 reports completion of preparation to radio base station 30-2 using channel CH2 (3116).

Upon receiving this report, the wireless base station 30-2- performs step 5.
Radio base station 30 using channel CH2 prepared in step 112
-2 confirms that the preparation is complete and issues a report (S117).

The radio system control device 2 indicates the completion of communication preparation between the radio base station 30-2 and the mobile radio device 50 using the channel CH2.
0 is confirmed (3118), the switch SW2 of the switch group 23 is left on, and the switch SW1 is also turned on (3119).

Therefore, the communication control unit 21 included in the radio system control device 20 transmits the mobile radio I! to the radio base station 30-2. A command is given to start communication with I50 using channel CH2 (3120).

Upon receiving this communication start command (3121>), the radio base station 30-2 sends the communication start command using channel CH2 (S122).The mobile radio device 50 uses an identification signal to identify the mobile radio device. Using the ID signal, the radio base station 30-2 confirms the start of communication using channel CH2 (8123), sends out a communication signal including the ID signal using channel CH2 (5124, FIG. 4D), and receives this communication signal. reports that it has started communication on channel Cl-12 (3125>).

S/N monitoring unit 2 of the wireless system control device 20 that received this report
2 measures the quality level of communication between the mobile radio device 50 and the radio base station 30-2, and when it detects that the quality level is 2 or more above a certain quality level (Sl 27YES), the radio base station 30-1 channel CH1 between and the mobile radio 50
The radio base stations 30-1 and 30-2 are instructed to stop the communication that was being performed using the radio base stations 30-1 and 30-2 (3128).

As a result, the wireless base station 30-1 uses channel Cl-1.
Communication by 1 is turned off (3129). Furthermore, the radio base station 30- which received the command to stop communication by channel CH1
2 transfers the command (3130), and this channel C
When the mobile radio 50 receives the communication stop command via H1 (8131), it stops the operation of the transmitter 51-1 and the receiver 53-1, and sends a channel CHI communication stop report using channel CH2 (S132). . The radio base station 30-2 that receives this transfers this channel CH1 communication stop report <3133>.

Radio system control device 2 that received the channel CHI communication stop report
The communication control unit 21 of No. 0 is a switch SW of the switch group 23.
1 remains on, and switch SW2 is turned off (S
134).

As a result, when switch SW1 is in the on state, channel CH2, downlink frequency E2. Using upstream frequency f2, 1!1150 before moving is between $2 base Q30-2 and -
Communication can be continued without instantaneous interruption or noise (3135).

In the above explanation, the control signal associated with channel switching is
We have explained an example of sending using the same channel as the communication signal, but even if you set up a separate &l+ control channel,
The effect of the present invention remains unchanged.

FIG. 5 shows a case where such a control channel is provided separately. Components corresponding to those shown in FIG. 1 are given the same symbols.

In FIG. 5, mobile radio device 50 is connected to radio base station 30-2.
The radio control device 20 detects that the communication quality has deteriorated and instructs each @ line base station 30 to measure the reception state of the transmission signal of the frequency f1 emitted by the mobile radio 50. What is done is exactly the same as explained using FIGS. 1 to 4.

As a result of the measurement, it is determined that the mobile radio device 50 has moved to the zone covered by the radio base station 30-2, and the mobile radio device 50 moves to the zone covered by the radio base station 30-2.
The disconnection B request signal to the unused communication channel CI-(2 is transmitted to the mobile radio device 50 using the control transmitter 32-1 on the downlink channel dedicated to the control of the radio base station 30-1. Currently, in the mobile radio device 50, the transmitting section 51-1 and the receiving section 53-1 are in use, and the transmitting section 51-2 and the receiving section 53-2 always use the control channel transmitted in that zone. It is controlled by the control unit 5B so that it can receive the following information.

