JPH0331290B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for quickly and easily establishing a common control channel used between a base station and a mobile station (hereinafter also referred to as a mobile device) in a mobile communication system having a plurality of common control channels. It concerns how to select accurately.

[Conventional technology]

In the car telephone system currently in service, an incoming call control channel and an outgoing call control channel are provided as common control channels.
The incoming call control channel is primarily a control channel for performing calling and connection control when making a call to a mobile device.

If the power switch of the mobile device is ON and the mobile device is not talking or making a call, the mobile device is in a standby state (idle state), constantly receiving downlinks on the incoming call control channel, and preparing for an incoming call. ing.

There is a limit to the number of subscribers (mobile devices) that can be accommodated in one terminating control channel. Therefore, when the number of subscribers exceeds the maximum number of subscribers that can be accommodated by the first terminating control channel, a second terminating control channel is established, and the newly joining mobile station must belong to this second terminating control channel. become.

As the number of mobile stations increases in this way, groups are successively formed, such as a first group of mobile stations (a group of mobile stations corresponding to the first incoming call control channel), a second group, and so on.

Therefore, in large cities with a large number of subscribers, there will be multiple groups, and in areas with a small number of subscribers, only the first group will exist. Therefore,
For example, in the case of a mobile station in the second group, the second terminating control channel will be selected in a metropolitan area, and the first terminating control channel will be used when the mobile station goes to a rural area.

Incoming call control is carried out separately for each area, so incoming call control channels use different frequencies to avoid interference between adjacent areas, and the same frequency is used repeatedly at a sufficient distance. are doing. Therefore, by preparing, for example, seven waves for the first incoming call control channel, it is possible to cover all of Japan. Similarly, seven waves are prepared for the second incoming call control channel.

Therefore, in this case, each group of incoming call control has a maximum of seven frequencies. This frequency is stored in the mobile device. If there are three groups, the mobile device memorizes the frequencies of 21 waves.

[Problem that the invention seeks to solve]

When a mobile device is turned on or moved to another control zone, it is necessary to select the optimal incoming call control channel. Therefore,
First, the mobile device switches and receives the incoming call control channel of the group to which it belongs from among all the stored incoming call control channels, and selects, for example, the channel with the highest reception level. Once the selection has been completed, the group number and zone of location are registered (location registration) in preparation for an incoming call. If a reception level higher than the required value cannot be obtained even after receiving all the channels in the group, the most suitable incoming call control channel is selected by switching to receive the channels of other groups.

If selection is made in this manner, for example, if a third group of mobile devices goes to a zone where only the first incoming call control channel is available, a maximum of 21 waves will be switched and received.

As described above, the conventional control channel selection method has problems such as the mobile device having to memorize a large number of frequencies and the selection of a control channel sometimes taking a long time.

[Purpose of the invention]

In order to solve these problems, the present invention provides a control channel selection method that allows a mobile device to quickly switch to that channel by instructing the base station as to which channel the mobile device should stand by. The purpose is

According to the present invention, the above object is achieved by the means described in the claims.

EMBODIMENT OF THE INVENTION Hereinafter, the structure etc. of this invention will be described in detail based on the drawing of an Example.

〔Example〕

FIG. 1 is a diagram showing a regional facility model of incoming control channels, in which A to E indicate control zones, f ₁₁ to f ₃₁ indicate incoming control channels in the respective control zones, and 1 3 represent the first control channel group to the third control channel group, respectively, and 4 represents the wireless base station zone.

In FIG. 1, three incoming control channels are provided in control zone B, two incoming control channels are provided in control zone C, and one incoming control channel is provided in the other zones.

If the mobile station is a third group mobile station, the third incoming control channel is selected in control zone B, and the second incoming control channel is selected in control zone C (mobile stations in the third group select the second group). (if it is predetermined to do so), the first incoming call control channel may be selected in other zones.

In the present invention, this is achieved using the following two distinctive technologies.
This is achieved using means.

The first incoming call control channel broadcasts information regarding the presence or absence of the second and third incoming call control channels. The second incoming call control channel broadcasts information regarding the presence or absence of the third incoming call control channel.

When making initial channel selection and zone transition, the mobile device first receives the first incoming call control channel, obtains the above information, and then
Move to the channel of the group you should belong to.

Therefore, in control zone B, the first incoming control channel broadcasts information that the second and third incoming control channels exist. Furthermore, in the control zone C, information indicating the existence of the second incoming call control channel is similarly broadcast. When the mobile device turns on the power switch in control zone B, the mobile device learns from the above that the third incoming control channel exists, and the mobile devices in the third group can immediately shift to the third incoming control channel.

When the mobile station moves from control zone A to B, it can similarly shift to the third incoming control channel by first receiving the first incoming control channel in control zone B.

In control zone C, if it is predetermined in advance that the mobile terminals in the third group will select the second group, they can similarly immediately shift to the second terminating control channel. In this way, the control channel to be used can be quickly and accurately determined.

Further, by using the present invention, it is possible to accurately select a channel even when the area of the third control channel is configured to be narrow as shown in FIG.

In the case shown in FIG. 2, if the mobile device shifts to another zone while remaining in the standby state, it is impossible with the prior art to smoothly shift to the third control channel. The reason for this is that since the received electric field level of the first or second control channel does not decrease in zone B, no control channel selection operation is performed. Therefore, in order to improve this shortcoming, there is a method of forcing selection work to be carried out periodically, but this method has the drawbacks of lacking accuracy and increasing the number of missed calls. .

According to the present invention, even in such a case, it can be easily realized by broadcasting the information regarding the control channel only in the necessary areas, and no problems arise in terms of characteristics. By adopting such a zone configuration, an economical and flexible system can be realized depending on the traffic.

〔Effect of the invention〕

As explained above, according to the control channel selection method of the present invention, the mobile device can quickly determine the control channel that it will use, which has the advantage of reducing the occurrence of lost calls during that time.

Also, when multiple control channels exist,
Even if there is a control channel with a narrow area set among the plurality of control channels, the mobile device can smoothly transition to the control channel, so the control zone can be set according to the traffic in each region. Therefore, there is an advantage that an economical and flexible system can be constructed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a regionally viewed facility model of the incoming call control channel, and FIG. 2 is a diagram showing another example of the regionally seen facility model of the incoming call control channel. 1...First control channel group, 2...Second control channel group, 3...Third control channel group, 4...Radio base station zone.

Claims (1)

[Claims] 1. If a control zone using one or more common control channels is formed in each region and there is only one common control channel, the common control channel shall be included in the first control channel group. If there are multiple common control channels, one of them is included in the first control channel group and the other common control channels are included in different control channel groups, and multiple mobile stations are divided into groups corresponding to these control channel groups, and groups of common control channels to be used in control zones where multiple common control channels exist are predetermined for each group to which a mobile station belongs. In a communication method, information regarding the existence status of common control channels in each control zone is broadcast on the common control channel included in the first control channel group of each control zone, and mobile stations use the information based on the information. A control channel selection method characterized by selecting a common control channel that should be used.