JPH02192234A - Switching control system for control channel in radio telephone system - Google Patents

Abstract

PURPOSE:To offer automobile telephone service without stopping the function of a radio station even if a fault takes place in the data reception function of a call and reply sharing channel by so adopting a constitution that the call and reply sharing channel is revised into a call-only channel. CONSTITUTION:When a processor 20 receives a message from a channel equipment 23 and the message represents the occurrence of a fault, the occurrence of the fault is recognized by the data reception function of the call and replay sharing channel. In this case, the processor 20 stops the operation of a data reception control section 236 to revise the channel equipment 23 from the operation as the call and reply sharing channel having frequencies T1, R1 into the operation as a call-only channel having only the transmission frequency T1. That is, the constitution of the control channel of a radio base station 2 is revised from the constitution of the call and reply sharing channel and the reply-only channel into the constitution with the call-only channel (T1) and the reply-only channels (T2, R2). Thus, even if the fault takes place in the reception function of the sharing channel, the service is continued.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control channel switching control system for a radio base station in a radio telephone system such as a cellular car telephone system.

[Conventional technology]

Unlike telephones that are fixed in telephone booths, offices, etc. and connected by wire to a telephone station, car telephone systems are known in which calls are made from a mobile device such as a car via a base station that relays wirelessly. . This car phone system allows you to make a call to a desired person while you are moving, and it also allows you to call someone while you are moving in your car, so it has been attracting attention and being used as an effective device for busy businessmen. ing.

A car phone system is a “car phone network”
It is an organic connection between the Internet and a normal telephone line network. Currently, car telephone systems are implemented using the "cellular method." In this method, a certain area is regarded as a cell, and this area is arranged without any gaps. Each wireless base station (Cell) is located in this area.
5ite) and can constantly communicate by radio with cars driving in that area. Wireless communication is usually carried out at around 800 MHz, and is carried out at a high-level mobile telephone switching center (Mobile Telephone Switch).
ing office) and is connected by wire, forming a ``car phone network''.

FIG. 7 shows an example of a cellular car phone system.

Calls between the mobile terminals 5 and between them and fixed telephones connected by wire to offices and the like are carried out via the wireless base stations 2, 3 and 4 and the mobile telephone exchange 1. Telephone exchange 1
is connected to a general telephone line, and signal lines 50, 5
1.52, it is connected by wire to wireless base stations 2 and 3.4. These base stations 2, 3.4 are provided in fixed service areas 56, 57, and 58, respectively, and perform correspondence, response, and relay of calls. Seven antennas 53, 54.55 for this purpose are provided at each base station 2, 3.4. Although the figure representatively shows base stations 2, 3 and 4, other wireless base stations (not shown) are installed in each area divided without any gaps, and are connected by wire to the telephone exchange 1. There is.

FIG. 8 shows how the base station 2 further divides a fixed area in charge of Davis and performs transmission and reception.

The antenna 53 of the base station 2 includes three directional antennas 61
, 62.63. These antennas 61
to 63 are in charge of transmission and reception in each area 64, 65° 66, which is obtained by further dividing the 360° service area 56 centered on the wireless base station 2 into three 120° each.

Calls from and to mobile terminals are handled by telephone exchange 1. A call to the other party and a response 2 call are made via the radio base stations 2 to 4. Each of these base stations 2 to 4 is
After a wireless connection is established by calling and answering between mobile terminals using control channels such as a shared calling/response channel and a dedicated response channel, communication between the mobile terminal and the other terminal is established using a communication channel specified by the telephone exchange 1. Relay phone calls.

As a control channel, there is a response-only channel that is exclusively used for calling or responding from a mobile terminal, and a call that can be used in common for both the function of such a response channel and the function of a paging channel used when calling a mobile terminal. - A car phone system with a response sharing channel and two types of channels is known. In this system, only the above-mentioned paging/response shared channel can be used for calls from a wireless base station to a mobile terminal, but a response-only channel and a paging/response shared channel can be used for calls from a mobile terminal to a wireless base station. Both can be used, which is advantageous when there are many mobile terminals and the amount of uplink traffic (that is, to the base station) is large.

