WO2013111412A1 - 無線通信装置及び無線通信方法、並びに無線通信システム - Google Patents
無線通信装置及び無線通信方法、並びに無線通信システム Download PDFInfo
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- WO2013111412A1 WO2013111412A1 PCT/JP2012/078450 JP2012078450W WO2013111412A1 WO 2013111412 A1 WO2013111412 A1 WO 2013111412A1 JP 2012078450 W JP2012078450 W JP 2012078450W WO 2013111412 A1 WO2013111412 A1 WO 2013111412A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0032—Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
- H04L5/0035—Resource allocation in a cooperative multipoint environment
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/022—Site diversity; Macro-diversity
- H04B7/024—Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
- H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
- H04B7/0636—Feedback format
- H04B7/0645—Variable feedback
- H04B7/065—Variable contents, e.g. long-term or short-short
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0058—Allocation criteria
- H04L5/006—Quality of the received signal, e.g. BER, SNR, water filling
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W24/00—Supervisory, monitoring or testing arrangements
- H04W24/10—Scheduling measurement reports ; Arrangements for measurement reports
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/50—Allocation or scheduling criteria for wireless resources
- H04W72/56—Allocation or scheduling criteria for wireless resources based on priority criteria
- H04W72/563—Allocation or scheduling criteria for wireless resources based on priority criteria of the wireless resources
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
- H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
- H04B7/0621—Feedback content
- H04B7/063—Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
- H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
- H04B7/0636—Feedback format
- H04B7/0639—Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
- H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
- H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
- H04B7/0658—Feedback reduction
- H04B7/066—Combined feedback for a number of channels, e.g. over several subcarriers like in orthogonal frequency division multiplexing [OFDM]
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0053—Allocation of signaling, i.e. of overhead other than pilot signals
Definitions
- the technology disclosed in the present specification relates to a wireless communication apparatus and a wireless communication method that transmit and receive data simultaneously to a terminal in cooperation with another base station, and a wireless communication system, in particular, from a terminal that has received a reference signal.
- the present invention relates to a wireless communication apparatus, a wireless communication method, and a wireless communication system that determine a combination of base stations with respect to a terminal based on feedback of the communication.
- LTE Long Term Evolution
- 4G 4th generation
- 4G 4th generation
- FDD Frequency Division Duplex
- TDD Time Division Duplex
- an uplink-dedicated band and a downlink-dedicated band are used.
- the uplink and downlink use a radio frame format composed of 10 consecutive subframes.
- the uplink here refers to communication from a terminal station (UE terminal: User Equipment) to an LTE base station (eNodeB: evolved Node B), and the downlink refers to communication from the eNodeB to the UE terminal. That is.
- eNodeB evolved Node B
- a radio frame format composed of 10 consecutive subframes is used.
- TDD communication is performed using the same band in the uplink and downlink.
- Each subframe configuring the radio frame includes a control signal PDCCH (Phy Downlink Control Channel) from the eNodeB and a PDSCH (Phy Downlink Shared Channel) used as user data.
- PDCCH Physical Downlink Control Channel
- PDSCH Physical Downlink Shared Channel
- CoMP Coordinated Multi Point Transmission / Reception
- CoMP is a technique for increasing desired signal power and reducing interference from other cells by simultaneously transmitting and receiving data to and from one UE terminal by a plurality of eNodeBs.
- precoding, reference signals, measurement and feedback methods should be considered.
- LTE in Release 8, a method of hierarchizing cells of various sizes such as Macro / Micro / Pico / Femto called HetNet is considered, but CoMP includes communication to such a femto cell.
- UpLink CoMP and DownLink CoMP exist in CoMP, and UpLink CoMP is an important technology as well as DownLink CoMP, but below, it will be described as DownLink CoMP unless otherwise noted.
- a cell method for realizing CoMP there are a method in which a plurality of eNodeBs each perform autonomous distributed control, and a method in which one Macro eNodeB centrally controls a plurality of Pico eNodeBs.
- a plurality of base stations such as RRH (Remote Radio Head) are arranged for countermeasures against insensitiveness at the cell edge and the like, and an optical fiber is used between Macro eNodeBs that centrally control these base stations. Connected by a baseband signal (described later). Then, the Macro eNodeB performs baseband signal processing and control of each RRH, and collectively performs radio resource control between cells.
- RRH Remote Radio Head
- CoMP is performed on a certain UE terminal, that is, a combination of eNodeBs constituting a cooperative group is hereinafter referred to as Set of CoMP transmission point, or CoMP set for short.
- CoMP set determination it is necessary to determine which eNodeB is effective for the UE terminal. This will be referred to as CoMP set determination or point selection.
- a UE terminal receives a reference signal from each base station, measures RSRP (Reference Signal Received Power) for each base station, and selects an eNodeB located above it as a CoMP set The method of doing is mentioned.
- RSRP Reference Signal Received Power
- the base station transmits the cooperative group setting signaling with the Cell ID of the cell in the cooperative group selected for the user terminal to the user terminal, and the user terminal is attached to the cooperative group setting signaling.
- the base station allocates a part of the entire frequency band to bands used for single base station transmission (first transmission scheme) and multiple base station transmission (second transmission scheme), and receives one of them.
- Decide which transmission method to use based on the feedback information indicating the received quality that is, limit the feedback information to information indicating the received quality of a part of the entire frequency band to reduce the amount of feedback information
- Proposals have been made regarding wireless communication methods (see, for example, Patent Document 2).
- each base station apparatus receives quality information indicating communication quality between the base station apparatus capable of communicating with the target terminal apparatus from the target terminal apparatus and also exists in a cell of another base station apparatus.
- Proposal has been made for a wireless communication system that acquires schedule information indicating a communication schedule to and selects several base station apparatuses that function as base stations for the target terminal apparatus based on quality information and schedule information (for example, , See Patent Document 3).
- the point selection required for the frequency of point selection needs to be performed at certain intervals (that is, the CoMP set needs to be updated at certain intervals). That is, there is a problem whether the CoMP set of the UE terminal is updated to quasi-static (Semi-Static) or dynamically (Dynamic). Considering the movement of UE terminals, dynamic point selection that dynamically updates the CoMP set is desirable.
- An object of the technology disclosed in the present specification is to provide an excellent radio communication apparatus and radio that can suitably perform dynamic point selection based on feedback from a UE terminal that has received a reference signal by applying CoMP technology.
- a communication method and a wireless communication system are provided.
- a further object of the technology disclosed in the present specification is to provide an excellent radio communication device and radio communication method, and a radio that can improve the update frequency of point selection while suppressing overhead associated with feedback from a UE terminal. It is to provide a communication system.
- the present application has been made in consideration of the above problems, and the technology according to claim 1
- the reference signal transmitted from each base station is measured in the wideband and each subband.
- a reference signal measurement unit Among the measurement results obtained in the wideband and each subband by the reference signal measurement unit, measurement to select what is fed back to determine a cooperative group of base stations that perform multipoint coordinated transmission / reception with respect to the own device
- a result selector Among the measurement results obtained in the wideband and each subband by the reference signal measurement unit, measurement to select what is fed back to determine a cooperative group of base stations that perform multipoint coordinated transmission / reception with respect to the own device
- a result selector A feedback unit that feeds back a measurement result selected by the measurement result selection unit to a base station; Is a wireless communication device.
- the wireless communication device is in use as a transmission point of the cooperative group or becomes a transmission point candidate for each wideband and subband.
- the apparatus further includes a measurement target determining unit that selects a base station as a measurement target.
- the reference signal measurement unit is configured to measure the reference signal from the base station selected by the measurement target determination unit in the wideband and each subband.
- the measurement result selection unit of the wireless communication device uses a set of measurement results of base stations in a wideband as a population, and in each subband.
- the measurement results to be fed back to determine the cooperative group are selected so that the set of measurement results is a subset of the population.
- the measurement result selection unit of the wireless communication apparatus adds to the set of measurement results of the base station in the wideband, and the subband includes the measurement result selection unit.
- the measurement results to be fed back to determine the cooperative group are selected.
- the measurement result selection unit of the wireless communication device according to claim 1 is added to the set of measurement results of the base station in the wideband, and the subband includes the measurement result selection unit.
- the measurement result to be fed back to determine the cooperative group is selected so as to include the measurement result of the base station added to the combination of base stations in the measurement result set.
- the measurement result selection unit of the wireless communication apparatus gives priority to the measurement result of the subband that is highly likely to be updated in the cooperation group when fed back. And is configured to select.
- the measurement result selection unit of the wireless communication apparatus measures a subband that is highly likely to add a new base station to the cooperative group when fed back. It is configured to prioritize the results.
- the measurement result selection unit of the wireless communication apparatus described in claim 1 is a subband in which an unnecessary base station is highly likely to be deleted from the cooperative group when fed back. The measurement result is selected with priority.
- the wireless communication device further includes a measurement result evaluation unit that evaluates the measurement result of each subband by the reference signal measurement unit.
