JPH0738953A - Speech channel allocation system for mobile communication system - Google Patents

Abstract

PURPOSE:To provide a speech channel allocation system for a mobile communication system in which allocation of different priority groups is attained for adjacent base stations and the contention of the same speech channel allocated for the same time zone is minimized. CONSTITUTION:In the system by which one of divided frequency bands of speech channels into some groups is allocated as a priority group used by the station in use with priority to a base station 1 making radio communication with a mobile station, a priority group control means 4 of the base station 1 detects a priority group number of other base station received via a radio section 2 and the priority group of a number different from the detected priority group number is controlled to be allocated to the station in use and a control section 4' retrieves an idle speech channel of the priority group allocated by the means 4 and radio communication is made by the retrieved line of idle speech channel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speech channel allocation system in a mobile communication system. In PHP (simple mobile phone), call channels are assigned by the MCA (multi-channel access) method. This system searches for a free call channel for each call and assigns it to the call.

In the MCA system, in principle, a competition in which a plurality of base stations simultaneously allocate the same speech channel may occur. When contention occurs, the serviceability deteriorates because the call is lost or the time required for call connection is long due to the detouring process for allocating another speech channel again.

Therefore, there is a demand for a call channel assignment system which can prevent such a call channel assignment conflict as much as possible.

[0004]

2. Description of the Related Art FIG. 14 is a layout diagram of a PHP base station.
It is for explaining the priority allocation method of the communication channel in the PHP system.

In the figure, C1 to C6 are base stations. The service area Z1 is generated by radio waves transmitted from the base stations C1 to C6.
~ Z6 are formed. Further, priority group numbers G1 to G4 are assigned to the base stations C1 to C6. The priority group numbers G1 to G4 divide the frequency band of the speech channel transmitted from the base stations C1 to C6 to the PHP mobile station (not shown) into several groups, and the divided speech channel groups have different numbers. Is assigned so that the communication channel group having the same number is not allocated to the neighboring base stations.

Each of the base stations C1 to C6 is designed to preferentially use the speech channel group assigned to each base station. This call channel group used preferentially is defined as a priority group.

That is, the base stations C1 to C6 first perform an operation of searching and assigning a call channel belonging to the priority group of the own station as the first candidate when requested to assign the call channel due to the occurrence of a call. If there is no free channel in the priority group, another call channel group is searched.

[0008] As described above, a method is currently devised to reduce the contention of the speech channel allocation by operating and operating the base station so that the same speech channel is not allocated to the neighboring base stations as much as possible.

[0009]

By the way, in the above-mentioned system, for example, when the base station is mounted on a moving body such as an automobile or a train, the base station of the moving body (hereinafter, referred to as a mobile base station). Approaches or enters a fixed base station with the same priority group number, for example, the mobile base station C0 assigned with the priority group number G1 shown in FIG. 15 moves and the fixed base station with the same priority group number G1 moves. When approaching or entering C1, the same call channel group is set as the first candidate between neighboring base stations, so there is a problem that the probability of competition such as allocating the same call channel to the same time zone increases.

The present invention has been made in view of the above circumstances, and makes it possible to allocate different priority groups to neighboring base stations and to reduce the competition in which the same speech channel is allocated in the same time zone as much as possible. It is an object of the present invention to provide a call channel allocation method in a mobile communication system capable of performing the above.

[0011]

FIG. 1 shows the principle of the present invention. In the figure, reference numeral 1 is a base station that performs wireless communication with a mobile station.

A radio unit 2 receives various signals transmitted from a mobile station (not shown) and other base stations, and
It transmits various signals of its own station. Reference numeral 4 denotes a priority group control means, which is a characteristic element of the present invention, detects a priority group number of another base station input via the radio unit 2, and selects a priority group having a number different from the detected priority group number. It is controlled to be assigned to.

Reference numeral 4'denotes a control unit, which searches for a free call channel of the priority group assigned by the priority group control means 4 and controls so that wireless communication is performed on the searched free call channel. Is.

[0014]

According to the present invention described above, for example, the mobile base station can grasp the priority group being used by the neighboring base station from the reception control signal, and determine the priority group of the own station accordingly.

Therefore, the mobile base station can always determine its own priority group so that the priority group does not overlap with the neighboring base stations in the current location, and the competition of the communication channel assignment is made no matter where the mobile base station moves. Can be reduced.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram of a mobile base station for realizing the communication channel allocation system in the PHP system of the first embodiment of the present invention.

