JPH01231529A - Retrieving system for control channel of mobile communication system - Google Patents

Abstract

PURPOSE:To shorten the retrieving time when a mobile station retrieves a control channel by starting the retrieval with preference at and after the channel allocated to a radio zone where the control channel so far used is allocated. CONSTITUTION:A mobile station 2 contains a memory means which stores the channel allocation data showing the channel allocation states of the radio zones A-N respectively and a detection means which detects a control channel used for communication control based on said channel allocation data. When the control channel is retrieved at the station 2, the retrieval is started with preference at and after the channel allocated to the radio zone where the control channel so far used is allocated. Thus the time required for retrieval of the control channel switched within the same zones A-N can be shortened. Then a period when the outgoing/incoming states are impossible at the station 2 can be minimized.

Description

Detailed Description of the Invention (Purpose of the Invention) (Industrial Field of Application) The present invention provides a mobile communication system in which a plurality of wireless base stations are located within each wireless zone using a control channel designated by a control station. The present invention relates to a control channel search method in a mobile communication system that controls communication with a station.

(Prior art) For example, it consists of a plurality of radio base stations, a mobile station that moves between the respective radio zones of the radio base stations, and a control station υ0 interposed between these radio base stations and the mobile station. In a mobile communication system, a wireless base station uses one empty channel (control channel) designated under the control of a control station from among multiple channels assigned to each wireless zone. It controls communication with mobile stations within the wireless zone of the person concerned.

FIG. 3 is a schematic diagram for explaining a conventional search method for control channels in this type of mobile communication system.

In FIG. 3, channels (CH3-Cl-16) that are permitted to be used are assigned to the radio base stations J shallow layer 1A to 1N so as not to overlap, respectively. A mobile station 2 is arranged so as to be movable between each radio zone A-'-N.

Suppose now that the mobile station 2 is in the wireless zone B of the non-FA base station 1B, and is performing communication control using channel CH8 among the multiple channels assigned to this wireless zone B as a control channel. It is assumed that there is

In such a situation, the control channel 17 may change to another channel as channel CH8 begins to be used for telephone calls, or the mobile station 2 may be connected to another radio base station (IC
If the mobile station 2 loses the ability to recognize Chitnel CH8 as a control channel as it moves to the wireless zone (C to N) of the mobile station 2 (IN), the mobile station 2 will control the subsequent communication using dark blue:
In order to continue, a new control channel must be acquired.

In this type of conventional mobile communication system 11, the order 3 in which to search for bran control channels is determined in advance, and the searches are repeated cyclically in the same direction.

As a result, the mobile station 2 sequentially switches the chitnel to be detected according to the search order 3 and proceeds with the search to see if it is a control channel.

And when the control channel is detected by this parsimony,
Thereafter, this control channel is captured and used for communication control as described above.

In such a conventional control channel search method, for example, in a situation where a previously used control channel starts to be used for a call and this control channel changes to another channel, a newly specified control channel is searched. If the channel has the search order immediately before the control channel that was used until then (in the example in Figure 3, the platform changes from channel CH8 that was used until then to Chitnel CH19), this Until the newly designated control channel (Buyanel Cl-(19)) is acquired,
- 1J to the mobile communication system according to the arrangement search Jundake 3
When searching almost all the allocated channels, it took 11U to 22.

Until this newly designated control channel can be captured, the mobile station 2 is unable to make or receive calls, so in the conventional mobile communication system, which takes a long time to search for a working channel as described above, it is difficult to carry the system. It was inevitable that the call volume would drop significantly.

This situation tends to become more pronounced as the number of wireless zones increases (or the number of channels allocated per wireless zone increases).

(Problem to be Solved by the Invention) As described above, in the control channel search method in the conventional mobile communication system described above, when the control channel that was previously used starts to be used for calls, etc., other channels become When switching occurs, all channels assigned to the system are searched cyclically in a fixed order, so the switched control channel has the search order immediately preceding the previously used control channel. In such cases, the search time becomes extremely long,
During this time, as the mobile station became unable to make and receive calls, the available capacity of the system decreased, making it impossible to operate the system efficiently.

The present invention has been made in view of the above-mentioned circumstances, and is a mobile communication system that can contribute to efficient system operation by reducing the search time for a switched control channel as much as possible and maintaining the communication that can be carried as a system. The purpose of this paper is to provide a search method for control channels in a system.

[Structure of the invention]

(Means for Solving the Problems) A search method for a control channel in a mobile communication system of the present invention includes, in a mobile station, a storage means for storing channel allocation data indicating channel allocation status for each wireless zone;
A detection means for detecting a control channel used for communication control based on the channel allocation data is provided, and when the mobile station searches for an 11η tuning channel, the control channel that has not been used until then is detected. The present invention is characterized in that the search is preferentially started from the assigned channel tJ in the assigned wireless zone.