- the said measurement result selection part is comprised so that the measurement result of the subband fed back in order to determine the said cooperation group may be selected based on the evaluation result of each subband by the said measurement result evaluation part.
- the measurement result evaluation unit of the wireless communication device evaluates the quality of each subband, and the measurement result selection unit determines that the quality is not good.
- the measurement results of the predetermined number of subbands to be fed back are selected so as to include the measurement results of the predetermined number of subbands.
- the measurement result evaluation unit of the wireless communication device is configured such that when the measurement result is fed back for each subband, the cooperation group is updated.
- the expected value of quality improvement is predicted, and the measurement result selection unit is configured to select the measurement results of a predetermined number of subbands to be fed back based on the predicted expected value.
- the radio communication device of claim 11 predicts how the cooperative group is determined by feeding back a measurement result for each subband. And a measurement target determining unit that selects a base station to be measured by the reference signal measurement unit based on the predicted result. And the said measurement result evaluation part is comprised so that the expected value of the improvement of the quality by the predicted said cooperation group may be estimated.
- the measurement result evaluation unit of the wireless communication apparatus may be configured such that when the measurement result is fed back for each subband, a wasteful base station from the cooperative group is returned.
- the measurement result selection unit is configured to select the measurement results of a predetermined number of subbands to be fed back based on the possibility that a useless base station is removed.
- the radio communication device of claim 13 predicts how the cooperative group is determined by feeding back a measurement result for each subband. And a measurement target determining unit that selects a base station to be measured by the reference signal measurement unit based on the predicted result.
- the measurement result evaluation unit is configured to evaluate how many useless base stations are removed by the predicted cooperative group.
- the measurement result selection unit of the wireless communication apparatus is configured such that the combination of base stations that are continuous in the frequency direction and that constitute the cooperative group is the same.
- a group of bands is grouped into subband groups, and the measurement results are selected so as to be fed back in units of subband groups.
- the technique described in claim 16 of the present application is: In order to determine the range for measuring and feeding back the reference signal transmitted from each base station in a communication environment that uses the entire system band as a wideband and divides the system band into multiple subbands.
- a notification unit for notifying the terminal station of information Based on information fed back from the terminal station, a cooperative group determining unit that determines a cooperative group of base stations that perform multipoint coordinated transmission and reception for the terminal station in the wideband and each subband; Is a wireless communication device.
- the notification unit of the wireless communication device is configured to notify the terminal station of information regarding the cooperation group determined for each subband by the cooperation group determination unit. It is configured.
- the notification unit of the wireless communication apparatus is the most frequently used information indicating a range in which the information notified to the terminal station may be measured. It is configured to be divided into three types, that is, information indicating a range of information and information indicating the range of a base station that is additionally used for each subband, and notification is performed at different update frequencies for each information.
- the technology described in claim 19 of the present application is: In the communication environment where the entire system band is used as a wideband and the system band is divided into a plurality of subbands, the reference signal transmitted from each base station is measured in the wideband and each subband.
- a reference signal measurement step Among the measurement results obtained in the wideband and each subband by the reference signal measurement step, measurement to select what is fed back in order to determine a cooperative group of base stations that perform multipoint coordinated transmission / reception with respect to the own device
- a result selection step A feedback step of feeding back the measurement result selected in the measurement result selection step to the base station;
- a wireless communication method is: In the communication environment where the entire system band is used as a wideband and the system band is divided into a plurality of subbands, the reference signal transmitted from each base station is measured in the wideband and each subband.
- a reference signal measurement step Among the measurement results obtained in the wideband and each subband by the reference signal measurement step, measurement to select what is fed back in order to determine a cooperative group of
- the technique described in claim 20 of the present application is: In order to determine the range for measuring and feeding back the reference signal transmitted from each base station in a communication environment that uses the entire system band as a wideband and divides the system band into multiple subbands. A notification step of notifying the terminal station of the information; Based on information fed back from the terminal station, a cooperative group determination step of determining a cooperative group of base stations that perform multipoint coordinated transmission / reception for the terminal station in the wideband and each subband; A wireless communication method.
- the technology described in claim 21 of the present application is: A plurality of base stations transmitting reference signals; A terminal station that receives a reference signal from the base station and performs measurement for determining a cooperative group that performs multipoint cooperative transmission and reception for the local station; Comprising The terminal station uses the entire system band as a wideband, and a reference transmitted from each base station in the wideband and each subband in a communication environment in which the system band is divided into a plurality of subbands. Measure the signal, select and feed back the measurement results necessary to determine the cooperative group of base stations that perform multipoint coordinated transmission / reception for the device itself, A wireless communication system.
- system here refers to a logical collection of a plurality of devices (or functional modules that realize specific functions), and each device or functional module is in a single housing. It does not matter whether or not (hereinafter the same).
- the technology described in claim 22 of the present application is: A plurality of base stations transmitting reference signals; A terminal station that receives a reference signal from a base station and performs measurement and feedback for determining a cooperation group of base stations that perform multipoint coordinated transmission and reception for the own station; and Comprising At least one base station uses the entire system band as a wideband and measures and feeds back a reference signal transmitted from each base station in a communication environment in which the system band is divided into a plurality of subbands. Inform the terminal station of information for determining the range to be performed; A wireless communication system.
- information for determining an effective combination by CoMP can be transmitted from the UE terminal to the eNodeB without an increase in overhead, thereby suppressing uplink overhead for point selection.
- the update frequency of the point selection can be improved and the throughput can be increased.
- FIG. 1 is a diagram schematically showing a form in which a Macro eNodeB and a plurality of RRHs subordinate thereto are connected.
- FIG. 2 is a diagram illustrating subbands.
- FIG. 3 is a diagram for explaining the UE Selected mode.
- FIG. 4 is a diagram illustrating an example in which only a subset is fed back in the subband independently of the wideband measurement result (when the wideband is used as a population).
- FIG. 5 is a diagram illustrating an example of performing feedback not included in the wideband in the subband.
- FIG. 6 is a diagram illustrating another example in which feedback that is not included in the wideband is performed in the subband.
- FIG. 1 is a diagram schematically showing a form in which a Macro eNodeB and a plurality of RRHs subordinate thereto are connected.
- FIG. 2 is a diagram illustrating subbands.
- FIG. 3 is a diagram for explaining the UE Selected mode.
- FIG. 7 is a flowchart showing a processing procedure for performing dynamic point selection based on feedback of a predetermined number of subbands.
- FIG. 8 is a flowchart showing a processing procedure for performing feedback on a predetermined number of subbands selected by increasing the priority of subbands whose degree of quality improvement by feedback is high.
- FIG. 9 is a flowchart showing a processing procedure for performing feedback for a predetermined number of subbands selected by increasing the priority of subbands where unnecessary eNodeBs may be removed from CoMP by feedback.
- FIG. 10 is a diagram illustrating a state in which identical CoMP sets are continuous in subbands that are continuous in the frequency direction, or CoMP sets are continuous.
- FIG. 11 is a flowchart showing a processing procedure for a UE terminal to group a group of subbands continuous in the frequency direction and perform measurement and feedback for point selection in units of subbands.
- FIG. 12 is a diagram illustrating a state in which the information that the Serving eNodeB notifies the UE terminal is divided.
- FIG. 13 is a diagram schematically illustrating a configuration example of a wireless communication apparatus 1300 that operates as a Serving eNodeB.
- FIG. 14 is a diagram schematically illustrating a configuration example of a wireless communication device 1400 that operates as a UE terminal.
- FIG. 15 is a diagram illustrating an LTE downlink radio frame configuration.
- FIG. 16 is a diagram illustrating a state in which CRS is inserted in a subframe.
- LTE is a communication system based on the OFDM modulation system, and OFDMA is adopted as a downlink radio access system.
- FIG. 15 illustrates an LTE downlink radio frame configuration. As shown in the figure, the radio frame is hierarchized into three layers of a time slot (Slot), a subframe (Subframe), and a radio frame (Radio Frame) in ascending order of time units.
- Slot time slot
- Subframe subframe
- Radio Frame radio frame
- a time slot of 0.5 millisecond length is composed of 7 OFDM symbols (in the case of normal unicast transmission), and is a unit of demodulation processing when receiving on the user (UE terminal) side.
- a subframe having a length of 1 millisecond is composed of two consecutive time slots (14 OFDM symbols), and is a transmission time unit of one data packet subjected to correction coding.
- a radio frame having a length of 10 milliseconds is composed of 10 consecutive subframes (that is, 20 time slots) and is a basic unit for multiplexing all physical channels.
- the subframe is divided into a control area PDCCH used as a control signal from the eNodeB and a data area PDSCH used as user data.
- Each user can communicate without interfering with each other by using different subcarriers or different time slots.
- resource block RB
- the scheduler installed in the base station eNodeB
- the scheduler installed in the base station allocates radio resources to each user in resource block units.