[Problem to be solved by the invention]

In conventional systems such as these, if the data reception function of the above-mentioned shared channel fails due to interference, jamming waves, circuit failure, etc., data transmission and reception on this channel will no longer be possible. sending function,
Both reception functions were stopped.

However, if the above-mentioned failure occurs in a wireless base station, which is a system that does not have a response-only channel but only a call origination/response shared channel, service will be suspended within the area covered by the failed station. There was a problem with this.

Furthermore, even in a system that has a plurality of shared channels in the same service area, the quality of the car phone service deteriorates to the extent that the function of one channel stops, and providing a large number of shared channels increases costs.

Furthermore, even in a system equipped with a response-only channel and a shared channel as described above, the response-only channel becomes unusable, making it impossible to call a mobile terminal.

Further, a car telephone system that switches and uses one of the speech channels as a control channel in the event of a failure of such a control channel is disclosed in U.S. Pat. No. 4,434,5.
It is disclosed in No. 06.

However, this system inevitably reduces the number of available communication channels.

The purpose of the present invention is to eliminate the above-mentioned conventional problems and to
An object of the present invention is to provide a control channel switching control method that allows service to be continued even if a failure occurs in the reception function of the shared channel as described above in a wireless telephone system having both a response shared channel and a response dedicated channel. .

[Means to solve the problem]

In order to achieve the above object, the present invention provides a control channel for transmitting and receiving control information between a plurality of mobile telephone terminals and a wireless base station. A wireless device consisting of a response-only channel used exclusively as a response channel for sending and receiving, and a paging/response shared channel that can be used both as a paging channel for calling the terminal and as the response channel. In the telephone system, the base station includes a fault detection means for detecting a fault in the information receiving function in the paging/application shared channel, and a paging channel such as the paging/response shared channel when the fault detection means detects the fault. and a channel control means for controlling the channel to be used as a paging-only channel by fixing the function of the channel, and when the failure occurs, the paging-only channel is used to send and receive information regarding operations other than the previous paging.

〔Example〕

Referring to FIG. 1, in one embodiment of the present invention, a switching center 1 includes a network switch 10 and a network switch 10.
Trunks 15 to 18 accommodated in 0 and switch 1
0, a call processing control section 12 that controls call processing, a base station control section 13 that controls each radio base station 2 to 4, information regarding call processing, and information regarding base station control. It has a message transmission/reception control section 14 for transmitting and receiving messages to and from each of the radio base stations 2 to 4. Trunk 18 is connected to the general public telephone network. Trunk 15
is connected to the telephone line to the wireless base station 2. The trunks 16, 17 are each connected to other radio base stations 3.4.

Since the wireless base stations 2, 3.4 have the same configuration, the base station 2 will be explained as an example. The base station 2 includes a main processor 20 connected to the message transmission/reception control unit 14 of the exchange 1 by a control information line, a plurality of communication channel devices 21 to 22 connected to the trunk 15 by communication lines, and 2.
control channel devices 23 and 24 and an antenna 53. The control channel devices 23, 24 and the communication channel devices 21-22 are connected to and controlled by the main processor 20 via data lines, and are also connected to the antenna 53 via signal lines.

Since the control channel devices 23 and 24 can have the same configuration,
A detailed explanation will be given by taking the channel device 23 as an example. The channel device 23 functions here as a call/response sharing channel, and is connected to the data transmission control section 230 and the data reception control section 23.
6 and a transmitter/receiver duplexer 235. The data transmission control unit 230 includes a control data receiving unit 231 connected to the main processor 20 and receiving control data from the stomach processor 20, and a control data receiving unit 231 that is connected to the main processor 20 and outputs the control data to be transmitted to the mobile terminal 5 in a certain data format described later. A transmission data control section 232 and a modulation section 2 that modulates this transmission data.
33 and a transmitter 234. The data reception control unit 236 also includes a receiver 240 that receives data received by the antenna 53 via a sharing device 235, a demodulation unit 239 that demodulates the received signal, and a reception data that determines the received data after demodulation. It includes a control section 238 and a control data transmitting section 237 that notifies the main processor 20 of information based on the received data.

