JPS6288446A - Mobile communication system - Google Patents

Abstract

PURPOSE:To improve the utilizing efficiency of a control channel by applying idle line control in the unit of each radio zone. CONSTITUTION:An idle line signal is sent repetitively uniformly to radio zones 60a, 60b, 60c, 60d and 60e at a prescribed time interval. Then suppose that a mobile station 21 confirms an idle line signal No.2 in the radio zone belonging to a radio base station 61 and sends a call signal in synchronizing with the timing of an idle line signal No.3 and the call signal is received by radio base stations 61, 63. Then the radio base stations 61, 63 stop the sending of the idle linen signal No.3 to send the inhibition signal and a channel designation signal follows the inhibition signal. On the other hand, radio base stations 62, 64 and 65 not receiving the call signal send the idle line signal No.3 succeeding to the idle line signal No.2 and the channel designation signal follows thereafter. As a result, the idle line control in the unit of radio zones and the control channel is utilized effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a mobile communication system, and particularly to an idle line control technique for performing collision avoidance control of control signal transmission requests randomly generated from a plurality of mobile stations.

(Prior art) The car telephone system as a mobile communication system is
As shown in the figure, there are a plurality of wireless zones 60a, 60b, and 60c that divide the service area.

Radio base stations 61. Same 62. Same 63. Same 64. and 65, and each wireless base station 61. Same 62. Same 63. 64 and 65
a wireless network control station 70 that collectively manages the mobile stations 21. Same 22. Same 23. 24° and 25°, and the radio line control station 70 is connected to the general telephone switching network.

This car telephone system has a control channel used for controlling appropriate allocation of call channels in response to call requests from subscribers.

This control channel consists of an incoming control channel used for incoming call connection to the mobile station and broadcasting of control information, and an outgoing control channel used for outgoing call connection from the mobile station and reporting/registration of the status of the mobile station. This control channel is arranged with a plurality of radio zones controlled by the radio network control station 70 as one unit.

In other words, multiple zone control is employed.

In such a multi-zone control system, since calls and location registrations from mobile stations occur randomly, multiple mobile stations simultaneously send control signals (calling signals or location registrations) via the same calling control channel. Idle line control is performed to control signal collision when a registered signal is sent.

That is, an idle line control signal is provided on the downlink transmission control channel,
The mobile station is enabled to transmit a control signal when the idle line control signal is an "empty line signal", and is prohibited from transmitting when it is a "prohibition signal". The "idle line signal" indicates that the uplink transmission control channel is "empty" as there is no control signal from the mobile station, and when a control signal is sent from one mobile station, the "idle line signal" becomes a "prohibition signal". can be switched to

This idle line control is performed by the radio line control station 7o, and each radio base station merely relays the information.

Note that the idle line control ff1 is used for the downlink transmission control channel.
The signal pond is provided with a channel (communication channel) designation signal corresponding to a calling signal and a location registration acceptance signal corresponding to a location registration signal.

(Problem to be Solved by the Invention) By the way, idle line control is adopted to prevent control signals sent by mobile stations from interfering with each other and colliding with each other on the transmission control channel, resulting in not being received by the radio base station. It is a technology that has been developed.

However, since conventional idle line control is performed in the same manner at all radio base stations controlled by the radio line control station 70, for example, the mobile station 21 sends out a control signal and a radio line is set up between the radio base stations 61. In this case, the mobile stations 24, 25, etc. which are not affected by the mobile station 21 will not be able to send out control signals, resulting in a disadvantage that the use efficiency of the outgoing control channel will be low.

An object of the present invention is to improve the efficiency of use of control channels by performing idle line control for each radio zone.

(Means for Solving the Problems) In order to achieve the above object, a mobile communication system according to the present invention includes: a mobile station; a radio network control station that unifies a plurality of radio zones and controls them using one control channel; a radio base station that is located in each of the plurality of radio zones and sets up a radio link with the mobile station within its own radio zone under the control of the radio link control station; In a mobile communication system in which transmission control of a control signal to be sent to a wireless base station is performed based on the contents of an idle line control signal from the wireless base station, the wireless base station: a prohibition signal generator that generates a signal; when a control signal is sent from the mobile station that has confirmed an idle line signal that is one of the idle line control signals, the prohibition signal is generated in place of sending the idle line signal; The present invention is characterized by comprising: a switching means for transmitting a prohibition signal from the generator; and;

(Function) Next, the single layer operation of the mobile communication system configured as above will be explained.

In each wireless zone, the mobile station confirms that the idle line control signal of the downlink control channel sent from the wireless base station side is an idle line signal, and responds to the transmission request by sending control signals (such as calling signals and location registration signals). etc.), the switching means in the wireless base station is activated and sends out an internally generated prohibition signal instead of the idle line signal as the idle line control signal for the downlink control channel.