- a maximum of 3 OFDM symbols from the top of the subframe are used for the control channel, that is, PDCCH.
- the scheduler of the base station can perform resource block allocation every subframe, that is, at an interval of 1 millisecond.
- Resource block location information is called scheduling. Both uplink scheduling information and downlink scheduling information are described in the downlink control channel. Each user can see the control channel and see the resource blocks assigned to him.
- a 0.5 mm long time slot is the smallest unit of allocation that can be used by each user.
- the scheduler installed in the base station (eNodeB) allocates time slots that may be used in units of time slots for each user.
- eNodeB In LTE, two communication methods, FDD and TDD, can be selected. In the case of TDD, it is possible to select whether to use for uplink or downlink for each subframe.
- the reference signal transmitted from the eNodeB includes CRS, CSI-RS, SRS, and the like. These reference signal measurements can generally be used for a variety of purposes.
- the first purpose is that the UE terminal searches for a handover destination eNodeB. When the quality of the Serving eNodeB deteriorates, the UE terminal performs measurement on the eNodeB of the neighboring cell in order to search for the next handover destination eNodeB.
- the second purpose is to acquire the quality of the channel. This is because the eNodeB side determines the precoding value (antenna weighting factor for beamforming) used in downlink transmission, and the eNodeB scheduler allocates radio resources to each UE terminal. A signal measurement is performed. Then, obtaining information necessary for point selection is added as a new purpose of measuring the reference signal. In addition to the feedback information of the reference signal, the UE terminal may feed back a measurement result that can be a material for determining the CoMP set.
- CRS Cell-specific Reference Signal
- FIG. 16 shows a state where CRS is inserted in the subframe.
- the third OFDM symbol from the beginning is PDCCH
- the fourth and subsequent OFDM symbols are PDSCH.
- the resource element portion filled in black corresponds to the CRS signal, but the CRS is inserted in both the PDCCH and PDSCH areas.
- the CRS is transmitted from the eNodeB even when it is not transmitted from the PDSCH user data or the eNodeB. This is because it is assumed that the UE terminal always uses CRS for acquisition of synchronization with eNodeB, channel estimation, eNodeB quality measurement, and the like.
- the CRS uses the same location (that is, the same resource element in the frequency and time directions) in each eNodeB (in FIG. 16, the resource element filled in black is used as the CRS insertion location in common with each eNodeB). Used). For this reason, it is necessary to ensure orthogonality between eNodeBs, and signals having different sequences for each eNodeB are used for CRS. There are 504 sequences in total. If the cell ID of the eNodeB is different, the CRS series is also different. In the sense that it is unique to each cell, it is called the Cell Specific Reference Signal Cell-specific Reference Signal.
- CSI-RS Channel State Information Reference Signal
- RRC Radio Resource Control: Radio Link Control Connection
- CSI-RS is a reference signal newly introduced in Release 3 of 3GPP.
- CSI-RS is also a signal specific to each cell, and can be called Cell-specific.
- the position of the resource element inserted by the CSI-RS in the subframe can also be changed by setting.
- a sequence for improving orthogonality between eNodeBs is also prepared for a signal to be inserted.
- CSI-RS is used as a reference signal for point selection. Since the transmission cycle can be set between 5 milliseconds and 80 milliseconds as described above, the CRS-RS has a great merit that the overhead occupied by the reference signal can be reduced. Also, even eNodeBs having the same Cell ID can assign CSI-RSs to different locations. Even when the same Cell ID is assigned to a plurality of Pico eNodeBs such as RRH as in the case of realizing CoMP by the centralized control method, if the CSI-RS is set separately, the UE terminal It is possible to perform measurement while distinguishing between the two. Therefore, the present inventors consider that CSI-RS is promising as a reference signal for point selection.
- SRS Soliding Reference Signal
- SRS is a reference signal included in the uplink subframe, and exists from Release 8 of 3GPP.
- the SRS is inserted over the entire frequency domain of the last OFDM symbol of the 14 OFDM symbols in the corresponding subframe.
- the insertion period of SRS can be changed from 2 milliseconds to 160 milliseconds.
- the eNodeB acquires the state of the uplink channel based on the SRS and uses it as information for scheduling.
- the uplink channel status can be acquired with little overhead. Since the reversibility of the channel is ensured in the case of TDD, in the case of TDD, it is possible for the eNodeB to use the SRS in order to acquire the status of the downlink channel.
- Scenario 1 is a scenario in which cells are divided into sectors and CoMP is performed between sectors.
- Scenarios 2 to 4 are scenarios in which RMP is used for CoMP.
- RRH transmits with high power equivalent to Macro eNodeB, whereas in scenarios 3 to 4, RRH transmission power is low.
- a unique Cell ID is assigned to each RRH, whereas in Scenario 4, the same Cell ID as that of Macro eNodeB is assigned to each RRH.
- FIG. 1 schematically shows a mode in which Macro eNodeB and a plurality of RRHs subordinate thereto are connected corresponding to scenario 3 and scenario 4.
- the RHH is arranged at a cell edge or the like as a countermeasure against undetection.
- the Macro eNodeB and each RHH (or Pico eNodeB) are connected by a baseband signal using an X2 interface constituted by an optical fiber or the like. Then, the Macro eNodeB performs baseband signal processing and control of each RRH, and collectively performs radio resource control between cells.
- Macro eNodeB and RRH perform CoMP by simultaneously transmitting and receiving data to and from the UE terminal.
- Macro eNodeB mainly operates as Serving eNodeB.
- each RRH has its own Cell ID, and the CRS series is also different. Therefore, even if this reference signal is transmitted from each RRH at the same time, the UE terminal can individually acquire the quality for each RRH. That is, in scenario 3, CRS can be used as a reference signal for point selection.
- scenario 4 the same Cell ID as Macro eNodeB is assigned to each RRH, and the CRS sequence is also the same. For this reason, the UE terminal cannot individually acquire the quality for each RRH from the CRS transmitted simultaneously from each RRH. That is, in scenario 4, it is difficult to use CRS as a reference signal for point selection. For this reason, in scenario 4, CSI-RS is considered promising as a reference signal for point selection. In that case, it is necessary to allocate CSI-RS to different locations for each RRH so that the UE terminal side can individually acquire channel information for each RRH (as described above, eNodeB having the same Cell ID) Even so, it is possible to assign CSI-RS to different locations).
- Implicit Feedback is also used in Release 10.
- Implicit Feedback is also used for Release 11 CoMP and CoMP MIMO communication.
- the procedure of the Implicit Feedback method will be described.
- 16 kinds of transmission weights (pre coding), for example, V (1),..., V (16) are prepared in a pre-designed codebook (codebook) (however, V (i) The number i in parentheses is an index number PMI (Predetermined Matrix Index).
- codebook codebook
- PMI Predetermined Matrix Index
- the mobile station receives the reference signal precoded with the transmission weight V (i) from the base station, the mobile station acquires channel information H between the base station and the mobile station.
- the mobile station tentatively determines which received power HV (1),..., HV (16) is the largest among the 16 types of transmission weight vectors V (1),.
- An index number indicating the provisionally determined transmission weight vector V is fed back to the base station. Thereafter, the base station transmits data using the transmission weight V corresponding to the fed back index number.
- CQI Channel Quality Index
- PMI Predetermined Matrix Index
- RI Rank Indicator
- CQI notifies the combination of modulation scheme and coding rate, and there are 16 types. There are three types of modulation, QPSK (Quadrature Phase Shift keying), 16QAM (Quadrature Amplitude Modulation), and 64QAM.
- PMI is an index number indicating the desirable transmission weight vector V described above.
- RI is an index indicating the rank of a channel, that is, approximately how many channels are spatially independent.
- the eNodeB refers to these three pieces of information CQI, PMI, and RI sent from the UE terminal, and determines the precoding, modulation scheme, and coding rate for transmission.
- Implicit Feedback will be described in more detail. Although there are a plurality of modes for feedback, the Release8 feedback mode will be described below.
- CQI feedback can be divided into wideband and subband (UE Selected).
- the wideband mode is a mode in which feedback information corresponding to 20 MHz is fed back as one piece of information when operating with a bandwidth of 20 MHz, for example.
- the subband is used by bundling a plurality of resource blocks, for example, by bundling a plurality of 12 subcarriers into a subband (see FIG. 2). For example, usage is such that 120 subcarriers are set to one band in the frequency direction.
- the UE Selected mode is a mode in which feedback for subbands is individually returned. Provide feedback for the M best subbands. In addition, the value of the wide band is also reported (see FIG. 3).
- ⁇ PMI feedback may or may not have feedback.
- Release 8 there is a feedback mode as shown in the following table by combining the feedback modes of PMI and CQI.
- the subband described above has nothing to do with CoMP or point selection, and is a feedback story in an environment where CoMP is not performed.
