TRANSMISSION SYSTEM, POWER CONTROL DEVICE, TRANSMISSION CONTROL METHOD, POWER CONTROL METHOD, AND PROGRAM

Abstract

In the present invention, a first transmission device receives, from a lower transmission device, a data signal transmitted by a communication device, and sets the received data signal as data units and transmits same. A second transmission device receives the data units transmitted by the first transmission device. A power control unit: calculates an arrival start timing that is a timing at which the data units including the data signal that was transmitted from the communication device will begin to arrive at the second transmission device, on the basis of a coding rate and the size of data transmission blocks used when the communication device transmits data signals; and controls a sleep state of a signal processing unit that performs processing on the data units at the second transmission device so as to be terminated before the arrival start timing.

Description

[Technical field]

[0001] The present invention relates to a transmission system, a power control device, Transmission control method, The present invention relates to a power control method and a program. [Background technology]

[0002] One technique for power saving in transmission devices is to use LPI (Low Power Idle) (see, for example, Non-Patent Document 1). FIG. 14 shows an example of LPI. In power saving using LPI, after the sleep state, the device periodically transitions between the quiet state and the refresh state. When the transmission device determines that communication has started, it transitions to the active state via the wake state, and then resumes communication. In LPI, the time T of the sleep state is set for each type of physical layer, such as 100BASE-TX, 1000BASE-T, XGXS (XAUI), and 10GBASE-KX4. s , Quiet state time T q and the time T in the Refresh state r Maximum and minimum values ​​are defined for each.

[0003] Another power saving technology is one that uses fast wake (see, for example, Non-Patent Document 2). As shown in Fig. 15, in power saving using fast wake, the time during which the transmission device is stopped is shorter than in LPI. Therefore, there is less delay until the transmission device returns from the power saving state (Fast wake signaling) to the active state.

[0004] On the other hand, there is a method called CO-DBA (Cooperative Dynamic Bandwidth Allocation) that reduces communication delays in a PON (Passive Optical Network), which relays data of a wireless system, by using scheduling information of the wireless system (see, for example, Non-Patent Document 3). In CO-DBA, the wireless system notifies an OLT (Optical Line Terminal) of determined scheduling information in advance. The scheduling information describes which user terminal will transmit upstream data and when. The OLT allocates communication bandwidth to an ONU (Optical Network Unit) based on the notified scheduling information. This reduces the time that the ONU waits for bandwidth allocation. This reduces communication delays when data of the wireless system is transferred between the OLT and ONU. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] IEEE Standard 802.3az, "Local and metropolitan area networks-- Specific requirements-- Part 3: Carrier Sense Multiple Access with Collision Detection (CSMA / CD) Access Method and Physical Layer Specifications, Amendment 5: Media Access Control Parameters, Physical Layers, and Management Parameters for Energy-Efficient Ethernet", 27 October, 2010. [Non-Patent Document 2] IEEE Std 802.3bj-2014, "IEEE Standard for Ethernet, Amendment 2: Physical Layer Specifications and Management Parameters for 100 Gb / s Operation Over Backplanes and Copper Cables", June 12, 2014 [Non-Patent Document 3] "5G wireless fronthaul requirements in a passive optical network context", ITU-T Series G Supplement 66, September, 2020 Summary of the Invention [Problem to be solved by the invention]

[0006] In the technology of Non-Patent Document 1, as shown in FIG. 14, when a frame arrives in the quiet state, the transmission device transitions to the wake state after the quiet period ends. The transmission device processes the arrived frame after the wake state ends. Therefore, a maximum delay of the sum of the quiet time and the wake time occurs. In the technology of Non-Patent Document 2, the delay is reduced compared to the technology of Non-Patent Document 1, but the effect of reducing power is small.

[0007] In both of the techniques of Non-Patent Document 1 and Non-Patent Document 2, the timing at which traffic arrives at the transmission device is unknown. Therefore, if traffic arrives at the transmission device during power saving, the traffic is actually detected after the transmission device becomes in a state where it can be detected. After detection, the transmission device transitions to an Active state. Therefore, either the delay time or the power saving effect is sacrificed.

[0008] On the other hand, the technology of Non-Patent Document 3 does not use the scheduling information obtained in advance to reduce the power consumption of the transmission device. Also, when the time from deciding the scheduling information to notifying it is short, it is difficult to utilize the scheduling information.

[0009] In view of the above circumstances, the present invention provides a transmission system and a power control device capable of controlling a transmission device so as to save power and reduce delay. Transmission control method, An object of the present invention is to provide a power control method and program. [Means for solving the problem]

[0010] A transmission system of one embodiment of the present invention includes a first transmission device that receives a data signal transmitted by a communication device from a lower transmission device and sets the received data signal as a data unit and transmits it; a second transmission device that receives the data unit transmitted by the first transmission device; and a power control unit that calculates an arrival start timing, which is the timing at which the data unit including the data signal transmitted from the communication device starts to arrive at the second transmission device, based on the coding rate and data transmission block size used when the communication device transmits the data signal, and controls the sleep state of a signal processing unit that processes the data unit in the second transmission device to end before the arrival start timing.

[0011] A power control device of one embodiment of the present invention includes a power control unit that calculates an arrival start timing, which is the timing at which a data unit transmitted by a first transmission device that receives a data signal transmitted by a communication device from a lower transmission device, starts to arrive at a second transmission device, based on the coding rate and data transmission block size used when the communication device transmits the data signal, and controls the sleep state of a signal processing unit that processes the data unit in the second transmission device to end before the arrival start timing.

[0012] A power control method of one embodiment of the present invention includes a transmitting step in which a first transmission device receives a data signal transmitted by a communication device from a lower transmission device, sets the received data signal as a data unit, and transmits it; a receiving step in which a second transmission device receives the data unit transmitted by the first transmission device; and a power control step in which a power control unit calculates an arrival start timing, which is the timing at which the data unit including the data signal transmitted from the communication device starts to arrive at the second transmission device, based on the coding rate and data transmission block size used when the communication device transmits the data signal, and controls the sleep state of a signal processing unit that processes the data unit in the second transmission device to end before the arrival start timing.

[0013] A power control method of one embodiment of the present invention includes a calculation step of calculating an arrival start timing, which is the timing at which a data unit transmitted by a first transmission device receiving a data signal transmitted by a communication device from a lower transmission device, including the data signal transmitted by the communication device, starts to arrive at a second transmission device, based on the coding rate and data transmission block size used when the communication device transmits the data signal, and a power saving control step of controlling a sleep state of a signal processing unit in the second transmission device that processes the data unit to end before the arrival start timing.