In FIG. 2, reference numeral 1a is a mobile base station.
The mobile base station 1a is mounted on a moving body such as an automobile or a train, and assigns a channel of a predetermined channel to each of a large number of PHP mobile stations (not shown) to control radio communication performed by the mobile station. Is.

In the mobile base station 1a, 2 is a radio unit, 3 is
Is an antenna. FIG. 3 shows an internal block configuration diagram of the wireless unit 2. As shown in FIG. 3, the wireless unit 2 includes a synthesizer unit 31, a modulation unit 32, a power amplification unit 33, and a reception RF.
It is configured to include a unit 34, a reception IF unit 35, and a demodulation unit 36.

The radio section 2 modulates a communication signal such as a control signal and a call signal into a control channel signal or a call channel signal in a radio frequency band whose frequency is controlled by the synthesizer section 31 by the modulating section 32, and power The signal is amplified by the amplifier 33 and transmitted to the PHP via the antenna 3.

On the other hand, a reception RF unit 34 and a reception IF unit 35 receive control channel signals and call channel signals in the radio frequency band.
And is demodulated into communication signals such as control signals and communication signals by the demodulation unit 36.

Reference numeral 4a shown in FIG. 2 is a channel assignment control device, which controls the mobile base station 1a by a CPU as a whole, and which is a characteristic element of this embodiment, CSI.
It comprises a D (base station identification number) detector 5 and a priority group calculator 6.

Further, the channel allocation control device 4a is shown in FIG.
It can be realized by the hardware configuration shown in. In this case, the processing operations of the CSID detection unit 5 and the priority group calculation unit 6 described later can be realized by software.

That is, the ROM 41 or the RAM 4 shown in FIG.
The above software (program) may be stored in any one of the two, and the CPU 43 may perform the processing operation according to the stored program.

Hereinafter, the processing operation by the program will be described as the processing operation of the CSID detection unit 5 and the priority group calculation unit 6 shown in FIG. The CSID detection unit 5 receives the control signal of the control channel output from the wireless unit 2.

The control signal has a layer 1 slot structure as shown in FIG. 5, and includes a CSID field having a length of 42 bits starting from the 104th bit. This CSID
Is the CSID of another base station in the vicinity.

First, the CSID detection section 5 receives the C signal from the control signal, as shown in step S1 of the flowchart of FIG.
Extract the SID. Next, as shown in step S2,
The priority group is obtained from the CSID by a known method. Since the remainder of the CSID divided by the grouping number is used as the priority group number, which priority group is obtained by calculating the priority group number from the inverse calculation.

Then, the determined priority group number is notified to the priority group calculation unit 6 as shown in step S3. As shown in step S4, the priority group calculation unit 6 refers to the priority group calculation table shown in FIG. 7 and selects a priority group number (eg, 6) of its own station different from the priority group number of another station (eg, 2). To do. That is,
Control is performed such that a communication channel group different from the communication channel group of the near base station notified by the CSID detection unit 5 is set as a lower priority group.

Note that another base station (not shown) supplements the communication channel by a known method of determining its own priority group using the CSID as a parameter. In such a configuration, when the mobile station notifies the channel allocation control device 4a of the call channel allocation request via the radio unit 2 of the mobile base station 1a, the CSID detection unit 5 causes the neighboring base station to perform the above-described operation. A priority group number used by the station is detected, and a priority group number different from the detected priority group number is selected and set by the priority group calculation unit 6.

After that, by the control performed by the CPU as in the prior art, an empty call channel belonging to the priority group set in the own station is searched, and wireless communication is performed using the line of the searched empty call channel. A request is made to the wireless unit 2 and a command is issued to the wireless unit 2 to notify the mobile station of the request.

According to the first embodiment described above, the CSID detection unit 5 of the mobile base station 1a knows the priority group being used by the neighboring base station based on the CSID included in the layer 1 information in the control channel signal. Therefore, a different group can be set as the priority group of the own station accordingly. This makes it possible to reduce the contention of the speech channel allocation.

Therefore, when the priority group is fixedly set in advance to the base station, which has been a problem in the related art, the priority group is the same as the neighboring base station of the moving destination due to the movement of the mobile base station, and the channel allocation is performed. It is possible to solve the deterioration of the service such as a call loss and a long connection time due to the competition.