Here, in the control channel device 23, the data transmission control section 230 uses a transmission frequency T as a paging/response shared channel.
1, and the data reception control unit 236 uses the reception frequency R1.
It is working to receive.

Further, the channel device 24 operates as a response-only channel so that the data transmission control section 241 transmits at the transmission frequency T2, and the data reception control section 242 receives at the reception frequency R2.

Further, details of the mobile terminal 5 are shown in FIG. The mobile terminal 5 includes an antenna 70, a transmitter/receiver duplexer 71, a receiver demodulator 74 that demodulates received waves, a data receiver 77 that receives control data from the demodulated waves, and detects the presence or absence of received radio waves. a control unit 78 that controls the entire mobile terminal 5; a transmission modulation unit 72 that modulates data and audio signals to be transmitted and transmits them from the antenna 70 via the duplexer 71; a data transmitter 76 that assembles control data to be transmitted to the station and outputs it to the transmission modulator 72; a synthesizer 73 that changes the frequencies of the modulator 72 and the demodulator 74 according to instructions from the controller 78;
The audio signal line connected to the modulator 72 and the demodulator 74 is connected to the microphone 80 . A switch section 79 connected to each speaker 81 and a keypad/display device 8
3, a keypad/display, and a device controller 82.

This example was developed by EIA (Electronic
Industries Association) specification, and the control data from the wireless base stations 2 to 4 to each mobile terminal 5 is based on this EIA standard ClS-3-A or Cl
OHM (System Pa
Message)
Sent by. This OHM has an antenna 70° duplexer 71. Reception demodulator 74. The data is input to the control section 78 via the data reception section 77, and the control section 78 controls each section.

The first word word 1 sent as OHM above
(40 bits), and in the second word word2 (40 bits), as shown in FIG.
The 5 bits of the 14 bits are information "N-1" regarding the number of paging channels, the 16th bit is information "CPA" indicating the configuration of the control channel, and the 7 bits from the 17th to 23rd bits are information regarding the number of response channels. CMAX-1'' (
Only information directly related to the present invention will be explained here).
That is, when CPA=1, it indicates a normal state in the system of this embodiment, and indicates that a paging/response shared channel exists. Also, when CPA=0,
In this system, the above-mentioned failure state is indicated, indicating that the calling-only channel and the response-only channel are separated. Further, N indicates the number of paging channels in this system, and N-1 indicates the total number of paging channels starting from the channel defined as the first paging channel.

Further, CMAX indicates the number of response channels in this system, and CMAX-1 indicates the total number of response channels starting from the channel defined as the first response channel. Now, to make the explanation easier to understand, let's take the first call channel KO as the 301st channel as an example.

Set the first response channel to 4. N=10.0MAX=20,
A response-only channel in the service area 56.

Assume that the paging and answering shared channels are Kl and 2, respectively.

Note that adjacent service areas use different frequencies as control channels.

Next, the operation related to the occurrence of a failure in the system configured as described above will be explained.

In FIG. 1, the control channel device 230 functions as a paging/response shared channel with a transmission frequency TI and a reception frequency R1, as described above. - On the other hand, the control channel device 236 has the transmission frequency T2. Reception frequency R
It functions as a response-only channel for 2 responses. This channel device 230 uses only the transmission frequency T1 when calling the mobile terminal 5 as a paging channel.

