JP3683207B2 - Mobile communication system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mobile communication system, and more particularly to a mobile communication system that can effectively use radio resources in broadcast communication or group communication performed for each group.
[0002]
[Prior art]
In a mobile communication system, in addition to normal calls where individual calls are made between mobile stations, a group is formed with a specific mobile station, and group broadcast communication is used for simultaneous communication within the group. There is group communication for calling (hereinafter, both are group communication).
[0003]
The mobile station device has an individual number provided individually, and normal call control, location registration management of each mobile station device, and also control by group communication are identified by the individual number. Identification and management were not performed. The reason why location registration management is not performed with group numbers is that if only individual numbers are registered, memory for the number of mobile stations may be secured as location registration information. This is because, in addition to the memory of several minutes, it is necessary to manage very large location registration information corresponding to the number of base stations × the number of groups, which requires a very large memory. Along with this, there is a problem that the time for searching for the mobile station apparatus increases and the traffic of the control channel increases.
[0004]
For this reason, the conventional group communication has been started by assigning a communication channel for group communication to all base station apparatuses having free communication channels.
[0005]
[Problems to be solved by the invention]
However, every time group communication is started, if a communication channel for group communication is assigned to all base stations that have a vacant communication channel, a base station in which no mobile station device exists is assigned. In other words, the communication channel is allocated, the communication channel is wasted, and radio resources are wasted.
[0006]
On the other hand, Japanese Patent Application No. 08-299848 and Japanese Patent Application No. 08-071611 disclose that after assigning channels to all base stations, a wireless zone in which no mobile station device exists is detected. There has been proposed a method of releasing a channel in a wireless zone in which there is no network. However, the processing in the control device is complicated, and it is necessary to use an accurate carrier sense function.
[0007]
It is an object of the present invention to provide a mobile communication system capable of operating radio resources efficiently with simple configuration and without waste of communication channels for group broadcast communication, group communication, and the like.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, a mobile communication system is configured as follows.
[0009]
When base stations that handle group communication are set in advance for each group and group communication or the like of a certain group is performed, group communication or the like is performed only from a preset base station apparatus. Thereby, it is not necessary to handle group communication in all base stations, and radio resources can be used effectively. The base station is set so that mobile stations that cannot participate in group communication are minimized based on the distribution of mobile stations and the like.
[0010]
Further, the base station transmits group information related to group communication handled by the base station. On the other hand, if there is a base station that emits group information for performing group communication of the group to which the mobile station belongs, the mobile station belongs to the base station if the radio field strength is not less than a predetermined value even if it is not the maximum base station. A base station that performs group communication of the group is selected as a standby base station. As a result, the number of mobile stations that cannot participate in group communication or the like can be reduced.
[0011]
That is, in a system in which a radio zone is configured by a plurality of base station devices, when considering the action range for each group composed of one or more mobile station devices, the group is scattered over the entire service area or a specific radio zone Various states are assumed, such as concentrating on.
[0012]
If a group to be concentrated in a specific radio zone is known in advance, group communication of that group is performed by a base station apparatus that is likely to have a mobile station apparatus that belongs to the group or that exists. If channel allocation is performed, radio resources can be used efficiently.
[0013]
Also, in general specifications (standards), it is not known whether the group communication to which the own station belongs is performed in the base station that is waiting, so if the mobile station device can receive radio waves from multiple base station devices, A base station with a high reception level waits for a paging signal that is an incoming message to the local station. It is assumed that the base station waits (no group communication to which the own station belongs) and cannot participate in group communication.
[0014]
Therefore, the group number of group communication serviced by the own base station is notified for each base station. In addition, when the mobile station apparatus can receive the radio waves of the base station serving the group communication to which the mobile station belongs, the mobile station apparatus waits at the base station in the best reception state among them. As a result, the mobile station can wait at the base station where the group communication of the mobile station is performed as much as possible.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
FIG. 1 is an example of an area configuration diagram of a mobile communication system according to the present invention.
[0017]
The mobile communication system is connected to the control station device 1, the base station devices 21, 22, and 23 connected to the control station device 1 via a wired line, and the base station devices 21, 22, and 23 via a wireless line. Mobile station devices 31, 32, 33, 41, 42, 43, 44 and the like.