[0014] A program according to one aspect of the present invention is a program for causing a computer to function as the above-described power control device. Effect of the Invention

[0015] According to the present invention, it is possible to control a transmission device so as to save power and reduce delay. [Brief description of the drawings]

[0016] [Figure 1] 1 is a configuration diagram showing a mobile NW system according to a first embodiment. [Diagram 2]FIG. 2 is a diagram showing a configuration of a remote station according to the embodiment. [Diagram 3] FIG. 2 is a diagram showing a configuration of a transfer device according to the embodiment. [Figure 4] A diagram showing the timing of transmission and arrival of upstream data in the same embodiment. [Diagram 5] A diagram showing the timing of transmission and arrival of upstream data in the same embodiment. [Figure 6] FIG. 2 is a diagram showing an MCS (Modulation and Coding Scheme) table according to the embodiment. [Figure 7] FIG. 4 is a diagram showing a coding rate table according to the same embodiment. [Figure 8] FIG. 11 is a diagram showing the relationship between MCS index and coding rate according to the embodiment. [Figure 9] FIG. 11 is a diagram showing a TBS (Transport Block Size) table according to the embodiment. [Figure 10] FIG. 11 is a diagram showing the timing of transmission and arrival of upstream data according to the second embodiment. [Figure 11] FIG. 11 is a configuration diagram showing a mobile NW system according to a third embodiment. [Figure 12] FIG. 2 is a diagram showing a configuration of a remote station according to the embodiment. [Figure 13] 2 is a diagram illustrating a hardware configuration of a transfer device and a distributed station according to the embodiment. [Figure 14] FIG. 1 illustrates a conventional power saving technique. [Figure 15] FIG. 1 illustrates a conventional power saving technique. [Figure 16] FIG. 1 is a diagram showing the timing of arrival of upstream data in a conventional mobile network system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0018] [First embodiment] FIG. 1 is a diagram showing a configuration example of a mobile NW system 10 according to a first embodiment. The mobile NW system 10 is an example of a transmission system having a plurality of hierarchical transmission devices. The mobile NW system 10 is a mobile communication system of a fourth generation mobile communication system (4G) or a fifth generation mobile communication system (5G). The mobile NW system 10 includes a user terminal 1, an antenna station 2, a distributed station 3, a transfer device 4, and a central station 5. The antenna station 2, the distributed station 3, the transfer device 4, and the central station 5 configure a mobile NW. The central station 5 is connected to a higher-level NW (network) 20. The number of the user terminals 1, the antenna stations 2, the distributed stations 3, the transfer devices 4, and the central station 5 is arbitrary. FIG. 1 shows an example in which there are two user terminals 1, two antenna stations 2, and two distributed stations 3, and one transfer device 4 and one central station 5.

[0019] The user terminal 1, the antenna station 2, the distributed station 3, and the central station 5 are 4G or 5G User Equipment (UE), Radio Unit (RU), Distributed unit (DU), and Central unit (CU), respectively. The distributed station 3 and the central station 5 constitute a radio access network (RAN) device such as an eNB (eNodeB) or a gNB (gNodeB). The eNB is a 4G LTE (Long Term Evolution) base station. The eNB is a 5G NR (New Radio) base station. A mobile fronthaul (MFH) is between the antenna station 2 and the distributed station 3, a mobile midhaul (MMH) is between the distributed station 3 and the central station 5, and a mobile backhaul (MBH) is between the central station 5 and the upper NW 20. The direction from the user terminal 1 to the upper NW 20 is described as uplink, and the direction from the upper NW 20 to the user terminal 1 is described as downlink.

[0020] The user terminal 1 and the antenna station 2 communicate wirelessly. The antenna station 2 and the distributed station 3, the distributed station 3 and the transfer device 4, and the transfer device 4 and the central station 5 are connected by wired transmission paths. In this embodiment, the antenna station 2 and the distributed station 3, the distributed station 3 and the transfer device 4, and the transfer device 4 and the central station 5 transmit and receive U-Plane data by optical signals. In this case, the transmission path is an optical transmission path such as an optical fiber, and the transfer device 4 is an optical gateway that relays the optical signal. Note that the antenna station 2 and the distributed station 3, the distributed station 3 and the transfer device 4, and the transfer device 4 and the central station 5 may transmit and receive U-Plane data by electrical signals. In this case, the transfer device 4 is, for example, a layer 2 switch or a router. The mobile NW system 10 further has a transmission path for transmitting and receiving control signals including C-Plane signals and CTI (Cooperative transport interface) signals between the devices. The control signals between the devices may be electrical signals or optical signals. A bearer signal in which U-Plane data is set and a control signal including a C-Plane signal may be logically separated and transmitted / received over the same transmission path.

[0021] The user terminal 1 transmits and receives radio signals to and from the antenna station 2 using radio resources allocated from the mobile network. Radio resources allocated for transmitting uplink signals include resource blocks, modulation schemes, coding rates, transport block sizes (TBS), and the number of transmission layers. A resource block is represented by a combination of a channel and time. A different frequency is used for each channel. Channels of consecutive frequencies are used for resource blocks. Time can be represented by the number of slots. A slot is a scheduling unit for transmitting and receiving data in a radio frame. A TBS is the size of a data block, which is a unit for performing processes such as data transmission in the physical layer. The number of transmission layers indicates the number of antennas used when transmitting radio signals using MIMO (Multiple Input Multiple Output). A number of transmission layers of 1 indicates that MIMO is not used.

[0022] The antenna station 2 wirelessly communicates with the user terminal 1. The antenna station 2 sets the uplink data received wirelessly from the user terminal 1 as an uplink signal, and transmits the uplink signal to the upper distributed station 3 via a wired transmission path. For example, the antenna station 2 downconverts the wireless uplink signals received by each antenna element (not shown) and then converts them into digital signals. The antenna station 2 performs FFT (Fast Fourier Transform) on the uplink signals, then multiplies the uplink signals received by each antenna element for each channel by a weight and adds them. The antenna station 2 converts the uplink signal, which is an aggregate of the uplink signals for each channel, from an electrical signal to an optical signal, and outputs it to the transmission path between the antenna station 2 and the distributed station 3.

[0023] Furthermore, the antenna station 2 receives a downstream signal from the upper distributed station 3 via a wired transmission path. The downstream signal includes downstream data addressed to the user terminal 1. The antenna station 2 transmits the received downstream signal to the user terminal 1 wirelessly. For example, the antenna station 2 converts the received downstream signal from an optical signal to an electrical signal, and then converts it into a downstream signal to be transmitted from each antenna element. The antenna station 2 performs an IFFT (Inverse Fast Fourier Transform) on the downstream signal for each antenna element, converts it from a digital signal to an analog signal, multiplies it by a weight for beamforming, and transmits it wirelessly from the corresponding antenna element.

[0024] The remote station 3 receives an uplink signal from the antenna station 2 under its control. The uplink signal received by the remote station 3 includes uplink data received by the antenna station 2 from the user terminal 1 under its control. The remote station 3 generates an uplink signal that aggregates the uplink data, and transmits the generated uplink signal to the central station 5 to which the remote station is connected. The remote station 3 also receives a downlink signal, in which downlink data addressed to the user terminal 1 under its control is set, from the central station 5 to which the remote station is connected. The remote station 3 converts the received downlink signal into a downlink signal corresponding to the wireless signal transmitted from each antenna station 2. The remote station 3 transmits the converted downlink signal to the antenna station 2 corresponding to the downlink signal.

[0025] The transfer device 4 is connected to the remote station 3 and the central station 5. The transfer device 4 transfers an upstream signal received from the remote station 3 to the destination central station 5 along the transfer path. The transfer device 4 also transfers a downstream signal received from the central station 5 to the destination remote station 3 along the transfer path.

[0026] The central station 5 aggregates uplink signals received from the subordinate remote stations 3 and transfers them to the host NW 20. The central station 5 also receives downlink signals in which downlink data addressed to the user terminal 1 is set from the host NW 20, and transfers the received downlink signals to the remote stations 3 connected to the destination user terminal 1.