Now, when the transmitting and receiving functions of the channel device 230 are working normally, the CPA in the OHM (FIG. 3) is 1. On the mobile terminal 5 side, by receiving this OHM, channels within a range of (N-1) from the predefined first paging channel KO can be used as paging channels, and channels from 4 to (( CMA
It is recognized that channels in the range X-1') are channels that can be used as response channels. Each channel is set every several Hz. Therefore, the frequency T
I, R1, T2. R2 are located at the positions shown in FIG. 4(A). When each mobile terminal 5 needs to use a paging channel or a response channel, it scans channels within a defined range, detects a control channel in the area in which it exists, and uses it. On the same side, 4 is the 301st channel for the first call channel KO and the first response channel, so the 301st to 310th channels (i.e., KO+(N-1)=301+(10-1)
) = 310) are channels that can be used for calling, and channels 301st to 320th (that is, K
O+(CMAX-1)=301+(20-1)=320
) are the channels that can be used for responses. That is,
The 301st to 310th channels are call/response shared channels, and the 3J1 to 320th channels are response-only channels.

Here, processing when interference waves occur at frequency R1 will be explained with reference to FIGS. 5 and 6.

When the received data control unit 238 of the channel device 23 recognizes the reception of the carrier (step Sl), it checks whether there is received data (step 82). - If data cannot be received despite receiving the carrier for a fixed period of time (step S3), it is assumed that the problem is due to reception of interference waves,
Main processor 20 via control data transmitter 237
(steps S4 and S'5). Note that step S4 is a process to avoid reporting the failure again to the processor 20 that has already reported the failure.

The processing of the processor 20 when the occurrence of a failure is reported will be explained with reference to FIG. When the processor 20 receives a message from the channel device 23, it determines whether it is a message related to a failure (step 5ll).
, if this message indicates that a failure has occurred (step 8
12) The processor 20 recognizes that a failure has occurred in the data reception function of the paging/response shared channel. At this time, the shared channel cannot function as a response channel for transmitting and receiving data because there is an interference wave at the reception frequency R1. However, since the transmission function of the data transmission control unit 230 is normal, it is possible to call the mobile terminal 5 using the transmission frequency T1. Therefore, processor 2
0 stops the operation of the data reception control unit 236 and changes the channel device 23 from operating as a paging/response shared channel with frequencies TI and R1 to operating as a paging-only channel with only the transmission frequency TI. (Steps 813-515).

In other words, the configuration of the control channel of the wireless base station 2 has been changed from a paging/response shared channel and a response-only channel to a paging-only channel (TI) and a response-only channel (T2).
．． R2). At this time, in order to notify the mobile terminal 5 of this change using a new OHM, the processor 20 changes the values of CPA and CMAX-1, and notifies the transmission data control unit 232 of the changes. This process (because the range of response channels that can be used by the mobile terminal 5 changes, the new CMAX-1 value is set to the value obtained from the old (CMAX-1)-N), and the channel device 2, which is used exclusively for calls,
3 to the mobile terminal 5. Specifically, the new CMAX-1 is 19-10=9. The control unit 78 of the mobile terminal 50, which received this OHM, learns of the change to the separate configuration of the paging channel and response channel from the fact that the CPA has become 0. As a result, the range of the paging-only channel is
Channel 01 remains the same as channel 310, and the range of response-only channels extends from the final calling channel (channel 310) to channel 311 (KO+ (N-1
)+1) to the 320th channel (i.e., KO
+ (N-1)+1+new (CMAX-1)=301+
(10-1)+1+9=320).

In the service zone 56 that the base station 2 is in charge of, service continues using this control channel configuration. In other words, taking the example of an incoming call to the mobile terminal 5, the call is made on the paging channel (TI), and the called terminal responds on the response channel (T2/R2) and sends control data associated with the call. Send and receive.

Furthermore, when a call is made from the mobile terminal 5, the call signal is sent using only the response dedicated channel (T2/R2). The main processor 20 of the base station 2 sends a signal via the signal line 50 indicating that the control channel configuration has been changed due to the occurrence of a failure.
．． The message is reported to the base station control unit via the message transmission/reception control unit 14.

