Distributed antenna system, communication device, sleep control method and program

Abstract

To provide a technology capable of achieving proper sleep control depending on a usage state of a slave station device.SOLUTION: A distributed antenna system comprises: one or more slave station devices each of which comprises at least one transmission / reception unit transmitting / receiving a wireless signal to / from a wireless terminal via an antenna; and a master station device that transmits / receives the wireless signal to / from the slave station device directly or via a relay device. The slave station device comprises a determination unit that determines a transmission / reception state of the wireless signal with the wireless terminal and notifies the master station device of determination information representing the determination results. The master station device comprises a control unit that sets the transmission / reception unit to an operable mode in a state where transmission / reception of the wireless signal is performed, and controls the slave station device to set at least a part of the transmission / reception unit to a sleep mode in a state where no transmission / reception of the wireless signal is performed, on the basis of the determination information.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a distributed antenna system, a communication device, a sleep control method, and a program. [Background technology]

[0002] Distributed Antenna Systems (DAS) are one type of wireless communication system. DAS distributes communication signals transmitted and received by base stations of a wide-area mobile communication network to multiple antennas distributed indoors, for example, to extend the communication area of ​​the network to indoor locations such as buildings and basements where radio waves are difficult to reach.

[0003] A DAS includes, for example, a master station connected to a base station of a mobile communication network, a plurality of slave stations that are distributed indoors and connected to the master station via relay devices, and antennas connected to these slave stations. The connections between the base station and master station, between the master station and each slave station, and between the slave station and the antenna are all made using wired communication media with low transmission loss, such as coaxial cables or optical cables.

[0004] Generally, in a DAS, the slave station device is in a constant operating state whether it is communicating with a wireless terminal or in a standby state where no communication is taking place, and therefore power consumption of the slave station device in a standby state tends to be high.

[0005] Meanwhile, some mobile communication systems are equipped with a function to reduce the power consumption of communication devices used in base stations of a mobile communication network, etc. For example, Patent Document 1 describes a technology in which, in a system in which multiple small cell base stations are placed within a macrocell to compensate for local bandwidth shortages in the macrocell base station, an optical terminal device sets the optical terminal device and the small cell base stations connected thereto into a sleep state based on wireless terminal information managed by the macrocell base station in order to reduce the power consumption of the multiple small cell base stations.

[0006] However, the technology described in Patent Document 1 uses wireless terminal information managed by the macrocell base station to set the optical terminal equipment and small cell base stations to a sleep state. Therefore, while sleep control for the entire system is possible, it is difficult to perform sleep control for each small cell base station according to its usage state. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2018-207457 Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved by the present invention is to provide a technique for realizing appropriate sleep control according to the usage state of a slave station device. [Means for solving the problem]

[0009] According to an embodiment, the spatial antenna system includes one or more slave station devices each having at least one transceiver unit for transmitting and receiving wireless signals to and from a wireless terminal via an antenna, and a master station device for transmitting and receiving the wireless signals to and from the slave station devices directly or via a relay device. The slave station devices include a determination unit that determines a transmission / reception state of the wireless signals by the transceiver unit and notifies the master station device of determination information representing the determination result. The master station device includes a control unit that controls the slave station devices based on the determination information to set the transceiver units to an operable mode when the wireless signals are being transmitted and received, and to set at least some of the transceiver units to a sleep mode when the wireless signals are not being transmitted or received. The control unit includes a determination processing unit that determines, based on the information representing the transmission and reception state, whether a reception quality index is lower than a first threshold or whether the reception quality index is equal to or higher than the first threshold and lower than a second threshold, a first control processing unit that sets a first receiving function unit of the transceiver unit to a sleep mode when it is determined that the reception quality index is equal to or higher than the first threshold and lower than the second threshold, and a second control processing unit that sets both the first receiving function unit and a second receiving function unit of the transceiver unit to a sleep mode when it is determined that the reception quality index is lower than the first threshold. The first control processing unit performs a first process that stops a calibration operation of a digital-to-analog converter provided in the transceiver unit and a characteristic compensation operation of a transmission power amplifier. When it is determined that the index of reception quality is lower than the first threshold, the second control processing unit, in addition to the first processing, further performs a second processing of stopping the supply of an operating clock to the baseband processing unit and the digital / analog converter provided in the transceiver unit and the supply of operating power to the transmission power amplifier. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram showing an example of the configuration of a distributed antenna system according to a first embodiment of the present invention. [Figure 2] 2 is a block diagram showing an example of the configuration of a slave station device of the distributed antenna system shown in FIG. 1; [Figure 3] 3 is a block diagram showing an example of the functional configuration of a control unit of the slave station device shown in FIG. 2; [Figure 4] FIG. 2 is a block diagram showing an example of the configuration of a master station device of the distributed antenna system shown in FIG. [Figure 5] 5 is a block diagram showing an example of the functional configuration of a control unit of the master station device shown in FIG. 4. [Figure 6] 4 is a flowchart showing an example of the procedure and content of a control process executed by a control unit of a slave station device shown in FIG. 3; [Figure 7] 5 is a flowchart showing an example of the procedure and content of a control process executed by a control unit of the parent station device shown in FIG. 4; [Figure 8] 3 is a block diagram showing an example of a sleep operation performed on a transmission / reception unit in the slave station device shown in FIG. 2; [Figure 9]2 is a diagram illustrating an example of a state in which a normal operation mode is set for a slave station device in the distributed antenna system shown in FIG. 1. FIG. [Figure 10] 2 is a diagram illustrating an example of a state in which a sleep mode is set in a slave station device in the distributed antenna system shown in FIG. 1. FIG. [Figure 11] 2 is a diagram illustrating an example of a state in which all slave station devices are set to a normal operation mode in the distributed antenna system shown in FIG. 1. FIG. [Figure 12] 2 is a diagram illustrating an example of a state in which some of the slave station devices are set to a forced sleep mode and other parts of the slave station devices are set to a sleep mode in the distributed antenna system shown in FIG. 1. FIG. [Figure 13] FIG. 10 is a block diagram showing an example of a state in which a receiving function unit operates in a normal operation mode in a slave station device according to a second embodiment of the present invention. [Figure 14] FIG. 10 is a block diagram showing an example of a state in which some functions of a receiving function unit are set in a sleep mode in a slave station device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] A distributed antenna system according to an embodiment, a communication device used in the system, a sleep control method, and a program will be described below with reference to the drawings.

[0012] [First embodiment] (Configuration example) (1) System FIG. 1 is a block diagram showing an example of the configuration of a distributed antenna system 100 according to the first embodiment.

[0013] The distributed antenna system 100 includes a master station (MU) 1, a hub station (HUB) 2 that functions as a relay station, multiple slave station units (RUs) 3-1 to 3-m, and multiple antennas 4-1 to 4-m connected to the slave station units 3-1 to 3-m. The master station 1 and the hub station 2, and the hub station 2 and each of the slave station units 3-1 to 3-m, are connected via optical cables. Note that the master station 1 and some of the slave station units 3 may be connected directly without going through the hub station 2.

