JPH0759105B2 - Mobile communication system - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a public car telephone system, and more particularly to mobile communication having a tracking exchange function when a mobile station moves to a plurality of radio base stations while continuing a call. It is related to the method.

[Conventional technology]

Generally, a mobile communication system is composed of a plurality of service areas, a plurality of radio base stations that handle the service areas, a mobile station and a circuit control station, and a radio base station to be connected when the mobile station moves between the plurality of service areas. It switches and tracks stations. FIG. 3 is a block diagram showing a mobile communication system in a conventional public car telephone system. In the figure, 1 to 10 are radio base stations that respectively cover the service areas 1a to 10a, 11 is a mobile station moving on the route 11a, and 12 is the details of the radio base station 6 as shown in FIG. Is a line control station provided with a storage means (hereinafter referred to as a peripheral zone table) 13 for the service area 6a, 14 is a control line, and 15 is a telephone line. In this peripheral zone table 13, the mobile station 11 can move from the service area 6a, that is, the adjacent service areas 2a, 3a, 5
a, 7a, 9a and 10a are written.

Next, the mobile communication of the mobile communication system having the above configuration will be briefly described. First, when the mobile station 11 moves while making a call on the route 11a, the line control station 12 uses the peripheral zone table 13 to handle the radio base stations 2, 3, 5, 7, 9
In response to a request for monitoring the received electric field of the mobile station 11 to 10 and 10, the received electric field value is obtained. Therefore, the line control station 12 is a mobile station.
You can see in which service area 11 exists.

[Problems to be solved by the invention]

In the conventional mobile communication system described above, for example, in the section from the point 16a to the point 16b on the moving route 11a, there is abnormal propagation of radio waves due to complicated terrain, and when the mobile station 11 makes a call at the point 16a, the wireless base station 4 is called. If the wireless base station 6 is not connected and the wireless base station 6 is connected, the wireless base station 6 handles the call from the point 16a to the point 16b, but if the point 16b is exceeded, abnormal propagation disappears and the wireless base station 6 provides its own service. Since the call is from outside the area, the received electric field is weak, and a request for switching to another service area is sent to the line control station 12 through the control line 14. However, since the mobile station 11 exists in the service area 4a, there is no received electric field reaching each of the radio base stations 2, 3, 5, 7, 9 and 10. For this reason, the line control station 12 cannot determine the location of the mobile station 11, and there is a drawback that the call is interrupted.

[Means for Solving the Problems] A mobile communication system according to the present invention provides a line control station with a destination service area adjacent to the source service area or a wireless base serving the source service area as a source. A first storage means in which the station is preset and a predetermined destination service area located relatively far from the source service area and not adjacent to the source service area, or a radio base serving the same. The station is provided with a second storage unit preset and the line control station
In response to the switching request transmitted from the source wireless base station based on the decrease in the received electric field due to the movement of the mobile station, the source wireless base station is used as the source and the first storage means is referred to so that the adjacent destination service is provided. While extracting the area,
Within each destination service area, send a monitoring request to each wireless base station that is in charge of each extracted destination service area, and based on the received electric field value for the mobile station returned from each wireless base station in response. If the presence of the mobile station cannot be confirmed in each destination service area by searching for the presence of the mobile station with, the source radio base station is used as the source and the second storage means is referred to. In addition to extracting a predetermined destination service area at a remote location, as well as searching for a mobile station for an adjacent destination service area, the mobile station within the extracted predetermined destination service area at a relatively remote location It is a search for existence.

[Action]

This invention can be performed without interruption in a place where radio waves are overreached due to abnormal propagation.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of a mobile communication system according to the present invention. In the figure, 17 indicates the details of the second
As shown in the figure, for example, a mobile station in the service area 6a
A first storage means (hereinafter, referred to as a first peripheral zone table) 18 in which service areas 2a, 3a, 5a, 7a, 9a and 10a adjacent to the service area 6a where 11 is likely to move are stored 18 (FIG. 2 (a)) and the second storage means (hereinafter referred to as the second peripheral zone table) 19 in which the service area in which the mobile station 11 has a low probability of moving, for example, the service area 4a is stored (FIG. 2 (a)). It is a line control station provided with (Fig. 2 (b)).