[0027] Fig. 2 is a block diagram showing the configuration of the remote station 3. Only functional blocks related to this embodiment are shown in Fig. 2. The remote station 3 includes a transceiver unit 31, a communication unit 33, a control unit 34, and a power source 35.

[0028] The transmitting / receiving unit 31 transmits and receives optical signals. The transmitting / receiving unit 31 includes a first separating unit 311, a first receiving unit 312, an upstream signal generating unit 313, a first transmitting unit 314, a second separating unit 315, a second receiving unit 316, a downstream signal generating unit 317, and a second transmitting unit 318.

[0029] The first separation unit 311 separates the upstream signal and the downstream signal based on the wavelength. The first separation unit 311 outputs the upstream optical signal input from the transmission path between the first separation unit 311 and the antenna station 2 to the first reception unit 312, and outputs the downstream optical signal input from the second transmission unit 318 to the transmission path between the first separation unit 311 and the antenna station 2.

[0030] The first receiving unit 312 performs a receiving process of the uplink signal. Specifically, the first receiving unit 312 converts the received uplink signal from an optical signal to an electrical signal. The first receiving unit 312 extracts an uplink signal of a channel and time included in the resource block of the user terminal 1 for each user terminal 1 from the received signal converted to an electrical signal. The first receiving unit 312 performs equalization, demodulation, and decoding on the extracted uplink signal to obtain uplink data. Note that when the first separating unit 311 receives uplink signals from multiple antenna stations 2 at different wavelengths, the remote station 3 may include a first receiving unit 312 corresponding to each antenna station 2.

[0031] The upstream signal generation unit 313 sets the upstream data of each user terminal 1 input from the first reception unit 312 into an SDU (protocol data unit) to generate an upstream signal addressed to the aggregation station 5. An SDU is a unit by which a protocol processes data. The upstream signal generation unit 313 outputs an upstream signal including the SDU to the first transmission unit 314. The first transmission unit 314 converts the upstream signal input from the upstream signal generation unit 313 from an electrical signal to an optical signal, and outputs the converted signal to the second separation unit 315.

[0032] The second separation unit 315 separates the upstream signal and the downstream signal by wavelength. The second separation unit 315 outputs the upstream signal input from the first transmission unit 314 to the transmission path between the second separation unit 315 and the transfer device 4. The second separation unit 315 outputs the downstream signal input from the transmission path between the second separation unit 315 and the transfer device 4 to the second reception unit 316.

[0033] The second receiving unit 316 performs reception processing of the downlink signal. The second receiving unit 316 converts the downlink signal input from the second separating unit 315 from an optical signal to an electrical signal. The second receiving unit 316 acquires downlink data addressed to each user terminal 1 from the downlink signal converted to an electrical signal, and outputs the data to the downlink signal generating unit 317. The downlink signal generating unit 317 generates a downlink signal to be transmitted from each antenna station 2. The downlink signal generating unit 317 sets downlink data addressed to the user terminal 1 under the antenna station 2 in the downlink signal to be transmitted from the antenna station 2. The second transmitting unit 318 converts the downlink signal input from the downlink signal generating unit 317 from an electrical signal to an optical signal, and outputs the signal to the first separating unit 311.

[0034] The communication unit 33 transmits and receives control signals to and from other devices including the antenna station 2, the transfer device 4, and the central station 5. The control signals include C-plane control signals and CTI signals. The control unit 34 controls the entire remote station 3 according to the control signals transmitted and received via the communication unit 33. The control unit 34 may set the control signal to an uplink signal or a downlink signal and transmit it. In this case, the control unit 34 outputs the control signal to the uplink signal generating unit 313, and the uplink signal generating unit 313 sets the control signal to the uplink signal. In addition, the control unit 34 outputs the control signal to the downlink signal generating unit 317, and the downlink signal generating unit 317 sets the control signal to the downlink signal. The control unit 34 may acquire the control signal from the uplink signal or the downlink signal. In this case, the first receiving unit 312 outputs the control signal included in the uplink signal to the control unit 34, and the second receiving unit 316 outputs the control signal included in the downlink signal to the control unit 34. The control unit 34 includes a scheduler 341.

[0035] The scheduler 341 determines radio resources to be allocated to each user terminal 1. To this end, the scheduler 341 receives a CQI (Channel Quality Indicator) transmitted by each user terminal 1 via a control signal from the antenna station 2 or the aggregate station 5. The CQI indicates the radio reception quality between the antenna station 2 and the user terminal 1 measured by the user terminal 1. The scheduler 341 stores in advance a resource determination model that indicates the correspondence between reception quality and radio resources. The scheduler 341 uses the value of the reception quality indicated by the received CQI as input to the resource determination model to determine the radio resources to be allocated to the user terminal 1. The resource determination model may use other information in addition to the CQI as input. For example, the resource determination model may further use the amount of uplink data in the user terminal 1. The scheduler 341 uses the value of the reception quality indicated by the CQI notified from the user terminal 1 and the amount of uplink data as input to the resource determination model to determine the radio resources to be allocated to the user terminal 1. The scheduler 341 notifies the central station 5 of information on the radio resources allocated to the user terminal 1 by a control signal. The central station 5 sets information on the radio resources allocated to the user terminal 1 in a C-Plane control signal, and notifies the user terminal 1 from the antenna station 2. The power source 35 supplies power to each component of the remote station 3.

[0036] 3 is a block diagram showing the configuration of the transfer device 4 of the present embodiment. The transfer device 4 includes a first transceiver 41, a second transceiver 42, a main signal transfer unit 43, a communication unit 44, a power source 45, and a power control unit 46.

[0037] The transfer device 4 has one or more first transceivers 41. The first transceiver 41 is connected to the distributed station 3 via a transmission path. The first transceiver 41 includes a first separator 411, a first receiver 412, and a first transmitter 413. The first separator 411 separates an upstream signal and a downstream signal by wavelength. The first separator 411 inputs an optical signal transmitted through the transmission path between the distributed station 3 and the first receiver 412, and outputs the input optical signal to the first receiver 412. The first separator 411 also outputs a signal input from the first transmitter 413 to the transmission path between the distributed station 3. The first receiver 412 inputs an optical signal from the first separator 411, transmits an optical signal of a preset wavelength, and outputs the optical signal to the main signal transfer unit 43. The first transmitter 413 inputs an optical signal from the main signal transfer unit 43, transmits an optical signal of a preset wavelength, and outputs the optical signal to the transmission path between the distributed station 3. The first receiving unit 412 and the first transmitting unit 413 may amplify the optical signal.

[0038] The transfer device 4 has one or more second transceivers 42. The second transceiver 42 is connected to the aggregation station 5 via a transmission path. The second transceiver 42 includes a second separator 421, a second receiver 422, and a second transmitter 423. The second separator 421 separates an upstream signal and a downstream signal by wavelength. The second separator 421 inputs an optical signal transmitted through the transmission path between the aggregation station 5 and outputs the input optical signal to the second receiver 422. The second separator 421 also outputs a signal input from the second transmitter 423 to the transmission path between the aggregation station 5. The second receiver 422 inputs an optical signal from the second separator 421, transmits an optical signal of a preset wavelength, and outputs the optical signal to the main signal transfer unit 43. The second transmitter 423 inputs an optical signal of a preset wavelength from the main signal transfer unit 43, transmits an optical signal of a preset wavelength, and outputs the optical signal to the second separator 421. The second receiving unit 422 and the second transmitting unit 423 may amplify the optical signal.