As described above, according to the present invention, idle line signals may be generated by a radio base station or by a radio network control station, but in either case, a prohibition signal can be sent at the radio base station's own discretion. Therefore, idle line control can be performed for each wireless zone.

As a result, the uplink control channel can be used in wireless zones other than the wireless zones where there is a possibility that the wireless base station may not be able to receive signals due to signal collision on the uplink control channel, and the efficiency of use of the control channel is improved.

(Example) Hereinafter, each example of the present invention will be described with reference to the drawings. Note that the following explanation will focus on the radio base station, and the configuration of the entire system including the mobile station and the radio network control station is the same as that shown in FIG. 6 above. FIG. 1 shows the configuration of a wireless base station according to an embodiment of the present invention.

This radio base station includes a transmitting section composed of a demodulator 1, a jitter suppressor 2, a switching circuit 3, and a transmitter 4, a receiver 5,
A receiving section consisting of an uplink signal processing section 6 and a modulator 7, an idle line control section consisting of a relay signal detector 8 and a prohibition signal generator, and an antenna 10 for transmitting and receiving radio waves with a mobile station. It basically includes an antenna 10 and a duplexer 11 that connects the transmitting section and the receiving section.

Demodulator 1 and modulator 7 are connected to a radio network control station via a control line. Each signal of the control channel for the radio network control station to control a plurality of zones is transmitted to the control line.

Here, the configuration of the control channel is the same in the present invention as in the prior art, or the generator of the idle line control signal (the idle line signal and the prohibition signal) on the downlink side of the outgoing control channel is as follows in this first embodiment. It looks like this. That is, the radio channel control station generates only an idle line signal, and the prohibition signal is generated by the prohibition signal generator 9 of the radio base station.

In other words, each signal of the downlink transmission control channel input to the demodulator 1 constitutes a relay signal that is transmitted as is to the mobile station, and this relay signal is restored by the demodulator 1 and sent to the jitter suppressor 2.
is input. The jitter suppressor 2 receives the demodulated output and outputs a restored relay signal free of jitter components to one input terminal of the AND gate 31 of the switching circuit 3 and the relay signal detector 8, and also outputs the clock signal ck extracted from the demodulated output. is output to the relay signal detector 8 and prohibition signal generator 9, respectively. As a result, the relay signal generator 8 and the prohibition signal generator 9 operate in synchronization with the clock of the radio network control station.

When the relay signal detector 8 detects an idle line signal among the relay signals, it sets its output to the 0'' level, and when it detects a signal other than the idle line signal (i.e., a channel designation signal, etc.), its output changes to the '1'' level. This output state is passed through one input terminal of the OR gate 12 to the AND of the switching circuit 3.
It is applied to the other input terminal of gate 31.

The switching circuit 3 includes two AND gates 31. 32, an inverter 33, and an OR gate 34. AND
One input terminal of the gate 32 is connected to the other input terminal of the AND gate 31 via an inverter 33, and the other input terminal is connected to the output terminal of the inhibit signal generator 9. Also, the OR gate 34 is the output (relay signal) of the AND gate 31.
and the output (inhibition signal) of the AND gate 32 are input, and either one of the outputs is given to the transmitter 4.

The transmitter 4 receives the output of the switching circuit 3 and transmits it to the mobile station via the duplexer 11 and the antenna 10.

On the other hand, each signal (upper redata) of the uplink transmission control channel generated by the mobile station is transmitted to the antenna 10. Dual transmitter/receiver 11. Receiver 5. Upstream data processing unit 6. and is transmitted to the radio network control station via the modulator 7.

At this time, the receiver 5 has a function of detecting and outputting the presence or absence of upstream data, and the detection output is given to the other input of the OR gate 12 via the inverter 13.
It is input to the reset terminal R of the prohibition signal generator 9. This detection output is set to a level of 1 when an upstream signal is detected.

Note that the upstream data processing section 6 mainly performs error control. The prohibition signal generator 9 is initialized in response to the detection output from the receiver 5 being input to the reset terminal R, and generates a prohibition signal of a predetermined time width based on the clock signal ck.

Next, the operation of the radio base station configured as above will be explained. First, the radio network control station repeatedly sends out idle line signals at predetermined time intervals. This is inputted to one input terminal of the AND gate 31 of the switching circuit 3 via the demodulator 1 and the jitter suppressor 2.

At this time, the relay signal detector 8 detects the idle line signal and sets the output to the "0" level. However, since the upstream signal detection output of the receiver 5 is at the "0" level, this
3 and becomes the "1" level, which is input to the other input terminal of the AND gate 31 via the OR gate 12. As a result, the idle line signal is output to OR gate 34. Transmitter 4. The signal is transmitted to the mobile station via the duplexer 11 and antenna 10.