- a set of measurement results of base stations in a wide band is a population, and a set of measurement results in each subband is a subset of the population. For example, the measurement result to be fed back from the UE terminal to determine the CoMP set is selected.
- a certain UE terminal feeds back the measurement results of the reference signals from the four base stations eNodeB 1, 2, 3, and 4 as the measurement results for determining the CoMP set in the wide band.
- a set of measurement results for eNodeBs 1, 2, 3, and 4 is a population.
- subband 1 not the measurement results for all the populations, but only the measurement results for eNodeBs 1 and 2 that are subsets thereof are selected, and feedback for determining the CoMP set is performed.
- subband 2 only the measurement results for eNodeB3, which is a subset of the population, are selected and fed back, and in subband 3, only the measurement results for eNodeB4, which is a subset of the population, are selected and fed back. (See FIG. 4).
- the wideband is the population, and only the subset is fed back in the subband independently of the wideband measurement result. This makes it possible to reduce the amount of feedback from the UE terminal.
- the wideband and subband in this case include both measurement for an eNodeB in use as a CoMP transmission point and measurement of an eNodeB that is a transmission point candidate.
- the UE terminal returns a general trend on the eNodeB side that has received the feedback by returning information that determines what is the desired eNodeB for all frequencies of the UE terminal in wideband feedback. There is a merit that it becomes possible to grasp.
- the rough tendency is information on which eNodeB should be added to the CoMP set for this UE terminal.
- the UE terminal may select and feed back only information more important for each subband. For example, measurement results of a base station that is currently participating in a CoMP set in a subband, a base station that is under consideration whether it should be removed from the CoMP set due to quality degradation, a base station that is under consideration whether it should be newly added to the CoMP set, etc. Becomes more important feedback information for the subband.
- the wideband feedback from the UE terminal has a relatively long cycle and the subband feedback cycle is shortened.
- each subband includes the measurement result of the base station other than the measurement result set. And selecting a measurement result to be fed back for determining the CoMP set from the UE terminal.
- a certain UE terminal feeds back the wideband measurement results for the four base stations eNodeB 1, 2, 3, and 4 as the measurement results for determining the CoMP set in the wideband.
- the measurement results are fed back so as to include eNodeBs 5 and 6 other than eNodeBs 1, 2, 3, and 4.
- the measurement result is fed back so that eNodeB8 other than eNodeB1, 2, 3, 4 is included
- subband 3 the measurement result is included so that eNodeB7 other than eNodeB1, 2, 3, 4 is included. Feedback is performed (see FIG. 5).
- the measurement result for the eNodeB not included in the wideband is fed back.
- the UE terminal can reduce the amount of feedback by performing measurement of an additional eNodeB by measurement of a part of the band for the measurement considering all bands.
- the measurement result of the base station in addition to the measurement result set of the base station in the wideband, in each subband, the measurement result of the base station added to the combination of the base stations in the measurement result set
- the measurement result to be fed back for determining the CoMP set from the UE terminal may be selected so as to include.
- a certain UE terminal feeds back the wideband measurement results for the four base stations eNodeB 1, 2, 3, and 4 as the measurement results for determining the CoMP set in the wideband.
- eNodeBs 5 and 6 are added to eNodeBs 1, 2, 3, and 4, and the measurement results are fed back.
- eNodeB 8 is added to eNodeBs 1, 2, 3, and 4 to feed back measurement results
- eNodeB 7 is added to feed back measurement results (see FIG. 6).
- an eNodeB not included in the wideband is added and the measurement result is fed back.
- the derivative type of means 1-2 is suitable for the case where it is desired to measure the information of each subband in more detail because the subband measures more eNodeBs than the wideband.
- the priority of the subband to be fed back is determined by the UE terminal. Or, in some cases, determined by the base station. When determined by the base station, information on the determined priority is notified from the base station to the UE terminal.
- the selection of the base station here refers to both addition and deletion of base stations included in the CoMP set.
- the reception quality of the UE terminal can be expected to improve in that subband.
- it is decided to delete a certain base station from the CoMP set by feeding back the measurement result of a certain subband it is possible to improve throughput by suppressing unnecessary radiation from unnecessary base stations. .
- the measurement results of subbands that are likely to delete unnecessary base stations from the cooperation group are selected with priority.
- means 2 for solving the second problem it is possible to give priority to feedback of subband information that is highly likely to be determined on the network side as to whether a base station is to be added or deleted.
- a new base station is added to CoMP when feedback is performed, and a subband measurement result that is highly likely to improve reception quality is selected with priority, and unnecessary base stations are deleted from the CoMP set when feedback is performed.
- Priority is given to the measurement results of subbands that have a high possibility.
- the UE terminal When feeding back information on the M subbands selected on the UE terminal side, in Release 8, the UE terminal selects M subbands because of higher quality.
- the advantage of feeding back the measurement result cannot be derived. That is, the measurement result of a subband with good quality does not significantly affect the selection of a base station that performs CoMP transmission, and the second problem cannot be solved.
- it is necessary to update the point selection that is, to replace the base station that becomes the CoMP set).
- the CoMP set will not be improved, and the subband will be of quality It will be left behind without being good.
- FIG. 7 shows a processing procedure in the form of a flowchart in which the UE terminal feeds back a set of measurement results in a predetermined number of subbands and performs dynamic point selection based on the set of measurement results.
- N the number of subbands that can be used in the UE terminal
- M the number of subbands that feed back measurement results
- the UE terminal selects M subbands with poor quality from the N subbands (step S701).
- the UE terminal performs measurement for point selection using the CSI-RS transmitted from each base station in the selected M subbands (step S702).
- the UE terminal selects information to be fed back, that is, which base station measurement result is fed back, in each of the selected M subbands (step S703). For example, a measurement result of an eNodeB being used as a transmission point in the current CoMP set or an eNodeB that is a transmission point candidate is selected.
- the UE terminal feeds back the measurement result selected in step S703 to the Serving eNodeB in each of the M subbands selected in step S701 (step S704).
- the Serving eNodeB side When receiving the feedback from the UE terminal, the Serving eNodeB side performs point selection for the M subbands (step S705).
- the UE terminal increases M subbands to be fed back by increasing the priority of subbands whose quality is improved by feedback. Is selected. That is, regardless of whether the quality of the subband is superior or inferior, the measurement result of the new eNodeB is fed back in a specific subband, and the new eNodeB is used for downlink in the subband (that is, in the CoMP set). When the expected value of quality improvement by adding a new base station is large, this subband is preferentially included in M.
- FIG. 8 is a flowchart showing a processing procedure for performing dynamic point selection by performing feedback on a predetermined number of subbands selected by increasing the priority of subbands whose degree of quality improvement is high by feedback. Is shown.
- the UE terminal selects one subband from the N subbands (step S801).
- the UE terminal performs measurement for point selection using the CSI-RS transmitted from each base station in the selected subband (step S802).
- the UE terminal selects information to be fed back in the selected subband, that is, which base station measurement result is fed back (step S803).
- the UE terminal when feeding back the measurement result of the base station selected in step S803, the UE terminal predicts what point selection is performed for this subband on the Serving eNodeB side (step S804). Then, the subband is evaluated by predicting the SINR of reception by the predicted point selection (step S805).
- the UE terminal When the UE terminal completes the above evaluation for all N subbands (step S806), the UE terminal selects M subbands from the one with the greatest improvement in SINR (step S807).
- the UE terminal feeds back the measurement result measured in step S802 to the Serving eNodeB in each of the selected M subbands (step S808).
- the Serving eNodeB side When receiving the feedback from the UE terminal, the Serving eNodeB side performs point selection for the M subbands (step S809).
- the UE terminal performs feedback by increasing the priority of subbands that are likely to remove useless eNodeB from the CoMP set by feedback. For example, selecting M subbands.
- the measurement result of the eNodeB being used as a CoMP set is fed back in a specific high-quality subband, the eNodeB that hardly contributes to the quality improvement is likely to be removed from the CoMP set in this subband. Therefore, a measurement result in a subband that can be fed back a measurement result that is expected to be excluded from the CoMP set should be fed back.
- FIG. 9 shows a process for performing dynamic point selection by performing feedback on a predetermined number of subbands selected by increasing the priority of subbands where unnecessary eNodeB may be removed from CoMP by feedback.
- the procedure is shown in the form of a flowchart.
- the UE terminal selects one subband from the N subbands (step S901).
- the UE terminal performs measurement for point selection using the CSI-RS transmitted from each base station in the selected subband (step S902).
- the UE terminal selects information to be fed back in the selected subband, that is, which base station measurement result is fed back (step S903).
- the UE terminal predicts what kind of point selection is performed for this subband on the Serving eNodeB side (step S904). Then, this subband is evaluated by evaluating how many useless eNodeBs are removed from the CoMP set by the predicted point selection (step S905).
- step S906 When the UE terminal completes the above evaluation for all N subbands (step S906), it is more likely that a useless eNodeB is removed from the CoMP set (for example, as a result of the evaluation in step S905, it is removed from the CoMP set). M subbands are selected from those having a larger number of eNodeBs (step S907).