(Function) In the present invention, when a mobile station newly searches for a control channel, the search is started from the assigned channel in the wireless zone to which the previously used control channel is assigned. In particular, the time required to search for a control channel that has been switched within the same wireless zone can be significantly reduced, making it possible to minimize the period during which mobile stations are unable to make or receive calls. become.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a schematic diagram for explaining a control channel search method in the mobile communication system of the present invention, and shows the arrangement of radio base stations 18 to 1N, channel assignment in each radio zone A to N, and movement. The movement form of station 2 is similar to that shown in FIG.

The reason why the control channel search method according to the present invention is different from the conventional one is that when the mobile station is forced to switch, for example, channel CH8, which had been used as a control channel, starts to be used for telephone calls. 2, the search for this new control channel is carried out in accordance with search order 4.

To realize this search, the mobile station 2 is provided with a storage means for storing the channel allocation status for each wireless zone (assumed to have the same form as shown in FIG. 1) as channel allocation data. There is.

As a method for storing this channel allocation data in the storage means, after the mobile station 2 turns on the power,
At the time when the channel for l is detected, the mobile station 2 requests the radio base stations 1A to 1N for data in the channel allocation, and in response to the request, the radio base stations 1A to 1N allocate the corresponding channel to the mobile station 2. Various methods are possible, such as transmitting allocation data.

Based on the data on channel Z1J thus collected, the mobile station 2 can always know in which wireless zone it is currently located.

The mobile station 2 is also equipped with detection means for detecting a control channel based on the Gooyennel allocation data.

Based on such requirements, an example of a control channel search method according to the present invention will be described in detail below with reference to flowchart 1- in FIG. 2.

Here, for example, assume that the control channel (CH3) that had been used until then has started to be used for telephone calls, and as a result, it becomes necessary to search for a new control channel that has been switched to another channel.

As a first step in this case, the mobile station 2 recognizes its own zone (wireless zone B) based on the channel assignment data described above, and then checks the channels assigned to the zone. The channel with the first search order (CH21) is set as the channel to be detected by the detection means (step 100).

Thereafter, the mobile station 2 uses the detection means to search for the first set channel to determine whether it is a control channel (step 101).

If it is detected through this search that the set channel corresponds to a control channel, the mobile station 2 captures this as a new control channel (step 102).
).

Thereafter, the mobile station 2 uses the acquired control channel to implement various communication systems under the control of a control station (not shown).

Separately, in the search in step 101, if it is detected that the set channel does not correspond to a control channel, then the mobile station 2 detects the detection target channel of the detection means (in the same zone). Set the channel (C1, 119) with the next search order (step 10).
3).

Furthermore, the mobile station 2 searches whether the search up to the last channel (CH6) as to whether it is a control channel has been completed or not (step 104), and if it is detected that the search up to the last channel has not been completed. Step 10 again
Return to 1 and check whether the set 21 funnel is the control button 1? Perform a search to see if it is a channel.

Further, if it is detected in step 104 that the search up to the last channel has been completed, the mobile station 2 selects the first channel 1z (of all channels) from the detection target channel.
CH3) and continues searching for a control channel (step 105).

The mobile station 2 repeatedly performs this type of search process, captures the control channel when it is detected, and thereafter performs various communication controls using this control channel.

According to this search process, for example, within wireless zone B (if the control channel is switched on the wireless zone, at most 5
It is possible to capture the corresponding control channel by searching twice (one time is required for the platform switching from channel CH8 to channel CH19). Search time will be significantly reduced compared to communication systems.

In this defense, a situation in which the control channel must be searched five or more times occurs when the mobile station 2 moves to another wireless zone, but such cases are rare in mobile communication systems with operational modes. If you select l\ and adopt this method, you can fully receive 9 benefits from 1 to 9.

[Effect of excuse]

As explained above, according to the control channel search method in the mobile communication system of this defense, when a mobile station searches for a new control channel, the previously used control channel is Since the search is started with priority from the assigned channel in the assigned wireless zone, the search time will be significantly reduced, especially when searching for a control channel that has been switched within the same wireless zone. It has the excellent advantage that it is possible to shorten the number of calls, and that efficient system operation can be achieved by minimizing the period during which calls cannot be made or received at the mobile station during d3.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining a control channel search method in a mobile communication system according to the present invention, and FIG. 2 is an example of @ elementary processing operation of a control channel in a mobile communication system according to the present invention. Flowcharts 1 to 3 are schematic diagrams for explaining a conventional search method for a control channel in this type of mobile communication system.

Claims (2)

[Claims] (1) A mobile station located within each radio zone where a plurality of radio base stations use one empty channel designated under the control of a control station from among a plurality of channels assigned to each radio zone. In a mobile communication system that controls communication with the mobile station, the mobile station includes a storage means for storing channel allocation data indicating channel allocation status for each wireless zone, and a control device used for the communication control based on the channel allocation data. When the mobile station searches for the control channel, the search is started preferentially from the channel assigned to the wireless zone to which the control channel previously used is assigned. A search method for a control channel in a mobile communication system, characterized in that: (2) When the mobile station first detects a control channel after turning on the power, the mobile station requests the channel allocation data from the radio base station, and in response to the request, the radio base station transfers the channel allocation data. 2. The control channel search method in a mobile communication system according to claim 1, wherein channel allocation data corresponding to the station is transmitted and collected and stored in the storage means.