JPH03196722A - Mobile communication system - Google Patents

Abstract

PURPOSE:To minimize the interruption of communication attended with channel changeover by arranging small zones and large zones while they are overlapped with each other, using a small zone for the talking connection at sending or receiving a call and deciding the changeover of zones during talking according to the attribute of a mobile station. CONSTITUTION:Large zones RZb1-RZb3 are arranged to small zones RZa1-RZa3 while being overlapped with each other. When a station MSS stays exists in a zone RZa4 and makes a call, a call signal including an MSSNo is sent from the station MSS. A control station MCS discriminates a radio base station MSa4 of a small zone having sent a largest reception level and sends a talking channel designation signal to the station MSS through the station MSa4. While the station MSS is in the talking state, the station MSS moves from the station MSa4 toward the zone RZa1, then the attribute of the station MSS is checked. when the moving speed of the attribute of the station MSS is large, the channel is switched into a talking channel of the large zone provided overlapped with the small zone used at present. When the moving speed is small, the station is connected to a talking channel of a small zone around the preceding zone.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J] The present invention relates to a mobile communication system capable of accommodating mobile stations with different moving speeds.

[Prior art] Generally, in mobile communication systems, in order to increase frequency usage efficiency, a method is used in which frequencies are reused locally by forming small zones, so that even if a mobile station moves between zones during a call, Inter-talk zone channel switching is performed to maintain the call.

[Problem to be solved by the invention]

Therefore, in order to increase the number of subscribers that can be accommodated, a method of creating small zones is used to reduce the size of the zone. However, it has the disadvantage that it cannot be divided into small zones sufficiently. Also, if channel switching during a call causes temporary call interruptions, the call quality will deteriorate, and it is undesirable for this to occur more frequently. This problem is more likely to occur for car phones that move at high speeds.

An object of the present invention is to provide a mobile communication system that solves the above problems.

[Means to solve the problem]

In order to achieve the above object, the mobile communication system according to the present invention divides a service area into zones, arranges a wireless base station in each zone, and centrally controls them by a control station. A large zone with a larger area is placed in an overlapping manner to cover multiple small zones, and a mobile station that connects a call in the large zone is transmitted using at least two types of transmission corresponding to the small zone and the large zone. The output is configured so that it can be switched according to instructions from the base station, and when making and receiving calls, it is done in a small zone, and when the mobile station moves after connection, channel switching between zones during a call is done according to the attributes of the mobile station. Therefore, the system is configured to determine which communication channel to switch to, the small zone or the large zone.

〔Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an example of zone arrangement according to the present invention, and FIG. 2 is a diagram showing a station configuration of a mobile communication system to which the present invention is applied.

In the mobile communication system of the present invention, a service area is covered by small zones, and a large zone having a larger area than these small zones is placed so as to overlap with a small zone so as to cover a plurality of small zones. The outgoing/receiving connection is performed in the small zone, and when the mobile station moves after the connection, it is determined whether to switch to the large zone or to the small zone during channel switching between zones during a call, depending on the attributes of the mobile station. For example, if you include the size of movement speed in the attributes, when changing the channel between zones during a call for a mobile station in the attribute of high movement speed, switch to the large zone, and in the case of a mobile station with the attribute of slow movement speed. The device is configured to switch to a small zone. In addition, the mobile station is configured so that the transmission output for the large zone and the small zone can be switched according to instructions from the base station, and the transmission output for the small zone is used when making/receiving calls, and when switching channels during a call. is switched based on the transmission output specification included in the signal specifying the switching destination channel.

The present invention will be specifically explained below.

In FIG. 1, RZa+ t RZa, t RZa
, +++ RZa, + is a small zone, RZb,
, RZb, , RZb, is a large zone.

The large zone is arranged to overlap the small zone.

FIG. 2 shows an example of the system configuration of the present invention, in which MBSa,
, MBSa, , -MBSaw+ are the radio base stations of the small zones RZa, , RZam f'''RZa# I, respectively, and MBSb, , MBSb, , -M
BSb, is the large zone RZb, , RZb, respectively.
, RZb, is a radio base station. Each radio base station is connected to and controlled by control station MC3. In the system of the present invention, since the connection of calls to and from the station MSS is performed in the small zone, the radio base station located in the large zone does not need the function of transmitting and receiving control signals for connection of calls to and from the station MSS.

The operation of the system of the present invention will be explained below using FIGS. 3 to 9, taking as an example a case where a call is originated from the station MSS.

First, the call connection sequence will be explained using FIG.

When station MSS is in zone RZa4 and makes a call, station M
A calling signal including the MSS No. is sent from the SS over the control radio channel. MBSb4, which receives it, and nearby wireless base station MBS in a small zone (for convenience, in Figure 4,
MBSx) adds the reception level of the received calling signal and sends the calling signal to the control station MC5.

