JP2009206549A - Base station configuring plural radio communication areas and its radio unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base station for achieving low power consumption and its radio unit. <P>SOLUTION: The base station includes a plurality of radio units 10.1-10.N configuring a plurality of radio communication areas 12.1-12.N respectively, and a signal processing unit 11, connected to the plurality of radio units 10.1-10.N, for processing transmission/reception of baseband signals. The plurality of radio units 10.1-10.N respectively have area monitoring units 106.1-106.N for monitoring the state of a corresponding radio communication unit and detecting at least two states, and a transmission power control unit 105 for controlling transmission output of the radio unit in accordance with the detected state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a base station of a mobile communication system, and more particularly to a base station and a radio unit thereof constituting a plurality of radio communication areas.

  In a mobile communication system composed of a mobile station and a radio base station, various techniques for reducing power consumption of a battery-driven mobile station have been generally proposed. For example, when the mobile station is in a standby state, power consumption is reduced by performing intermittent reception. Japanese Patent Laying-Open No. 2006-50243 (Patent Document 1) discloses that when it is determined that a broadband / low latency is unnecessary by detecting changes in ambient brightness, radio wave conditions, and the like, a power saving state is established. A wireless communication device that shifts to is disclosed.

JP 2006-50243 A

  However, power saving is demanded not only for mobile stations but also for radio base stations, and especially when installing multiple radio base stations in office buildings, etc., low power consumption should be considered. . Hereinafter, the reduction of power consumption in the radio base station will be briefly described.

  FIG. 3 is a schematic block diagram for explaining radio communication between a radio base station and a mobile station in a general mobile communication system. Here, it is assumed that the wireless communication area 300 is configured by the wireless base station 301. In general, the radio base station 301 always transmits a pilot signal (also referred to as a reference signal) to the mobile station 302 located in the radio communication area 300. The mobile station 302 receives the pilot signal transmitted from the radio base station 301 to determine whether the mobile communication service is in or out of service.

  For example, when the mobile station 302 is outside the area 300, the mobile communication service cannot be received because the pilot signal from the radio base station 301 cannot be received. When this mobile station 302 moves into the area 300 as indicated by an arrow in the figure, it is determined that it is within range by receiving a pilot signal from the radio base station 301 and communication to the radio base station 301 is started. be able to. The radio base station 301 can check the status of a mobile station within the radio communication area 300 and perform communication control based on a response from the mobile station 302 to the pilot signal.

  The size of the radio communication area 300 is determined by the radio transmission output of a pilot signal transmitted from the radio base station 301. Therefore, the radio transmission amplifier of the radio base station 301 consumes a relatively large amount of power in the base station function unit, and the reduction in power consumption of the radio transmission amplifier is a major factor for reducing the power of the entire base station.

  However, since the grasping of the location information of the plurality of mobile stations 302 existing in the radio communication area 300 is all based on the response of the pilot signal transmitted from the radio base station 301, the mobile station is not in the range. Even so, the radio base station 301 cannot stop the pilot signal radio transmission.

  For example, in a closed space indoor area, a mobile communication service may become unnecessary depending on the time and flow of people in a limited private area such as a holiday office or a store outside business hours, and in an outdoor area such as a theme park. The wireless base station 301 must continue to transmit the pilot signal, even though the mobile communication service is not necessary. This is because the overall power outage of the radio base station 301 causes a decrease in radio frequency stability, and further resetting with the upper network of the mobile communication system requires a long time to restart. is there. Further, since the base station controller (RNC) on the mobile communication network performs transmission power control of the radio base station based on the propagation quality report from the mobile station, when the mobile station does not exist in the area In the first place, there is no need to control the power of the radio base station.

  As described above, the radio base station 301 needs to constantly transmit the pilot signal regardless of whether or not there is a communication target in the radio communication area, and the large power consumption in the transmission amplifier reduces the power consumption of the radio base station. It is one of the factors that prevent In particular, in the case of an office building where it is necessary to arrange wireless communication areas in a plurality of closed spaces, an increase in power consumption of the wireless base station becomes a big problem.

  Therefore, an object of the present invention is to provide a base station and a radio unit thereof that can achieve low power consumption.

  A base station according to the present invention is a base station that has a plurality of radio communication areas and performs radio communication with a mobile station, and includes a plurality of radio units each constituting the plurality of radio communication areas, and the plurality of radio units And a signal processing unit that processes transmission / reception baseband signals, and each of the plurality of radio units monitors a situation in a corresponding radio communication area and detects at least two situations And control means for controlling the transmission output of the radio unit according to the detected situation.

  According to the present invention, low power consumption of the base station can be achieved.

1. FIG. 1 is a block diagram illustrating a schematic configuration of a base station according to an embodiment of the present invention. The base station according to this embodiment includes N base station radio units 10.1 to 10. N and the base station signal processing unit 11 are connected to each other, and wireless communication areas 12.1 to 12.N by the N base station radio units. Let N be configured respectively. In other words, from the viewpoint of the mobile communication network, one base station has N radio communication areas (or sectors). The mobile station MS is located in an arbitrary radio communication area, and thus can receive a pilot signal from the base station and perform radio communication.