- the UE terminal feeds back the measurement result measured in step S9802 to the Serving eNodeB in each of the selected M subbands (step S908).
- the Serving eNodeB side When receiving the feedback from the UE terminal, the Serving eNodeB side performs point selection for the M subbands (step S909).
- a group of subbands that can be handled in a group is grouped as a subband group (Group of Subband), and measurement for point selection is performed on the subband. -Implementing in group units and feeding back measurement results in subband groups.
- FIG. 10 shows a state in which the same CoMP set is continuous in the subbands continuous in the frequency direction, or the CoMP set is continuous.
- the CoMP set is formed by the three eNodeBs 1, 3, and 5, so that they can be grouped as the subband group 1.
- the CoMP set is formed by the three eNodeBs 1, 3, and 6 in the subbands 6 to 8, they can be grouped as the subband group 2, and in the subbands 9 to 12, all Since the CoMP set is formed by the three eNodeBs 1, 4, and 6, they can be grouped as subband group 3. Further, the CoMP set continuously changes between subband group 1 and subband group 2 and between subband group 2 and subband group 3.
- the UE terminal can reduce the amount of processing required for the measurement and the amount of information to be fed back by performing the measurement for point selection and the feedback for each subband group.
- FIG. 11 shows, in the form of a flowchart, a processing procedure for the UE terminal to group a group of subbands continuous in the frequency direction and perform measurement and feedback for point selection in units of subbands.
- the Serving eNodeB notifies the UE terminal of the CoMP set for each subband (step S1101).
- the UE terminal Upon receiving the notification of the CoMP set for each subband, the UE terminal groups a group of subbands having the same CoMP set from all N subbands into a subband group (step S1102).
- the UE terminal performs point selection measurement for each subband group (step S1103), and performs feedback of the measurement result for each subband group (step S1104).
- the Serving eNodeB side When receiving the feedback from the UE terminal, the Serving eNodeB side performs point selection for M subbands (step S1105) (where N ⁇ M).
- the Serving eNodeB provides support for selecting an effective measurement target for each subband on the UE terminal side. Specifically, the Serving eNodeB notifies the UE terminal of information for determining a range in which measurement for point selection is performed in each subband, such as CoMP set information for each subband. Based on the received information, the UE terminal can suppress the amount of processing for point selection measurement and the amount of information to be fed back in each subband, while suppressing the uplink overhead for point selection, It is possible to improve the update frequency of point selection and increase the throughput.
- the Serving eNodeB provides support for the UE terminal to select an effective measurement target for each subband by notifying the UE terminal of information related to the CoMP set for each subband.
- the information notified to the UE terminal by the Serving eNodeB as shown in FIG. 12, information indicating the range that may be measured, the most frequently used range
- the control signal can be reduced by dividing the notification into three types of information, ie, information indicating the range of eNodeB additionally used for each subband.
- the range that can be measured has a low update frequency, the update frequency of the most frequently used range is moderate, and the update frequency of the eNodeB range additionally used for each subband is increased.
- a method of using the means 3-2 is assumed.
- the means 3-2 it is possible to suppress an increase in overhead that keeps updating the set of eNodeBs currently used for each subband (that is, the CoMP set).
- the Serving eNodeB uses the means 3-1, 3-2 to the UE terminal that implements the means 2-1, 2-1-1, 2-1-2 and uses the CoMP for each subband. Information about the set may be notified.
- FIG. 13 schematically shows a configuration example of a radio communication device 1300 that operates as a Serving eNodeB (Macro eNodeB) in the radio communication system (FIG. 1) according to the present embodiment.
- a Serving eNodeB Macro eNodeB
- FIG. 1 schematically shows a configuration example of a radio communication device 1300 that operates as a Serving eNodeB (Macro eNodeB) in the radio communication system (FIG. 1) according to the present embodiment.
- functional modules that perform basic operations as the Macro eNodeB such as radio resource management in the Macro Cell and transmission of various reference signals are omitted as appropriate.
- the wireless communication apparatus 1300 includes an RF communication processing unit 1301 that performs analog processing of a radio signal transmitted and received by an antenna, and a digital communication processing unit 1302 that performs modulation of a digital transmission signal and demodulation processing of a digital reception signal.
- the digital communication processing unit 1302 exchanges transmission / reception data with the upper layer protocol of the communication layer of the own device 1300.
- the digital communication processing unit 1302 communicates with other eNodeBs via an X2 interface, S-GW (Serving Gateway), and MME (Mobility Management Entity).
- the digital communication processing unit 1302 performs baseband signal processing and control of each RRH subordinate to the own device 1300 via the X2 interface.
- the measurement result holding unit 1303 holds the measurement results for each wideband and subband fed back from each UE terminal existing in the own cell via the uplink.
- the CoMP set determination unit 1304 determines a CoMP set for each wideband and subband for each UE terminal based on the measurement result of each UE terminal held in the measurement result holding unit 1303.
- the notification unit 1305 notifies the UE terminal of information related to the CoMP set for each subband to each UE terminal existing in the own cell so that the UE terminal selects an effective measurement target for each subband.
- the notification unit 1305 realizes the above means 3-1 by notifying information for determining a range for performing measurement for point selection in each subband, such as information on a CoMP set for each subband.
- the notification unit 1305 includes information indicating a range that may be measured, information indicating a range that is most frequently used, and a base station that is additionally used for each subband.
- the above-described means 3-2 is realized by dividing the information into three types of information indicating the range of information and notifying the information at different update frequencies.
- FIG. 14 schematically shows a configuration example of a radio communication apparatus 1400 that operates as a UE terminal in the radio communication system (FIG. 1) according to the present embodiment.
- functional modules that perform basic operations as a UE terminal are omitted as appropriate.
- the wireless communication apparatus 1400 includes an RF communication processing unit 1401 that performs analog processing of a radio signal transmitted and received by an antenna, and a digital communication processing unit 1402 that performs modulation of a digital transmission signal and demodulation processing of a digital reception signal.
- the digital communication processing unit 1402 exchanges transmission / reception data with the upper layer protocol of the communication layer of the own device 1400.
- the grasping unit 1403 grasps information related to the eNodeB used in the CoMP set for the own device 1400 and the range in which the own device 1400 performs the measurement for point selection.
- the grasping unit 1403 can basically grasp these pieces of information based on a notification from the Serving eNodeB.
- the measurement target determination unit 1404 determines an eNodeB that performs measurement for point selection for each subband.
- the measurement target determining unit 1404 basically selects a base station that is in use as a CoMP transmission point or a transmission point candidate as a measurement target.
- the measurement target determining unit 1404 determines how the CoMP set is determined on the Serving eNodeB side by feeding back the measurement result. And the eNodeB to be measured is selected.
- the measurement target determining unit 1404 groups the subband group that can be handled in a group as a subband group, and sets the subband group as the measurement target. decide.
- the reference signal measurement unit 1405 performs measurement for point selection in each subband using the CSI-RS from the eNodeB selected as the measurement target by the measurement target determination unit 1404.
- the measurement result evaluation unit 1406 evaluates the measurement result measured by the reference signal measurement unit 1405 for each subband. When realizing the means 2-1-1, the measurement result evaluation unit 1406 evaluates an expected value of improvement in reception SINR by predicted point selection. In addition, when realizing the means 2-1-2, the measurement result evaluation unit 1406 evaluates the number of useless eNodeBs that are removed from the CoMP set by the predicted point selection.
- the measurement result selection unit 1407 selects one to be fed back to the Serving eNodeB from the measurement results in each subband by the reference signal measurement unit 1405.
- the selected measurement result is transmitted to the Serving eNodeB via the digital communication processing unit 1402 and the RF communication processing unit 1401.
- the measurement result selection unit 1407 uses a set of measurement results of base stations in the wideband as a population, and the set of measurement results in each subband is a subset of the population. The measurement results to be fed back are selected to determine the CoMP set.
- the measurement result selection unit 1407 adds to the set of measurement results of the base station in the wideband, and base stations other than the set of measurement results in each subband.
- the measurement results to be fed back to determine the CoMP set are selected so as to include the measurement results.
- each subband in addition to the measurement result set of the base station in the wideband, each subband includes the measurement result of the base station added to the combination of the base stations in the measurement result set. The measurement results to be fed back are selected to determine the CoMP set.
- the measurement result selection unit 1407 selects what is fed back to the Serving eNodeB based on the result of the measurement result evaluation unit 1406 evaluating the measurement result for each subband by the reference signal measurement unit 1405.
- the measurement result selection unit 1407 selects M subbands with poor quality when realizing the above means 2-1. Further, when realizing the means 2-1-1, the measurement result selection unit 1407 obtains the measurement result of the subband evaluated by the measurement result evaluation unit 1406 as having a high degree of improvement in quality by feedback. Select with priority.