[0014] The master station device 1 is connected, for example, via a coaxial cable, to a base station device BS of a mobile communication system that covers a wide area, such as outdoors. The master station device 1 transmits and receives radio signals to and from the base station device BS. The master station device 1 converts the radio signals received from the base station device BS into downstream (downlink) digital transmission signals and transmits them to the slave station devices 3-1 to 3-m directly or via the hub station device 2. The master station device 1 also converts upstream (uplink) digital transmission signals transmitted from the slave station devices 3-1 to 3-m directly or via the hub station device 2 into radio signals and transmits them to the base station device BS.

[0015] The slave station devices 3-1 to 3-m transmit and receive radio signals to and from the wireless terminals MT1 to MTn via antennas 4-1 to 4-m. The slave station devices 3-1 to 3-m convert the radio signals received from the wireless terminals MT1 to MTn into upstream digital transmission signals and transmit them to the master station device 1 directly or via the hub station device 2. The slave station devices 3-1 to 3-m also convert downstream digital transmission signals transmitted from the master station device 1 directly or via the hub station device 2 into radio signals and transmit them to the wireless terminals MT from the antennas 4-1 to 4-m.

[0016] The distributed antenna system 100 includes a management terminal 7 used by a system administrator or the like. The management terminal 7 is connected to the master station device 1 via a network NW configured by, for example, a LAN (Local Area Network) and a router 6, and transmits and receives control data to and from the master station device 1.

[0017] (2) Equipment (2-1)Slave station device 3-1~3-m 2 is a block diagram showing an example of the configuration of a communication device used as the slave station devices 3-1 to 3-m. Note that since the slave station devices 3-1 to 3-m all have the same configuration, only the slave station device 3-1 will be described here as an example, and descriptions of the other slave station devices 3-2 to 3-m will be omitted.

[0018] The slave station device 3-1 includes a slave station control unit 30, a plurality of transceiver units 31 to 3k each corresponding to a band, an uplink processing unit 35, a downlink processing unit 36, a transmission interface (hereinafter, interface will be referred to as I / F) unit 37, and a power supply / clock supply unit 38.

[0019] The slave station control unit 30 includes a hardware processor such as a central processing unit (CPU), a program storage unit, a data storage unit, and an input / output interface unit. The slave station control unit 30 performs various predetermined signal processing and control processing by causing the hardware processor to execute middleware such as an operating system (OS) and application programs stored in the program storage unit. The hardware processor may be configured using a programmable logic device (PLD), a field programmable gate array (FPGA), or the like.

[0020] The transmitting / receiving units 31 to 3k include analog / digital converters (ADC) 321 to 32k, digital / analog converters (DAC) 331 to 33k, and antenna I / F units 341 to 34k, respectively.

[0021] The antenna I / F units 341 to 34k have, for example, a transmission power amplifier (PA) and a low noise amplifier for reception, and transmit and receive radio signals to and from the radio terminals MT1 to MTn via the antennas 4-11 to 4-1k.

[0022] The ADCs 321 to 32k convert the radio signals of each band received by the antenna I / F units 341 to 34k into upstream digital radio signals, and output the converted upstream digital radio signals to the slave station control unit 30.

[0023] The slave station control unit 30 performs predetermined baseband signal processing on each of the upstream digital radio signals output from the ADCs 321 to 32k to convert them into baseband upstream transmission signals, and outputs these upstream transmission signals to the uplink processing unit 35 together with a control signal generated by the slave station control unit 30.

[0024] The uplink processing unit 35 multiplexes the upstream transmission signal and the control signal output from the slave station control unit 30 to generate an upstream multiplexed transmission signal, and sends the generated upstream multiplexed transmission signal to the transmission I / F unit 37. The transmission I / F unit 37 converts the upstream multiplexed transmission signal output from the uplink processing unit 35 into an optical signal, and sends it to the master station device 1 directly or via the hub station device 2.

[0025] The transmission I / F unit 37 also receives a downstream multiplexed transmission signal made up of an optical signal transmitted from the hub station device 2 or the parent station device 1, converts it into an electrical signal, and then outputs it to the downlink processing unit .

[0026] The downlink processing unit 36 ​​separates the downstream multiplexed transmission signal output from the transmission I / F unit 37 into multiple transmission signals and control signals for each band, and inputs the separated transmission signals and control signals for each band to the slave station control unit 30.

[0027] The slave station control unit 30 performs predetermined baseband signal processing on the downstream transmission signals of each band output from the downlink processing unit 36 ​​to convert them into downstream digital transmission signals, and then outputs them to the corresponding transmission / reception units 31 to 3k.

[0028] The transmission / reception units 31 to 3k convert the downstream digital transmission signals output from the slave station control unit 30 into analog signals using DACs 331 to 33k, respectively, and input the converted analog downstream transmission signals to the antenna I / F units 341 to 34k. The antenna I / F units 341 to 34k convert the analog downstream transmission signals into radio signals and transmit the converted radio signals from the antennas 4-1 to 4-m to the radio terminals MT1 to MTn.

[0029] The power and clock supply unit 38 generates an operating power output VC based on the main power output supplied from the system power supply unit BT and supplies it to each unit in the slave station equipment 3-1. The power and clock supply unit 38 also supplies an operating clock CK generated by a clock generation circuit to each unit in the slave station equipment 3-1.

[0030] Incidentally, the slave station control unit 30 has a function for realizing the sleep control according to the first embodiment in addition to the above-mentioned baseband signal processing function. FIG. 3 is a block diagram showing the functional configuration for realizing the sleep control.

[0031] The slave station control unit 30 includes a reception level detection processing unit 301, a reception level detection signal transmission processing unit 302, and a power supply / clock control processing unit 303 as functions for realizing sleep control.

[0032] The reception level detection processing unit 301 detects the reception level (e.g., received field strength indicator (RSSI)) for each of the transmission / reception units 32 to 3k, i.e., for each band, based on the radio signals received by the antenna I / F units 341 to 34k, and notifies the reception level detection signal transmission processing unit 302 of the detected value.

[0033] The reception level detection signal transmission processing unit 302 generates a reception level detection signal including the detection value notified from the reception level detection processing unit 301 and an identification ID of the band to be detected. Then, the reception level detection signal transmission processing unit 302 outputs the generated reception level detection signal to the uplink processing unit 35 as one of the control signals.

[0034] The power supply and clock control processing unit 303 receives an operation mode control signal transmitted from the parent station device 1 via the downlink processing unit 36. Then, in accordance with the received operation mode control signal, the power supply and clock control processing unit 303 performs processing to issue instructions to the power supply and clock supply unit 38 to control the supply of the operating power output VC and the operating clock CK to the transceiver units 31 to 3k in the child station device 3-1. (2-2) Master station device 1 FIG. 4 is a block diagram showing an example of the configuration of a communication device used as the master station device 1 according to the first embodiment.