Next, when the uplink data from the mobile station is input to the receiver 5 via the antenna 10° duplexer 11, the receiver 5 outputs the uplink data to the radio network control station via the uplink data processing unit 6 and modulator 7. At the same time, the upstream data detection output is set to 1 level. Then, in the switching circuit 3, AN
The other input of the D gate 31 becomes 0 level, and the output becomes 0 level. On the other hand, one input of the AND gate 32 becomes the ``1'' level due to the action of the inverter 33, and the output of the inhibit signal generator 9 applied to the other input can pass through.

At the same time, the prohibition signal generator 9 causes the output of the inverter 13 to be “0”.
In response to the change to the `` level, an inhibition signal of a predetermined time width is output.As a result, the switching circuit 3
・Instead of the idle line signal sent through 31, AND
A prohibition signal will be sent through the gate 32.

On the other hand, the radio network control station that received the uplink data,
For example, a channel designation signal for instructing a calling mobile station to select a communication channel is sent out subsequent to the idle line signal that has been sent out so far.

Then, the relay signal detector 8 detects the channel designation signal and sets the output to the "1" level, so the switching circuit 3
Gate switching from D gate 32 to AND gate 31 is performed. As a result, a channel designation signal is sent from antenna 10 toward the mobile station.

What should be noted here is that the idle line signal and channel designation signal sent out by the radio network control station are the same for each radio base station, and only the idle line signal is used as a prohibition signal for each radio base station as appropriate. This means that it can be switched to. Therefore, the idle line control of the entire system as shown in FIG. 6 centered on the radio line control station is performed as shown in FIG. 2.

In FIG. 2, first, each wireless zone 60a.

A vacant line signal is uniformly and repeatedly transmitted to the same 60b, 60C1, 60d, and 60e at predetermined time intervals (FIG. 2(A)). Next, for example, it is assumed that the mobile station 21 confirms the idle line signal #2 in the wireless zone 60a belonging to the wireless base station 61 and sends out a calling signal in synchronization with the generation timing of the idle line signal #3. )), this calling signal is sent to the wireless base station 61. Suppose that it was received at 63.

Then, the wireless base station 61. At step 63, transmission of idle line signal #3 is stopped and a prohibition signal is transmitted, and this prohibition signal is followed by a channel designation signal (FIG. 2(C)). On the other hand, the wireless base station 62. which did not receive the calling signal. Same 64
At 65, idle line signal #3 is sent out following idle line signal #2, followed by a channel designation signal (FIG. 2(D)). As described above, according to the present invention, idle line control can be performed in units of wireless zones, and control channels can be used effectively.

Next, FIG. 3 shows a wireless base station according to another embodiment of the present invention. Note that the same parts as in FIG. 1 are designated by the same reference numerals and their explanations will be omitted.

In the second embodiment, in addition to a relay signal detector 31 having the same function as the relay signal detector 8, an idle line signal generator 32 and a switching circuit 33 are added, and the idle line control signal is transmitted to the radio base station. It is something that is going to happen on the side. Therefore, the downlink signal (relay signal) generated by the radio network control station is a channel designation signal, a location registration acceptance signal, etc. The relay signal detector 31 sets its output to the "1" level when a downlink signal is sent out from the radio channel control station, and sets its output to the "0" level when no downlink signal is sent out. This relay signal detector 31
The output is input to the other input terminal of the AND gate 31 of the switching circuit 3 and the reset terminal R of the idle line signal generator 32, respectively.

The idle line signal generator 32 is initialized when the output of the relay signal detector 31 is at the level 1', and when it is at the "o" level, it repeatedly generates an idle line signal at predetermined time intervals. Note that the idle line signal generator 32 operates together with the relay signal detector 31 and the prohibition signal generator 9 using the clock signal ck from the jitter suppressor 2.

The switching circuit 33 includes two AND gates 331 and 332.
, an inverter 333, and an OR game 1-334. One input terminal of the AND gate 331 is connected to the output terminal of the idle line signal generator 32, and the other input terminal is connected to the connection point between the output terminal of the inverter 333 and the reset terminal R of the inhibit signal generator 9. There is. AND gate 332
One input terminal is connected to the output terminal of the prohibition signal generator 9, and the local input terminal is connected to the input terminal of the inverter 333 and the receiver 5.
It is connected to the connection point with the upstream signal detection output terminal of. The OR gate 334 is connected to both AND gates 331 and 33.
Each output of 2 is input, and the output is AND of switching circuit 3.
to the other input of gate 32.

Next, the operation of the radio base station according to the second embodiment will be explained according to the flowchart shown in FIG.