- the measurement result selection unit 1407 when realizing the above means 2-1-2, the measurement result evaluation unit 1406 has evaluated that it is highly likely that unnecessary eNodeB will be removed from the CoMP set by feedback. Select the band measurement results with priority.
- the system frequency is divided into a plurality of subbands
- information for determining an effective combination by CoMP can be transmitted from the UE terminal to the eNodeB without an increase in overhead, while suppressing the uplink overhead for point selection.
- the point selection update frequency can be improved and the throughput can be increased.
- the technology disclosed in the present specification can also be configured as follows. (1) In the communication environment in which the entire system band is used as a wideband and the system band is divided into a plurality of subbands, the reference signal transmitted from each base station in the wideband and each subband is used. A reference signal measurement unit that performs measurement, and a measurement result obtained in the wideband and each subband by the reference signal measurement unit to determine a cooperation group of base stations that perform multipoint coordinated transmission / reception with respect to the own device A wireless communication apparatus comprising: a measurement result selection unit that selects what is to be fed back to the base station; and a feedback unit that feeds back a measurement result selected by the measurement result selection unit to a base station.
- the reference signal measurement unit further comprising a measurement target determination unit that selects, as a measurement target, a base station that is in use as a transmission point of the cooperative group or a transmission point candidate for each wideband and subband.
- the wireless communication device wherein the reference signal from the base station selected by the measurement target determination unit is measured in the wideband and each subband.
- the measurement result selection unit sets the coordinated group so that a set of measurement results of base stations in a wide band is a population, and a set of measurement results in each subband is a subset of the population.
- the wireless communication apparatus according to (1), wherein the measurement result to be fed back for selection is selected.
- the coordinated group is configured so that the measurement result selection unit includes a measurement result of a base station other than the measurement result set in each subband in addition to the measurement result set of the base station in a wide band.
- the wireless communication apparatus according to (1), wherein a measurement result to be fed back is selected in order to determine the value.
- the measurement result selection unit includes the measurement result of the base station added to the combination of the base stations in the measurement result set in each subband, in addition to the measurement result set of the base station in the wideband. As described above, the wireless communication apparatus according to (1), wherein the measurement result to be fed back is selected to determine the cooperative group.
- the radio communication apparatus wherein the measurement result selection unit preferentially selects a measurement result of a subband that is highly likely to be updated when a feedback group is fed back.
- the measurement result selection unit preferentially selects a measurement result of a subband that is highly likely to add a new base station to the cooperative group when fed back.
- the measurement result selection unit preferentially selects a measurement result of a subband that is highly likely to delete an unnecessary base station from the cooperative group when fed back. apparatus.
- the apparatus further includes a measurement result evaluation unit that evaluates the measurement result of each subband by the reference signal measurement unit, and the measurement result selection unit is configured based on the evaluation result of each subband by the measurement result evaluation unit.
- the radio communication apparatus according to (1), wherein a measurement result of a subband to be fed back to select a cooperation group is selected.
- the measurement result evaluation unit evaluates the quality of each subband, and the measurement result selection unit includes a predetermined number to be fed back so as to include the measurement results of a predetermined number of subbands in order of poor quality.
- the wireless communication device according to (9), wherein the measurement result of the subband is selected.
- the measurement result evaluation unit predicts an expected value of quality improvement due to the cooperation group being updated, and the measurement result selection unit predicts The wireless communication apparatus according to (9), wherein measurement results of a predetermined number of subbands to be fed back are selected based on the expected value. (12) Predicting how the cooperative group is determined by feeding back measurement results for each subband, and selecting a base station to be measured by the reference signal measurement unit based on the predicted results.
- the measurement result evaluation unit evaluates whether or not a useless base station is removed from the cooperative group when the measurement result is fed back for each subband.
- the wireless communication device according to (13), further including a measurement target determination unit that performs evaluation of how many useless base stations are removed by the predicted cooperative group.
- the measurement result selection unit groups subband groups that are continuous in the frequency direction and have the same combination of base stations forming the cooperative group as subband groups, and feeds back in units of subband groups.
- a wireless communication apparatus comprising: a cooperative group determination unit for determining.
- the wireless communication device wherein the notification unit notifies the terminal station of information regarding the cooperation group determined for each subband by the cooperation group determination unit.
- the notification unit includes information indicating a range that may be measured, information indicating a range that is most frequently used, and a base that is additionally used for each subband.
- the wireless communication device wherein the wireless communication device is divided into three types of information indicating a station range and notified at different update frequencies for each information.
- the reference signal transmitted from each base station in the wideband and each subband is used.
- a reference signal measurement step for performing measurement, and a measurement result obtained in the wideband and each subband by the reference signal measurement step to determine a cooperation group of base stations that perform multipoint coordinated transmission / reception with respect to the own device A radio communication method comprising: a measurement result selection step for selecting what is fed back to the base station; and a feedback step for feeding back the measurement result selected in the measurement result selection step to a base station.
- the cooperative group is set so that a set of base station measurement results in a wide band is a population, and a set of measurement results in each subband is a subset of the population.
- each subband includes the measurement results of base stations other than the set of measurement results, so that the cooperative group
- the wireless communication method according to (19), wherein the measurement result to be fed back is selected in order to determine
- each subband includes the measurement result of the base station added to the combination of the base stations in the measurement result set.
- the radio communication method according to (19), wherein measurement results to be fed back are selected in order to determine the cooperative group.
- the method further includes a measurement result evaluation step for evaluating the measurement result of each subband in the reference signal measurement step, and the measurement result selection step is based on the evaluation result of each subband in the measurement result evaluation step.
- the radio communication method according to (19), wherein measurement results of subbands to be fed back are selected to determine the cooperation group.
- the measurement result evaluation step the quality of each subband is evaluated, and in the measurement result selection step, a predetermined number to be fed back so as to include a predetermined number of subband measurement results from the poorer quality
- subband groups that are continuous in the frequency direction and have the same combination of base stations forming the cooperative group are grouped as subband groups, and are fed back in subband group units.
- (28) In the communication environment in which the entire system band is used as a wide band and the system band is divided into a plurality of subbands, the range in which the measurement and feedback of the reference signal transmitted from each base station is determined
- a cooperative group determination step for determining In the communication environment in which the entire system band is used as a wide band and the system band is divided into a plurality of subbands, the range in which the measurement and feedback of the reference signal transmitted from each base station is determined.
- the information notified to the terminal station includes information indicating a range where measurement is likely to be performed, information indicating the most frequently used range, and a base additionally used for each subband.
- (30) A plurality of base stations that transmit reference signals, and a terminal station that receives the reference signals from the base stations and performs measurement for determining a cooperative group of base stations that perform multipoint coordinated transmission / reception for the own station The terminal station uses the entire system band as a wideband and divides the system band into a plurality of subbands, and uses the wideband and each subband from each base station in a communication environment.
- a wireless communication system that measures a reference signal to be transmitted, and selects and feeds back a measurement result necessary for determining a cooperative group that performs multipoint coordinated transmission / reception with respect to the own device.
- a plurality of base stations that transmit reference signals and the reference signals from the base stations are received, and measurement and feedback for determining a cooperative group of base stations that perform multipoint coordinated transmission / reception for the own station are performed.
- a terminal station is provided, and at least one base station uses the entire system band as a wideband, and is transmitted from each base station in a communication environment in which the system band is divided into a plurality of subbands.
- a wireless communication system for notifying a terminal station of information for determining a range for signal measurement and feedback.
- the embodiment applied to the cellular communication system according to LTE established by 3GPP has been mainly described, but the gist of the technology disclosed in this specification is not limited to this.
- the technology disclosed in this specification can be similarly applied to various cellular communication systems to which a technology in which a plurality of base stations cooperate and transmit / receive data to / from a terminal simultaneously is applied.