[0039] The main signal transfer unit 43 outputs an optical signal of a predetermined wavelength input from any of the first receiving units 412 to any of the second transmitting units 423 according to a preset transfer route. In addition, the main signal transfer unit 43 outputs an optical signal of a predetermined wavelength input from any of the second receiving units 422 to any of the first transmitting units 413 according to a preset transfer route. The wavelengths set in each of the first receiving units 412 and each of the second receiving units 422, the route between the first receiving unit 412 and the second transmitting unit 423, and the route between the second receiving unit 422 and the first transmitting unit 413 are set according to instructions from a route control device (not shown).

[0040] The communication unit 44 transmits and receives control signals to and from other devices including the antenna station 2, the transfer device 4, and the central station 5. The power supply 45 supplies power to each unit of the transfer device 4. The power control unit 46 includes a cooperation information acquisition unit 461, a timing determination unit 462, and a power saving control unit 463. The cooperation information acquisition unit 461 acquires cooperation information of each user terminal 1 from the central station 5. The cooperation information indicates radio resources allocated to the user terminal 1, and the antenna station 2, the central station 3, and the central station 5 to which the user terminal 1 is connected. Note that the cooperation information acquisition unit 461 may receive part or all of the cooperation information from the central station 3 or the antenna station 2.

[0041] The timing determination unit 462 calculates the timing at which the transfer device 4 starts and ends receiving the uplink signal based on the cooperation information acquired by the cooperation information acquisition unit 461. The timing determination unit 462 determines the start and end timings of the sleep state of the controlled unit based on the calculated timing. The controlled unit is a part or all of the first receiving unit 412, the second transmitting unit 423, and the main signal transfer unit 43. The sleep state is a state in which some functions cannot be executed by cutting off the power supply from the power source 45 to some circuits. The power consumption in the sleep state is smaller than that in the active state. The active state is a state in which all functions can be executed without cutting off the power supply from the power source 45 to the circuits. The power saving control unit 463 changes the state of the controlled unit according to the start and end timings of the sleep state determined by the timing determination unit 462.

[0042] In this embodiment, the case where the remote station 3 has the scheduler 341 will be described. However, the remote station 3 may not have the scheduler 341 and the transfer device 4 may have a function similar to that of the scheduler 341 .

[0043] FIG. 16 is a diagram showing the timing of uplink data arrival in a conventional mobile NW system. The uplink data U wirelessly transmitted by the user terminal at time t90 is transmitted from the antenna station to the remote station. The remote station transmits an uplink signal in which the received uplink data U is set. Conventionally, the modulation factor of the uplink signal was unknown. Therefore, the receiver of the U-Plane function in the RAN device of the MMH and MBH has set a guard time from the arrival start time t91 of the uplink signal when the maximum modulation factor is used to the arrival end time t92 of the uplink signal when the minimum modulation factor (and the minimum coding rate) is used. Therefore, when the modulation factor is unknown, the guard time becomes long. Since the receiver of the U-Plane function continues the Active state during the guard time, the power reduction effect is small.

[0044] The scheduler 341 of the remote station 3 in this embodiment determines radio resources to be allocated to each user terminal 1, as in the conventional technology. Specifically, the scheduler 341 schedules the timing, modulation level, coding rate, frequency, and amount of data to be transmitted by each user terminal 1 in the radio section. The central station 5 notifies the user terminal 1 of the result of this scheduling prior to the transmission of a radio signal from the user terminal 1. These are transmitted from the antenna station 2 to the user terminal 1 by control messages called RRC (Radio Resource Control) signaling and DCI (Downlink Control Information). The user terminal 1 transmits a radio signal with uplink data set according to the assigned timing, modulation level, coding rate, frequency, and time in accordance with the received control messages.

[0045] Before allocating wireless resources, the scheduler 341 of the remote station 3 receives a CQI (Channel Quality Indicator) transmitted by the user terminal 1 from the central station 5 or the antenna station 2. The CQI indicates the quality of the wireless channel measured in the user terminal 1. The scheduler 341 determines wireless resources to be allocated to the user terminal 1 based on the received CQI and a resource determination model stored in advance. When the power of the signal is stronger than the noise, the wireless quality is good. When the wireless quality is good, the scheduler 341 instructs the user terminal 1 to perform coding with a higher modulation factor and lower redundancy. This makes it possible to achieve a higher throughput. Conversely, when the wireless quality is bad, the scheduler 341 instructs the user terminal 1 to perform coding with a lower modulation factor and higher redundancy. This makes it possible for the user terminal 1 to deliver a signal to the antenna station 2 with a higher probability, thereby reducing retransmissions. The scheduler 341 may further use a BSR (Buffer Status Report) notified from the user terminal 1 to determine radio resources to be allocated to the user terminal 1. The BSR indicates the amount of uplink data buffered in the user terminal 1. The scheduler 341 obtains the BSR from the aggregation station 5 or the antenna station 2.

[0046] In the wireless section, a MAC (Medium Access Control) frame is divided into smaller TBSs for transmission. When a high modulation degree and low redundancy coding are used, the TBS can be set larger. The larger the TBS, the faster the remote station 3 can collect the number of information bits required to compose a PDU (Protocol Data Unit), which is the unit by which the protocol processes data. Therefore, the timing at which uplink data transmitted by the user terminal 1 arrives at the MMH also becomes faster. More specifically, the timing at which data is output from RLC (Radio link Control) to PDCP (Packet Data Convergence Protocol) and the timing at which data is output from PDCP to a higher layer become faster.

[0047] On the other hand, for the power saving control of the transfer device 4, it is important to grasp the arrival start timing and arrival end timing of the uplink data traffic at the transfer device 4. This is because if the transfer device 4 ends the sleep state and becomes active before the arrival of the traffic, the power reduction effect is reduced, and if the sleep state ends later than the arrival of the traffic, the delay increases. In addition, if the transfer device 4 starts the sleep state earlier than the end of the arrival of the traffic, a delay occurs at least for the uplink data that has not been transmitted, and if the sleep state is started after a time has passed since the end of the arrival, the power reduction effect is reduced. Furthermore, since the timing at which the PDU is constructed also changes depending on the TBS, the timing at which the uplink data arrives at the transfer device 4 changes not only depending on which resource block is used at which time, but also depending on the modulation degree and the coding rate. Note that the arrival here means that the head of the data is input to the transfer device.

[0048] Therefore, the timing determination unit 462 of the transfer device 4 calculates the transmission start timing and the transmission end timing of the uplink data in the remote station 3 based on the cooperation information acquired by the cooperation information acquisition unit 461 from the central station 5. The timing determination unit 462 calculates the arrival start timing and the arrival end timing of the uplink data to the transfer device 4 based on the transmission start timing and the transmission end timing of the uplink data in the remote station 3. The cooperation information includes the number of transmission layers (Tx Layers (MIMO)) notified to the user terminal 1 by RRC signaling, and the modulation degree, the coding rate, and the number of resource elements obtained based on the DCI notified to the user terminal 1. Furthermore, the cooperation information includes information on the antenna station 2, the remote station 3, and the central station 5 to which the user terminal 1 is connected. The modulation degree and the coding rate are specified by the MCS index set in the MCS field of the DCI. Moreover, the resource elements are calculated based on the number of resource blocks and the transmission duration set in the DCI.