The control station MCS receives the call signal from the station MBS (in this example, MB) that sent the call signal with the highest reception level.
Sa, ) is determined, and a speech channel designation signal is sent to the station MSS through the station MBS (MBSa, ).

The station MSS switches to the designated communication channel and sends out a switching completion signal. The switching completion signal is received by the corresponding communication channel radio of station MBSa4, and is sent to control station MC.
It will be relayed to 3rd. The control station MC3 acquires the corresponding station line that receives the switching completion signal. The dial signal from the station MSS is converted into a PB signal for the fixed telephone network at the control station MCS and sent out, and the other party answers and a call is established.

While station MSS remains on the line, stations MBSa, RZa,
When station MBSa moves in the direction, deterioration in the reception level of radio waves from station MSS is detected by the corresponding communication channel radio of station MBSa, and a channel switching request signal is sent to control station MC3, which causes channel switching between zones during the communication. The sequence is activated. When the control station MC5 receives the channel switching request signal, it first changes the attributes of the station MSS to M as shown in FIG.
Check from the SS number and attribute correspondence table.

When the attribute of station MSS is high moving speed, the channel switching sequence shown in FIG. 5 is executed. That is, from FIG. 8, we know that the large zone that is provided to overlap the small zone RZa that is currently in use by that station MSS is RZb, and then we know that the large zone surrounding RZb is RZb.
,, RZb, and those zones RZb
, , RZb, , RZb, and instructs each radio base station MBSb, , MBSb, , MBSb, to measure the reception level of the communication channel used by that station MSS by sending a measurement signal. station MBS
b, , MBSb, , MBSb.

returns the measured level to the control station MC8 as a measurement result signal. The control station MC5 compares these levels, selects the free call channel of the station MBSb that has sent the highest reception level, and selects the number of that call channel and the transmission power to be used through the call channel that the station MSS is currently talking to. (In this case, the transmission output corresponding to the large zone) is notified to the station MSS by a channel designation signal containing the information as information, and the station MBSb is designated with the communication channel to activate the communication radio.

When the station MSS completes switching to the specified channel and setting the transmission output, it sends out a switching completion signal on that channel, and when the control station MCS receives the switching completion signal, it switches to the station MBSa that was being used until then. The channel switching sequence ends by instructing station MBSa to release the radio for communication of , .

When the attribute of station MSS is mobile magic, the channel switching sequence shown in FIG. 6 is executed.

In this case, we know the small zone around RZa from Figure 7,
Those wireless base stations RZa, , RZa, ,
...Sends a measurement signal to RZa. Thereafter, processing is performed in the same manner as in the above case, and channel switching is completed. However, the transmission output specification included in the channel specification in this case is the transmission output corresponding to the small zone.

[Effects of the Invention] As explained above, the present invention arranges a small zone and a large zone in an overlapping manner, calls are made and received in the small zone, and the zone switching during a call is determined by the attributes of the mobile station. By configuring the system to determine whether to create a small zone or a large zone according to the above, mobile stations with different moving speeds can be accommodated while minimizing call interruptions caused by channel switching between zones during a call. There is.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of zone arrangement according to the present invention, FIG. 2 is a diagram showing a station configuration of a mobile communication system to which the present invention is applied, and FIG.
FIG. 4 is a diagram showing a call connection sequence of a mobile communication system to which the present invention is applied, FIG. 4 is a diagram showing attributes compatible with mobile stations,
FIG. 5 is a diagram showing a channel switching sequence between busy zones for a mobile station with a high moving speed attribute, and FIG. 6 is a diagram showing a channel switching sequence between busy zones regarding a mobile station having a low moving speed attribute. Figure 7 is a diagram showing the zone correspondence for measuring the reception level in the inter-zone channel switching sequence during a call regarding a mobile station with the attribute of slow movement, and Figures 8 and 9 are for mobile stations with the attribute of high movement speed. FIG. 4 is a diagram showing zone correspondence in which reception levels are measured in a channel switching sequence between busy zones regarding a station; RZa, ~RZa□・・・Small zone

Claims (1)

[Claims] (1) In a mobile communication system in which a service area is divided into zones, a wireless base station is placed in each zone, and these are centrally controlled by a control station, a small zone and a large zone with a larger area are divided into multiple small zones. The base station is configured such that a mobile station that connects a call in a large zone can be switched between at least two types of transmission output corresponding to a small zone and a large zone by instructions from the base station. , Connections for incoming and outgoing calls are made in the small zone, and when the mobile station moves after connection, channel switching between zones during a call is switched to either the small zone or the large zone depending on the attributes of the mobile station. A mobile communication system characterized in that the mobile communication system is configured to determine and carry out the operation.