- Wireless communication device (Serving eNodeB) DESCRIPTION OF SYMBOLS 1301 ... RF communication processing part 1302 ... Digital communication processing part 1303 ... Measurement result holding part 1304 ... CoMP set determination part 1305 ... Notification part 1400 ... Wireless communication apparatus (UE terminal) 1401 ... RF communication processing unit 1402 ... Digital communication processing unit 1403 ... Understanding unit 1404 ... Measurement target determination unit 1405 ... Reference signal measurement unit 1406 ... Measurement result evaluation unit 1407 ... Measurement result selection unit
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Abstract
Description
ある1つのUE端末に対してCoMPを行なう、すなわち協調グループを構成するeNodeBの組合せを、以下では、Set of CoMP transmission point、又は、略してCoMPセットと呼ぶことにする。
ポイント・セレクションは、ある一定期間毎に行なう必要がある(すなわち、CoMPセットを一定時間毎に更新する必要がある)。つまり、UE端末のCoMPセットを、準静的(Semi-Static)に更新するか、動的(Dynamic)に更新するかという問題がある。UE端末の移動を考慮すると、CoMPセットを動的に更新する、ダイナミック・ポイント・セレクションが望ましい。
ダイナミック・ポイント・セレクションを行なう場合、システム内での通信シーケンス中でリファレンス信号が占めることによるスループットの低下、言い換えればリファレンス信号によるダウンリンクのオーバーヘッドを考慮する必要がある。
システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、ワイドバンド及び各サブバンドで、各基地局から送信されるリファレンス信号の測定を行なうリファレンス信号測定部と、
前記リファレンス信号測定部によりワイドバンド及び各サブバンドで得られた測定結果のうち、自装置に対して多地点協調送受信を行なう基地局の協調グループを決定するためにフィードバックするものを取捨選択する測定結果選択部と、
前記測定結果選択部が選択した測定結果を基地局にフィードバックするフィードバック部と、
を具備する無線通信装置である。
システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、各基地局から送信されるリファレンス信号の測定とフィードバックを行なう範囲を決定するための情報を端末局に通知する通知部と、
端末局からフィードバックされた情報に基づいて、ワイドバンド及び各サブバンドで前記端末局に対して多地点協調送受信を行なう基地局の協調グループを決定する協調グループ決定部と、
を具備する無線通信装置である。
システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、ワイドバンド及び各サブバンドで、各基地局から送信されるリファレンス信号の測定を行なうリファレンス信号測定ステップと、
前記リファレンス信号測定ステップによりワイドバンド及び各サブバンドで得られた測定結果のうち、自装置に対して多地点協調送受信を行なう基地局の協調グループを決定するためにフィードバックするものを取捨選択する測定結果選択ステップと、
前記測定結果選択ステップで選択した測定結果を基地局にフィードバックするフィードバック・ステップと、
を有する無線通信方法である。
システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、各基地局から送信されるリファレンス信号の測定とフィードバックを行なう範囲を決定するための情報を端末局に通知する通知ステップと、
端末局からフィードバックされた情報に基づいて、ワイドバンド及び各サブバンドで前記端末局に対して多地点協調送受信を行なう基地局の協調グループを決定する協調グループ決定ステップと、
を有する無線通信方法である。
リファレンス信号を送信する複数の基地局と、
基地局からのリファレンス信号を受信して、自局のための多地点協調送受信を行なう協調グループの決定用の測定を行なう端末局と、
を具備し、
前記端末局は、システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、ワイドバンド及び各サブバンドで、各基地局から送信されるリファレンス信号の測定を行ない、自装置に対して多地点協調送受信を行なう基地局の協調グループを決定するために必要な測定結果を取捨選択してフィードバックする、
無線通信システムである。
リファレンス信号を送信する複数の基地局と、
基地局からのリファレンス信号を受信して、自局のための多地点協調送受信を行なう基地局の協調グループの決定用の測定及びフィードバックを行なう端末局と、
を具備し、
少なくとも1つの基地局は、システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、各基地局から送信されるリファレンス信号の測定とフィードバックを行なう範囲を決定するための情報を端末局に通知する、
無線通信システムである。
UE端末が、ワイドバンドとすべてのサブバンドに対応する、同一のeNodeBに対する測定結果をフィードバックすると、アップリンクのフィードバック・リソースを浪費して、オーバーヘッドが増加して、アップリンクのスループットが低下する、という第1の課題がある。
CoMPのダイナミック・ポイント・セレクションのために、UE端末がサブバンドで測定結果のセットを取捨選択してフィードバックする場合に、フィードバックするサブバンドの優先順位は、UE端末により、又は、場合によっては基地局により決定される。基地局によって決定される場合には、決定された優先順位に関する情報を、基地局からUE端末に通知するようにする。
UE端末は、サブバンド毎に測定結果のフィードバックを行なうためには、サブバンド毎に、現在どのeNodeBを使用してCoMPを行なっているかという情報が必要である。サブバンド毎のCoMPセットの情報がないと、UE端末は、サブバンド毎に効果的な測定対象を選択することができない、という第3の課題がある。また、CoMPセットの情報をServing eNodeBからUE端末にダウンリンクの信号を用いて伝えることは、この制御信号によるオーバーヘッドの増加により、ダウンリンクのスループットの低下を招来する。
図13には、本実施形態に係る無線通信システム(図1)において、Serving eNodeB(Macro eNodeB)として動作する無線通信装置1300の構成例を模式的に示している。但し、同図では、Macro Cell内の無線リソース管理や、各種リファレンス信号の送信など、Macro eNodeBとしての基本動作を行なう機能モジュールについては適宜図示を省略している。
(1)システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、ワイドバンド及び各サブバンドで、各基地局から送信されるリファレンス信号の測定を行なうリファレンス信号測定部と、前記リファレンス信号測定部によりワイドバンド及び各サブバンドで得られた測定結果のうち、自装置に対して多地点協調送受信を行なう基地局の協調グループを決定するためにフィードバックするものを取捨選択する測定結果選択部と、前記測定結果選択部が選択した測定結果を基地局にフィードバックするフィードバック部と、を具備する無線通信装置。
(2)ワイドバンド及びサブバンド毎に、前記協調グループのトランスミッション・ポイントとして使用中又はトランスミッション・ポイントの候補となる基地局を測定対象として選択する測定対象決定部をさらに備え、前記リファレンス信号測定部は、ワイドバンド及び各サブバンドで、前記測定対象決定部が選択した基地局からのリファレンス信号の測定を行なう、上記(1)に記載の無線通信装置。
(3)前記測定結果選択部は、ワイドバンドでの基地局の測定結果のセットを母集団とし、各サブバンドでの測定結果のセットが前記母集団に対するサブセットとなるように、前記協調グループを決定するためにフィードバックする測定結果を取捨選択する、上記(1)に記載の無線通信装置。
(4)前記測定結果選択部は、ワイドバンドでの基地局の測定結果のセットに追加して、各サブバンドでは前記測定結果のセット以外の基地局の測定結果を含むように、前記協調グループを決定するためにフィードバックする測定結果を取捨選択する、上記(1)に記載の無線通信装置。
(5)前記測定結果選択部は、ワイドバンドでの基地局の測定結果のセットに追加して、各サブバンドでは前記測定結果のセットの基地局の組合せに追加した基地局の測定結果を含むように、前記協調グループを決定するためにフィードバックする測定結果を取捨選択する、上記(1)に記載の無線通信装置。
(6)前記測定結果選択部は、フィードバックした場合に協調グループが更新される可能性が高いサブバンドの測定結果を優先して選択する、上記(1)に記載の無線通信装置。
(7)前記測定結果選択部は、フィードバックした場合に協調グループに新たな基地局が加わる可能性が高いサブバンドの測定結果を優先して選択する、上記(1)に記載の無線通信装置。
(8)前記測定結果選択部は、フィードバックした場合に協調グループから不要な基地局が削除される可能性が高いサブバンドの測定結果を優先して選択する、上記(1)に記載の無線通信装置。
(9)前記リファレンス信号測定部による各サブバンドの測定結果を評価する測定結果評価部をさらに備え、前記測定結果選択部は、前記測定結果評価部による各サブバンドの評価結果に基づいて、前記協調グループを決定するためにフィードバックするサブバンドの測定結果を取捨選択する、上記(1)に記載の無線通信装置。
(10)前記測定結果評価部は、各サブバンドの品質を評価し、前記測定結果選択部は、品質の良くない方から所定数のサブバンドの測定結果を含むように、フィードバックすべき所定数のサブバンドの測定結果を選択する、上記(9)に記載の無線通信装置。
(11)前記測定結果評価部は、サブバンド毎に、測定結果をフィードバックした場合に前記協調グループが更新されることによる品質の向上の期待値を予測し、前記測定結果選択部は、予測した期待値に基づいて、フィードバックすべき所定数のサブバンドの測定結果を選択する、上記(9)に記載の無線通信装置。