Next, a second embodiment will be described with reference to FIG. However, in FIG. 8, parts corresponding to the respective parts of the first embodiment shown in FIG. 2 are designated by the same reference numerals, and description thereof will be omitted. The feature of the second embodiment is that the priority group of neighboring base stations is known from the contents of the higher layer information of the received control channel signal.

In FIG. 8, the higher layer detecting section 7 receives the control signal of the control channel output from the radio section 2. The layer 1 slot structure of the control channel has an information field, and this information field contains the higher layer information of the configuration of the neighboring base stations shown in FIG.

The high layer detecting section 7 first determines whether or not the received control signal includes the priority group number, as shown in step S1 of the flowchart of FIG. As a result, if the priority group number is not included, the process proceeds to “NO” to receive the control signal again.

If the priority group number is included, the determination result is "YES", and the process advances to step S2 to extract the priority group number from the higher layer information shown in FIG. Then, as shown in step S3, the extracted priority group number is notified to the priority group calculation unit 6.

It should be noted that another base station (not shown) displays its own priority group in the higher layer information field of the control signal of the control channel. In such a configuration, when the mobile station notifies the channel allocation control device 4b of the call channel allocation request via the radio unit 2 of the mobile base station 1b, the higher layer detection unit 7 makes the neighbors closer to the channel allocation control unit 4b as described above. A priority group number used by the base station has been detected, and a priority group number different from the detected priority group number is selected and set by the priority group calculation unit 6.

After that, the CPU searches the free call channel from the priority group, performs wireless communication using the channel of this channel, and notifies the mobile station of that fact.
Command to.

According to the second embodiment described above, the higher layer detector 7 of the mobile base station 1b can know the priority group of the neighboring base stations included in the higher layer information in the control channel signal. Accordingly, different groups can be set as the priority group of the own station. This makes it possible to reduce the contention of the speech channel allocation.

Next, a third embodiment will be described with reference to FIG. However, in FIG. 11, parts corresponding to the respective parts of the first embodiment shown in FIG. 2 are designated by the same reference numerals, and description thereof will be omitted.

The feature of the third embodiment is that the priority group of its own station is determined so as to avoid a group having a large number of communication channels in use. The call channel detection unit 8 shown in FIG. 11 detects a group having many call channels in use by judging the available / used state of all call channels from the call channel electric field strength information received from the wireless unit 2. This is regarded as the priority group of the neighboring base stations and notified to the priority group calculation unit 6.

However, the call channel electric field strength information is shown in FIG.
RAM that can be written / read as a table as shown in
Are stored in storage means such as. The table shown in FIG. 12 is configured by arranging the group number, the electric field strength measurement result, and the determination result of whether the communication channel is idle or in use for each communication channel number.

The processing operation of the call channel detector 8 is shown in FIG.
This will be described with reference to the flowchart in FIG. First, as shown in step S1, the wireless unit 2 is requested to measure the electric field strength of the designated communication channel. In this case, the frequency and slot of the communication channel are designated.

In response to this request, as shown in step S2, the electric field strength measurement result of the designated channel is returned from the radio section 2 to the call channel detecting section 8. It is determined whether it is free or in use, and as shown in FIG. 12, information of free or in use is stored in the determination result column of the table according to the determination.

Next, as shown in step S3, it is judged whether or not the measurement of the electric field strength is completed in all the communication channels. If the determination result is NO, the process returns to step S1 and the measurement is performed again. If YES, step S4
As shown in FIG. 11, the communication channel electric field strength information table is referred to, and it is determined from the determination result therein that the group having the most used channels is the priority group used by the neighboring base station (neighboring base station). .

Then, as shown in step S5, the priority group number which is the result of the determination is notified to the priority group calculation unit 6. After that, the operations of steps S1 to S5 are appropriately repeated as indicated by the broken line.

In such a configuration, when the mobile station notifies the channel assignment control device 4c of the call channel assignment request via the radio section 2 of the mobile base station 1b, the call channel detecting section 8 as described above. The priority group number used by the neighboring base station is detected by the, and a priority group number different from the detected priority group number is selected and set by the priority group calculation unit 6.

After that, the CPU searches the idle call channel from the priority group, performs wireless communication using the channel of this channel, and notifies the mobile station of the fact so that the wireless unit 2 is notified.
Command to.

According to the third embodiment described above, the priority channel group of the neighboring base stations can be known from the speech channel field strength information by the speech channel detection unit 8 of the mobile base station 1c, and accordingly, a different group can be obtained. Can be the priority group of its own station. This makes it possible to reduce the contention of the speech channel allocation.