[0018]
Each base station apparatus 21 has a service area, area 51 is a service area of base station apparatus 21, area 52 is a service area of base station apparatus 22, and area 53 is a service of base station apparatus 23. It is an area.
[0019]
The mobile station device 31 and the like are individually provided with individual numbers, and call control and location registration management are performed by identifying the individual numbers. Further, each mobile station device 31 and the like belong to several groups. Specifically, the mobile station apparatuses 31, 32, and 33 belong to the group 30, and the mobile station apparatuses 41, 42, 43, and 44 belong to the group 40. One mobile station apparatus may belong to a plurality of groups, or there may be mobile station apparatuses that do not belong to a group.
[0020]
The control station device 1 is connected to each base station device 21 and the like by wire, and further connected to a communication network connected to a communication console or the like. The control station device 1 performs management and control of the base station device 21 and the like, the mobile station device 31 and the like, and resource management such as a communication channel, and secures a radio channel at the start of a call and moves the mobile station to the channel. Take control. In addition, the control station device 1 has information on a group including a mobile station device and a mobile station device and a communication console, and the base station device that is started up at the start of group communication for each group in the group information. Has a table.
[0021]
For example, since it is known that mobile station apparatuses 31, 32, and 33 belonging to the group 30 are very often present in the service area of the base station apparatus 21, the base station that handles group communication of the group 30 The station device 21 is selected. On the other hand, since it is known that the mobile station devices 41, 42, 43 and the like belonging to the group 40 are widely dispersed in each base station area, the group communication of the group 40 is handled by all the base stations. As described above, the control station apparatus 1 stores information on base stations handled for each group. Note that the base station to be started up at the start of group communication or the like can be changed as appropriate, or may be selected by another selection method. For example, a group representative may select a region or the like.
[0022]
Furthermore, each base station apparatus 21 etc. informs each mobile station of the group number of group communication serviced by itself. For example, the base station device 21 is “serving group communications 30 and 40”, the base station device 22 is “serving group communication 40”, and the base station device 23 is “group communication”. 40 is serviced. "
[0023]
In addition, each mobile station basically uses the base station with the best reception of radio waves as a standby base station, but if it is not a base station that handles group communication of its own station, it receives radio waves at a predetermined intensity or higher. Among the base stations that can be used, the base station that handles the group communication of the local station waits.
[0024]
If each mobile station waits at the base station with the best reception condition of radio waves with the normal setting, the mobile station apparatus 31 is in the state where the mobile station apparatus is located as shown in FIG. Thus, the mobile station device 33 waits at the base station device 23, and the mobile station devices 31 and 33 receive other radio waves from the base station device 21 that handles group communication to which the mobile station device belongs, but other base station devices. Since it waits at 22 and 23, it becomes impossible to participate in group communication of the group 30. Therefore, if the radio wave of the base station that handles group communication to which the own station belongs can be received at a predetermined intensity or higher, the base station is set as a standby base station.
[0025]
For example, as shown in FIG. 1, the mobile station device 31 is within the service area of both the base station device 21 and the base station device 22, and is close to the base station device 22 and has a radio wave reception state. Best. However, since there is no group number to which the own station belongs in the broadcast information of the base station device 22, the mobile station device 31 receives the base station device 21 with the next good reception state of radio waves. If the mobile station apparatus 31 confirms that the broadcast station information of the base station apparatus 21 has the group number to which the own station belongs, the mobile station apparatus 31 sets the base station apparatus 21 as a standby base station.
[0026]
Although the mobile station device 33 is also close to the base station device 23, the base station device 21 is set as a standby base station in the same manner as the mobile station device 31 because there is no group number to which the own station belongs in the broadcast information of the base station device 23. Further, the mobile station device 32 waits at the base station device 21 as it is because the group number to which the mobile station device belongs exists in the broadcast information of the base station device 21.
[0027]
In addition, since the mobile station apparatuses 41, 42, 43, and the like belonging to the group 40 can obtain a signal indicating that group communication is performed from each base station, the mobile station apparatuses 41, 42, 43, and the like wait on each base station without selection.
[0028]
Next, the operation of the mobile communication system will be described with reference to the drawings.