[0049] The timing determination unit 462 calculates a TBS based on the number of transmission layers, modulation factor, coding rate, and number of resource blocks assigned to the user terminal 1 for a radio transmission period at a certain time. The timing determination unit 462 determines whether or not uplink data of a data amount equivalent to 1 SDU can be obtained in one subframe based on the TBS and coding rate. One radio frame is 10 ms and consists of 10 subframes of 1 ms each. One subframe consists of one slot when the subcarrier spacing is 15 kHz, two slots when the subcarrier spacing is 30 kHz, four slots when the subcarrier spacing is 60 kHz, and eight slots when the subcarrier spacing is 120 kHz. One slot consists of 14 symbols.

[0050] FIG. 4 is a diagram showing the timing of transmission and arrival of uplink data when the amount of uplink data in one subframe is less than the amount of data for one SDU. The user terminal 1 is assigned radio resources for uplink communication from time t10 by a control signal. Time t10 is the reference transmission start time of a radio frame. When the amount of uplink data in one subframe is less than the amount of data for one SDU, it is necessary to receive multiple subframes before the remote station 3 transmits an SDU. Therefore, the timing determination unit 462 calculates the number of subframes n required to receive the amount of data for one SDU. The timing determination unit 462 sets the time t11 as the time at which the user terminal 1 ends transmission of the n-th subframe after transmitting the first subframe at time t10.

[0051] The timing determination unit 462 sets time t11 as the transmission start time of the SDU at the remote station 3. The timing determination unit 462 may add the transmission delay from the antenna station 2 to the remote station 3 to set the transmission start time of the SDU at the remote station 3. The timing determination unit 462 sets time t12, which is obtained by adding the transmission delay from the remote station 3 to the transmission start time t11, as the arrival start time of the SDU at the transfer device 4. The timing determination unit 462 calculates the transmission time of the SDU based on the size of the SDU in which n subframes of upstream data are set and the transfer rate from the remote station 3. The timing determination unit 462 sets the time obtained by adding the transmission time to the transmission start time t11 as the transmission end time of the SDU from the remote station 3. The timing determination unit 462 sets time t13, which is obtained by adding the transmission delay from the remote station 3 to the transmission end time of the SDU, as the arrival end time of the SDU at the transfer device 4. The timing determination unit 462 may calculate the arrival end time t13 by adding the transmission time to the arrival start time t12.

[0052] FIG. 5 is a diagram showing the timing of data transmission and arrival when the amount of uplink data in one subframe is the amount of data for one SDU. The user terminal 1 is assigned physical resources for uplink communication from time t20 by a control signal. When an SDU can be transmitted by receiving one subframe, the timing determination unit 462 of the transfer device 4 sets time t21, which is obtained by adding a transmission delay from the remote station 3 to the transfer device 4 to time t20 when the user terminal 1 transmits the subframe, as the arrival start time of the SDU at the transfer device 4. The timing determination unit 462 may set the arrival start time t21 by adding a transmission delay from the antenna station 2 to the remote station 3 and a transmission delay from the remote station 3 to the transfer device 4 to time t20. The timing determination unit 462 also calculates a signal processing time based on the size of the SDU and the RLC / PDCP processing speed in the remote station 3. The timing determination unit 462 sets the time obtained by adding the signal processing time to the transmission start time t20 as the transmission end time of the SDU from the remote station 3. The timing determination unit 462 determines time t22, which is the SDU transmission end time plus the transmission delay from the remote station 3 to the transfer device 4, as the arrival end time of the SDU at the transfer device 4. The timing determination unit 462 may calculate the arrival end time t22 by adding the signal processing time to the arrival start time t21.

[0053] As described above, times t12 and t21 are arrival start times taking into consideration the modulation degree and TBS, and times t13 and t22 are arrival end times taking into consideration the modulation degree and TBS. The timing determination unit 462 calculates the arrival start time and arrival end time of the SDU in the transfer device 4 as shown in FIG. 4 or FIG. 5, and then determines the start timing and end timing of the sleep state. The timing determination unit 462 determines the end timing of the sleep state to be a time T1 (T1≧0) earlier than the arrival start time. The timing determination unit 462 determines the start timing of the sleep state to be a time T2 (T2≧0) after the arrival end time.

[0054] The timing determination unit 462 obtains the end timing and start timing of the sleep state for each user terminal 1 as described above. The timing determination unit 462 calculates a period excluding the end timing to the start timing of the sleep state of each user terminal 1 during the period for which radio resources are allocated, and sets the period as a user terminal-specific sleep period. The timing determination unit 462 calculates the logical product of the user terminal-specific sleep periods of all user terminals 1 under the central station 5, and sets the period as a transfer device sleep period. The timing determination unit 462 calculates the logical product of the user terminal-specific sleep periods of all user terminals 1 under the central station 5, and sets the period as a central station-specific sleep period. The timing determination unit 462 calculates the logical product of the user terminal-specific sleep periods of all user terminals 1 under the central station 5, and sets the period as a central station-specific sleep period. The timing determination unit 462 notifies the power saving control unit 463 of the transfer device sleep period, the central station-specific sleep period for each central station 5, and the central station-specific sleep period for each central station 3. The timing determination unit 462 may use a sleep period of the transfer device instead of the central station-specific sleep period and the remote station-specific sleep period.

[0055] The power saving control unit 463 controls the main signal transfer unit 43 to enter a sleep state at the start time of the transfer device sleep period, and to enter a awake state or an active state at the end time of the transfer device sleep period. The power saving control unit 463 controls the second transmission unit 423 of the second transceiver unit 42 connected to the central station 5 to enter a sleep state at the start time of the central station-specific sleep period of the central station 5, and to enter a awake state or an active state at the end time of the sleep period. The power saving control unit 463 controls the second transmission unit 423 of the first transceiver unit 41 connected to the central station 3 to enter a sleep state at the start time of the central station-specific sleep period of the central station 3, and to enter a awake state or an active state at the end time of the sleep period.

[0056] A specific example of calculation of the arrival start timing and arrival end timing in Fig. 4 and Fig. 5 will be described. Here, the conditions of the mobile NW system 10 are as follows. The system band is 20 MHz (megahertz), and the subcarrier interval is 15 kHz. One physical resource block (PRB) is 0.5 ms with 7 OFDM (Orthogonal Frequency Division Multiplexing) symbols in the time direction and 12 subcarriers (180 kHz) in the frequency direction. The duplexing method is FDD (Frequency Division Duplex). The minimum unit of resource block allocation to the user terminal 1 is 1 RB in the frequency direction and 2 RBs (radio subframes) in the time direction. In addition, the user terminal 1 is instructed in advance to refer to the MCS table shown in Fig. 6, which will be described later, by a prior RRC message exchange between the user terminal 1 and the remote station 3. In addition, instructed in advance to use 1 MIMO layer for uplink transmission by a prior RRC message exchange between the user terminal 1 and the remote station 3.

[0057] FIG. 6 is a diagram showing an MCS (Modulation and Coding Scheme) table of LTE. The MCS table shown in FIG. 6 is a table equivalent to 3GPP TS 36.213 Table 8.6.1-1. The MCS table is divided into MCS indices ( MCS ) and Modulation Order (Q' m ) and the TBS index (I TBS ) and the redundant version (rv idx ) The MCS index is set in the DCI. The MCS index is information that specifies a combination of a modulation degree, a TBS index, and a redundancy version. The modulation degree indicates the modulation method. A modulation degree of "2" indicates QPSK (Quadrature Phase Shift Keying), a modulation degree of "4" indicates 16QAM (Quadrature Amplitude Modulation), and a modulation degree of "6" indicates 64QAM. The TBS index specifies the TBS.