[0049]

As described above, according to the present invention,
Since different priority groups can be assigned to neighboring base stations, there is an effect that contention in which the same communication channel is assigned in the same time zone can be reduced as much as possible.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a block configuration diagram of a mobile base station for realizing a speech channel allocation system in the PHP system of the first embodiment.

FIG. 3 is a block configuration diagram of a wireless unit.

FIG. 4 is a block configuration diagram of a control unit.

FIG. 5 is a diagram showing a structure of a control channel signal.

FIG. 6 is a processing flowchart of a CSID detection unit and a priority group calculation unit.

FIG. 7 is a diagram showing an example of a priority group calculation table used when the priority group calculation unit detects a priority group number.

FIG. 8 is a block configuration diagram of a mobile base station for realizing a speech channel allocation system in the PHP system of the second embodiment.

FIG. 9 is a diagram showing a structure of higher layer information.

FIG. 10 is a processing flowchart of a higher layer detection unit.

FIG. 11 is a block configuration diagram of a mobile base station for realizing a speech channel allocation system in the PHP system of the third embodiment.

FIG. 12 is a diagram showing an example of a speech channel electric field strength information table.

FIG. 13 is a processing flowchart of a call channel detection unit.

FIG. 14 is a layout diagram of a PHP base station.

FIG. 15 is an explanatory diagram of speech channel competition between a mobile base station and a fixed base station.

[Explanation of symbols]

 1 base station 2 radio section 4 priority group control means 4'control section

Claims (5)

[Claims] 1. A base station (1) for wireless communication with a mobile station,
In a call channel assignment method in a mobile communication system for performing control to assign one of the frequency bands of the call channel to several groups as a priority group that the local station preferentially uses, the base station (1) Priority group control means (4) for detecting the priority group number of another base station input via the radio section (2) and controlling so as to allocate a priority group number different from the detected priority group number to the own station. Is provided, and the control unit (4 ′) controls to search for an empty call channel of the priority group assigned by the priority group control means (4) and perform wireless communication on the line of the searched empty call channel. A communication channel allocation method in a mobile communication system, comprising: 2. A base station (1a) that wirelessly communicates with a mobile station,
In the communication channel allocation method in the mobile communication system for performing control to allocate one of the frequency bands of the communication channel into several groups as a priority group that the local station preferentially uses, the base station (1a) , A base station identification number detecting means for extracting a base station identification number from a control signal of another base station inputted via the radio section (2) and detecting a priority group number of the other base station from the base station identification number
(5) and a priority group calculation means (6) for controlling so that a priority group having a number different from the priority group number of the other base station is allocated to the own station, and the priority group calculation means (6) allocates the priority group. A call channel allocation method in a mobile communication system, characterized in that wireless communication is performed on a line of a free call channel of the priority group. 3. A base station (1b) for wireless communication with a mobile station,
In a call channel assignment method in a mobile communication system for performing control to assign one of the frequency bands of the call channel to several groups as a priority group that the own station preferentially uses, the base station (1b) , A higher layer detecting means (7) for detecting the priority group number of the other base station from the higher layer information of the control signal of the other base station input via the radio unit (2), and the priority group of the other base station A priority group calculation means (6) for controlling to assign a priority group of a number different from the number to its own station is provided, and the priority group calculation means (6) wirelessly communicates on the line of the idle call channel of the priority group assigned by A communication channel allocation method in a mobile communication system characterized in that communication is performed. 4. A base station (1c) that performs wireless communication with a mobile station,
In a call channel assignment method in a mobile communication system for performing control to assign one of the frequency bands of the call channel to several groups as a priority group that the local station preferentially uses, the base station (1c) , It is judged from the measurement results of the electric field strength of all the communication channels obtained by requesting the measurement to the wireless unit (2) that the communication channels are free / in use, and the group number with many communication channels in use is given priority to other base stations. A call channel detection unit (8) for setting a group number and a priority group calculation means (6) for controlling to assign a priority group having a number different from the priority group number of the other base station to the own station are provided. A call channel assignment method in a mobile communication system, wherein wireless communication is performed on a free call channel line of a priority group assigned by a computing means (6). 5. The communication channel allocation system in a mobile communication system according to claim 1, wherein the base station (1, 1a, 1b, 1c) is installed in a mobile body.