In the first step 1, the presence or absence of a downlink signal is determined by the relay signal detector 31. First, in the idle line control stage, there is no down signal, so the determination result in step 1 is negative (No) and the process proceeds to step 2.

That is, the relay signal detector 31 sets its output to the "o" level, switches the gate of the switching circuit 3, and makes the idle line signal generator 32 ready for operation.

In step 2, the receiver 5 determines whether or not an upstream signal is detected, and the gate of the switching circuit 33 is switched based on the result. When there is no upstream signal, the AND gate 331 is activated, and when an upstream signal is detected, the AND gate 332 is activated.

In this case, the stage is before uplink signal detection, so step 2
The judgment result is negative (No) and proceed to step 3.
An idle line signal is generated by the idle line signal generator 32, and the process returns to step 1. The generation of this idle line signal is repeated until the determination result in step 2 becomes affirmative (YES).

Next, if the determination result in step 2 is affirmative (YES), the prohibition signal generator 9 generates a prohibition signal, and the process returns to step 1. Then, the radio network control station that has received the uplink signal sends out a downlink signal, which is detected by the relay signal generator 31, and the determination result in step 1 becomes affirmative (YES).

As a result, gate switching is performed in the switching circuit 3,
The downlink signal is relayed as is to the mobile station (step 5)
. As described above, the same effects as in the first embodiment can be obtained in this second embodiment as well.

Note that the mobile station operates according to the flowchart shown in FIG. In FIG. 5, it is determined whether a call or location registration transmission request has occurred (step 11), and if there is a transmission request, it is determined whether an idle line signal has been received (step 12). When an idle line signal is received and the determination result in step 12 is affirmative (YES), processing for transmitting uplink signals such as a calling signal and a location registration signal is performed (step 13), and the process returns to step 11 to start a new transmission. Prepare for.

On the other hand, if an idle line signal cannot be received, that is, a prohibition signal or the like is received, the determination result in step 12 is negative (No).
The process then proceeds to step 14, where it waits for reception of an idle line signal for a specified time. Then, if the idle line signal cannot be received within the specified time, the judgment result in step 14 is affirmative (YES).
Then, the standby process is performed (step 15), and the process returns to step 11.

(Effects of the Invention) As detailed above, according to the mobile communication system of the present invention, the wireless base station includes a prohibition signal generator that generates a prohibition signal that is one of the idle line control signals, and a prohibition signal generator that generates a prohibition signal that is one of the idle line control signals. A switching means is provided for transmitting a prohibition signal from the prohibition signal generator instead of transmitting the vacant line signal when a control signal is transmitted from a mobile station that has confirmed an idle line signal, which is one of the control signals. Therefore, idle line control can be performed for each wireless zone. As a result, the control channel can be used in a wireless zone other than the wireless zone where there is a possibility that the wireless base station may not be able to receive signals due to signal collision on the control channel, and the efficiency of using the control channel is improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a wireless base station according to an embodiment of the present invention, FIG. 2 is an explanatory diagram for explaining idle line control for each wireless zone, and FIG. 3 is a block diagram showing the configuration of a wireless base station according to an embodiment of the present invention. FIG. 4 is a flowchart showing the operation of the radio base station shown in FIG. 3, FIG. 5 is a flowchart showing the operation of the mobile station, and FIG. 1 is a configuration diagram showing a car telephone system as a mobile communication system to which the invention is directed. DESCRIPTION OF SYMBOLS 1...Modulator, 2...Jitter suppression section, 3゜33...Switching circuit, 4...
Transmitter, 5... Receiver, 7... Modulator, 8, 31... Relay signal generator, 9.
...Prohibition signal generator, 32...Idle line signal generator.

Claims (4)

[Claims] (1) A mobile station; a radio network control station that oversees multiple radio zones and controls them using one control channel; and a mobile station that is located in each of the multiple radio zones and that operates under the control of the radio network control station. a wireless base station for setting up a wireless link with the mobile station in the wireless zone; In a mobile communication system based on content; the radio base station; a prohibition signal generator that generates a prohibition signal that is one of the idle line control signals; and a prohibition signal generator that generates an idle line signal that is one of the idle line control signals. A switching means for transmitting a prohibition signal from the prohibition signal generator instead of transmitting the idle line signal when a control signal is transmitted from the confirmed mobile station; Communications system. (2) The mobile communication system according to claim (1), wherein the idle line signal is generated by the wireless base station. (3) the idle line signal is generated by the wireless line control station;
The mobile communication according to claim (1), wherein the wireless base station includes a relay means for relaying the idle line signal; and a detection means for detecting passage of the idle line signal. system. (4) The radio base station is characterized in that it is provided with synchronization control means for synchronizing the sending point of the idle line control signal with the control signal sent by the radio network control station. mobile communication system.