JPH04213234A - Radio zone selecting method - Google Patents

Abstract

PURPOSE:To reduce a call loss at congestion by selecting a zone having lots of idle communication channels with priority in the case of selecting a radio zone. CONSTITUTION:A mobile station receives notice information of a radio zone A, measures reception electric fields LA, Lb-LG of a perch frequency of its own zone A and peripheral zones B-G and selects radio zones (communication enable zones) A, B, E, G whose reception level is a radio zone selection reception level threshold level Lev or over. A largest radio zone whose idle channel numbers EA, EB, EE, EG is highest is selected among communication enable zones A, B, E, G as a radio zone to set communication channels. Thus, the communication channel number is averaged and a call loss at congestion where communication channels of a radio zone are occupied is reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for selecting a radio zone in which a mobile station communicates in a mobile radio communication system.

0002

2. Description of the Related Art In a mobile radio communication system, as shown in FIG. While doing so, it selects one wireless zone and communicates with base stations within that wireless zone using a communication channel.

Conventionally, there are two methods for a mobile station to select a wireless zone. The first method is a method in which a base station measures radio waves emitted by a mobile station, compares the reception levels, and selects one wireless zone with the highest reception level. The second method is for the mobile station to select one wireless zone with the highest reception level by measuring and comparing the reception levels of channels assigned to each wireless zone.

However, in any of the above conventional methods, in order to select the radio zone with the maximum reception level, if mobile stations are concentrated in a certain radio zone and under certain propagation conditions, When the reception level is extremely high, calls for communication channel setup requests occur intensively in one wireless zone, and all communication channels are used for communication, resulting in congestion. Furthermore, when congestion occurs, a wireless zone is selected even though communication is not possible in that wireless zone, resulting in call loss.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the congestion that occurs when calls requesting communication channel settings occur intensively in one wireless zone, and to select a wireless zone that does not cause call loss during congestion. The purpose is to provide a method.

[0006]

[Means for Solving the Problems] The present invention is characterized in that a service area is composed of a plurality of wireless zones, a wireless base station is installed in each wireless zone, and each wireless base station transmits broadcast signals to mobile stations. In a wireless zone selection method, each base is equipped with a broadcasting wireless channel for transmission and a communication wireless channel for mobile stations to communicate, and selects a wireless zone in which a mobile station communicates from among a plurality of wireless zones. A wireless zone selection method in which a station broadcasts the number of free communication channels of its own base station and adjacent base stations through a broadcast channel, and a mobile station selects a zone from among communicable radio zones according to the number of free communication channels. be.

[0007]

According to the present invention, when a mobile station selects a wireless zone in which to communicate, it preferentially selects a wireless zone with many free communication channels among the wireless zones in which the mobile station can communicate. This method differs from the conventional technology in that the number of free communication channels in each wireless zone is taken into account when selecting wireless zones.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of a broadcast channel according to the present invention. The broadcast channel is one component of the control channel, along with the incoming channel and the dedicated cell signaling channel. This broadcast channel includes perch frequencies CHB to CHG, which are frequencies constantly transmitted in surrounding zones, which are necessary information in the wireless zone selection of the present invention, and the number of free communication channels EA in the own zone and surrounding zones. , EB to EG, and a wireless zone selection reception level threshold Lev. Perch frequency C
HB ~ CHG and number of free communication channels EA, EB ~
EG, except for A in its own zone, the corresponding pair is C.
HB and EB...CHG and EG are arranged and announced.

As shown in FIG. 2, even if a mobile station exists in wireless zone A, for example, it can listen not only to the channel of the base station in wireless zone A but also to the base stations in the surrounding wireless zones. It is also possible to communicate with channels. Here, as an example, it is assumed that communication is also possible with wireless zones B, E, and G.

Under these conditions, the mobile station selects a wireless zone for communication, as shown in the flowchart of FIG. First, the mobile station receives the broadcast information described above from the broadcast channel of wireless zone A (step 101). Next, the received electric fields LA, LB to LG of the perch frequencies of own zone A and surrounding zones B to G are measured (step 10).
2), wireless zones (communicable zones) A, B, whose reception level is higher than the wireless zone selection reception level threshold Lev;
Select E and G (step 103). Then, the number of free channels EA from communication zones A, B, E, and G,
Select the wireless zone with the largest EB, EE, and EG as the wireless zone for setting the communication channel (Step 1)
04).