Therefore, the receiving section 53-2 receives the control signal, and the transmitting section 51-2. :i; and the receiving section 53-2 is absent! ! ! It enters a standby state so that it can transmit and receive on the communication channel CH2 of the base station 30-2.

In the subsequent operation, communication with the mobile radio device 50 is continued using the channel CH2 of the radio base M30-2 by a process similar to that explained in FIGS. 1 to 4. .

Instead, the transmitting section 51-1 and the receiving section 53-1 enter a state in which the transmitting and receiving function of the call signal is suspended, but among these, the receiving section 53-1 receives the downlink control channel of the wireless base station 30-2. Performs channel acquisition operation for receiving. Then, it is put on standby so that channel switching is possible when the zone is changed again.

In the above explanation, the case where the other transmitter/receiver of the two transmitter/receivers of the mobile radio V150 does not participate in communication signals at all except when switching channels has been explained. It is possible to make further improvements.

However, in this case, it is necessary to transmit the control signal on the same channel as the communication channel.

[Effects of the Invention] As is clear from the above description, by applying the present invention to a mobile communication system that uses a small zone configuration, it is possible to eliminate the temporary interruption of communication when changing zones during communication, as in conventional systems. This will completely eliminate problems that occur in facsimile signals and data signals, such as image quality deterioration and burst-like signal errors, although they are not much of a problem in the case of telephone signals. , the present invention has an extremely large effect because it makes a great contribution to improving communication quality.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing one embodiment of the present invention; FIGS. 2(a) and (b) are spectrum diagrams and circuit configuration diagrams for explaining an example of the configuration of a control signal used in the present invention; The figure is a timing chart for explaining the operation of the system shown in Fig. 1, and Figs. 4A, 4B, 4C, and 4D are for showing the flow of the operation of the system shown in Fig. 1. FIG. 5 is a system configuration diagram showing another embodiment of the present invention, and FIG. 6 is a system configuration conceptual diagram for explaining a conventional system example. 10...Telephone network 11 ...Exchange machine 12...
・Radio line control station 13A-D...Radio base station 14A
-, -D...Zone 15...Mobile radio 16A
~D...Transmission path 20...Radio system control 1lII device 21...Communication control section 22...S/N monitoring section 23...Switch group 30-1, 30-2...Radio base Station 31-1.31-2...Transmission section 32-1.32-2...Control transmission section 33-1.33
-2...Receiving section 34-1.34-2...Control receiving section 50...Mobile radio 51-1.51-2...Transmission, Sozu 53-1.53-2...・Receiving section 55-1.55-2...Synthesizer 56.57...
・Hybrid circuit 58.58A...Control section 59...Telephone section 91.
...Digital encoding circuit 92...Multiple conversion circuit.

Claims (12)

