JPH06334586A - Mca radio communication system - Google Patents

Abstract

PURPOSE:To perform a general message speedily even in the case of call congestion and to simplify the operation for the general message as to the MCA system (multichannel access system) radio communication system which shares general speaking channels with the general message. CONSTITUTION:A control center sends out a general message command transmission request by an upstream control CH (CU). A repeater station once receiving the general message command transmission request sends out a call end signal through a speaking channel (4D) for general message and also sends the general message command through a downstream control CH (CD). A mobile station which is using the speaking channel (4D) for general message receives the general message command and stops using it, so the stop is detected and the transmission of the general message command is stopped. The control center monitors the down stream control CH (CD) after the general message command transmission request and is so controlled as to enter a general message state once the absence of incoming call of the CH is detected. When a general message channel becomes free, the general message can be performed immediately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system of the MCA system (multi-channel access system) which uses a general communication channel for simultaneous notification.

[0002]

2. Description of the Related Art FIG. 3 is a schematic diagram of an MCA wireless communication system to which the present invention is applied. In the figure, 1 is a control center, 2 is a plurality of mobile stations, and 3 is a relay station (MCA control station).
Is.

In this system, for example, in the 800 MHz band, for example, 4 of # 1 to # 4, each of which is made up and down.
The communication channel of CH and the control channel of 1CH of #C can be used, and the control center 1 and the mobile station 2 transmit to the relay station 3 on the upstream CH and receive on the downstream CH. The relay station 3 is connected to the control center 1 via the downlink control channel.
A call CH is assigned to each mobile station and control by various commands is performed, and a call between the control center 1 and the mobile station 2 is relayed.

Such a small-capacity MCA system radio system is often used in, for example, a regional disaster prevention radio system, and in an emergency, the control center sends a simultaneous notification to mobile stations. This broadcast mode includes an all-station capture mode and an immediate mode. The all-stations capture mode is intended for thorough reporting, and is a mode in which all mobile stations make a broadcast after confirming that all mobile stations have been captured by the broadcast channel, and the immediate mode is for the purpose of prompt notification. This is a mode in which all mobile stations can make simultaneous notification as soon as possible even if they cannot be completely captured.

In such an MCA type wireless system, since the number of usable call channels is small, it is not always possible to leave a call channel dedicated to a simultaneous call such as an emergency call. When a broadcast request is made, a call CH (for example, # 4-ch) that is predetermined for broadcast is forcibly released and used for broadcast. It should be noted that this call channel for broadcast is assigned to the channel assignment request last in the lowest priority order during normal operation.

When it becomes necessary to notify all mobile stations of the simultaneous notification from the control center 1, and when there is a call congestion in which all the 4CH calls are used, the control center issues a request for a simultaneous notification command. , The relay station continuously sends a capture signal on the control CH for 25 seconds to notify the mobile stations in communication that a predetermined communication CH (for example, # 1-c).
After being captured in h), make a simultaneous report. This is because it is necessary to make a thorough call to the mobile stations that are in the call, leaving the mobile station that is using the same channel (# 4-ch) as the call as it is and making a call using the same call channel. When you do
Since the same channel transmissions collide, the relay station (MCA
This is to prevent inconveniences such as the occurrence of beats due to interference of the same wave at the receiving unit of the control station) and the simultaneous notification may not be given due to masking.

FIG. 4 is a time chart of a conventional mobile station acquisition operation at the time of simultaneous broadcast. As shown in the figure, the conventional method for acquiring the mobile station at the time of simultaneous notification is performed as follows. The control center that needs the simultaneous notification is the relay station (M
The CA control station) sends a broadcast notification command transmission request using the uplink control CH (#CU). When the relay station receives the request to send the broadcast command,
2 simultaneous broadcast commands via downlink control CH (#CD)
Transmit continuously for 5 seconds. On the other hand, all mobile stations in a normal communication state are configured to monitor the downlink control CH (#CD) at intervals of 20 seconds, and detect the reception of the broadcast notification command when monitoring the control CH. Then, the normal call is ended, and the receiving side is switched to the simultaneous notification channel # 4D-ch and stands by. All mobile stations are controlled so that transmission activation is prohibited and the mobile station is in a reception waiting state. After about 25 seconds have passed, the control center sends a simultaneous notification via # 4-ch.

[0008]

When a broadcast call is made during a call congestion in which the broadcast channel is used for normal calls, the above-mentioned prior art cannot confirm whether or not this channel is available. In order to ensure that the station can receive the broadcast command, consider the worst case (that is, when the control channel is monitored by the mobile station transmitting on the broadcast channel immediately before the start of the broadcast command transmission). Therefore, when the time is longer than the control channel monitor cycle, for example, when the monitor cycle is 20 seconds, it is necessary to wait 25 seconds before issuing the simultaneous notification.

