JP2000228645A - Power saving method for base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce excessive emitted radio waves and to reduce the power consumption of a base station by thinning and arranging simultaneous calling channels and channels for separate cells in accordance with the number of mobile terminals whose positions are already registered within the service area of a base station. SOLUTION: A base station transmitter-receiver consists of an antenna 1, a transmitting and receiving part 2, a communication controlling part 3 and a thinning controlling part 4. The part 4 thinns and arranges simultaneous calling channels (PCH) and channels (SCCH) for a separate cell of a control channel in a down super frame in accordance with the number of mobile terminals whose positions are already registered within the service area of a base station. Thus, it is possible to reduce the emission of radio waves in slots for communication control of the down super frame and to reduce the power consumption of the base station by thinning and arranging the control channels of the PCH or the SCCH in the down super frame in accordance with the number of mobile terminals within the area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power saving method of a base station for mobile communication, which can reduce power consumption by reducing information of a control channel.

[0002]

2. Description of the Related Art In recent years, mobile phones and the like utilizing wireless communication have been widely used, and many mobile communication terminals have been used. In a mobile communication, when a call is made between a mobile terminal and another mobile terminal, communication is performed via the base station in the service area where the calling mobile terminal is located and the base station in the service area where the called mobile terminal is located. Is what you do. Therefore, when a mobile terminal starts a call in a service area of a certain base station, or when waiting for a call from another mobile terminal, it is necessary to first determine in which service area of the base station the mobile terminal is located. It is necessary to register (location registration) with the base station. Generally, wireless communication control in mobile communication is performed by transmitting and receiving various control information including the location registration between a base station and a mobile terminal through a control channel. FIG. 2A is a schematic configuration diagram illustrating an example of a base station transmitting / receiving apparatus of a conventional mobile communication system. This base station transmission / reception device (hereinafter, referred to as a base station) includes an antenna 1, a transmission / reception unit 2, and a communication control unit 3. The transmission / reception unit 2 amplifies radio waves received from the mobile terminal by the antenna 1, The received radio wave is demodulated by a demodulation method based on the received signal and a demodulated signal is output to the communication control unit 3, or a control signal from a base station to a mobile terminal is modulated by a modulation method based on a communication system and output to the antenna 1. The communication control unit 3 has a control function to be described in detail below, such as arrangement of a control channel to be output to a mobile terminal in a service area, control of the content of a message of the control channel, and the like.

FIG. 2B is a configuration diagram of a communication frame and a superframe transmitted and received between a base station and a mobile terminal in a digital mobile communication system based on the TDMA system. As shown in the figure, the length of the communication frame is 2
At 0 ms, each frame is divided into three slots # 1 to # 3 (slot length: 6.6 ms). In the # 1 slot, a control channel for transmitting control information or an information channel for transmitting user information such as voice is arranged.
In three slots, an information channel for transmitting user information such as voice is arranged. That is, between the base station and the terminal, a radio wave in which all three slots # 1 to # 3 have information channels arranged therein, and a control channel is arranged in the slot # 1;
In the slots # 2 and # 3, two types of radio waves, in which an information channel is arranged, are transmitted. The downlink control channel includes a broadcast channel (BCCH), a dedicated cell channel (SCCH), and a paging channel (PCH).
CH) is allocated, and an uplink control channel transmitted from the mobile terminal to the base station is a dedicated cell channel (SCC).
H) only. The superframe is 36
It is composed of a series of consecutive communication frames. FIG.
(C) is a configuration diagram showing an example of a configuration of only a control channel in a downlink superframe. As shown in the figure, the base station transmits control information of the broadcast channel (BCCH) in the first frame of the superframe, control information of the dedicated cell channel (SCCH) in the second frame, and control information of the paging channel (PCH) in the third frame. The individual cell channel (SCCH) and the paging channel (PCH) are alternately arranged from the fourth frame to the 36th frame. On the other hand, in the uplink super frame, as shown in FIG. 2D, dedicated cell channels (SCCH) are arranged in all control channels.

[0004] The functions of the broadcast channel (BCCH), dedicated cell channel (SCCH) and paging channel (PCH) are as follows. (1) Broadcast channel (hereinafter simply referred to as BCCH) A downlink one-way channel for broadcasting control information from a base station to a mobile station. Transfers information about the channel structure, system information, and the like. (2) Individual cell channel (hereinafter simply referred to as SCCH) This is a point-to-point bidirectional channel for transferring information required for call connection between a base station and a mobile station, and transfers independent information for each cell. The uplink channel is random access. Information about location registration is transmitted and received on this channel. (3) Paging channel (hereinafter simply referred to as PCH) A point-to-multipoint downlink in which the same information is simultaneously transferred from a base station to a mobile station over a single cell or a wide area (paging area) of a plurality of cells. One-way channel. The incoming signal is transmitted from the base station on this channel.

In a service area where control information is transmitted in a superframe configuration shown in FIG.
When the mobile terminal turns on the power of the device, or when the mobile terminal enters the area where the radio wave of the control information of the base station does not reach and the radio terminal reaches, the mobile terminal is transmitted from the base station. The electric field strength of a radio wave (perch channel) in which the control channel is arranged is measured, and if a radio wave of a predetermined electric field strength can be received, the BCCH is received to confirm the structure of the control channel. Then, the mobile terminal synchronizes with the frame based on the downlink superframe from the base station, and transmits a location registration request signal to the base station using the SCCH slot of the uplink superframe. In response to the request signal, the base station transmits the SCC in the downlink superframe.
A location registration response signal is transmitted in the H slot, and the mobile terminal receives the signal. By the above operation, the mobile terminal is in a state in which it can wait in the area for the first time.