[0058] FIG. 7 is a diagram showing a coding rate table. FIG. 7 shows a coding rate table for LTE when the system band is 20 MHz, the subcarrier spacing is 15 kHz, and the number of resource blocks is 100. The coding rate table is MCS ) and the TBS index (I TBS ), modulation scheme, TBS, user data size, and coding rate. Fig. 8 is a diagram showing the relationship between the MCS index and the coding rate in the coding rate table shown in Fig. 7.

[0059] FIG. 9 is a diagram showing a TBS table. The TBS table includes a TBS index ( TBS ) and the number of physical resource blocks (N PRB ) is used to determine the TBS.

[0060] In the case of Fig. 4, the scheduler 341 of the remote station 3 determines the MCS index for uplink transmission from the user terminal 1 at time t10 to be "2" based on the reception strength and error rate of the uplink signal in the wireless section transmitted from the user terminal 1, and transmits this to the user terminal 1 by a control signal. In this case, according to the MCS table shown in Fig. 4, the modulation index representing the modulation level is "2". In other words, QPSK, which allows transmission of 2 bits per symbol, is used as the modulation scheme for uplink communication from the user terminal 1. Similarly, the TBS index is also determined to be "2".

[0061] Furthermore, based on the amount of uplink data indicated by the BSR transmitted in advance from the user terminal 1 and the degree of congestion in the resource blocks managed by the remote station 3, the scheduler 341 allocates 50 physical resource blocks (PRBs) to the user terminal 1 (N PRB According to the TBS table shown in FIG. 9, the TBS has MCS index=2 and N PRB = 2216 bits (277 bytes) corresponding to 50.

[0062] Furthermore, the ratio of redundant bits is determined by the coding rate described in the coding rate table of Fig. 7. In other words, the actual (significant) number of bits in the subframe transmitted from the user terminal 1 is further reduced. If one SDU is 1500 bytes, five or more subframes are required in the time direction under the above conditions. Therefore, the remote station 3 will combine data of multiple transport blocks and start outputting an uplink signal to the MBH at least five subframes after it starts receiving the first subframe from the antenna station 2.

[0063] The timing determination unit 462 of the transfer device 4 determines the time when the remote station 3 finishes receiving five subframes as the transmission start time t11 of the SDU from the remote station 3. The timing determination unit 462 determines the time obtained by adding the transmission delay from the remote station 3 to the transfer device 4 to the transmission start time t11 of the SDU from the remote station 3 as the arrival start time t12 of the SDU at the transfer device 4. The timing determination unit 462 determines the arrival end time of the SDU as the time t13 when a transmission time calculated based on the size of the SDU and the transfer rate from the remote station 3 has elapsed from the arrival start time t12 of the SDU at the transfer device 4. The timing determination unit 462 determines the sleep time so that the sleep state ends before the arrival start time t12 and starts after the SDU arrival end time t13.

[0064] In the case of FIG. 5, the scheduler 341 of the remote station 3 determines the MCS index for uplink transmission of the user terminal 1 at time t20 to be "28" and transmits it to the user terminal 1 by a control signal. When the MCS index is "28", the TBS index is "26". According to the TBS table shown in FIG. 9, when the MCS index is "26" and 50 physical resource blocks are assigned to the user terminal 1, the TBS is 36696 bits (4587 bytes). In other words, one SDU can be transmitted in one subframe. The timing determination unit 462 of the transfer device 4 determines the time t21, which is the time t20 when the user terminal 1 transmits the first subframe plus the transmission delay from the remote station 3 to the transfer device 4, as the arrival start time of the SDU at the transfer device 4. Furthermore, the timing determination unit 462 determines the time t22 obtained by adding the signal processing time in the remote station 3 to time t20 and the transmission delay from the remote station 3 to the transfer device 4 as the arrival end time of the SDU at the transfer device 4. The timing determination unit 462 determines the end time and start time of sleep based on the arrival start time and arrival end time in the same manner as above.

[0065] [Second embodiment] In this embodiment, the sleep state of the transfer device is controlled based on the subframe of the wireless section to which the uplink is assigned. This embodiment will be described focusing on the difference from the first embodiment. The configuration of the mobile NW system of this embodiment is the same as that of the first embodiment.

[0066] 10 is a diagram showing the timing of transmission and arrival of uplink data in the mobile NW system 10. The user terminal 1 transmits a BSR (Buffer Status Report) in addition to a CQI by a control signal. The scheduler 341 of the remote station 3 determines the radio resources to be allocated to the user terminal 1 based on the CQI and BSR transmitted from the user terminal 1. For example, the scheduler 341 determines the MCS index to be "2". The remote station 3 notifies the user terminal 1 of DCI setting information of the determined radio resources by a UL Grant. The control unit 34 of the remote station 3 notifies the transfer device 4 of cooperation information based on the radio resources allocated to the user terminal 1.

[0067] Similar to the TDD_config of LTE, the subframes of the wireless communication between the user terminal 1 and the antenna station 2 are set by repeating DSUUU. In the subframes, the uplink of TDD (Time Division Duplex) is written as U, the downlink as D, and the special subframe at the time of switching is written as S. The beginning of the wireless frame corresponds to the beginning of the TTI (Transmission Time Interval).

[0068] The amount of data in each subframe is determined by the modulation factor. In addition, the effective amount of uplink data, excluding redundant bits, received in each subframe is determined by the coding rate. The transmitter / receiver 31 of the remote station 3 obtains effective uplink data for one PDU from the uplink signal from the antenna station 2, and then sets the uplink data in a PDU and transmits it to the transfer device 4. A PDU is a unit of data transmission and reception in a certain protocol.

[0069] Therefore, the timing determination unit 462 of the transfer device 4 calculates the effective amount of data to be obtained from each subframe based on the modulation factor and coding rate determined by the MCS index. The timing determination unit 462 calculates the number of subframes required to obtain the amount of data for one PDU based on the data size of the PDU and the effective amount of data obtained in one subframe. The timing determination unit 462 determines that the remote station 3 will transmit the PDU after finishing receiving the calculated number of subframes.

[0070] For example, under the same conditions as in the first embodiment and FIG. 4, when MCS is "2", PDU data addressed to the central station 5 is transmitted from the central station 3 seven subframes after the top uplink data of the PDU arrives at the central station 3. Note that FIG. 10 shows a case where PDU data addressed to the central station 5 is transmitted from the central station 3 six subframes after the subframe in which the top uplink data of the PDU is set. The uplink data transmitted by the user terminal 1 at time t30 arrives at the central station 3 at time t31. The timing determination unit 462 of the transfer device 4 calculates time t30 based on the resource block assigned to the user terminal 1. The timing determination unit 462 calculates time t31 by adding a one-way delay from the antenna station 2 to the central station 3 to time t30.

[0071] Furthermore, the timing determination unit 462 calculates time t32 when one PDU's worth of upstream data is ready at the remote station 6, based on the cooperation information and the PDU size. In Fig. 10, the timing determination unit 462 determines the end time of reception of the sixth subframe of upstream data from time t31 to time t32. The timing determination unit 462 determines time t33, which is time t32 when the remote station 6 transmits the first upstream data of the PDU, plus the transmission delay from the remote station 3 to the transfer device 4, as the arrival start time of the SDU at the transfer device 4.

