JPH02206235A - Communication channel switching system in mobile communication - Google Patents

Abstract

PURPOSE:To attain the changeover independently of a central controller by providing a means measuring a reception level of a radio wave from a mobile equipment and sending the level to the mobile station and a communication channel changeover means to a base station and providing a means returning the information of a reception level from the base station during communication to the mobile equipment. CONSTITUTION:A reflected signal from a mobile equipment is demodulated by a reception level measuring receiver 21 and reaches a controller 22. Then the reception level measuring receiver 21 measures a reception level and informs the result to the controller 22 via a demodulation signal interconnection 26. The controller 22 compares level information A in the reflected signal from the demodulation signal interconnection 25 with level information B from a demodulation signal interconnection and in the case of A<B, it is discriminated that the mobile equipment is moving to its own zone. When it is discriminated that plural base stations are moved to their own zones, a base station with the largest value of B-A is discriminated to be final destination and switching over of the busy channel is assigned to the base station.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a mobile communication system in which a service area is composed of a plurality of zones, when a mobile device moves to another zone during communication. The present invention relates to a method for detecting and switching channels during communication.

[Conventional technology]

If a mobile device changes zones during communication, it is necessary to change the base station with which the mobile device communicates from the base station in the previous zone to the base station in the destination zone to continue communication.

Hereinafter, a technique for controlling zone transition in a conventional car telephone system will be described.

FIG. 1 is a diagram showing an example of a system configuration of a car telephone system.

In the figure, 1 2 3 are zones, 4 5
6 is a base station corresponding to each zone, 7 is a mobile device, 8, 10, 12 is a leap communication line between the central controller and each zone, and 9°11.13 is a dark line between the central controller and each zone. Control line 14 represents a central control unit.

If mobile device 7 shifts from zone 1 to zone 2 during communication,
The receiver of the communication channel of the base station 4 detects a decrease in the reception level, and this is detected by the central controller 14 in the control circuit M9.
Notify. In the central control unit 14, base stations (5,
6) is instructed to monitor the reception level of radio waves from the mobile device 7 and report the results.

Each base station usually has a multi-channel switching receiver used for this purpose, and in response to instructions from the central controller 14, this receiver is switched to the channel being used by the mobile device 7. Measure the reception level of radio waves from. The central controller 14 receives the reception level report from each base station, identifies the base station with the highest reception level from among them, and thereby indicates that the mobile device 7 has moved from zone 1 to the wireless zone of the base station. know. Then, the central controller 14 switches the communication channel 118 to 10 and switches the channel used by the mobile device 7 to one of the channels assigned to the base station 5.

As a result, the mobile 1fJ7 continues to communicate with the central control station 14 via the base station 5 and the communication line 10.

[Problem to be solved by the invention]

As mentioned above, in the conventional communication channel switching method, there are three methods: ■ Monitoring the reception level at the base station receiver, ■ Notifying the central controller when the reception level drops, and ■ Informing the central controller of the reception level to surrounding base stations. Measurement instructions, ■Measurement of reception levels at surrounding base stations and reporting to the central controller, ■Determination of the migration destination zone by the central controller, ■Switching to the communication line and wireless channel used in the migration destination zone, A six-stage operation was required.

Central control unit 1 necessary to perform such operations
4. Functions include: ■ Management of a list of surrounding zones whose reception level should be monitored when the mobile device migrates from each zone, and a signal transmission/reception function that instructs reception level measurement to the 0 surrounding zone. It is necessary to compare the reception levels from each base station and determine the maximum value, and as the number of zones increases, the scale of the central control device increases, causing economic problems.

In particular, in a system that eliminates dead areas and improves communication quality, there is a large overlap between zones, which necessitates increasing the number of surrounding zones, making the central control unit even more complex.

Further, the concentration of functions in the central control unit and its large scale are also undesirable from the viewpoint of system reliability, since the system is greatly affected by failures in the central control unit.

In view of such conventional problems, the present invention enables switching without relying on a central control device when determining a destination zone when a mobile device changes zones, or
It is an object of the present invention to provide a means for reducing the negative potential of the central control fArIt.

[Means to solve the problem]

According to the invention, the above objects are achieved by the means specified in the claims.

