JPH0247137B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a mobile radio communication system, and particularly to a communication system in a public automobile radio telephone system in which service areas are arranged in a honeycomb pattern.

[Prior art]

An example of the conventional method will be explained using the drawings. 1st
The figure is a plan view showing the positional relationship between a service area served by a wireless base station and a mobile station. Wireless base stations 1, 2, and 3 have service areas 4, 5, and 6, respectively.
The mobile station 8, which is in charge of the call, moves along the moving route 9. Also, 7 is a control station, 10 to 15 and 1
9 indicates the point. By the way, there is a level difference between the input electric field distribution that the mobile station 8 on the moving route 9 receives from the wireless base stations 1 to 3, and the input electric field distribution that the wireless base stations 1 to 3 each receive from the mobile station 8. have similar shapes, so the levels of both are standardized and matched to form one distribution curve 16, 17, 1 respectively.
8, and their input electric field distribution diagram is shown in FIG. In FIG. 2, wireless base stations 1 to 3 are mobile stations 8
When the input electric field strength received from the wireless base station reaches E1, each wireless base station sends a channel switching request signal to the control station 7. However, when the input electric field strength becomes lower than E2, neither the mobile station 8 nor each radio base station can receive signals from each other.

Now, a case where service areas 4 to 6 are located on flat terrain will be explained. When the mobile station 8 is within the service area 4, it is connected to the wireless base station 1, but when it moves to the point 11, the input electric field strength received by the wireless base station 1 becomes E1, so the wireless The base station 1 determines that the mobile station 8 is moving outside the service area 4 and sends a channel switching request signal to the control station 7.

The control station 7 issues an electric field measurement request signal for the mobile station 8 to each radio base station serving a service area adjacent to the service area 4, and determines the movement destination from the measurement results from each radio base station. In this conventional example, it is determined that the mobile station 8 has moved to the service area 5, and the control station 7 identifies an empty call channel (referred to as a "switching destination channel") of the wireless base station 2, and transmits the switching channel designation signal a to the wireless It is sent from the base station 1 to the mobile station 8 through the communication channel to which it was connected up until then. During these processes, mobile station 8 moves to point 19.
However, the mobile station 8 receives the switching destination channel designation signal a at a level higher than the input electric field strength E2, which is the lowest receivable level, and switches to the frequency of the switching destination channel. On the other hand, in the control station 7, the fixed line connected to the radio base station 1 is switched to the radio base station 2, and a communication line for the mobile station 8 is established via the radio base station 2, and the communication is continued.

Next, a case will be described in which the service area 5 in FIG. 1 is inside a tunnel and the points 11 and 13 are entrances and exits. FIG. 3 is a received input electric field distribution diagram at this time. Wireless base station 1 from inside the tunnel
and 3 cannot be seen, the received input electric fields from the radio base stations 1 and 3 at the mobile station in the tunnel rapidly attenuate, and the electric fields 20 and 22 in FIG.
shows the distribution of When the mobile station 8 advances to the point 11 in the same way as in the case of the flat terrain, the wireless base station 1 sends a channel switching request signal to the control station 7, and the control station 7 starts channel switching processing.
However, when the wireless base station 1 sends the switching destination channel designation signal a to the mobile station 8, the mobile station 8 has already moved to the point 19 in the tunnel, so the received input electric field strength of the mobile station 8 is E3 in the diagram
This becomes lower due to the receivable input electric field strength E2. Therefore, the mobile station 8 cannot receive the switching destination channel designation signal a and switch channels, and the call is disconnected.

In this way, the conventional method is effective in flat terrain where the electric field at the boundary of the service area changes gently, but in areas where the electric field at the boundary of the service area changes rapidly, such as in tunnels or mountainous areas, it is difficult to continue the call by switching channels. The drawback was that it was impossible.

[Purpose of the invention]

An object of the present invention is to provide a mobile radio communication system that eliminates the drawbacks of the above-mentioned conventional systems and allows continuous communication as a service area even in tunnels or mountainous areas.

[Structure of the invention]

A mobile radio communication system according to the present invention includes a plurality of service areas that are adjacent to each other and each has an assigned area, and a plurality of service areas that are arranged corresponding to each of the plurality of service areas and have unique communication channels. A wireless base station, a control station that supervises the plurality of wireless base stations, and a plurality of mobile stations that move within the plurality of service areas, and a mobile station that is on a call and moves to an adjacent service area, For mobile radio communication systems that allow calls to continue by switching channels to the call channel of the radio base station that handles the service area of the destination, channel designation allows any call channel to be set within some radio base stations. For a mobile station in a call that flows into a service area served by a wireless base station equipped with a transmitter and the channel designation transmitter, the channel designation transmitter instructs the mobile station to switch the call channel; For active mobile stations that enter the service area of a wireless base station that is not equipped with a channel designation transmitter, the wireless base station to which they were connected before the inflow instructs them to switch the call channel. Features.