[0035] The master station device 1 includes a master station control unit 10 , a transmission I / F unit 11 , an uplink processing unit 12 , a downlink processing unit 13 , a DAC 14 , an ADC 15 , and a wireless I / F unit 16 .

[0036] The master station control unit 10 includes a hardware processor such as a central processing unit (CPU), a program storage unit, a data storage unit, and an input / output interface unit. The master station control unit 10 performs various predetermined signal processing and control processing by having the hardware processor execute middleware such as an OS and application programs stored in the program storage unit. The hardware processor may also be configured using a PLD, FPGA, or the like.

[0037] The transmission I / F unit 11 receives an upstream multiplexed transmission signal consisting of an optical signal transmitted from the slave station devices 3-1 to 3-m directly or via the hub station device 2, converts it into an electrical signal, and then outputs it to the uplink processing unit 12.

[0038] The uplink processing unit 12 separates the upstream multiplexed transmission signals output from the slave station devices 3-1 to 3-m into transmission signals and control signals, and inputs the separated transmission signals and control signals to the master station control unit .

[0039] The master station control unit 10 performs predetermined baseband signal processing on the input upstream transmission signal, and then outputs the signal to the DAC 14. The DAC 14 converts the upstream transmission signal output from the master station control unit 10 into an analog signal, and outputs the converted analog upstream transmission signal to the wireless I / F unit 16. The wireless I / F unit 16 converts the analog upstream transmission signal into a wireless signal and transmits it to the base station device BS.

[0040] The wireless I / F unit 16 receives a downstream wireless signal transmitted from the base station device BS and outputs it to the ADC 15. The ADC 15 converts the downstream wireless signal into a digital wireless signal and inputs the converted downstream digital wireless signal to the master station control unit 10.

[0041] The master station control unit 10 converts the downstream digital radio signal input from the ADC 15 into a baseband downstream transmission signal by performing predetermined baseband signal processing. The master station control unit 10 then outputs the baseband downstream transmission signal to the downlink processing unit 13 together with a control signal generated by the master station control unit 10.

[0042] The downlink processing unit 13 multiplexes a control signal onto the downlink transmission signal to generate a downlink multiplexed transmission signal, and outputs the generated downlink multiplexed transmission signal to the transmission I / F unit 11. The transmission I / F unit 11 transmits the downlink multiplexed transmission signal to the slave station devices 3-1 to 3-m directly or via the hub station device 2.

[0043] Incidentally, the master station control unit 10 has, in addition to the above-mentioned baseband signal processing function, a function for executing control of the operation modes of the slave station devices 3-1 to 3-m according to the first embodiment. Fig. 5 is a block diagram showing the configuration of the functions for realizing the above-mentioned operation mode control.

[0044] The parent station control unit 10 has the following functions for realizing the sleep control: a reception level detection signal reception processing unit 101, an operation mode setting control processing unit 102, an operation mode control signal transmission processing unit 103, and a setting information storage unit 104.

[0045] The setting information storage unit 104 is used to store an operation mode controllable period that specifies the period during which switching control of the operation mode of the slave station devices 3-1 to 3-m is possible, a forced sleep setting period that specifies the period during which the operation mode of the slave station devices 3-1 to 3-m is forcibly set to sleep mode, and a threshold value TH1 for determining the reception level.

[0046] The reception level detection signal reception processing unit 101 receives reception level detection signals sent as control signals from the slave station devices 3-1 to 3-m, and then performs processing to extract reception level detection values ​​of the respective transmission / reception units from the received reception level detection signals.

[0047] The operation mode setting control processor 102 compares the reception level detection value of each transceiver unit with a determination threshold value TH1 stored in advance in the setting information storage unit 104 for each of the slave station devices 3-1 to 3-m, and performs processing to set an operation mode for each transceiver unit based on the determination result. There are two operation modes: a "normal operation mode" in which both transmission and reception operations are performed, and a "sleep operation mode" in which reception operations are stopped and only transmission operations are performed, and the operation mode setting control processor 102 sets one of these operation modes.

[0048] Furthermore, when the operation mode setting control processing unit 102 performs setting control of the operation mode based on the determination result of the reception level detection value, it compares the current time measured by a timer (not shown) with the operation mode controllable period and the forced sleep setting period pre-stored in the setting information storage unit 104, and performs the operation mode setting control by further considering this determination result. An example of this operation will be described in the operation example.

[0049] The operation mode control signal transmission processing unit 103 receives the setting result of the operation mode from the operation mode setting control processing unit 102, and generates an operation mode control signal for each of the slave station devices 3-1 to 3-m, specifying the operation mode for each of the transmission / reception units. Then, the operation mode control signal transmission processing unit 103 performs processing to output the generated operation mode control signal to the downlink processing unit 13.

[0050] (Example of operation) Next, an example of the operation of the slave station devices 3-1 to 3-m and the master station device 1 of the distributed antenna system 100 configured as described above will be described. Note that, although the explanation here takes as an example a case where the master station device 1 controls the operation mode of the slave station device 3-1, the same applies to the other slave station devices 3-2 to 3-m.

[0051] (1) Detection of reception level in slave station equipment 3-1 FIG. 6 is a flowchart showing an example of the procedure and content of the sleep control executed by the slave station control unit 30 of the slave station equipment 3-1.

[0052] During system operation, the slave station control unit 30 of the slave station device 3-1 first selects one band in step S11 under the control of the reception level detection processing unit 301. Then, in step S12, the reception level detection processing unit 301 determines whether the current time is a period for detecting the reception level or a period for controlling the operation mode. If the result of this determination is that it is a period for detecting the reception level, the reception level detection processing unit 301 proceeds to step S13 and detects the reception level (RSSI value) of the wireless signal received by the transceiver unit corresponding to the selected band.

[0053] Thereafter, the reception level detection processing unit 301 similarly performs the above-mentioned reception level detection processing sequentially for all bands provided in the slave station equipment 3-1.

[0054] When the reception level detection process for all bands is completed, the slave station control unit 30 then generates a reception level detection signal including the reception level detection value obtained for each band and the identification ID of each band that was the detection target in step S14 under the control of the reception level detection signal transmission processing unit 302. Then, the reception level detection signal transmission processing unit 302 transmits the generated reception level detection signal to the master station device 1.

[0055] (2) Operation mode setting control by the master station device 1 The master station control unit 10 of the master station device 1 executes processing related to setting control of the operation mode for each band for the slave station devices 3-1 to 3-m as follows.

[0056] Prior to executing the above-mentioned operation mode setting control process, for example, a system administrator operates the management terminal 7 to initially register, in the setting information storage unit 104 provided in the master station control unit 10 of the master station device 1, the operation mode controllable period, the forced sleep setting period, and the threshold value TH1 for determining the reception level for each of the slave station devices 3-1 to 3-m.

[0057] FIG. 7 is a flowchart showing an example of the processing procedure and processing content of the operation mode setting control executed by the parent station control unit 10.