[0029]
Normal communication between mobile stations is performed based on the identification number assigned to the mobile station apparatus as in the prior art, position information based on a control signal with the base station, and the like. And the case where the mobile station apparatus 32 in the group 30 performs group communication is demonstrated.
[0030]
Since one mobile station device (for example, mobile station device 32) included in the group 30 starts group communication, when the operation to that effect is performed from the mobile station device 32, the control station device 1 Information from the table. Since the base station device 21 to be handled in advance is set for the group communication of the group 30, an instruction to perform the group communication is issued to the base station device 21 and all identification numbers of the mobile station devices belonging to the group 30 are sent. .
[0031]
The base station device 21 instructed from the control station device 1 transmits a calling signal to the mobile station devices 31, 32, 33, etc. belonging to the group 30. The mobile station 31 or the like included in the group 30 that has received the paging signal transmitted from the base station device 21 starts communication with the base station device 21 and starts group communication within the group 30. In group communication, one caller in a group to which the group belongs can communicate with all the receivers in the group, and the caller can also be changed.
[0032]
Since the mobile station apparatuses 31, 32, 33, etc. belonging to the group 30 are usually present in the area 51 of the base station apparatus 21, the group communication of the group 30 is sufficiently serviced only by the handling of the base station apparatus 21, and the group 30 When the group communication is started, the mobile station devices 31, 32, and 33 can all participate in the group communication and do not use useless radio resources.
[0033]
Further, for example, since it is known in advance that the mobile station devices 41, 42, 43, 44 belonging to the group 40 are scattered throughout the system, the group communication of the group number 40 is performed by all the base station devices 21, 22, 23. It is registered in the control station apparatus 1 so as to be handled by the base station. Therefore, group communication can be reliably performed even for mobile stations that are widely distributed, such as the group 40.
[0034]
As a result, it is possible to greatly increase the probability of participation in group communication, and it is possible to save radio resources without degrading serviceability as compared with the case where channels are allocated to all base station apparatuses.
[0035]
Note that group communication may be broadcast communication in which transmission is not performed between mobile stations in a group but only transmitted from a base station to each mobile station in the group.
[0036]
【The invention's effect】
According to the mobile communication system of the present invention, since base stations that handle group communication are efficiently determined for each group in advance, mobile station devices belonging to a group to be group-communicated are not included in the area. Channel assignment is not performed during group communication, channels can be assigned to other communications, and radio resources can be used effectively.
[0037]
Group information related to the group handled by the base station is transmitted from each base station to the mobile station, and the mobile station selects a base station according to the group information, so that the mobile station device belonging to the group can appropriately select the standby base station. , Mobile stations that can perform group communication but cannot participate in group communication can be reduced as much as possible.
[Brief description of the drawings]
FIG. 1 is a diagram showing an area configuration diagram of a mobile communication system according to the present invention.
[Explanation of symbols]
1 Control station apparatus 21, 22, 23 Base station apparatus 31, 32, 33 Mobile station apparatus (belongs to group 30)
41, 42, 43, 44 Mobile station devices (belonging to group 40)
51, 52, 53 area

Claims (5)

In a mobile communication system in which group communication to a specific mobile station grouped in advance is performed,
For each group of the identified mobile stations, a table in which base stations that set communication channels in group communication in the group are registered in advance,
Each base station transmits the group information registered in the table regarding the group handled by the own station to the mobile station as appropriate,
Each mobile station waits for radio waves from the base station that has transmitted group information indicating that the group to which the mobile station belongs is handled among base stations that can receive radio waves at a predetermined intensity or higher,
At the start of group communication, only a base station registered in the table for a group performing the group communication secures a communication channel for the group communication. system.   The mobile communication system according to claim 1, further comprising means for notifying the group information from the base station to the mobile station using a control message transmitted on a control channel.   3. The mobile communication system according to claim 2, wherein the group information is transmitted from the base station using a slot in which empty information has been transmitted and a control message or the like in a call connection has not been transmitted.   The mobile communication system according to any one of claims 1 to 3, wherein the group communication is communication for making a call within a group.   The mobile communication system according to any one of claims 1 to 3, wherein the group communication is communication performed from a base station to mobile stations in the group.

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