[0006]

However, the base station continuously transmits radio waves of control information using a control channel for mobile terminals that communicate within the area.
Therefore, even when the number of mobile terminals using the control radio wave is small, in the communication radio wave in which the control channel is allocated, the control information is transmitted in the # 1 slot of all communication frames, so that the There is a problem that the equipment power must be supplied. The present invention has been made to solve the above problems, and has as its object to provide a method capable of reducing the power consumption of a base station by reducing unnecessary emission waves.

[0007]

In order to solve the above-mentioned problems, in the base station power saving method according to the present invention, at least a broadcast channel (BCCH), a broadcast channel (BCCH), In a digital mobile communication system having a paging channel (PCH) and a dedicated cell channel (SCCH), the paging channel (PCH) and the dedicated cell channel (SCCH) are registered in the service area of the base station. The number of mobile terminals is thinned out and arranged according to the number of mobile terminals.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings. FIG. 1A is a schematic configuration diagram showing an example of an embodiment of a base station transmitting / receiving apparatus according to the present invention. As shown in FIG. 1, the base station transmitting / receiving apparatus (hereinafter, referred to as a base station) includes an antenna 1, a transmitting / receiving unit 2, a communication control unit 3, and a thinning control unit. The present base station has a configuration in which a thinning-out control unit 4 is newly added to a conventional base station, and a control channel in a superframe is thinned out by the thinning-out control unit 4, and a method described below is used. Sends the control information.

FIG. 1B is a layout diagram of control channels showing the structure of control information transmitted from the base station in a downlink superframe. As shown in the drawing, the arrangement of the control information of the downlink superframe transmitted from the base station is such that when there are few mobile terminals in the service area, the BCCH is allocated in advance to the first frame and the PCH is allocated to the 19th frame. I do. At this time, the other (P) and (S) frames are set as empty slots, and the necessary number of PCHs or SCCHs are added to the frames at predetermined positions and arranged in accordance with the increase in the number of mobile terminals in the area. Further, in the control process, a downlink SCCH may be arranged as needed in correspondence with the SCCH from the mobile terminal.

In a service area in which control information is transmitted from a base station using a downlink superframe having a configuration as shown in FIG. 1B, a BCCH is arranged in order for a mobile terminal to measure electric field strength. The transmission radio wave of the specified frequency (perch channel) is received and measured. If there is a predetermined electric field strength, the mobile terminal receives the BCCH and checks the structure of the control channel. Then, the mobile terminal synchronizes with the frame based on the downlink superframe from the base station, and transmits a location registration request signal to the base station using the SCCH slot of the uplink superframe. The base station arranges an SCCH control channel in an empty slot in the downlink superframe in response to the position registration request signal, issues a position registration permission response signal, and receives the response signal from the mobile terminal. The registration control operation is completed. Here, when a mobile terminal that has completed location registration makes a call, first, S
A call request signal is transmitted to the base station using the CCH slot. The base station that has received the request signal arranges the SCCH at the position indicated by (s) in the empty slot of the downlink superframe in FIG. 1B and transmits a call response signal.
When the terminal receives this response signal, a calling operation is performed and communication can be started.

The above operation is performed when the number of terminals in the service area is extremely small. When the number of terminals registered in the area is large, call requests and incoming calls increase. This is addressed by increasing the number of slots to be used. In the downlink superframe, at least the first BCCH and the first 1
Since two of the ninth PCHs are arranged, the time required for the mobile terminal to receive the control channel and measure the electric field strength is at most 360 ms if there is no information channel communicating in another slot. , The electric field strength of the base station can be measured in an average time of 180 ms. If the measurement needs to be performed in a shorter time, the number of PCH or SCCH control channels that always emit radio waves during a superframe may be increased as appropriate. At this time, when it becomes necessary to simultaneously transmit a large number of incoming signals to mobile terminals in the area, if the number of PCH control channels is small, a large number of incoming signals will be sequentially transmitted, and it takes time.
It is desirable to increase the number of slots so as to prioritize the arrangement.

As described above, it is possible to arrange the control channels of the PCH or SCCH in the downlink superframe in a thinned-out manner according to the number of mobile terminals in the area.
Therefore, the emission of radio waves in the # 1 slot for communication control of the downlink superframe can be reduced, and the power consumption of the base station can be reduced.

[0013]

As described above, according to the present invention, since the information arranged in the control channel of the superframe is reduced, the transmission power is reduced when the use degree of the control channel is small. This can contribute to a reduction in power consumption in the base station.

[Brief description of the drawings]

FIG. 1A is a schematic diagram of a configuration of a base station transmitting / receiving apparatus according to the present invention, and FIG. 1B is a layout diagram of a control channel in which the base station transmitting / receiving apparatus of FIG.

2A is a schematic configuration diagram illustrating an example of a conventional base station device, FIG. 2B is a configuration diagram illustrating an example of a conventional communication frame and a superframe, and FIG. FIG. 3D is a layout diagram of control channels transmitted in an uplink superframe.

[Explanation of symbols]

1. Antenna, 2. Transmitter / receiver, 3.
Communication control unit 4. Thinning-out control unit according to the present invention

Claims (1)

[Claims] 1. A digital mobile communication system having at least a broadcast channel (BCCH), a paging channel (PCH), and a dedicated cell channel (SCCH) as control information in a downlink superframe transmitted from a base station. A base station power saving method, wherein a paging channel (PCH) and a dedicated cell channel (SCCH) are thinned out according to the number of mobile terminals whose positions are registered in the service area of the base station.