[0058] That is, in step S21, the master station control unit 10 of the master station device 1 monitors the transmission of reception level detection signals from each of the slave station devices 3-1 to 3-m under the control of the reception level detection signal reception processing unit 101. Then, for example, when a reception level detection signal is sent from the slave station device 3-1, the reception level detection signal reception processing unit 101 receives the reception level detection signal. The reception level detection signal reception processing unit 101 also performs similar reception processing on reception level detection signals transmitted from the other slave station devices 3-2 to 3-m.

[0059] When the parent station control unit 10 receives the reception level detection signal from the child station devices 3-1 to 3-m, it controls the setting of the operation mode for the child station devices 3-1 to 3-m as follows, under the control of the operation mode setting control processing unit 102. Note that the following description will be given assuming that the child station device 3-1 is the control target.

[0060] That is, in step S22, the operation mode setting control processing unit 102 first determines whether or not an operation mode controllable period corresponding to the slave station device 3-1 is registered in the setting information storage unit 104. If the result of this determination is that an operation mode controllable period is not registered, the operation mode setting control processing unit 102 ends the process without performing operation mode setting control.

[0061] On the other hand, suppose that an operation mode controllable period corresponding to the slave station device 3-1 is registered in the setting information storage unit 104. In this case, in step S23, the operation mode setting control processor 102 determines whether the current time measured by a timer (not shown) is within the operation mode controllable period. If the result of this determination is that the current time is outside the operation mode controllable period, the operation mode setting control processor 102 ends the process without performing operation mode setting control.

[0062] On the other hand, suppose the current time is within the operation mode controllable period. In this case, the operation mode setting control processing unit 102 next determines in step S24 whether the current time is within the forced sleep setting period stored in the setting information storage unit 104. If the result of this determination is that the current time is outside the forced sleep setting period, the operation mode setting control processing unit 102 proceeds to step S25. Note that the forced sleep setting control when the current time is within the forced sleep setting period will be described later.

[0063] In step S25, the operation mode setting control processing unit 102 compares the detection values ​​of the reception level detection signals for each band of the slave station device 3-1 received in step S21 with the threshold value TH1 stored in the setting information storage unit 104, and determines whether the detection values ​​of the reception levels have been less than the threshold value TH1 continuously for a predetermined period of time or more.

[0064] If the result of this determination is that there is a band in which the detected value of the reception level has been below the threshold value TH1 for more than a predetermined time, the operation mode setting control processor 102 proceeds to step S26 and sets the operation mode of that band to "sleep operation mode." Note that for bands in which the detected value of the reception level has remained above the threshold value TH1 for more than a predetermined time, the operation mode setting control processor 102 maintains the operation mode of that band to "normal operation mode" in step S27.

[0065] Upon completion of the operation mode setting process, the parent station control unit 10 then generates an operation mode control signal including setting information for the operation mode of each band of the child station equipment 3-1 in step S28 under the control of the operation mode control signal transmission processing unit 103. Then, the operation mode control signal transmission processing unit 103 outputs the generated operation mode control signal to the downlink processing unit 13. As a result, the operation mode control signal is transmitted from the downlink processing unit 13 to the child station equipment 3-1.

[0066] The above-described series of operation mode setting control and operation mode control signal transmission processes are similarly performed for the other slave station devices 3-2 to 3-m.

[0067] (3) Operation mode control in slave station equipment 3-1 When the current time falls within the operation mode control period, the slave station control unit 30 of the slave station device 3-1 receives, in step S15, an operation mode control signal transmitted from the master station device 1 under the control of the power supply / clock control processing unit 303. Subsequently, in step S16, the power supply / clock control processing unit 303 generates a power supply / clock control signal based on the received operation mode control signal and supplies it to the power supply / clock supply unit 38.

[0068] For example, the power supply / clock control processing unit 303 generates a control signal for maintaining the supply of the operating power output VC and the operating clock CK to the transceiver unit corresponding to the band whose operating mode is set to "normal operating mode" in accordance with the operating mode setting information for each band contained in the operating mode control signal, and supplies the control signal to the power supply / clock supply unit 38.

[0069] On the other hand, for the transceiver unit corresponding to the band whose operating mode is set to "sleep operating mode", the power supply / clock control processing unit 303 generates a control signal to control the supply of the operating power output VC and operating clock CK to correspond to the sleep state, and supplies it to the power supply / clock supply unit 38.

[0070] The power supply / clock supply unit 38 controls the supply of the operating power output VC and the supply of the operating clock CK to each of the transmission / reception units 31 to 3k individually in accordance with the control signal supplied thereto.

[0071] For example, consider a case where the transceiver unit 31 of the transceiver units 31 to 3k is set to the "sleep operation mode." Fig. 8 shows an example of the configuration of the transceiver unit 31 and the downlink system block of the slave station control unit 30. As shown in Fig. 8, the downlink system block of the slave station device 3-1 has a transmission power amplifier 3411 provided in the antenna I / F unit 341, a DAC 331, and a downlink baseband processing unit 39 in the slave station control unit 30. The downlink baseband processing unit 39 includes, for example, a quadrature modulation processing function.

[0072] When the power supply / clock supply unit 38 sets the downlink system block to the "sleep operation mode," it stops supplying the operating power output VC to the transmission power amplifier 3410, and stops supplying the operating clock CK to the DAC 331 and the downlink baseband processing unit 39 in the slave station control unit 30. As a result, the transmission / reception unit 31 of the slave station device 3-1 and the downlink system block in the slave station control unit 30 transition to sleep operation, thereby reducing power consumption.

[0073] In addition, the operating power output VC and operating clock CK are supplied to the transmitting / receiving units and downlink system blocks within the slave station control unit 30 for which "normal operation mode" has been specified by the power supply / clock control processing unit 303, and normal operation is maintained.

[0074] The above-described control process of the operation mode is similarly performed for each band in the other slave station devices 3-2 to 3-m.

[0075] An example of the execution of the above-mentioned operation mode control will be described with reference to Fig. 9 and Fig. 10. Fig. 9 shows an example of the operating state of the slave station devices 3-1 to 3-2 at a timing before the operation mode control is performed, while Fig. 10 shows an example of the operating state of the slave station devices 3-1 to 3-2 at a timing after the operation mode control is performed.

[0076] In the state shown in Figure 9, wireless terminals MT1, MT2, and MT3 communicate using bands B1, B2, and B3 of slave station device 3-1, respectively, and wireless terminals MT4 and MT5 communicate using bands B4 and B5 of slave station device 3-2.

[0077] After that, suppose that the wireless terminals MT1 to MT5 end their communications and another wireless terminal MTi starts communications using band B1 of the slave station device 3-1. In this case, by performing the series of operation mode controls described above, only the block corresponding to band B1 of the slave station device 3-1 remains in the "normal operation mode," and all of the blocks corresponding to the other bands of the slave station devices 3-1 and 3-2 are set to the "sleep operation mode," as shown in Fig. 10.

[0078] Therefore, the power consumption of the slave station devices 3-1 to 3-m is reduced compared to when the slave station devices 3-1 to 3-m are constantly operated in the "normal operation mode".