[0072] Furthermore, the timing determination unit 462 calculates time t34 at which the transfer device 4 finishes receiving one PDU's worth of upstream data that the remote station 3 started transmitting at time t32, based on the PDU size, the link speed of the transmission path between the remote station 6 and the transfer device 4, and the one-way delay. That is, the timing determination unit 462 calculates the transmission time of one PDU, based on the PDU size and the transfer speed between the remote station 3 and the transfer device 4. The timing determination unit 462 adds the transmission time of the SDU to time t33 to calculate the arrival end time t34 of the PDU at the transfer device 4.

[0073] The timing determination unit 462 sets the end timing of the sleep state to a time T3 (T3≧0) earlier than the arrival start time t33, and sets the start timing of the sleep state to a time T4 (T4≧0) after the arrival end time t34. This allows the transfer device 4 to end the sleep state earlier than the arrival of the upstream optical signal, and to receive and transfer the PDU amount of data to the aggregation station 5 without any delay due to sleep. Furthermore, a higher power saving effect can be expected in the transfer device 4.

[0074] The remote station 3 may start transmitting a PDU before completing reception of one PDU's worth of data from the antenna station 2. For example, if reception of six upstream subframes is required to configure a PDU as described above, the remote station 3 may start transmitting a PDU to the transfer device 4 before completing reception of the sixth subframe. However, the remote station 3 starts transmitting a PDU at a timing such that the transmission of the PDU is completed after the reception of six upstream subframes is completed.

[0075] The timing determination unit 462 may determine the arrival start timing of the PDU at the transfer device 4 based on the start timing of the TTI and the position of the uplink subframe in the radio frame. That is, the timing determination unit 462 may calculate the arrival start time and the arrival end time of the PDU at the transfer device 4 by using the time when the start of the TTI arrives at the remote station 3 and the position of the first uplink radio frame in the radio frame. When calculating the arrival start time, the timing determination unit 462 assumes the maximum modulation factor that can be taken in the mobile NW system 10. The timing determination unit 462 sets the modulation factor and the coding rate used when calculating the arrival end time to the minimum modulation factor and the minimum coding rate that can be taken in the mobile NW system 10.

[0076] [Third embodiment] In this embodiment, the remote station includes a power control unit. This embodiment will be described focusing on the differences from the first and second embodiments described above.

[0077] Fig. 11 is a diagram showing the configuration of a mobile NW system 11 of this embodiment. In Fig. 11, the same components as those in the mobile NW system 10 of the first embodiment shown in Fig. 1 are given the same reference numerals, and their description will be omitted. The mobile NW system 11 differs from the mobile NW system 10 of the first embodiment in that the mobile NW system 11 includes a remote station 6 instead of the remote station 3.

[0078] Fig. 12 is a block diagram showing the configuration of the remote station 6. In Fig. 12, the same components as those in the remote station 3 of the first embodiment shown in Fig. 2 are given the same reference numerals, and the description thereof will be omitted. The remote station 6 differs from the remote station 3 of the first embodiment in that it further includes a power control unit 61.

[0079] The power control unit 61 includes a cooperation information acquisition unit 611, a timing determination unit 612, and a power saving control unit 613. The cooperation information acquisition unit 611 acquires, from a control signal received from another device or the scheduler 341, cooperation information for a user terminal 1 under its own station, similar to that of the cooperation information acquisition unit 461 included in the power control unit 46 of the transfer device 4.

[0080] Based on the cooperation information acquired by the cooperation information acquisition unit 611, the timing determination unit 612 calculates the transmission start time and the transmission end time from the remote station 3 for each of the user terminals 1 under its control by the same process as the timing determination unit 462 included in the power control unit 46 of the transfer device 4. The timing determination unit 612 determines the end timing of the sleep state to be a time T5 (T5≧0) earlier than the transmission start time, and determines the start timing of the sleep state to be a time T6 (T6≧0) after the transmission end time. The timing determination unit 612 calculates the period excluding the end timing to the start timing of the sleep state of each user terminal 1, and determines it as the user terminal-specific sleep period. The timing determination unit 612 calculates the logical product of the user terminal-specific sleep periods calculated for the subordinate user terminals 1, and determines it as the transmission sleep period. The timing determination unit 612 outputs the calculated transmission sleep period to the power saving control unit 613.

[0081] The power saving control unit 613 changes the state of the first transmission unit 314 in accordance with the start timing and end timing of the transmission sleep state determined by the timing determination unit 612. The power saving control unit 613 controls the first transmission unit 314 to enter the sleep state at the start time of the sleep period and to enter the wake state or active state at the end time of the sleep period.

[0082] In addition, when the coding rate is low, the timing determination unit 462 may lengthen the times T2 and T4 in consideration of retransmission. For example, the lower the coding rate, the longer the times T2 and T4 are set by the timing determination unit 462. Similarly, when the coding rate is low, the timing determination unit 612 may lengthen the time T5.

[0083] In the above-described embodiment, the timing determination unit 462 uses the MCS index notified to each user terminal 1 when calculating the sleep end timing and sleep start timing. However, the timing determination unit 462 may acquire the maximum MCS index and the minimum index for each remote station 3 from among the MCS indices notified to each user terminal 1. When calculating the arrival start time of uplink data at the transfer device 4 for each user terminal 1 under the control of the remote station 3, the timing determination unit 462 uses the maximum MCS index obtained for that remote station 3. Also, when calculating the arrival end time for each user terminal 1 under the control of the remote station 3, the timing determination unit 462 uses the minimum MCS index obtained for that remote station 3. The same applies to the timing determination unit 612.

[0084] In the above, the timing determination unit 462 acquires the MCS index notified to the user terminal 1, but may acquire the CQI, or the CQI and the amount of uplink data, notified from the user terminal 1. The timing determination unit 462 estimates radio resources using a resource determination model similar to that of the scheduler 341 and the notified CQI, or the CQI and the amount of uplink data. The timing determination unit 462 performs the same process as above, using the estimated radio resources as cooperation information. In this way, the timing determination unit 462 can start calculating the start and end timings of the sleep state before the CQI of the user terminal 1 is determined. The same applies to the timing determination unit 612.

[0085] Furthermore, in the above embodiment, the timing determination unit 462 calculates the user terminal-specific sleep period for all user terminals 1, but may calculate the user terminal-specific sleep period for a high priority user terminal 1. The timing determination unit 462 outputs cooperation information only for the high priority user terminal 1 to the transfer device 4 from the aggregation station 5. Alternatively, the transfer device 4 acquires information on the high priority user terminal 1 from the aggregation station 5. The same applies to the timing determination unit 612.

[0086] 13 is a diagram showing an example of the hardware configuration of the transfer device 4 and the distributed station 6. The transfer device 4 and the distributed station 6 each include a processor 71, a storage unit 72, a communication interface 73, a user interface 74, and a power supply device 75.