The fifth section describes the behavior when the system recovers from a failure state.
This will be explained with reference to FIGS. Reception data control unit 23
8, after the interference carrier is no longer received (
In step Sl), if no carrier is received for a certain period of time (step S6), it is determined that the interference waves have disappeared and the fault has been recovered, and the recovery is reported to the main processor 20 (step 87.38).

The main processor 20 receives this recovery report (step S11.512) and returns the control channel configuration to the original configuration of a paging/response shared channel and a response-only channel. For this, OHM's CPA.

Processing is performed to restore the value of CMAX-1 and transmit it to the mobile terminal 5 (steps 816 to 518).

In the above explanation, the radio base station 2 has been described, but similar control channel switching control is performed for each other radio base station.

In addition, in FIG. 5, a failure due to the generation of interference waves has been explained, but in the case of a device failure, there is a method in which the main processor 20 periodically checks the state of the data reception control unit 236, a method in which the main processor 20 periodically checks the state of the data reception control unit 236, a method in which the main processor 20 periodically checks the status of the receiver 240 and the demodulation unit 239, etc. The data control unit 23 receives an abnormality.
The present invention can be similarly implemented by means such as detecting the occurrence of a failure by the processor 8 and reporting the occurrence of the failure to the processor 20.

〔Effect of the invention〕

As explained above, according to the present invention, the paging/response shared channel can be changed to a paging-only channel, so even if a failure occurs in the data reception function of the paging/response shared channel, the wireless base station function will be stopped. It is possible to provide car phone service without having to do so. Further, it is possible to prevent a decline in car telephone service in a wireless base station where a plurality of shared calling/response channels exist.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of a mobile terminal, FIG. 3 is a diagram showing an example of a message transmitted from a wireless base station to a mobile terminal, and FIG. 4 is a block diagram showing an example of a mobile terminal.
Figures (A) and (B) are diagrams showing the arrangement of control channels in normal times and when a failure occurs, respectively, and Figure 5 is a flowchart explaining the operation of the channel device of the wireless base station. Flowchart explaining the operation in the processor of the wireless base station, No. 7
8 is a diagram showing an outline of a cellular car phone system, and FIG. 8 is a diagram showing a detailed example of the zone configuration in FIG. 7. l...Car telephone exchange, 2,3.4...
...Radio base station, 5...Mobile terminal, 20...
... Main processor, 21, 22 ... Communication channel device, 23°24 ... Control channel device, 230, 241 ... Data transmission control section, 236, 242...Data reception control unit. Agent Susumu Uchihara, Patent Attorney Figure 6 Figure S Figure 8

Claims (3)

[Claims] (1) A control channel for transmitting and receiving control information between multiple mobile terminals and a wireless base station is used exclusively as a response channel for transmitting and receiving information based on calls from the terminals and responses from the terminals. In a wireless telephone system comprising a response-only channel and a paging/response shared channel that can be used both as a paging channel for calling the terminal and as the response channel, the base station includes: failure detection means for detecting a failure in the information reception function in the response shared channel; and when the failure detection means detects the failure, the paging/response shared channel is fixed to the function of the paging channel and used as a paging-only channel. and a channel control means for controlling such that when the failure occurs, only information for calling from the base station to the terminal is transmitted from the base station on the paging-only channel, and information for calls other than calls to the terminal is transmitted on the response-only channel. A control channel switching control method characterized by transmitting and receiving information regarding operations. (2) The radio telephone system according to claim (1), wherein the channel control means notifies the terminal of information regarding a new control channel configuration that has been switched and controlled when the failure occurs, through the paging dedicated channel. control channel switching control method in (3) when the detection means detects recovery from the failure;
The wireless telephone system according to claim 2, wherein the channel control means returns the paging-only channel to the paging/response shared channel and notifies the terminal of the restoration of the control channel configuration due to this fault recovery. Control channel switching control method.