Next, the operation of the mobile communication system having the above configuration will be described. First, for example, from point 16a to point 16b on travel route 11a
There is mobile propagation of radio waves in the section of due to the complicated terrain, and when the mobile station 11 reaches this point 16a, it is connected to the radio base station 6 due to abnormal propagation, and the call from the point 16a to the point 16b is made to the radio base station. The station 6 takes charge. Then, when the mobile station 1 passes the point 16b, abnormal propagation disappears, and the radio base station 6
Since the received electric field is weak, a request for switching to another service area is sent to the line control station 17 through the control line 14. Therefore, since the line control station 17 is the switching request signal generated from the radio base station 6, the service area 2a, 3a, 5 which is adjacent to the service area 6 using the first peripheral zone table 18 is used.
Radio base stations 2, 3, 5, 7, 9 and 1 which are responsible for a, 7a, 9a and 10a
A request for monitoring the reception electric field of the mobile station 11 is sent to 0, and the reception electric field value is reported, but none of them can obtain a sufficient value because they are outside the service area, and the service shown in the first peripheral zone table 18 There are no mobile stations 11 in the area. Therefore, the mobile station is next to the radio base station 4 which is in charge of the service area 4a shown in the second peripheral zone table 19.
Service area by sending 11 received electric field monitoring requests
It is possible to continue the call by detecting the presence within 4a, switching the line to the radio base station 4 and performing the tracking exchange. In addition, the mobile station 11 during a call from outside the service area 6a to the outside
In contrast, since the destination can be detected by using the first peripheral zone table 18, the time required for switching can be shortened for a normal mobile station.

In the above description, the tracking exchange function in the wireless base station 6 has been described, but it goes without saying that other wireless base stations can be similarly subjected to tracking exchange. Also, although the case of abnormal propagation has been described, when there is an extreme difference in the moving probability of the mobile station from the service area to the adjacent service area due to, for example, the road width or the congestion degree, the service area having a low probability is set as the second. It is needless to say that the mobile station can be narrowed in the search range to shorten the processing time required for the tracking exchange and to reduce the equipment load by storing it in the peripheral zone table.

〔The invention's effect〕

As described in detail above, according to the mobile communication system according to the present invention, a call can be made without interruption even in a place where radio waves are overreached due to abnormal propagation in a service area having a complicated terrain with a large height difference. There is an effect such as being able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a mobile communication system according to the present invention, FIG. 2 is a diagram showing stored contents of a peripheral zone table of FIG. 1, and FIG. 3 is a block showing a conventional mobile communication system. FIG. 4 and FIG. 4 are views showing the stored contents of the first peripheral zone table and the second peripheral zone table of FIG. 1-10 …… Wireless base station, 1a-10a …… Service area, 1
1 ... Mobile station, 14 ... Control line, 15 ... Telephone line, 16a and 16b ... Point, 17 ... Line control station, 18 ... First peripheral zone table, 19 ... Second peripheral zone table.

Claims (1)

[Claims] 1. A plurality of service areas and a plurality of radio base stations respectively responsible for the service areas, mobile stations, and circuit control stations, each of which is within a predetermined service area according to movement of the mobile station between the service areas. In the mobile communication system, wherein the mobile station is searched for, and the tracking exchange is performed for the mobile station by switching and connecting the line being used by the mobile station to the radio base station in which the existence of the mobile station is confirmed, First storage means in which a destination service area adjacent to the source service area or a radio base station which is in charge of the source service area is preset in the line control station, and individual service areas Is the source of the movement, and it is located in a predetermined destination service area or in a relatively remote area that is not adjacent to the source service area. And a second storage unit in which a radio base station in charge of the mobile station is set in advance, wherein the line control station responds to a switching request transmitted from the source radio base station based on a decrease in a received electric field due to the movement of the mobile station. Then, by referring to the first storage means with the source wireless base station as a source, adjacent destination service areas are extracted, and each wireless base station that is in charge of each of the extracted destination service areas To the mobile station in response to the received electric field value for the mobile station returned from each radio base station, search for the presence of the mobile station in each destination service area, If the presence of the mobile station cannot be confirmed in the destination service area, the source radio base station is used as a source to refer to the second storage means, so that the mobile station is relatively remote. The presence of the mobile station within a predetermined destination service area extracted in a relatively remote location is extracted in the same manner as the search for the mobile station with respect to the adjacent destination service area while extracting the predetermined destination service area. A mobile communication method characterized in that it is adapted to search.