[0009] However, when it is desired to make an emergency contact to a mobile station by a simultaneous report in the immediate mode, it is necessary to wait for 25 seconds without fail, which is a problem that the contact speed is insufficient.

Further, the control center needs to perform the operation for the simultaneous notification after 25 seconds have elapsed after issuing the request for the simultaneous notification command, which is a problem that the operation is troublesome.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an MCA communication system that can promptly make a simultaneous call even when a call is congested, and that is simple in operation for the simultaneous call.

[0012]

In order to solve the above problems, in the MCA wireless communication system of the present invention, when the relay station receives a request for transmission of a simultaneous call command from the control center, a call for simultaneous notification is made. A call end signal is sent out via the channel, and a broadcast command is sent out via the control channel. When the call channel for broadcast is not received, it is controlled to stop sending the broadcast command. The control center has a configuration in which after the broadcast notification command transmission request, when the control channel is monitored and it is detected that there is no incoming call on the control channel, the control center is controlled to enter the broadcast notification state.

[0013]

[Operation] Downlink CH for simultaneous notification (for example, # 4D-c
The receiving side of the mobile station making a general call using h)
Since the call end signal from the relay station is received via the call channel in use, it immediately returns to the control CH and enters the standby state, receives the broadcast notification command via the control CH, and receives the broadcast channel for broadcast notification ( # 4D-ch) enters standby mode.

In addition, an upstream call CH (for example, #
The mobile station on the transmitting side, which is using 4U-ch), detects the general call command when monitoring the control CH at a predetermined monitor cycle, and thus immediately terminates the general call and enters the general call reception state. As a result, the use of the upstream call channel (# 4U-ch) for broadcast is stopped, so that the relay station detects that the incoming call of # 4U-ch has stopped, recognizes that this call channel is empty, and broadcasts it. Stop sending the report command. The control center monitoring this control channel detects the termination of this broadcast command
It can be recognized that the broadcast channel has become available, and it will automatically enter the broadcast state.

Therefore, the start time of the broadcast notification changes depending on where the monitoring timing of the mobile station which is using # 4 Uch is during the broadcast command transmission period, and the monitoring cycle changes from immediate to the longest. What could be broadcast only after a fixed time corresponding to the time, will be able to broadcast immediately as soon as the broadcast channel becomes available. In addition, the control center automatically detects that the broadcast channel has become empty and enters the broadcast state, which simplifies the operation.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram of an MCA wireless communication system of the present invention, and FIG. 2 is an operation time chart at the time of simultaneous notification in the present invention.

This system comprises the control center, the mobile station and the relay station described above with reference to FIG. 3, has 4 channels # 1 to # 4 as a general communication channel and a control channel Cch, and uses # 4 channel for simultaneous notification. Shall be used.

In FIG. 1, (a) is a control center, (b) is a mobile station, and (c) is a relay station (MCA control center). The control center (a) has a broadcast channel (#
4-ch) for at least 2 channels of radio receiving unit RX1 and radio transmitting unit TX1 for receiving / transmitting, and radio receiving unit RXC and radio transmitting unit TXC for receiving / transmitting control channel (# C-ch). It has a radio section. In addition, the incoming call disconnection detection unit 11, the operation unit 12,
It has a signal controller 13, a 25-second timer 14, a speaker 16, a microphone 17, and a microphone switch 18. The incoming call detection unit 1
When the disconnection of the CD-ch is detected after the broadcast operation, a timer stop signal is generated.

The mobile station apparatus (b) switches between a radio receiving section RX and a radio transmitting section TX which are used for switching to any one of the call channels # 1 to # 4 and the control channel (C-ch), and this channel switching. It has a control unit 21 for controlling, a speaker 22, and a microphone 23,
The control unit 21 switches and sets the communication channel to be used for the wireless transmission unit TX and the wireless reception unit RX according to the channel designation received from the relay station via the downlink control channel (CD-ch),
Controls the radio receiver RX once every 20 seconds during a call for only 1 second
Switch to reception and monitor the command from the relay station. Further, during non-call, the control CH reception state is set and always waits for an instruction from the relay station. In either case, when the broadcast notification command is received on this control CH, the reception channel of the radio reception unit RX is controlled to be switched to the broadcast # 4D-ch.

The relay station device (c) consists of independent radio receivers RX1 to RX4, RXC and radio transmitters TX1 to TX4, TXC for 5 channels.
Are provided corresponding to the channels (however, 3CHs of # 1 to # 3 are not shown), and have a signal control device 31, a 25-second timer 32, and an incoming call disconnection detection unit 33. The incoming call detection unit 33 generates a timer stop signal when detecting disconnection of # 4 Dch. In addition, the radio receiving unit RXC of the control channel generates a timer start signal for starting the timer 32 when receiving a simultaneous notification command generation request from the control center via the control channel. During normal operation, the signal control device 22 relays the upstream reception signals of the respective speech channels received by the wireless reception units RX1 to 4 to the wireless transmission units TX1 to TX4 of the corresponding channel and sends them as downstream transmission signals. Relay calls between mobile stations.