[0079] (4) Recovery from sleep mode to normal mode In the sleep operation mode, the slave station control units 30 of the slave station devices 3-1 to 3-m continue the reception level detection process in preparation for access from the wireless terminals MT1 to MTn. Then, the slave station control units 30 transmit the reception level detection signals obtained by the reception level detection process to the master station device 1.

[0080] In response to this, when the master station control unit 10 of the master station device 1 receives the reception level detection signals transmitted from the slave station devices 3-1 to 3-m, it determines in step S25 whether the reception level detection value for each band of each of the slave station devices 3-1 to 3-m has reached or exceeded threshold value TH1. When a band for which the reception level detection value has reached or exceeded threshold value TH1 is detected, the process proceeds to step S27, where it changes the operation mode of the corresponding band to "normal operation mode" and transmits an operation mode control signal to the corresponding slave station devices 3-1 to 3-m.

[0081] When the slave station control unit 30 of the slave station devices 3-1 to 3-m receives the above-mentioned operation mode control signal from the master station device 1, it resumes supplying the operating power output VC and the operating clock CK to the transceiver unit corresponding to the band designated as the control target by this operation mode control signal and to the downlink system block of the slave station control unit 30.

[0082] (5) Execution of forced sleep control In the parent station control unit 10 of the parent station device 1, it is assumed that the operation mode setting control processing unit 102 determines in step S24 shown in FIG. 7 that the current time is within the forced sleep setting period stored in the setting information storage unit 104.

[0083] In this case, the operation mode setting control processing unit 102 proceeds from step S24 to step S26 without determining the operation mode based on the detected value of the reception level. Then, in step S26, the operation mode setting control processing unit 102 outputs a control signal to forcibly set the slave station device to the sleep operation mode based on the forced sleep setting period information stored in the setting information storage unit 104.

[0084] For example, the forced sleep setting period information is individually set in association with each of the slave station devices 3-1 to 3-m. Therefore, the operation mode setting control processing unit 102 collectively sets the operation mode to the "sleep operation mode" for all bands of the slave station devices for which the forced sleep setting period information is set.

[0085] That is, by setting a forced sleep setting period for each of the slave station devices 3-1 to 3-m, it is possible to forcibly set the operation mode of all bands for each slave station to the sleep operation mode. Figures 11(a), (b) and 12(a), (b) show examples of the forced sleep control.

[0086] This example shows a distributed antenna system in which slave station devices 3-1 to 3-m are distributed across the floors of an office building, and these slave station devices 3-1 to 3-m are grouped together on multiple floors and connected to hub station devices 2, 2, ..., which are then connected to a master station device 1.

[0087] 11(a) and 11(b) show the state when all slave station devices 3-1 to 3-m are set to operate in "normal operation mode." On the other hand, 12(a) and 12(b) show the operating state of each slave station device 3-1 to 3-m when a "forced sleep period" is set for the slave station devices on the upper floors among the slave station devices 3-1 to 3-m, but a "forced sleep period" is not set for the slave station devices on the middle and lower floors.

[0088] 11(a), (b) and 12(a), (b), slave station equipment operating in "normal operation mode" is indicated by 3 (on), slave station equipment set to "forced sleep mode" is indicated by 3 (off). Furthermore, among slave station equipment not set to "forced sleep mode," slave station equipment set to "sleep operation mode" is indicated by 3 (sleep).

[0089] As shown in this example, for example, if different tenants occupy the upper, middle, and lower floors, by setting forced sleep setting information for the slave station devices on the corresponding floors according to the working hours of each tenant, it becomes possible to forcibly set all of the slave station devices on the upper floors to the sleep operating mode during times other than working hours, for example, for tenants on the upper floors. This makes it possible to reduce power consumption even more efficiently.

[0090] Furthermore, since slave station equipment on upper floors far from the system power supply device BT generally has a long power supply path and a large voltage drop, constantly supplying the operating power output VC to the slave station equipment on the upper floors reduces the power efficiency of the system. Therefore, a forced sleep period is set for the slave station equipment on the upper floors. This makes it possible to suppress the reduction in power efficiency of the system. In this case, the slave station equipment on the upper floors cannot communicate while the forced sleep period is set. However, in a hierarchical installation environment such as an office building, wireless signals leaking from the middle floors can be received on the upper floors through windows, etc., so wireless communication between the wireless terminals TM1 to TMn can be maintained.

[0091] (effect) As described above, in the first embodiment, the slave station devices 3-1 to 3-m detect the reception level of the radio signal for each band and notify the master station device 1 of the detection results. Then, based on the detection results of the reception levels, the master station device 1 determines whether the operation mode for each of the slave station devices 3-1 to 3-m for each band should be the normal operation mode or the sleep operation mode, and based on the determination results, each of the slave station devices 3-1 to 3-m controls the operation mode of the downlink system blocks such as the transmission / reception units 31 to 3k for each band.

[0092] Therefore, compared to when the operating mode of the slave station devices 3-1 to 3-m is always fixed to the "normal operating mode," it is possible to reduce the power consumption of the slave station devices 3-1 to 3-m during periods when wireless communication is not being performed with the wireless terminals MT1 to MTn.

[0093] In the first embodiment, a forced sleep setting period is set for each of the slave station devices 3-1 to 3-m, and during this period, each of the slave station devices 3-1 to 3-m is forced to enter the sleep operation mode. As a result, during periods when the slave station devices 3-1 to 3-m are not actually used, their operation modes are forced to enter the sleep operation mode all at once, making it possible to more effectively reduce the power consumption of the system.

[0094] [Second embodiment] In the second embodiment, in addition to the threshold value TH1 used in the first embodiment to determine whether or not to set the sleep operation mode, a threshold value TH2 is set between this threshold value TH1 and the reception level during normal operation as a threshold value for determining the reception level detection value. The threshold value TH2 is used for determining the operation restriction mode. Then, in the second embodiment, when the reception level detection value falls to a value between the threshold values ​​TH2 and TH1, only the operation of the control system of the downlink system blocks of the transmission / reception units 31 to 3k and the slave station control unit 30 is stopped.

[0095] 13 is a diagram showing an example of the configuration of the control system of the downlink system block of the transmission / reception units 31 to 3k of the slave station devices 3-1 to 3-m and the slave station control unit 30 in the distributed antenna system according to the second embodiment. Note that other parts of the slave station devices 3-1 to 3-m and the master station device 1 will be described with reference to FIGS. 2 to 5.

[0096] 13, the transmitting / receiving units 31 to 3k include a feedback control system made up of a branch circuit 411, a level detection circuit 421, and an ADC 431 in addition to a DAC 331 and a transmission power amplifier 341.

[0097] The branching circuit 411 branches the radio signal output from the transmission power amplifier 341 into two, and outputs one to the antennas 4-11 to 4-1k and the other to a level detection circuit 421. The level detection circuit 421 rectifies the radio signal to detect the signal level and outputs the detection signal. The ADC 431 converts the detection signal of the signal level into a digital signal and inputs it to the downlink baseband processing unit 39.