[0087] The processor 71 is a central processing unit that performs calculations and control. The processor 71 is, for example, a CPU. The processor 71 reads out a program from the storage unit 72 and executes it. Some of the functions of the power control unit 46 of the transfer device 4 and the power control unit 61 and control unit 34 of the distributed station 6 may be realized using hardware such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array). The storage unit 72 further has a work area when the processor 71 executes various programs. The communication interface 73 is connected to other devices so as to be able to communicate with them. The communication interface 73 corresponds to the first transceiver unit 41, the second transceiver unit 42, the main signal transfer unit 43, and the communication unit 44 of the transfer device 4, and the transceiver unit 31 and the communication unit 33 of the distributed station 6. The user interface 74 is an input device such as a keyboard, a pointing device (mouse, tablet, etc.), a button, a touch panel, etc., or a display device such as a display. A human operation is input through the user interface 74. A power supply unit 75 supplies power to each component.

[0088] In the above-described embodiment, the transfer device 4 includes the power control unit 46, but the power control device connected to the transfer device 4 may include the power control unit 46. Similarly, in the above-described embodiment, the remote station 6 includes the power control unit 61, but the power control device connected to the remote station 6 may include the power control unit 61. The power control device including the power control unit 46 and the power control device including the power control unit 61 may be the same device. The hardware configuration of the power control device is similar to that of FIG. 13.

[0089] The power control device may be realized by a plurality of computer devices connected to a network. In this case, it is possible to arbitrarily select which of the plurality of computer devices is used to realize each functional unit of the power control device. Also, the same functional unit may be realized by a plurality of computer devices.

[0090] According to the above-described embodiment, the transmission system includes a first transmission device, a second transmission device, and a power control unit. For example, the transmission system is the mobile NW system 10 of the embodiment, the first transmission device is the distributed station 3 of the embodiment, and the second transmission device is the transfer device 4 of the embodiment. The first transmission device receives a data signal transmitted by the communication device from a lower transmission device, sets the received data signal as a data unit, and transmits the data unit. The communication device is, for example, the user terminal 1 of the embodiment. The second transmission device receives the data unit transmitted by the first transmission device. The second transmission device includes a signal processing unit that performs processing on the data unit. The signal processing unit is, for example, the first receiving unit 412, the main signal transfer unit 43, and the second transmitting unit 423 of the embodiment. The power control unit calculates an arrival start timing, which is the timing at which the data unit including the data signal transmitted from the communication device starts to arrive at the second transmission device, based on the coding rate and the size of the data transmission block used when the communication device transmits the data signal. The power control unit controls the sleep state of the signal processing unit of the second transmission device to end before the arrival start timing.

[0091] The power control unit calculates an arrival end timing, which is the timing at which the data unit including the data signal transmitted by the communication device ends arriving at the second transmission device, based on the coding rate, the size of the data transmission block, and the amount of data transmitted by the data unit. The control unit controls the signal processing unit of the second transmission device to start a sleep state after the arrival end timing.

[0092] A communication device transmits a data unit wirelessly. A power control unit obtains a coding rate and a size of a data transmission block based on an MCS (Modulation and Coding Scheme) index notified to the communication device. Alternatively, the power control unit obtains the coding rate and the size of a data transmission block based on a wireless reception quality in the communication device.

[0093] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and designs that do not deviate from the gist of the present invention are also included. [Explanation of symbols]

[0094] 1 User terminal 2 Antenna Station 3 Distributed station 4. Teleportation Device 5 Aggregation Station 6 Distributed station 10, 11 Mobile Network Systems 31 Transmitter / receiver 33, 44 Communications Department 34 Control section 35, 45 Power supply 41 First Transmitter / Receiver 42 Second Transceiver Unit 43 Main signal transfer section 46, 61 Power control section 71 Processor 72 Memory section 73 Communication Interface 74 User Interface 75 Power supply 311, 411 First separation section 312, 412 First receiving section 313 Signal Generator 314, 413 First Transmission Unit 315, 421 Second separation section 316, 422 Second Receiving Unit 317 Signal Generator 318, 423 Second Transmission Department 341 Scheduler 461, 611 Collaboration Information Acquisition Department 462, 612 Timing determination unit 463, 613 Power saving control unit

Claims

1. a first transmission device that receives a data signal transmitted by a communication device from a lower transmission device, sets the received data signal into a data unit, and transmits the data unit; a second transmission device that receives the data unit transmitted by the first transmission device; A power control device; Equipped with The power control device includes an acquisition unit that acquires a coding rate and a size of a data transmission block used when the communication device transmits a data signal from the first transmission device or an aggregate station connected to the power control device; a timing determination unit that calculates an arrival start timing, which is a timing at which the data unit including the data signal transmitted from the communication device starts to arrive at the second transmission device, based on the coding rate and the size of the data transmission block acquired by the acquisition unit, and controls a sleep state of a signal processing unit that processes the data unit in the second transmission device to end before the arrival start timing. Transmission system.

2. A power control device, an acquisition unit that acquires, from a first transmission device or an aggregation station connected to the power control device, a coding rate and a size of a data transmission block used when a communication device transmits a data signal; a timing determination unit that calculates an arrival start timing, which is a timing at which a data unit transmitted by the first transmission device that receives a data signal transmitted by the communication device from a lower transmission device, including the data signal transmitted by the communication device, starts to arrive at a second transmission device, based on the coding rate and the size of the data transmission block acquired by the acquisition unit, and controls a sleep state of a signal processing unit that processes the data unit in the second transmission device to end before the arrival start timing; A power control device comprising:

3. the timing determination unit calculates an arrival end timing, which is a timing at which the data unit including the data signal transmitted by the communication device ends arriving at the second transmission device, based on the coding rate, the size of the data transmission block, and the amount of data transmitted by the data unit, and controls the signal processing unit to start a sleep state after the arrival end timing. The power control device according to claim 2 .

4. The communication device transmits the data unit wirelessly; The acquisition unit acquires a size of the data transmission block based on a number of resource blocks and a transmission period set in Downlink Control Information (DCI) notified to the communication device. The power control device according to claim 2 or 3.

5. The communication device transmits the data unit wirelessly; The acquisition unit acquires the coding rate based on an MCS (Modulation and Coding Scheme) index notified to the communication device. The power control device according to claim 2 or 3.

6. a transmitting step in which a first transmission device receives a data signal transmitted by a communication device from a lower transmission device, sets the received data signal as a data unit, and transmits the data unit; a receiving step in which a second transmission device receives the data unit transmitted by the first transmission device; an acquisition step in which a power control unit acquires, from the first transmission device or an aggregate station connected to the power control device, a coding rate and a size of a data transmission block used when the communication device transmits a data signal; a timing determination step of calculating an arrival start timing, which is a timing at which the data unit including the data signal transmitted from the communication device starts to arrive at the second transmission device, based on the coding rate and the size of the data transmission block acquired in the acquisition step, and controlling a sleep state of a signal processing unit that processes the data unit in the second transmission device to end before the arrival start timing; A transmission control method comprising:

7. A power control method for use by a power control device, comprising: an acquisition step of acquiring a coding rate and a size of a data transmission block used when a communication device transmits a data signal from a first transmission device or an aggregate station connected to the power control device; a calculation step of calculating an arrival start timing, which is a timing at which a data unit transmitted by the first transmission device that receives the data signal transmitted by the communication device from a lower transmission device starts arriving at a second transmission device, based on the coding rate and the size of the data transmission block acquired in the acquisition step; a timing determination step of controlling a sleep state of a signal processing unit that processes the data unit in the second transmission device to end before the arrival start timing; The power control method includes:

8. Computer, A program for causing the power control device according to any one of claims 2 to 5 to function as the power control device.

Images