That is, the present invention provides a mobile communication system in which a service area is composed of a plurality of zones and has a base station corresponding to each zone, in which a base station measures the reception level of radio waves from a mobile device in communication, A means for superimposing the measurement result on a communication signal for the mobile station as a reception level A, and a receiver for receiving the signal by sequentially switching communication channels, are used to detect the radio waves of a mobile station communicating with another base station. means for receiving the radio wave and comparing the reception level B at the own station with the reception level A value included in the radio wave, and the difference between the reception level B value and the reception level A value is determined in advance. When the value exceeds the value, a means is provided to perform an operation for switching the communication channel after a delay time determined according to the difference between the value of reception level B and the value of reception level A has elapsed, and the mobile terminal is This is a communication channel switching system in mobile communication that is provided with a means for sending back information of reception level A received from a base station with which communication is being performed by radio waves to the base station.

〔Example〕

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention, in which (a) shows an example of the configuration of a base station device, and (b) shows an example of the configuration of a mobile station device.

In the figure, 8-1. 8-2 is a communication line, 9-1 is a control line, 15.29 is an antenna for a base station and a mobile device, respectively, 16.30 is a transmission/reception duplexer, 17 is a reception distributor, 19 is a transmission duplexer, 19-1. 19-2 and 20-1゜20-2 are communication channel receivers and transmitters, 21 is a reception level measurement receiver, 22 is a control device,
23-1.23-2.27-1.27-2 is the communication signal connection, 24-1.24-2 28-1 28-2 is the control signal connection, and 2526 is the reception level measurement receiver 2.
1 is a demodulated signal connection, 30 is a transmitting/receiving duplexer for the mobile device, 31
is a receiver, 32 is a transmitter, 33.35 is a communication signal connection, 34 36 is a control signal connection, 37 is a control device, 38
39 represents a terminal connection, and 39 represents a terminal.

The mobile device transmits I for the communication channel of the base station! 19-1 and communication channel transmitter 20-1. The signal from the mobile device is received by the communication channel reception 1f.
119-1, the communication signal connection 23-1, the control device 22, and the communication line #18-1 to the central control device! (corresponding to 14 in FIG. 1, the same applies hereinafter) detects the reception level at the reception 1119-1 for one communication channel, and notifies the control device 22 through the control signal connection 24-1.

On the other hand, the communication signal from the central control unit is transmitted through the communication line 8-1,
The control device ff122, i [Ft signal reaches the transmitter 20-1 via the monthly salary 41127-1, and further transmits the transmission duplexer 18,
Reception for 0 communication channel transmitted to the mobile device via the transmitter/receiver duplexer 16 and antenna 15! The reception level at 'l' 119-1 is encoded in the control device 22 for the transmitter and sent via the control signal connection 28-1 to the communication channel a2.
0-1, and the communication channel transmitter 20-1 modulates the signal simultaneously with the communication signal and sends it to the mobile device.

In the mobile device, the communication signal is received by the receiver 31 via the antenna 29 and the transmitter/receiver splitter 30, and the communication signal is demodulated, passes through the communication signal link M33, and the control device 137, and then reaches the terminal 39.
Transmission for communication channel? The reception level signal of the communication channel receiver 19-1 simultaneously sent out from the communication channel receiver 19-1 is demodulated by the reception fi 31 and input to the control device 37 via the control signal connection 34. The control device 37 returns this signal and sends it back to the base station by the transmitter 32 via the control signal connection 36.

The communication signal from the terminal 39 is transmitted to the base station through the terminal connection 38, the control device 37, and the communication signal connection 35 at the same time as the return signal.

The return signal is received by surrounding base stations, and based on this, the surrounding base stations determine whether the mobile device has moved into its own zone.

The method will be explained below.

Each base station sequentially switches and receives all communication channels used in its system or all communication channels used by neighboring base stations. In this case, the return signal from the mobile device is demodulated by the reception level measuring receiver m21 and reaches the control device 22 via the demodulated signal connection 25.

On the other hand, the reception level measuring reception @ 21 measures the reception level and sends the result to the control unit @ 21 via the demodulation signal connection 26.
Notify 22. The control device 22 connects the demodulated signal connection #12
Compare the level information (A) in the return signal from 5 and the level information (B) from the demodulated signal connection 26, and if the level from the demodulated signal connection 26 is higher (A<B)
, it is determined that the mobile device is moving into its own zone.

By the way, since zones generally overlap with each other, the number of base stations that determine that the zone has shifted is not limited to just one, but may be multiple.

In this way, when it is determined that multiple base stations have migrated to the own zone, the most failed base station of B-A among them, that is, the base station that the mobile device came closest to, is selected as the final base station. It is necessary to determine that this is the transfer destination and have this base station switch the channel during communication.

An example of such control is a method using a central controller.

In this method, each base station changes the timing of notifying the central controller that a mobile station has moved to its own zone via a control line with the central controller depending on the value of B-A.