[0098] The downlink baseband processing unit 39 further includes, in addition to the quadrature modulation processing function, a calibration processing function for correcting local frequency leakage and quadrature error during modulation, and a DPD (Digital Pre-Distortion) processing function 391 for compensating for the characteristics of the transmission power amplifier 341.

[0099] When the master station control unit 10 of the master station device 1 receives the reception level detection signals for each band transmitted from the slave station devices 3-1 to 3-m, the operation mode setting control processing unit 102 compares the detection values ​​of the reception levels included in the reception level detection signals for each band with thresholds TH1 and TH2 for each of the slave station devices 3-1 to 3-m. If the comparison shows that the detection values ​​of the reception levels have fallen below threshold TH1, the operation mode setting control processing unit 102 sets the "sleep operation mode." On the other hand, if the detection values ​​of the reception levels are equal to or greater than threshold TH1 but have fallen below threshold TH2, the operation mode setting control processing unit 102 sets the "restricted operation mode."

[0100] Through the above processing, the parent station control unit 10 transmits the setting information of the operation mode set for each band for each of the child station devices 3-1 to 3-m to each of the child station devices 3-1 to 3-m under the control of the operation mode control signal transmission processing unit 103.

[0101] In response to this, when the slave station control unit 30 of the slave station devices 3-1 to 3-m receives the operation mode control signal, the power supply / clock control processing unit 303 generates a control signal for controlling the supply of operating power and operating clock in accordance with the operation mode setting information for each band included in the operation mode control signal, as follows, and provides the control signal to the power supply / clock supply unit 38.

[0102] That is, if the operation mode is set to "sleep operation mode" according to the operation mode setting information, a control signal for setting the downlink system block of the transceiver unit and the slave station control unit 30 to a sleep state is generated and given to the power supply / clock supply unit 38.

[0103] On the other hand, if the operation mode is set to the "operation restricted mode" according to the operation mode setting information, a control signal for stopping the operation of the control system of the downlink system block of the transceiver units 31 to 3k and the slave station control unit 30 is generated and given to the power supply / clock supply unit 38.

[0104] When the power / clock supply unit 38 first receives a control signal for setting the sleep state, it stops supplying the operating power output VC to the transmission power amplifier 3410, and stops supplying the operating clock CK to the DAC 331 and the downlink baseband processing unit 39 in the slave station control unit 30. As a result, the transmission / reception units 31 to 3k of the slave station device 3-1 and the downlink system blocks in the slave station control unit 30 transition to sleep operation.

[0105] On the other hand, when a control signal for setting the operation restriction mode is received, the power supply / clock supply unit 38 stops supplying the operating power output VC to the level detection circuit 421 in the transceiver unit 31 to 3k, and also stops supplying the operating clock CK to the ADC 431 and DPD 391.

[0106] As a result, in the transceiver units 31 to 3k, the operation of the control system of the downlink system block (the part indicated by the dashed line) is stopped, although the operation of the downlink radio signal transmission is maintained, as shown in Fig. 14. In other words, part of the operation of the downlink system block is restricted, and power consumption is reduced accordingly.

[0107] As described above, according to the second embodiment, when the reception level of the radio signal in the slave station devices 3-1 to 3-m drops, if the reception level has not yet dropped to the threshold TH1 at which the slave station devices 3-1 to 3-m transition to the sleep operation mode but has dropped below threshold TH2, the operation of the control system of the downlink block of the slave station devices 3-1 to 3-m is stopped. This makes it possible to further reduce the power consumption in the slave station devices 3-1 to 3-m, thereby further enhancing the effect of reducing power consumption in the system.

[0108] [Third embodiment] The third embodiment has a function to calculate the availability of slave station devices 3-1 to 3-m, and generates warning information or recommendation information to encourage system improvements based on the calculation results, and outputs the generated information to the system administrator.

[0109] For example, the slave station control unit 30 of each slave station device 3-1 to 3-m measures the time that each slave station device 3-1 to 3-m operates in the normal operation mode and the time that each slave station device 3-1 to 3-m operates in the sleep operation mode, and periodically or at a predetermined timing calculates the availability of each slave station device 3-1 to 3-m based on the measured time in each operation mode.Then, information indicating the calculated availability is transmitted to the master station device 1.

[0110] Based on the information indicating the availability rates sent from the slave station devices 3-1 to 3-m, the master station device 1 generates warning information or recommendation information to prompt system improvement. For example, when the availability rate of a slave station device falls below a threshold value TH3, the master station device 1 generates and outputs warning information regarding the usage status of the slave station device.

[0111] Furthermore, the master station device 1 determines, for each area, the availability rate of multiple slave station devices located in that area, and based on the determination results, generates and outputs recommendation information that encourages the reduction and rearrangement of each slave station device in the area. In this case, the recommendation information may be, for example, map data showing the layout of the slave station devices after rearrangement.

[0112] Based on the above alarm information and recommendation information, the system administrator can relocate the slave station equipment 3-1 to 3-m, thereby reducing the number of slave station equipment that are essentially unnecessary and further improving the power efficiency of the system.

[0113] In the above description, the parent station device 1 generates the alarm information, but the child station devices 3-1 to 3-m may also be equipped with the function of generating the alarm information. Also, the calculation of the availability of the child station devices 3-1 to 3-m may be performed collectively by the parent station device 1 instead of by the child station devices 3-1 to 3-m.

[0114] [Other embodiments] (1) In the first embodiment, the description has been given of an example in which the detection and determination process for the reception level for each band, which is executed by the slave station control unit 30, and the control process for the operation mode for each band in accordance with the operation mode signal sent from the master station device 1 are performed alternately in separate operation periods. However, the present invention is not limited to this, and the above control processes may be performed in parallel without separating the operation periods.

[0115] (2) In the first and second embodiments, the slave station devices 3-1 to 3-m only perform detection processing of the reception level of each band and send the detected value to the master station device 1, and the master station device 1 compares the detected value of the reception level with thresholds TH1 and TH2 to make a judgment. However, this is not limiting, and the slave station devices 3-1 to 3-m may perform detection and judgment processing of the reception level of each band and send the judgment result to the master station device 1, and the master station device 1 may use the judgment result of the received reception level to control the setting of the operating mode.

[0116] (3) In each of the first to third embodiments, an example has been described in which the master station device 1 is provided with an operation mode setting control function. However, this is not limiting. For example, the detection results of the reception levels detected by the slave station devices 3-1 to 3-m may be transferred from the slave station devices 3-1 to 3-m directly or via the master station device 1 to the management terminal 7 shown in FIG. 1, and the management wireless terminal may collectively control the operation mode setting of the slave station devices 3-1 to 3-m. In this case, the management terminal 7 transmits operation mode setting control information set by the operation mode setting control to the slave station devices 3-1 to 3-m directly or via the master station device 1, and controls the supply of power and clock to the slave station devices 3-1 to 3-m.