The wireless zone selection method described above selects a wireless zone with many free channels from among zones where communication is always possible, compared to the conventional method of selecting the zone with the maximum reception level. It is possible to equalize the number of channels used for communication in the zone. Therefore, even if mobile stations are concentrated in a certain radio zone, or even if the reception level in one radio zone is extremely high under certain propagation conditions, only the channels in one radio zone are extremely high. It is not used often, and has the advantage that the number of transceivers installed at each base station can be reduced compared to conventional systems. Furthermore, even when channels in one wireless zone become full and congestion occurs, another wireless zone with free channels is selected, which has the advantage of reducing call losses during congestion.

On the other hand, how the above wireless zone selection process is used in a base station will be explained with reference to FIG. The wireless base station has a transceiver 1 that transmits control channels including broadcast channels, and a transceiver 2 for communication channels.
1 to 2n, and a transmission/reception control panel 3 that manages them.
, line control panel 4 for interfacing with higher-level stations
, and a central controller 5 that manages the entire base station equipment.
are connected by mutual data lines or data buses. The central control device 5 monitors the usage status of all communication transceivers via the transceiver control panel 3, and
The usage status of communication transceivers of surrounding base stations is constantly monitored through the upper station. Using this result, it is possible to configure information on the number of available communication channels in the own wireless zone and surrounding wireless zones included in the broadcast information.

[0013] In the embodiment described above, when selecting a wireless zone, the zone with the most free channels is uniquely selected among the communicable zones. There is a way to do that. For example, if the number of free channels in communication zones A, B, E, and G is E
A, EB, EE, EG, zones A, B, E,
The probability of assigning to G is EA /ETOTAL, EB
/ETOTAL,...,EG /ETOTAL and select the zone probabilistically (here, ETO
TAL = EA + EB + EE + EG). The actual allocation is, for example, A, B, so that the above probability is achieved.
, E, and G, and allocate channels according to the randomly drawn spheres electrically. With this method, zones are selected probabilistically, and calls concentrated in the zone with the most free channels can be distributed to other communication zones to some extent, reducing the number of communication channels in each zone. It has the advantage of being able to simultaneously achieve leveling and dispersion of non-processable items.

[0014]

[Effects of the Invention] As explained above, the method of the present invention
This has the advantage that the number of communication channels used in each wireless zone can be equalized, and the number of transceivers installed at each base station can be reduced. Another advantage is that call losses can be reduced during congestion when the communication channels in the wireless zone are full.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a broadcast channel sent from a base station to a mobile station.

FIG. 2 is a diagram showing that there are multiple wireless zones in which communication is possible.

FIG. 3 is a flowchart showing the operation of a mobile station in the wireless zone selection method of the present invention.

FIG. 4 shows the configuration of a wireless base station.

FIG. 5 is a diagram showing that a plurality of zones constitute a service area in mobile communication.

[Explanation of symbols]

Claims (2)

[Claims] Claim 1: A service area consists of a plurality of wireless zones, a wireless base station is installed in each wireless zone, and each wireless base station has a broadcasting wireless channel for transmitting broadcasting signals to mobile stations, and a mobile station. In a wireless zone selection method in which a mobile station is equipped with a communication wireless channel for communication and selects a wireless zone in which a mobile station communicates from among a plurality of wireless zones, each base station 1. A wireless zone selection method, characterized in that the number of free communication channels of a station is announced through a broadcast channel, and the mobile station selects a zone from among communicable wireless zones according to the number of free communication channels. 2. In the wireless zone selection method according to claim 1, each base station broadcasts the number of free communication channels of its own base station and adjacent base stations through a broadcast channel, and the mobile station A wireless zone selection method characterized in that each wireless zone is weighted in proportion to the number of free communication channels in that wireless zone, and one wireless zone is selected according to the probability based on the weighting.