〔Example〕

An embodiment of the present invention will be described using FIGS. 1 and 3. It is assumed that a mobile station 8 in a call within a service area 4 moves on a moving route 9, that the service area 5 is inside a tunnel, and that the entrances and exits of the tunnel are points 11 and 13.

When the mobile station 8 moves to point 11, the received input electric field strength at the connected wireless base station 1 becomes E1 in FIG. 3, and the wireless base station 1 determines that the mobile station 8 has moved outside the service area 4. and sends a channel switching request signal to the control station 7. The control station 7 sends an electric field measurement request signal for the mobile station 8 to each wireless base station in charge of a service area adjacent to the service area 4, and based on the measurement result report from each wireless base station, It is determined that the mobile station 8 has moved, and the idle communication channel (switching destination channel) of the wireless base station 2 is identified. Next, the control station 7 sends a transmission stop signal for the transmitter connected to the mobile station 8 to the radio base station 1, and sends a transmission stop signal to the channel designation transmitter of the radio base station 2 to the radio base station 1. The station 1 sends out a communication channel designation signal b specifying the communication channel number connected to the mobile station 8 and a transmission activation signal c. Further, the channel designation transmitter of the radio base station 2 instructs the mobile station 8 to switch to the designated communication channel. At this time, the mobile station 8 is located at a point 19 in the tunnel.
However, since the input electric field strength from the wireless base station 2 is E4 in FIG. 3, the switching destination channel designation signal a can be accurately received, the communication path is switched to the wireless base station 2, and the call is started. will continue.

Also, from service area 5 to service area 6
A switching destination channel designation signal a is sent to the mobile station 8 moving to the mobile station 8 and the mobile station 8 moving between other service areas in the same manner as in the conventional method.

Next, FIG. 4 shows the configuration of the wireless base stations 1 and 3. The radio base stations 1 and 3 are similar to radio base stations in the conventional system, and are composed of an antenna 23, an antenna sharing device 24, a receiver 25, and a transmitter 26, and the receiver 25 and transmitter 26 are connected to each radio base. It has a channel number (ie, line frequency) unique to the station, and forms a communication path with the mobile station 8.

FIG. 5 shows the configuration of the wireless base station 2. The radio base station 2 includes a receiver 29 and a transmitter 30 for communication paths, as well as a transmitter 32 for specifying a channel. Channel designation transmitter 32 sets the transmission frequency of call channel designation signal b from control station 7 to the corresponding call channel, and sends switching destination channel designation signal a to mobile station 8 upon receiving transmission activation signal c. Further, since the transmission output d has a frequency other than the line frequency of the radio base station 2, the antenna 31 is separated from the antenna 27 without using the antenna duplexer 28.

〔Effect of the invention〕

As is clear from the above description, by applying the present invention, it is possible to provide high-quality mobile communication services even in areas with special topography where electric fields fluctuate rapidly, such as in tunnels and in mountainous areas. Moreover, the system configuration cost is low because it does not require complicated equipment such as relay amplifiers, and has a simple configuration that simply adds a channel designation transmitter to the wireless base station that handles special terrain. This effect can be obtained.

[Brief explanation of drawings]

Figure 1 is a plan view showing the positional relationship between the service area of a wireless base station and a mobile station, Figure 2 is an input electric field distribution diagram in a flat area, and Figure 3 is an input electric field distribution diagram in an area including tunnels. be. Fourth
The figure is a block diagram showing the configuration of a conventional wireless base station.
FIG. 5 is a block diagram showing the configuration of a radio base station serving special areas such as inside tunnels in one embodiment of the present invention. 1 to 3...Radio base station, 4 to 6...Service area, 7...Control station, 8...Mobile station, 9...Movement route, 1
0-15, 19...points, 16-18, 20-22
...Input electric field distribution, 23, 27, 31...Antenna, 2
4, 28... Antenna sharing device, 25, 29... Receiver, 26, 30... Transmitter, 32... Channel designation transmitter, E1, E2, E3, E4... Input electric field strength, a... Switching destination channel designation signal, b... Call channel designation signal, c... Transmission activation signal, d... Transmission output.

Claims (1)

[Scope of Claims] 1. A plurality of service areas that are adjacent to each other and each have an assigned area; a plurality of wireless base stations that are arranged corresponding to each of the plurality of service areas and each have a unique communication channel; It consists of a control station that supervises the plurality of wireless base stations and a plurality of mobile stations that move within the plurality of service areas, and a mobile station that is in a call flowing into an adjacent service area receives a call in the destination service area. In a mobile radio communication system in which a call is continued by switching the channel to a call channel of a radio base station that has a mobile radio base station, some of the radio base stations are equipped with a channel designation transmitter that can set an arbitrary call channel, and the said channel For a mobile station in a call that flows into the service area of a wireless base station equipped with a designated transmitter, the channel designated transmitter instructs the mobile station to switch the call channel, and the channel designated transmitter is switched on. Mobile radio communication characterized in that, for a mobile station in a call that flows into a service area served by a radio base station that is not equipped with the mobile station, a call channel switching instruction is given from the radio base station to which it was connected before the inflow. method.