  Base station radio section 10.1-10. Since N has the same circuit configuration, the base station radio unit 10.1 shown in FIG. 1 will be described. The radio transmission / reception unit of the base station radio unit 10.1 includes a reception amplifier 101 and an RF reception unit 102, an RF transmission unit 103, and a transmission power amplifier 104. The receiving amplifier 101 amplifies the received radio (RF) signal, and the RF receiving unit 102 outputs a baseband signal obtained by demodulating the received RF signal. The RF transmission unit 103 modulates the transmission baseband signal and outputs the RF transmission signal to the transmission power amplifier 104. The transmission power amplifier 104 amplifies the power and transmits the amplified signal to the wireless communication area 12.1.

  The transmission output of the transmission power amplifier 104 is controlled by the transmission power control unit 105. The transmission power control unit 105 controls the transmission output of the transmission power amplifier 104 according to the monitoring signal from the area monitoring unit 106.1. For example, if the area monitoring unit 106.1 determines that there is no user in the wireless communication area 12.1, the transmission power control unit 105 can stop the transmission output of the transmission power amplifier 104. Further, the transmission power control unit 105 can be controlled to stop the transmission output only for the transmission operation at the time of providing a specific service according to the control signal from the base station signal processing unit 11.

  The area monitoring unit 106.1 may be any means that can detect the status of the wireless communication area 12.1, such as the use / non-use of a room or the entry / exit of a person, and various existing monitoring methods may be employed. it can. For example, the area monitoring unit uses a light sensor when turning off the lights when the room is unused, and an automatic door operation detector when using the automatic door opening / closing operation when leaving the room. It can be adopted as 106.1. It is also possible to adopt a monitoring method that detects the movement of a person using a plurality of optical sensors or determines the presence or absence of a person by image analysis using an imaging device. Alternatively, when a room entrance / exit management system is installed, the management signal can be used as a monitoring signal for the area monitoring unit.

  The base station radio unit 10.1 is connected to the base station signal processing unit 11 through the interface 107, and exchanges the reception and transmission baseband signals of the RF reception unit 102 and the RF transmission unit 103.

  The base station signal processing unit 11 includes an interface 110 for transmitting and receiving a reception baseband signal from each base station radio unit and a transmission baseband signal to each base station radio unit, and processes the transmission / reception baseband signal. The signal processing unit 111 and the control unit 112 that performs overall operation control of the base station signal processing unit 11 are included. Note that the control unit 112 can also control the radio transmission / reception unit and the transmission power control unit 105 of an arbitrary base station radio unit through the interface 110.

  Base station radio section 10.2-10. N has the same configuration as that of the base station radio unit 10.1, and the base station radio units 10.1 to 10. N and the base station signal processing unit 11 constitute one base station.

  As described above, the base station according to this embodiment includes the base station radio units 10.1 to 10. N and the base station signal processing unit 11, and the area monitoring units 106.1 to 106. N is used to monitor the situation in each wireless communication area, and the base station radio units 10.1 to 10. N transmission outputs can be individually controlled. Thereby, for example, the transmission output of the base station radio unit in the room where there is no user can be stopped, and the transmission power of unnecessary pilot signals and other transmission signals can be reduced.

  Even in the service OFF state, the reception amplifier 101, the RF reception unit 102, and the RF transmission unit 103 of the wireless transmission / reception unit are in the active state. Therefore, when the area monitoring unit 106.1 detects the service ON condition, the pilot signal is transmitted only by turning ON the output of the transmission power amplifier 104, and the mobile station MS enters the service area, so the service is immediately resumed. It becomes possible. On the other hand, as described in the section “Problems to be solved by the invention”, in the existing system, it is necessary to start up the apparatus, wait for frequency stabilization, connect to the RNC, etc., and restart the service. It took time to.

2. Embodiment FIG. 2 is a block diagram showing an example of a mobile communication indoor system to which a base station according to an embodiment of the present invention is applied. Here, N = 3, and blocks having the same functions as those shown in FIG.

  Base station radio units 10.1 to 10.3 are distributed and arranged on the first to third floors of the building 201, and optical sensors are employed as the area monitoring units 106.1 to 106.3. The base station signal unit 11 is connected to the mobile communication network 203 together with other base stations 202. As described above, the base station radio units 10.1 to 10.3 and the base station signal processing unit 11 constitute one base station similar to the other base stations 202.

  The base station radio units 10.1 to 10.3 arranged on each floor can communicate with the mobile station MS by radio signals, and can provide mobile communication services in the respective radio communication areas. In addition to this, the base station radio units 10.1 to 10.3 according to the present embodiment include optical sensors 106.1 to 106.3 that detect the brightness of light, and the sensor outputs of the respective optical sensors. Accordingly, the transmission output of the base station radio unit can be individually controlled.