[0117] (4) In addition, the configurations, processing functions, processing procedures, processing contents, etc. of the communication devices used as the slave station devices and master station devices may be configured in a manner other than those of the above-described embodiments.

[0118] Although multiple embodiments have been described in detail above, the above descriptions are merely examples in every respect. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. In other words, specific configurations according to the embodiments may be appropriately adopted in implementing the present invention.

[0119] In short, this invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. The following is a summary of the scope of claims as originally filed in this application. [C1] one or more slave station devices each having at least one transmitting / receiving unit for transmitting and receiving wireless signals to and from a wireless terminal via an antenna; a master station device that transmits and receives the wireless signal to and from the slave station device directly or via a relay device; Equipped with the slave station device includes a determination unit that determines a transmission / reception state of the wireless signal by the transmission / reception unit and notifies the master station device of determination information representing the determination result; The master station device includes a control unit that controls the slave station device based on the determination information to set the transceiver units to an operable mode when the wireless signal is being transmitted or received, and to set at least a part of the transceiver units to a sleep mode when the wireless signal is not being transmitted or received. Distributed Antenna System. [C2] the determination unit of the slave station device detects an index representing a reception quality of the wireless signal transmitted from the wireless terminal, determines whether the detected index satisfies a preset condition, and notifies the master station device of the determination result as the determination information; The control unit of the master station device controls the slave station device to set the receiving function unit of the transceiver unit to a sleep mode based on the determination information when the wireless signal is not being transmitted or received. [C3] In a distributed antenna system including one or more slave station devices each having at least one transceiver unit for transmitting and receiving wireless signals to and from a wireless terminal via an antenna, and a master station device for transmitting and receiving the wireless signals to and from the slave station devices directly or via a relay device, a communication device used as the master station device or the slave station device, an acquisition unit that acquires information representing a transmission / reception state of the wireless signal by the transmission / reception unit of the slave station device; a control unit that controls the operation mode of the slave station device based on the acquired information representing the transmission / reception state, so as to set the transmission / reception unit to an operable mode when the wireless signal is being transmitted / received, and to set at least a part of the transmission / reception unit to a sleep mode when the wireless signal is not being transmitted / received; A communication device comprising: [C4] When the slave station device includes a plurality of the transmission / reception units for transmitting and receiving the radio signals, the acquisition unit acquires information representing the transmission and reception state of the wireless signal for each of the transmission and reception units; the control unit controls the operation mode for each of the transceiver units based on information representing the transmission / reception state corresponding to the transceiver unit. The communication device according to C3. [C5] a first storage unit that stores control period designation information that designates a controllable period or an uncontrollable period of the operation mode; the control unit sets at least some of the transmission / reception units of the slave station devices to the sleep mode during the controllable period and during a period when the wireless signal is not being transmitted or received, based on the control period designation information stored in the first storage unit and the information indicating the transmission / reception state. The communication device according to C3. [C6] The control unit of the communication device described in C3 stops supplying an operating clock to the baseband processing unit and digital / analog converter provided in the transceiver unit in the sleep mode, and stops supplying operating power to the transmit power amplifier. [C7] The control unit a determination processing unit that determines whether a reception quality index is lower than a first threshold value, or whether the reception quality index is equal to or higher than the first threshold value and lower than a second threshold value, based on the information representing the transmission and reception state; a first control processing unit that sets a first receiving function unit of the transceiver unit to a sleep mode when it is determined that the index of reception quality is equal to or greater than the first threshold value and lower than the second threshold value; a second control processing unit that sets a second receiving function unit in addition to the first receiving function unit of the transceiver unit to a sleep mode when it is determined that the index of reception quality is lower than the first threshold value; The communication device according to C3, [C8] the first control processing unit performs a first process of stopping a calibration operation of a digital-to-analog converter included in the transceiver unit and a characteristic compensation operation of a transmission power amplifier when it is determined that the index of reception quality is equal to or greater than the first threshold value and lower than the second threshold value; When it is determined that the index of reception quality is lower than the first threshold, the second control processing unit performs, in addition to the first processing, a second processing of stopping the supply of an operating clock to the baseband processing unit and the digital / analog converter provided in the transceiver unit and the supply of operating power to the transmission power amplifier. A communication device as described in C7. [C9] When a plurality of slave station devices are installed, a second storage unit that stores preset forced sleep period designation information corresponding to each of the plurality of slave station devices; The communication device according to C3, wherein the control unit forcibly sets, for each of the slave station devices, the operation mode of the slave station device to a sleep mode for a period designated by the forced sleep period designation information. [C10] When a plurality of slave station devices are installed, The control unit acquires or calculates, for each of the plurality of slave station devices, information representing an availability rate of the slave station device based on a setting ratio between the operable mode and the sleep mode, and generates and outputs information regarding the suitability of the placement state of the plurality of slave station devices based on the information representing the availability rate. [C11] 1. A sleep control method executed by one or more slave station devices having at least one transceiver unit for transmitting and receiving wireless signals to and from a wireless terminal via an antenna, or a communication device used as a master station device for transmitting and receiving the wireless signals to and from the slave station devices directly or via a relay device, comprising: acquiring information representing a transmission / reception state of the wireless signal by the transmission / reception unit of the slave station device; a step of controlling the operation mode of the slave station device based on the acquired information indicating the transmission / reception state so as to set the transmission / reception units to an operable mode when the wireless signal is being transmitted / received, and to set at least a part of the transmission / reception units to a sleep mode when the wireless signal is not being transmitted / received; A sleep control method comprising: [C12] A computer program that causes a computer to function as the communication device according to any one of C3 to C10. [Explanation of symbols]

[0120] BS...base station device, MT1 to MTn...wireless terminal, BT...system power supply device, 100...distributed antenna system, 1...master station device, 2...hub station device, 3-1 to 3-m...slave station devices, 7...management wireless terminal, 10...master station control unit, 11...transmission I / F unit, 12...uplink processing unit, 13...downlink processing unit, 14...DAC, 15...ADC, 16...wireless I / F unit, 101...received level detection signal receiving processing unit, 102...operation mode setting control processing unit, 1 03...operation mode control signal transmission processing unit, 104...setting information memory unit, 30...slave station control unit, 31 to 3k...transmitting / receiving unit, 321 to 32k...ADC, 331 to 33k...DAC, 341 to 34k...antenna I / F unit, 35...uplink processing unit, 36...downlink processing unit, 37...transmission I / F unit, 38...power and clock supply unit, 301...receiving level detection processing unit, 302...receiving level detection signal transmission processing unit, 303...power and clock control processing unit.