FIG. 2 is an operation time chart showing the broadcast channel capturing operation at the time of call congestion in the MCA wireless communication system having the above-mentioned configuration. When performing a simultaneous call, if the call channel for the simultaneous call is not used, there is no problem because the simultaneous call channel can be used immediately after notifying all mobile stations of the simultaneous call by the simultaneous call command. Therefore, the broadcast notification operation at the time of call congestion in which the broadcast channel (# 4-ch) is also used for general calls will be described with reference to FIGS.

The control center properly operates the operation unit 12.
(For example, pressing the "simultaneous notification" button) causes the signal control unit 13 to output a "simultaneous notification signal request command", which is transmitted from the control CH wireless transmission unit TXC. At the same time, the timer 14 is started. In the conventional technology, the timer is set to the standby state for 25 seconds and no operation is accepted, but in the present embodiment, the timer operation is stopped and the standby state is released by the timer stop signal from the incoming call detection unit 11. Then, the microphone switch 18 operates and the broadcast message can be input to the # 1CH wireless transmission unit TX1.

When the control station receives the "simultaneous notification signal request command" from the control center at the radio receiving unit RXC for control CH, the signal control device 31 first sends the # 4 D-ch radio transmitting unit TX4. , # 4D-ch is used to send an end signal to the mobile station in communication (about 1 second). As a result, the mobile station ends the general call and enters the CD-ch standby state. Then, the signal control device 31 detects all mobile station acquisition signals (#
4D-CH standby instruction), and the wireless transmitter TXC for the control channel
Sends to all the mobile stations and starts the 25-second timer 33. As a result, the all mobile station acquisition signal (broadcast notification command) is sent for a maximum of 25 seconds.

Since this system is a simplex system, the end signal from the control station via # 4D-ch cannot be received by the mobile station that is transmitting the call on # 4U-ch. However, regardless of transmission / reception, all mobile stations in a call will switch from the call channel to the CD-ch momentarily every 20 seconds by the monitor function, and will monitor the CD channel. Can be received.

The mobile station receiving the broadcast notification command immediately stops transmission and waits on # 4D-ch. Subsequent transmissions are prohibited. In the relay station, when there is no incoming call to the # 1U-ch wireless receiving unit, the call stop detection unit 32 outputs a timer stop signal, and the 25-second timer 33 stops. As a result, the # CD-ch wireless transmission unit TXC of the relay station is stopped.

# CD-ch radio receiving section of control center device
When there is no RXC incoming call, the call termination detection unit 11 outputs a timer stop signal and the 25-second timer 14 stops. As a result, the microphone switch 18 is turned on, and the microphone 17 broadcasts all the voice signals. This voice signal is transmitted to the # 1 U-ch wireless transmitter TX1.
Is transmitted to the relay station via.

The relay station receives the broadcast message via the # 1 U-ch radio reception unit RX1, and this notification voice is transmitted to all mobile stations via the # 1D radio transmission unit TX1. Since each mobile station is in the # 1 D-ch standby state, it can receive the broadcast voice.

[0028]

As described above, according to the present invention, when a forced interruption for broadcast from the control center is made during a call congestion during use of all the call channels, the relay station uses the broadcast channel. It is possible to quickly detect the end of the call of the mobile station being used and notify the control center, and the control center can automatically set the simultaneous call status, so even in an emergency, a quick and reliable simultaneous call can be sent. The effect is that it can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of an MCA wireless communication system of the present invention.

FIG. 2 is an operation time chart for simultaneous notification according to the present invention.

FIG. 3 is a schematic diagram of an MCA wireless communication system to which the present invention is applied.

FIG. 4 is an operation time chart for simultaneous notification of the related art.

[Explanation of symbols]

1 ... Control center, 11 ... Call disconnection detection unit, 12 ... Operation unit, 13 ...
Signal control unit, 14 ... 25 second timer, 2 ... Mobile station, 3 ... Relay station
(MCA control station) 2, 31 ... Signal control device, 32 ... Call disconnection detection unit,
33 ... 25 second timer

Claims (1)

[Claims] 1. A mobile station comprising a plurality of mobile stations and a control center for simultaneous notification to the mobile stations, and a relay station for relaying and controlling communication between the mobile stations, and having a plurality of communication channels. M, which also uses one of them as a broadcast channel
In the CA wireless communication system, when the relay station receives a broadcast notification command transmission request from the control center, the relay station sends out a call end signal via the call channel for broadcast and sends a broadcast notification command via the control channel. When the broadcast channel is sent out and there is no incoming call on the call channel for broadcast, it is controlled to stop sending the broadcast command, and the control center monitors the control channel after requesting the broadcast command transmission. A multi-channel access wireless communication system, wherein the multi-channel access wireless communication system is controlled so as to enter a simultaneous notification state when it is detected that the incoming call has been lost.