JPH0629912A - Mobile object communication system - Google Patents

Abstract

PURPOSE:To simplify the position registration of a terminal station by dividing a speech channel into plural small zones in a wide zone and using them. CONSTITUTION:Plural base stations 11-13 are installed almost at an equal interval in an area 1a where a call channel reaches from a center 1, and a signal transmitted through a speech channel from the base stations 11-13 is sent with a comparatively small power. Then areas 11a-13a where the transmission signal of the speech cannel reaches from the base stations 11-13 are selected to be comparatively small ranges. Furthermore, transmission frequencies are different from each other in a call channel and a speech channel. Thus, the large area (large zone) 1a where the transmission signal of a call channel reaches from the center 1 is divided into plural small areas (small zones) 11a-13a whose communication is available through a speech channel from the base stations 11-13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system suitable for application to a radio telephone system.

[0002]

2. Description of the Related Art In a mobile communication system such as a car telephone system, what is called a cellular system has been put into practical use. In this cellular system, the communicable area is divided into a plurality of cells (zones), a base station (fixed station) is provided for each cell, and between this base station and a mobile unit (terminal station) in the cell. It is designed to communicate. In this case, each mobile body side transmits and receives to and from the base station, and receives a control signal to determine which cell of the base station can communicate with. That is, for example, in the case of a mobile telephone system using a digital line, the communication data structure when each mobile unit accesses a base station has a frame structure in which frames of a predetermined length are continuous as shown in FIG. A transmission slot T from the mobile unit, a reception slot R in the mobile unit, and an idle slot I are allocated in time division. In this case, as shown in FIG. 5, for example, a mobile unit configured by repeating 26 frames from the 0th frame to the 25th frame and using the transmission slot T and the reception slot R from the 0th frame to the 24th frame. Communication with the base station such as voice data is performed, and control data from the base station is received in the 25th frame. As described above, the communication method in which the reception slot and the transmission slot are arranged in a time division is a TDMA method (Time Division Mult).
iple Access) is called.

During the idle slot I period,
The electric field strength of the cell adjacent to the cell currently in communication is measured. That is, the control signal transmitted from the base station of the adjacent cell is received in the idle slot I, and the electric field strength is judged from the reception level of the electric field strength judgment control signal. in this case,
The frequency (channel) of the electric field strength determination control signal is assigned to each cell, and the adjacent cells are set so that the frequency of the control signal is different. Based on this determination, when the electric field strength of the cell currently in communication is stronger, the communication with the same base station is continued as it is, and when the electric field strength of the adjacent cell is stronger, it is determined that the base station of the adjacent cell is approached. Then, a command for switching to communication with the base station of the adjacent cell is transmitted to the base station. When switching to the communication with the adjacent cell, after transmitting this command, the communication with the adjacent cell is switched at a predetermined timing based on an instruction from the base station side. The measurement of the received electric field strength is performed even when each terminal station is in the standby state.

At the same time, the base station side updates the data of the current position of the terminal station (that is, the data in which cell each terminal station is located). That is, when the command for switching the station to communicate is transmitted from each terminal station side, the data of the current position of each terminal station registered in the base station side is updated. The data of the current position of each terminal station thus updated is used to call each terminal station. That is,
In the case of performing communication in the zone-divided cellular system as described above, the base station cannot call each terminal station unless it is known in advance which zone each terminal station is in.

[0005]

However, if the location registration is performed so that the data for registering the current location on the base station side is transmitted from the terminal station at any time in this way, the power consumption of the terminal apparatus is increased by the operation other than during the call. Therefore, there is a disadvantage that the battery life of the terminal is shortened. Further, on the side of the base station, it is necessary to frequently update the position data of each terminal station, which causes a problem that it takes time to process the position data of each terminal station.

An object of the present invention is to simplify the location registration work of a terminal station in a cellular mobile communication system.

[0007]

The present invention is, for example, as shown in FIG. 1, in a mobile communication system in which communication is performed by radio communication between a base station and a terminal station, from the base station to the terminal station. A call channel for transmitting call data and a call channel for performing predetermined data transmission between the base station and the terminal station are prepared, and the call channel is commonly used in the wide area 1a, and the call channel is wide area. A plurality of small zones 11a, 12a, 13a within the zone.
It is designed to be used by dividing it into.

