JPH0583191A - Mobile communication radio cell selection system - Google Patents

Abstract

PURPOSE:To reduce a call loss when a base station restricts access by selecting a cell of other radio base station whose reception level is a standard value or over so as to connect a communication channel when the access of a cell selected by a mobile station is restricted. CONSTITUTION:A mobile station 6 is informed as to whether or not its access is restricted from radio base stations 7a,7b. The mobile station 6 stores the noticed restriction state to a memory. The mobile station 6 measures a reception level of a transmission wave from peripheral base stations 7a,7b at a call request (or an incoming call reply) and selects a base station (e.g., 7a) having a highest level. When the memory is referred and the base station 7a is subject to access restriction, a code of the base station whose result of level measurement is a specified value or over is added to a call request (incoming reply) signal and the result is sent to the base station 7a. When the access of the base station 7a is restricted, other base station 7b whose result of level measurement is a specified value or over is selected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention divides a service area into a plurality of radio cells, and compares the reception levels of transmission waves from each radio base station at the time of requesting an incoming / outgoing connection with a mobile station to establish a connection. The present invention relates to a wireless cell selection method in a mobile communication system, which is provided with the above-described function of selecting a wireless cell, and restricts access to its own wireless base station to a mobile station on standby by a wireless base station on a wireless channel. ..

[0002]

2. Description of the Related Art FIG. 1 is a diagram showing an example of the configuration of a mobile communication system for explaining a cell selection method of a conventional mobile communication system. In the figure, the situation immediately after the call origination request is input (or the incoming signal is received) in the waiting mobile station 10 will be described. The mobile station 10 measures the level of each of the transmission waves 12a, 12b, 12c from the base stations 11a, 11b, 11c of each cell, and selects one or more cells whose level is equal to or higher than a specified value.

When the mobile station 10 makes an outgoing call or an incoming call response, the base station of the cell having the highest level among the selected cells is sent to the base station of the call request (incoming call response) signal in the neighboring cells. Add the reception level and send. When the wireless base station (for example, 11a) receives a call request (incoming call response) signal, it determines whether communication is possible in its own cell, and when there is no available communication channel, the surroundings from the mobile station If there is a free communication channel or an inquiry free communication channel in another cell (for example, 11b) that is determined to be connectable from the cell reception level, a connection process is performed in the cell 11b to start communication.

[0004]

[Problems to be Solved by the Invention] As described above,
Conventionally, a series of signals exchanged between a mobile station and a wireless base station is normally performed by randomly accessing the transmission control channel, but when the transmission frequency increases, collisions of transmission signals occur and efficient connection is established. There was a problem that could not be done.

Therefore, when the frequency of transmission becomes higher than a certain level, the radio base station transmits a signal for restricting transmission to mobile stations waiting in the vicinity of its own cell to maintain the quality of the transmission control channel. Is common. In such a conventional method, there is a problem that a call loss becomes large due to a transmission restriction (access restriction).

It is an object of the present invention to reduce the call loss caused by access restriction in a mobile communication system in which the above-mentioned access restriction is performed and high quality transmission control is performed.

[0007]

As described in "Claims", the present invention divides a service area into a plurality of radio cells, and a mobile station transmits from each radio base station at the time of requesting an outgoing / incoming call connection. Equipped with a function to select one or more wireless cells that can be connected by comparing wave reception levels, and restrict access to its own wireless base station on the wireless channel for mobile stations waiting for the wireless base station. In a mobile communication system having means for performing, the mobile station transmits information related to the reception level of the signal from each base station to the base station, and the cell selected by the mobile station is under access restriction. Is a mobile communication wireless cell that excludes the cell from the connection candidates and selects a cell of another base station whose reception level transmitted and informed to the base station is a standard value or more to connect a communication channel. It is a selection method.

[0008]

According to the present invention, when a mobile station tries to access a base station having the highest reception level and the base station is under access regulation and communication cannot be started, the reception level of the mobile station exceeds a prescribed value. The other cell is selected and communication is performed in the cell. Conventionally, after cell selection, connection was not possible if access control was performed in the cell, but the present invention differs from the prior art in that communication can be performed in other cells.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the system of the present invention, a waiting mobile station is informed from each radio base station through a common control channel as to whether or not access is being restricted. An example of the signal format is shown in FIG. In the figure, numeral 1 indicates the signal structure, and numeral 2 indicates the detailed structure of the layer 3 in the signal. As is clear from this figure, the signals are layer 1, layer 2, layer 3
The regulation information is embedded in the layer 3. As this regulation information, a method of notifying the regulation information of the neighboring cells in addition to the regulation information of the own station can be considered.

Upon receipt of the notification, the mobile station stores the regulation status in the memory in the format as shown in FIG. In the figure, 3a, 4a and 5a are codes assigned to the respective radio base stations, and 3b, 4b and 5b are flags showing whether or not the regulation is being performed by "1" or "0".

The situation when the mobile station receiving such a notification makes a call request (or an incoming call response) will be described with reference to FIG. In the figure, the mobile station 6 measures the reception level of the transmission waves from the peripheral base stations 7a and 7b when a call request (or an incoming call response) is made, and by comparing the results, the base station with the best effect (for example, 7a ) Is selected and the memory is referred to, and if the access of the base station 7a is not restricted, the code of the radio base station whose level measurement result is a specified value or more in the call origination request (call response) signal to the base station 7a Is added and transmitted.

An example of the signal format at this time is shown in FIG.
Shown in. Then, if the base station 7a has a free channel, communication is designated and communication is started, but if there is no free channel, the wireless base station reported from the mobile station 6 in the signal of FIG. The channel is searched and communication is started by the found free channel. If the access to the base station 7a is restricted, another radio base station 7b whose level measurement result is equal to or higher than the specified value is selected, the memory is referenced again, and the same procedure as above is performed. FIG. 6 is a flow chart showing the control procedure in the present invention described above, in which (a) shows the control procedure on the radio base station side and (b) shows the control procedure on the mobile station side.

[0013]

As described above, according to the method of the present invention, even when a radio base station accessed by a mobile station restricts access, the mobile station receives another radio having a high reception level. Since it is possible to connect to the base station, there is an advantage that the number of lost calls can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an example of a configuration of a mobile communication system.

FIG. 2 is a diagram showing an example of a signal format of a common control channel.

FIG. 3 is a diagram showing an example of a format in which a mobile station stores a regulation status.

FIG. 4 is a diagram showing an example of a configuration of a mobile communication system for explaining the operation of the mobile station.

FIG. 5 is a diagram showing an example of a format of a signal transmitted by a mobile station.

FIG. 6 is a flowchart showing an example of control of a base station and a mobile station in the present invention.

[Explanation of symbols]

 1 signal structure 2 detailed structure of layer 3 3a, 4a, 5a code of radio base station 3b, 4b, 5b flag 6 mobile station 7a, 7b base station

Claims (1)

[Claims] 1. A service area is divided into a plurality of radio cells, and a mobile station selects one or more connectable radio cells by comparing reception levels of transmission waves from each radio base station when a call origination / termination connection request is made. In a mobile communication system having a function and having means for restricting access to its own wireless base station on a wireless channel to a mobile station waiting for the wireless base station, the mobile station transmits signals from each base station. The information related to the reception level of is transmitted to the base station, and when the cell selected by the mobile station is under access restriction, the cell is excluded from the connection candidates and transmitted to the base station to notify. A mobile communication wireless cell selection method, characterized in that a cell of another base station whose received level is equal to or higher than a standard value is selected and a communication channel is connected.