Specifically, if the value of B-A is large, notification is made after a short period of time. Conversely, if the value of B-A is small, the notification is sent after a long period of time. The central control unit can switch the active channel to the base station closest to the mobile device by instructing the mobile unit to change the active channel based only on the first signal received.

In the above description, an example has been described in which there is a central control device, but the present invention does not necessarily require the central control device as an essential component.

A switching method that does not depend on the central control device will be described below.

FIG. 3 is a diagram illustrating such a switching method, and there are contact lines 40, 41 between the base stations 4m, 5m, and 6m.
．． 42 are provided.

For example, the mobile station communicating with base station 4a @) 1j17
A case where a moves to the area of zone 2a will be explained. Suppose that base stations 5m and 6a detect movement 1j17m into their own zone, and base station 5a detects (
It is assumed that the value of reception level B - reception level A) is larger than the value at the base station 6a. At this time, the base station 5a informs the base station 4a via the contact line 41 ahead of the base station 6a that the mobile device 7a has moved into its own zone area and that the channel should be switched to the base station 5a. to contact you. At the same time, the base station 5a selects one of its own free communication channels and notifies the base station 4a of this channel number.

Upon receiving this signal, the base station 4a transmits the signal to the receiver 19-1.
, sends the information signal transmitted to the mobile station via the transmission a20-1 to the base station 5a via the contact line 41, and also transmits the above-mentioned number notified to the mobile unit 7a from the base station 5a. Commands to switch to a communication channel.

The base station 5a transmits and receives information signals sent from the base station 4a via the communication line 41 via the transmitter and receiver of the communication channel, thereby forming a communication path with the mobile 137a.

After the base station 5a starts the above-described operation, the base station 60 starts the same operation fWR, but at this time, the base station 4a has already received the channel switching request from the base station 5a. The request from the base station 6a is ignored.

〔Effect of the invention〕

As explained above, according to the method of the present invention, the migration destination base station itself determines the migration destination of the mobile device, which simplifies the functions and equipment configuration of the central control unit, making the system economical. Great reliability benefits.

In addition, even if there are multiple base stations that determine that the base station has moved to its own zone and the central control unit is used to determine the switching destination, the reception level at the own station and the reception level at the communicating base station will be different. If the difference value is large, the central controller is notified at an early timing, whereas if the difference value is small, the central controller is notified at a later timing. can be recognized.

Therefore, there is an advantage that the channel can be switched to the base station with the maximum reception level, that is, the base station closest to the mobile device, with very easy control.

[Brief explanation of the drawing]

tIS1 is a diagram showing an example of a system configuration of a car telephone system, FIG. 2 is a block diagram showing a configuration of an embodiment of the present invention, and FIG. 3 explains a case where channel switching decisions do not depend on the central control 11rIl. This is a diagram. 1.1m, 2.2m, 3.3m ・=-zone,
4.4a, 5.5a, 6.6m...Base station, 7
．． 7a...Mobile device, 8. 8-1゜8-2 10, 12...Communication line,
9t9-1, 11, 13...
...Control line, 14...Central control unit,
15 29 ...Antenna,
16, 30... Transmission/reception duplexer,
17... Reception distributor, 18...
- Transmission duplexer, 19-1. 19-2010000 communication channel receiver, 20-1.20-2...
...Communication channel transmitter, 21... Reception level measurement receiver (i machine, 22.37... Control device, 23-1.23-2.27-1゜27- 2.
... Communication signal connection, 24-1゜24-2
28-1.28-2 ... Connection for control signals, 31 ... Receiver, 32 ... Transmitter, 33 , 35 ... For communication signals Connection, 3436 ,... Control signal connection, 38
...Connection for terminal, 39 ...Terminal, 25゜2G ...Connection for demodulation signal, 40,41゜42 ...Contact line agent, patent attorney Takashi Honma / Figure 2

Claims (1)

[Claims] In a mobile communication system in which a service area is composed of a plurality of zones and has a base station corresponding to each zone, the base station measures the reception level of radio waves from a mobile device that is communicating, A means for superimposing the measurement result on a communication signal for the mobile station as a reception level A, and a receiver for receiving the signal by sequentially switching communication channels, are used to detect the radio waves of a mobile station communicating with another base station. means for receiving and comparing the reception level B of the radio wave at its own station and the reception level A value included in the radio wave; When the value exceeds the value, a means is provided to perform an operation to switch the communication channel after a delay time determined according to the difference between the value of reception level B and the value of reception level A has elapsed. 1. A communication channel switching system in mobile communication, characterized in that a means is provided for transmitting information of a reception level A received from a base station by radio waves to the base station.