[Claims] (1) between each radio base station that covers a plurality of zones and constitutes a service area, and each mobile radio that moves across the plurality of zones and communicates with the radio base station; In the method of controlling the radio base station and the mobile radio so that the call quality is always above a certain value, the mobile radio is provided with two sets of transmitting/receiving units, and at least one set of the transmitting/receiving units is used. communicates with the radio base station, monitors the communication between the one set of transmitting/receiving units, and when the communication quality of the communication falls below a predetermined value, transmits the best signal to the other set of the transmitting/receiving units. 1. A wireless channel switching method for mobile communication, characterized in that control is performed to have a period of simultaneous transmission and reception with another wireless base station that improves call quality. (2) After the period in which the one set of transmitting/receiving units and the other set of transmitting/receiving units transmit/receive at the same time, the operation of the one set of transmitting/receiving units is stopped, and the operation of the one set of transmitting/receiving units is stopped, and 2. The wireless channel switching method for mobile communication according to claim 1, further comprising continuing communication with said other wireless base station that has provided said best call quality. (3) After the period in which the one set of transmitting/receiving units and the other set of transmitting/receiving units transmit/receive simultaneously, the two sets of transmitting/receiving units, the wireless base station, and the one that brought about the best call quality The wireless channel switching method for mobile communication according to claim 1, wherein diversity communication is performed by communicating in parallel with other wireless base stations. (4) Each of the radio base stations transmits and receives control signals to control the mobile radio, and the control transceiver unit transmits and receives control signals to one of the two sets of transceivers of the mobile radio using a dedicated channel. A wireless channel switching method for mobile communication according to claim 1, wherein communication for control is performed with one side. (5) each radio base means each covering a plurality of zones to constitute a service area; each mobile radio means moving across the plurality of zones and communicating with the radio base means; Mobile communication using radio system control means for controlling the radio base means and the mobile radio means so that the communication quality between the radio base means and the mobile radio means is always above a certain value. In the wireless channel switching system, the mobile radio means communicates with the radio base means using two sets of transmitting/receiving means, each including a transmitting means, a receiving means, and a synthesizer, and at least one set of the transmitting/receiving means. , another radio base that provides the best communication quality to the other set of transmitting/receiving means based on instructions from the radio system control means when the communication quality of the one set of transmitting/receiving means drops below a predetermined value. 1. A wireless channel switching system for mobile communication, comprising: a control means for controlling a period of simultaneous transmission and reception between the wireless channel switching system and the wireless channel switching system. (6) After the period in which the one set of transmitting/receiving means and the other one set of transmitting/receiving means simultaneously transmit/receive, the control means stops the operation of the one set of transmitting/receiving means, and
Radio channel switching for mobile communication according to claim 5, wherein control is performed so as to continue a call between the transmitting/receiving means of the group and the other radio base means that has obtained the best call quality. system. (7) After the period in which the one set of transmitting/receiving means and the other set of transmitting/receiving means simultaneously transmit/receive, the control means controls the communication between the two sets of transmitting/receiving means, the wireless base means, and the best communication. The movement according to claim 5, wherein the two sets of transmitting/receiving means are controlled to perform diversity communication by communicating in parallel with the other radio base station that has brought quality. Wireless channel switching system for body communication. (8) The control means controls one of the two sets of transmitting/receiving means to communicate through the dedicated channel when channel switching control is performed between the wireless base means and the dedicated channel. A wireless channel switching system for mobile communication according to claim 5. (9) each radio base means each covering a plurality of zones to constitute a service area; each mobile radio means for moving across the plurality of zones and communicating with the radio base means; Radio system control means for controlling the radio base means and the mobile radio means so that the communication quality between the base means and the mobile radio means is always above a certain value. In the channel switching system, the radio system control means monitors speech quality when the mobile radio means including two sets of transmitting/receiving means communicates with the radio base means using at least one set of the transmitting/receiving means. communication quality monitoring means for determining the best quality of communication, upon receiving an output from the communication quality monitoring means, when the call quality has decreased below a predetermined value, the other set of the transmitting/receiving means of the mobile radio means receives the output from the communication quality monitoring means; 1. A wireless channel switching system for mobile communication, comprising: communication control means for selecting another wireless base means that provides quality and outputting a control signal so as to have a period of simultaneous transmission and reception. (10) After the period in which the one set of transmitting/receiving means included in the mobile radio means and the other one set of transmitting/receiving means simultaneously transmit and receive, A control signal is output for stopping the operation and continuing communication between the other set of transmitting/receiving means and the other wireless base means that brought about the best call quality. 10. The wireless channel switching system for mobile communication according to claim 9. (11) After the period in which the one set of transmitting/receiving means included in the mobile radio means and the other one set of transmitting/receiving means simultaneously transmit and receive, A patent claim that outputs a control signal for performing diversity communication by communicating in parallel between the radio base means and the other radio base station that has brought about the best call quality. 10. The wireless channel switching system for mobile communication according to item 9. (12) Each of the radio base means has a control transmitting and receiving means for transmitting and receiving control signals for controlling each of the mobile radio means using a dedicated channel. Wireless channel switching system for mobile communications.