Claims

1. one or more slave station devices each including at least one transmitting / receiving unit for transmitting and receiving wireless signals to and from a wireless terminal via an antenna; a master station device that transmits and receives the wireless signal to and from the slave station device directly or via a relay device; Equipped with the slave station device includes a determination unit that determines a transmission / reception state of the wireless signal by the transmission / reception unit and notifies the master station device of determination information representing the determination result; the master station device includes a control unit that controls the slave station device based on the determination information to set the transceiver units to an operable mode when the wireless signal is being transmitted or received, and to set at least a part of the transceiver units to a sleep mode when the wireless signal is not being transmitted or received, The control unit a determination processing unit that determines whether a reception quality index is lower than a first threshold value, or whether the reception quality index is equal to or higher than the first threshold value and lower than a second threshold value, based on the information representing the transmission and reception state; a first control processing unit that sets a first receiving function unit of the transceiver unit to a sleep mode when it is determined that the index of reception quality is equal to or greater than the first threshold value and lower than the second threshold value; a second control processing unit that sets a second receiving function unit in addition to the first receiving function unit of the transceiver unit to a sleep mode when it is determined that the index of reception quality is lower than the first threshold value; and the first control processing unit performs a first process of stopping a calibration operation of a digital-to-analog converter and a characteristic compensation operation of a transmission power amplifier included in the transceiver unit when it is determined that the index of reception quality is equal to or greater than the first threshold value and lower than the second threshold value; When it is determined that the index of reception quality is lower than the first threshold, the second control processing unit, in addition to the first processing, further performs a second processing of stopping the supply of an operating clock to a baseband processing unit and the digital-to-analog converter provided in the transceiver unit and the supply of operating power to the transmission power amplifier. Distributed Antenna System.

2. the determination unit of the slave station device detects an index representing a reception quality of the wireless signal transmitted from the wireless terminal, determines whether the detected index satisfies a preset condition, and notifies the master station device of the determination result as the determination information; 2. The distributed antenna system according to claim 1, wherein the control unit of the master station device controls the slave station device to set a receiving function unit of the transceiver unit to a sleep mode based on the determination information when the wireless signal is not being transmitted or received.

3. In a distributed antenna system including one or more slave station devices each having at least one transceiver unit for transmitting and receiving wireless signals to and from a wireless terminal via an antenna, and a master station device for transmitting and receiving the wireless signals to and from the slave station devices directly or via a relay device, a communication device used as the master station device or the slave station devices, comprising: an acquisition unit that acquires information representing a transmission / reception state of the wireless signal by the transmission / reception unit of the slave station device; a control unit that controls the operation mode of the slave station device based on the acquired information representing the transmission / reception state, so as to set the transmission / reception unit to an operable mode when the wireless signal is being transmitted / received, and to set at least a part of the transmission / reception unit to a sleep mode when the wireless signal is not being transmitted / received; Equipped with The control unit a determination processing unit that determines whether a reception quality index is lower than a first threshold value, or whether the reception quality index is equal to or higher than the first threshold value and lower than a second threshold value, based on the information representing the transmission and reception state; a first control processing unit that sets a first receiving function unit of the transceiver unit to a sleep mode when it is determined that the index of reception quality is equal to or greater than the first threshold value and lower than the second threshold value; a second control processing unit that sets a second receiving function unit in addition to the first receiving function unit of the transceiver unit to a sleep mode when it is determined that the index of reception quality is lower than the first threshold value; and the first control processing unit performs a first process of stopping a calibration operation of a digital-to-analog converter and a characteristic compensation operation of a transmission power amplifier included in the transceiver unit when it is determined that the index of reception quality is equal to or greater than the first threshold value and lower than the second threshold value; When it is determined that the index of reception quality is lower than the first threshold, the second control processing unit, in addition to the first processing, further performs a second processing of stopping the supply of an operating clock to the baseband processing unit and the digital / analog converter provided in the transceiver unit and the supply of operating power to the transmission power amplifier.

4. When the slave station device includes a plurality of the transmission / reception units for transmitting and receiving the radio signals, the acquisition unit acquires information representing the transmission and reception state of the wireless signal for each of the transmission and reception units; the control unit controls the operation mode for each of the transceiver units based on information representing the transmission / reception state corresponding to the transceiver unit. The communication device according to claim 3 .

5. a first storage unit that stores control period designation information that designates a controllable period or an uncontrollable period of the operation mode; the control unit sets at least some of the transmission / reception units of the slave station devices to the sleep mode during the controllable period and during a period when the wireless signal is not being transmitted or received, based on the control period designation information stored in the first storage unit and the information indicating the transmission / reception state. The communication device according to claim 3 .

6. 4. The communication device according to claim 3, wherein, in the sleep mode, the control unit stops supplying an operating clock to a baseband processing unit and a digital / analog converter provided in the transceiver unit, and stops supplying operating power to a transmission power amplifier.

7. When a plurality of slave station devices are installed, a second storage unit that stores forced sleep period designation information that is preset in correspondence with each of the plurality of slave station devices; The communication device according to claim 3 , wherein the control unit forcibly sets the operation mode of each of the slave station devices to a sleep mode for a period designated by the forced sleep period designation information.

8. When a plurality of slave station devices are installed, 4. The communication device according to claim 3, wherein the control unit acquires or calculates, for each of the plurality of slave station devices, information representing an availability rate of the slave station device based on a setting ratio between the operable mode and the sleep mode, and generates and outputs information regarding the suitability of the arrangement state of the plurality of slave station devices based on the information representing the availability rate.

9. 1. A sleep control method executed by one or more slave station devices having at least one transceiver unit for transmitting and receiving wireless signals to and from a wireless terminal via an antenna, or a communication device used as a master station device for transmitting and receiving the wireless signals to and from the slave station devices directly or via a relay device, comprising: acquiring information representing a transmission / reception state of the wireless signal by the transmission / reception unit of the slave station device; a step of controlling the operation mode of the slave station device based on the acquired information indicating the transmission / reception state so as to set the transmission / reception units to an operable mode when the wireless signal is being transmitted / received, and to set at least a part of the transmission / reception units to a sleep mode when the wireless signal is not being transmitted / received; Equipped with The controlling step comprises: a determining process step of determining whether a reception quality index is lower than a first threshold value or whether the reception quality index is equal to or higher than the first threshold value and lower than a second threshold value, based on the information representing the transmission and reception state; a first control process for setting a first receiving function unit of the transceiver unit to a sleep mode when it is determined that the index of reception quality is equal to or greater than the first threshold value and lower than the second threshold value; a second control process for setting a second receiving function unit in addition to the first receiving function unit of the transceiver unit to a sleep mode when it is determined that the index of reception quality is lower than the first threshold value; and the first control processing step performs a first process of stopping a calibration operation of a digital-to-analog converter and a characteristic compensation operation of a transmission power amplifier provided in the transceiver unit when it is determined that the index of reception quality is equal to or greater than the first threshold value and lower than the second threshold value; a second control processing step that, when it is determined that the index of reception quality is lower than the first threshold, further performs, in addition to the first processing, a second processing step of stopping the supply of an operating clock to the baseband processing unit and the digital-to-analog converter provided in the transceiver unit and the supply of operating power to the transmission power amplifier.

10. A computer program that causes a computer to function as the communication device according to any one of claims 3 to 8.

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