Further, in this case, when the terminal station is called by the calling channel in the wide area zone, the data which does not require the location registration of the terminal station is added to the calling data.

[0009]

By doing so, as long as the movement of the terminal station is within the wide zone 1a, the updating work of the position registration of the terminal station is unnecessary, and the number of times of updating the position registration of the terminal station is reduced. be able to.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

This example is applied to a cellular type digital radio telephone system in which communication is performed by a digital line, and is constructed as shown in FIG. That is, FIG.
In the figure, 1 indicates a center for controlling communication, and the center 1 controls communication for each terminal station. That is, the center 1 has a position registration unit that stores the current position data of all the registered terminal stations, and when any terminal station is called via the telephone line, the position registration unit stores it. The present position of the corresponding terminal station is determined from the obtained data, and processing based on the determined position is performed.

In this system, a call channel for transmitting the call data is prepared, and the call data is directly transmitted from the center 1 to each terminal station with relatively large power. This center 1
Area 1a where the transmission signal of the calling channel from
Is a relatively wide range.

In this example, a plurality of base stations 11, 12, 13, ... Are installed at substantially equal intervals in the area 1a to which the call channel from the center 1 reaches, and the base stations 11, 12, 13 ,. .. and the center 1 are connected by a dedicated communication line 2, and data such as voice data is transmitted from each base station 11, 12, 13 ,. . In this case, the signals transmitted from the base stations 11, 12, 13 ... On the call channel are transmitted with relatively low power, and the signals of the call channels from the respective base stations 11, 12, 13 ,. Areas 11a, 12a, 13a where the transmission signal reaches
Is a relatively narrow range. The call channel and the call channel have different transmission frequencies.
For example, the call channel has a relatively low transmission frequency of about several tens of MHz, which allows relatively easy reception, and the call channel has a relatively high transmission frequency of about several GHz, which has good transmission efficiency.

Therefore, the inside of the large area (large zone) 1a to which the transmission signal of the calling channel from the center 1 reaches, is a small area (small zone) in which the call from each of the base stations 11, 12, 13 ,. ) 11a, 12a, 13
It means that it is divided into multiple parts with a.

Then, the center 1 and the base stations 11, 1
A plurality of units on the base side, which are composed of 2, 13, ..., Are appropriately arranged according to the size of the service area for providing communication services. However, the position registration unit is provided only in the center of any one unit, and in the unit having no position registration unit in the other center, the corresponding data is obtained from the center side of the unit having the position registration unit.

Next, the terminal 2 used in this system
2, the terminal device 20 of the present example is configured to be small in size for carrying, and the signal received by the antenna 21 is supplied to the transmission / reception processing circuit 22 to demodulate a predetermined communication channel. Then, the processed reception data is supplied to the decoder 23 and is decoded (including analog conversion here) to be an analog audio signal, and this analog audio signal is output from the speaker 24. Further, the audio signal picked up by the microphone 25 is supplied to the encoder 26 to be converted into data for transmission (including digital conversion), and the converted data is supplied to the transmission / reception processing circuit 22 to be modulated into a predetermined communication channel. The transmission process is performed, and the processed transmission signal is wirelessly transmitted from the antenna 21. Here, this terminal 2
The transmission / reception at 0 is performed under the control of the central control unit 27 composed of a microcomputer, and the central control unit 27 controls the transmission frequency, the reception frequency, the transmission / reception timing, etc. in the transmission / reception processing circuit 22. Further, the transmission / reception processing circuit 22 can also receive a calling channel prepared separately from the call channel, and the calling channel data received by the transmission / reception processing circuit 22 is detected by the control data detection circuit 28 and detected. The control based on the data is performed by the central controller 27.

The operation when making a call using the terminal 20 having the above-described structure will be described. First, on the side of the center 1, there is an incoming signal to a predetermined terminal 20 from another telephone line side. When it is detected, it is determined in which area the corresponding terminal 20 is located from the data stored in the position registration unit of the center 1. When it is determined that the terminal 20 is in the area 1a shown in FIG. 1, the center 1 directly calls the terminal 20 having the corresponding individual number using the calling channel (step 101).

On the terminal 20 side, in the standby state, the signal of the calling channel is constantly received, and whether or not the individual number assigned to each terminal 20 is designated by the data transmitted on the calling channel. to decide. When it is determined that the terminal is instructed (that is, called) on the calling channel, a response signal is transmitted from the terminal 20 using the calling channel (step 102). Data of the individual number of the terminal device 20 that responded is added to the response signal. The response signal is transmitted using a common access channel for response prepared for each area, for example.