  In the example shown in FIG. 2, since the lighting is turned on and the user is present in the rooms on the first floor and the second floor, the transmission power control unit 105 controls the transmission power amplifier 104 by the output signals of the optical sensors 106.1 and 106.2. The normal base station radio units 10.1 and 10.2 are each controlled to a normal transmission output to transmit a pilot signal, thereby enabling radio communication with each mobile station MS. On the other hand, since the room on the third floor is turned off, the transmission power control unit 105 stops the transmission output of the transmission power amplifier 104 by the output signal of the optical sensor 106.3, and thereby the pilot signal is transmitted. All transmitted signals are not transmitted to the room on the third floor. Therefore, it is possible to reduce the transmission power of the third floor where the mobile service is no longer necessary while continuing to provide the necessary mobile services on the first and second floors.

  As described above, according to the present embodiment, the environment of the wireless communication area is monitored by the optical sensors 106.1 to 106.3. Therefore, when there is no person, a specific private wireless device such as a store outside business hours is used. In a situation where a mobile communication service is not required in the communication area, it is possible to stop transmission of all radio signals including pilot signals that are constantly transmitted, reducing the power consumption of the wasted radio amplifier unit. Can be reduced.

  Furthermore, since the transmission output of the wireless unit is directly controlled by the operation of the optical sensor installed in the desired wireless communication area, the transmission output of only the wireless unit installed in the area where the mobile communication service is not required Can be stopped, and efficient power reduction can be achieved without degrading service.

  In this embodiment, instead of the optical sensors 106.1 to 106.3, other types of monitoring means such as a detector for detecting the operation of an automatic door or the like may be employed. Further, the area monitoring units 106.1 to 106.3 do not have to adopt the same monitoring method, and the first floor is an optical sensor 106.1 and the second floor is an automatic door detector 106.2. What is necessary is just to employ | adopt the monitoring means suitable for a radio | wireless communication area.

3. Other Embodiments In the above embodiment, the transmission outputs of the base station radio units 10.1 to 10.3 can be individually stopped according to the monitoring status of the optical sensors 106.1 to 106.3. Under the control of the control unit 112 of the station signal processing unit 11, it is also possible to individually stop the transmission outputs of the base station radio units 10.1 to 10.3 only when transmitting a specific service. That is, the transmission of the pilot signal is continued as usual, but in the case of a specific service where the transmission power increases, the transmission output of the transmission power amplifier 104 may be stopped to reduce the power consumption.

  The present invention is applicable to an indoor system of a mobile communication system.

It is a block diagram which shows the schematic structure of the base station by one Embodiment of this invention. It is a block diagram which shows an example of the mobile communication indoor system to which the base station by one Example of this invention is applied. It is a typical block diagram for demonstrating the radio | wireless communication between the radio base station and mobile station in a general mobile communication system.

Explanation of symbols

10.1-10. N base station radio unit 11 base station signal processing units 12.1-12. N wireless communication area 101 reception amplifier 102 RF reception unit 103 RF transmission unit 104 transmission power amplifier 105 transmission power control unit 105
106.1-106. N area monitoring unit 107 interface 110 interface 111 signal processing unit 112 control unit

Claims (10)

A base station having a plurality of wireless communication areas and performing wireless communication with a mobile station,
A plurality of radio units that respectively configure the plurality of radio communication areas; and a signal processing unit that is connected to the plurality of radio units and performs transmission / reception baseband signal processing;
Each of the plurality of radio units is
Detection means for monitoring the situation in the corresponding wireless communication area and detecting at least two situations;
Control means for controlling the transmission output of the radio unit according to the detected situation;
A base station characterized by comprising:   The base station according to claim 1, wherein the control unit stops the transmission output when a predetermined situation is detected.   The base station according to claim 1, wherein the radio unit includes a transmission amplifier and a modulator, and the control unit stops the transmission amplifier when a predetermined situation is detected.   The base station according to claim 2 or 3, wherein the detecting means is an optical sensor, and the transmission output is stopped when an output of the optical sensor is lower than a predetermined level.   5. The base station according to claim 1, wherein each of the plurality of wireless communication areas is an indoor closed space.   A mobile communication system comprising the base station according to claim 1. A radio unit in a base station that performs radio communication with a mobile station,
Transmission power amplification means;
Interface means for connecting to the signal processing unit of the base station;
Detection means for monitoring the situation in the wireless communication area and detecting at least two situations;
Control means for controlling the transmission output of the transmission power amplification means in accordance with the detected situation;
A wireless unit comprising:   The radio unit according to claim 7, wherein the control unit stops the transmission output when a predetermined situation is detected.   The radio unit according to claim 7 or 8, wherein the control unit stops the transmission power amplifying unit when a predetermined situation is detected.   The wireless unit according to claim 8 or 9, wherein the detection unit is an optical sensor, and the transmission output is stopped when an output of the optical sensor is lower than a predetermined level.

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