Then, any one of the base stations 11, 12, 13
When the response signal is received by ..., the reception of the response signal from the receiving base station (for example, the base station 11 is assumed) to the center 1 side through the dedicated communication line 2 Inquire with the individual number (step 10)
3). When the center 1 side confirms the inquiry from the base station 11 (step 104), communication with the terminal 20 side via the communication channel is performed via the base station 11 (step 105).

Here, the processing when there is an incoming call has been described, but when making a call from the terminal side, instead of sending a response signal corresponding to the reception of a calling signal, a calling request is made directly. It becomes possible by transmitting a signal to the base station side.

Further, it is not necessary to register the location of the small zone in the large zone, but it is necessary to measure only the electric field strength received from the surrounding base stations at any time and to switch the small zone to be used for the call appropriately. .

In this way, only the call is sent to the center 1
As long as the terminal 20 is located in the large area 1a where the call signal from the center 1 arrives, the terminal 2
It is not necessary to update the registered position of 0, and it is sufficient to update it to the corresponding position only when moving outside the large area 1a. Therefore, the small area 11 corresponding to each base station as in the past
The work of registering the positions of a, 12a, and 13a is unnecessary,
The number of times each terminal transmits the data requesting the update of the registered position is significantly reduced. As a result, the power required for each terminal to transmit the location registration data can be significantly reduced, and the duration of the battery included in each terminal can be lengthened. On the side of the center 1 as well, the work of storing the current position of each terminal may be performed by determining the position in units of a large area, and the small areas 11a, 12a, 13a
Since it is not necessary to judge the position of the registered position, the amount of data to be handled is reduced, the amount of data stored as the registered position is reduced, and the number of times the registered position is updated is reduced. Can be done with simple control.

In the above embodiment, a plurality of large areas 1a centering on the center 1 are prepared.
If the large area 1a can cover the service area, only one center may be provided. In this case, location registration is completely unnecessary.

Alternatively, the location registration in the large area and the location registration in the small area may be combined. That is, only the area where the call signal reaches directly from the center side is set as a large area, and the area around it is not formed as a large area, and the call signal is also transmitted through the base station. In this case, if there is a terminal station in the large area, it is not necessary to register the location of the small area, but if the terminal station is located outside the large area, the location registration of the small area should be performed. Need to be on the side. Therefore, when the user is in the large area, it is necessary to perform control that makes the location registration of the small area unnecessary. As this control, for example, data that makes location registration of a small area unnecessary is added to call data transmitted on a call channel, and when this data is within a receivable range, each terminal station performs location registration of a small area. It may be controlled so as not to perform (or not perform location registration at all).

Further, in the above-mentioned embodiment, the communication system between the base station and the terminal station was not described, but various communication systems applied in mobile communication are applied. That is, the invention is not limited to the TDMA method described in the conventional example, and various mobile communication methods can be applied.

[0026]

According to the present invention, as long as the movement of the terminal station is within a wide zone where the signal of the calling channel arrives, the updating work of the position registration of the terminal station is unnecessary, and the updating work of the position registration of the terminal station is performed. It is possible to reduce the number of times of performing the registration, to reduce the power required for position registration, and to simplify the registration position control on the center side.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a terminal according to an embodiment.

FIG. 3 is a flow chart for explaining one embodiment.

FIG. 4 is a configuration diagram showing a slot configuration example of mobile communication.

FIG. 5 is a configuration diagram showing an example of a frame structure of communication data.

[Explanation of symbols]

 1 Center 1a Area (Large Area) 11, 12, 13 Base Stations 11a, 12a, 13a Area (Small Area) 20 Terminals

Claims (2)

[Claims] 1. In a mobile communication system in which wireless communication is performed between a base station and a terminal station, a calling channel for transmitting calling data from the base station to the terminal station, the base station and the Prepare a call channel that performs predetermined data transmission with the terminal station, use the call channel in common in the wide area zone, and divide the call channel into multiple small zones in the wide area zone. Mobile communication system. 2. The movement according to claim 1, wherein when calling the terminal station by the calling channel in the wide area zone, data which does not require location registration of the terminal station is added to the calling data. Body communication system.