(12)サブバンド毎に、測定結果をフィードバックすることにより前記協調グループがどのように決定されるかを予測し、予測した結果に基づいて前記リファレンス信号測定部による測定対象とする基地局を選択する測定対象決定部をさらに備え、前記測定結果評価部は、予測した前記協調グループによる品質の向上の期待値を予測する、上記(11)に記載の無線通信装置。
(13)前記測定結果評価部は、サブバンド毎に、測定結果をフィードバックした場合に前記協調グループから無駄な基地局が取り除かれるか否かを評価し、前記測定結果選択部は、無駄な基地局が取り除かれる可能性に基づいて、フィードバックすべき所定数のサブバンドの測定結果を選択する、上記(9)に記載の無線通信装置。
(14)サブバンド毎に、測定結果をフィードバックすることにより前記協調グループがどのように決定されるかを予測し、予測した結果に基づいて前記リファレンス信号測定部による測定対象とする基地局を選択する測定対象決定部をさらに備え、前記測定結果評価部は、予測した前記協調グループにより無駄な基地局がいくつ取り除かれるかを評価する、上記(13)に記載の無線通信装置。
(15)前記測定結果選択部は、周波数方向に連続し且つ前記協調グループを構成する基地局の組合せが同一となるサブバンドの集団をサブバンド・グループとしてグループ化し、サブバンド・グループ単位でフィードバックするよう、測定結果を取捨選択する、上記(1)に記載の無線通信装置。
(16)システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、各基地局から送信されるリファレンス信号の測定とフィードバックを行なう範囲を決定するための情報を端末局に通知する通知部と、端末局からフィードバックされた情報に基づいて、ワイドバンド及び各サブバンドで前記端末局に対して多地点協調送受信を行なう基地局の協調グループを決定する協調グループ決定部と、を具備する無線通信装置。
(17)前記通知部は、前記協調グループ決定部がサブバンド毎に決定した協調グループに関する情報を端末局に通知する、上記(16)に記載の無線通信装置。
(18)前記通知部は、端末局に通知する情報を、測定する可能性がある範囲を示す情報、最も良く使用されている範囲を示す情報、サブバンド毎に追加的に使用されている基地局の範囲を示す情報の3種類に分け、情報毎に異なる更新頻度で通知する、上記(16)に記載の無線通信装置。
(19)システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、ワイドバンド及び各サブバンドで、各基地局から送信されるリファレンス信号の測定を行なうリファレンス信号測定ステップと、前記リファレンス信号測定ステップによりワイドバンド及び各サブバンドで得られた測定結果のうち、自装置に対して多地点協調送受信を行なう基地局の協調グループを決定するためにフィードバックするものを取捨選択する測定結果選択ステップと、前記測定結果選択ステップで選択した測定結果を基地局にフィードバックするフィードバック・ステップと、を有する無線通信方法。
(20)前記測定結果選択ステップでは、ワイドバンドでの基地局の測定結果のセットを母集団とし、各サブバンドでの測定結果のセットが前記母集団に対するサブセットとなるように、前記協調グループを決定するためにフィードバックする測定結果を取捨選択する、上記(19)に記載の無線通信方法。
(21)前記測定結果選択ステップでは、ワイドバンドでの基地局の測定結果のセットに追加して、各サブバンドでは前記測定結果のセット以外の基地局の測定結果を含むように、前記協調グループを決定するためにフィードバックする測定結果を取捨選択する、上記(19)に記載の無線通信方法。
(22)前記測定結果選択ステップでは、ワイドバンドでの基地局の測定結果のセットに追加して、各サブバンドでは前記測定結果のセットの基地局の組合せに追加した基地局の測定結果を含むように、前記協調グループを決定するためにフィードバックする測定結果を取捨選択する、上記(19)に記載の無線通信方法。
(23)前記リファレンス信号測定ステップにおける各サブバンドの測定結果を評価する測定結果評価ステップをさらに有し、前記測定結果選択ステップでは、前記測定結果評価ステップにおける各サブバンドの評価結果に基づいて、前記協調グループを決定するためにフィードバックするサブバンドの測定結果を取捨選択する、上記(19)に記載の無線通信方法。
(24)前記測定結果評価ステップでは、各サブバンドの品質を評価し、前記測定結果選択ステップでは、品質の良くない方から所定数のサブバンドの測定結果を含むように、フィードバックすべき所定数のサブバンドの測定結果を選択する、上記(23)に記載の無線通信方法。
(25)前記測定結果評価ステップでは、サブバンド毎に、測定結果をフィードバックした場合に前記協調グループが更新されることによる品質の向上の期待値を予測し、前記測定結果選択ステップでは、予測した期待値に基づいて、フィードバックすべき所定数のサブバンドの測定結果を選択する、上記(23)に記載の無線通信方法。
(26)前記測定結果評価ステップでは、サブバンド毎に、測定結果をフィードバックした場合に前記協調グループから無駄な基地局が取り除かれるか否かを評価し、前記測定結果選択ステップでは、無駄な基地局が取り除かれる可能性に基づいて、フィードバックすべき所定数のサブバンドの測定結果を選択する、上記(23)に記載の無線通信方法。
(27)前記測定結果選択ステップでは、周波数方向に連続し且つ前記協調グループを構成する基地局の組合せが同一となるサブバンドの集団をサブバンド・グループとしてグループ化し、サブバンド・グループ単位でフィードバックするよう、測定結果を取捨選択する、上記(19)に記載の無線通信方法。
(28)システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、各基地局から送信されるリファレンス信号の測定とフィードバックを行なう範囲を決定するための情報を端末局に通知する通知ステップと、端末局からフィードバックされた情報に基づいて、ワイドバンド及び各サブバンドで前記端末局に対して多地点協調送受信を行なう基地局の協調グループを決定する協調グループ決定ステップと、を有する無線通信方法。
(29)前記通知ステップでは、端末局に通知する情報を、測定する可能性がある範囲を示す情報、最も良く使用されている範囲を示す情報、サブバンド毎に追加的に使用されている基地局の範囲を示す情報の3種類に分け、情報毎に異なる更新頻度で通知する、上記(28)に記載の無線通信方法。
(30)リファレンス信号を送信する複数の基地局と、基地局からのリファレンス信号を受信して、自局のための多地点協調送受信を行なう基地局の協調グループの決定用の測定を行なう端末局を具備し、前記端末局は、システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、ワイドバンド及び各サブバンドで、各基地局から送信されるリファレンス信号の測定を行ない、自装置に対して多地点協調送受信を行なう協調グループを決定するために必要な測定結果を取捨選択してフィードバックする、無線通信システム。
(31)リファレンス信号を送信する複数の基地局と、基地局からのリファレンス信号を受信して、自局のための多地点協調送受信を行なう基地局の協調グループの決定用の測定及びフィードバックを行なう端末局を具備し、少なくとも1つの基地局は、システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、各基地局から送信されるリファレンス信号の測定とフィードバックを行なう範囲を決定するための情報を端末局に通知する、無線通信システム。
1301…RF通信処理部
1302…ディジタル通信処理部
1303…測定結果保持部
1304…CoMPセット決定部
1305…通知部
1400…無線通信装置(UE端末)
1401…RF通信処理部
1402…ディジタル通信処理部
1403…把握部
1404…測定対象決定部
1405…リファレンス信号測定部
1406…測定結果評価部
1407…測定結果選択部
Claims (22)
- システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、ワイドバンド及び各サブバンドで、各基地局から送信されるリファレンス信号の測定を行なうリファレンス信号測定部と、
前記リファレンス信号測定部によりワイドバンド及び各サブバンドで得られた測定結果のうち、自装置に対して多地点協調送受信を行なう基地局の協調グループを決定するためにフィードバックするものを取捨選択する測定結果選択部と、
前記測定結果選択部が選択した測定結果を基地局にフィードバックするフィードバック部と、
を具備する無線通信装置。 - ワイドバンド及びサブバンド毎に、前記協調グループのトランスミッション・ポイントとして使用中又はトランスミッション・ポイントの候補となる基地局を測定対象として選択する測定対象決定部をさらに備え、
前記リファレンス信号測定部は、ワイドバンド及び各サブバンドで、前記測定対象決定部が選択した基地局からのリファレンス信号の測定を行なう、
請求項1に記載の無線通信装置。 - 前記測定結果選択部は、ワイドバンドでの基地局の測定結果のセットを母集団とし、各サブバンドでの測定結果のセットが前記母集団に対するサブセットとなるように、前記協調グループを決定するためにフィードバックする測定結果を取捨選択する、
請求項1に記載の無線通信装置。 - 前記測定結果選択部は、ワイドバンドでの基地局の測定結果のセットに追加して、各サブバンドでは前記測定結果のセット以外の基地局の測定結果を含むように、前記協調グループを決定するためにフィードバックする測定結果を取捨選択する、
請求項1に記載の無線通信装置。 - 前記測定結果選択部は、ワイドバンドでの基地局の測定結果のセットに追加して、各サブバンドでは前記測定結果のセットの基地局の組合せに追加した基地局の測定結果を含むように、前記協調グループを決定するためにフィードバックする測定結果を取捨選択する、
請求項1に記載の無線通信装置。 - 前記測定結果選択部は、フィードバックした場合に協調グループが更新される可能性が高いサブバンドの測定結果を優先して選択する、
請求項1に記載の無線通信装置。 - 前記測定結果選択部は、フィードバックした場合に協調グループに新たな基地局が加わる可能性が高いサブバンドの測定結果を優先して選択する、
請求項1に記載の無線通信装置。 - 前記測定結果選択部は、フィードバックした場合に協調グループから不要な基地局が削除される可能性が高いサブバンドの測定結果を優先して選択する、
請求項1に記載の無線通信装置。 - 前記リファレンス信号測定部による各サブバンドの測定結果を評価する測定結果評価部をさらに備え、
前記測定結果選択部は、前記測定結果評価部による各サブバンドの評価結果に基づいて、前記協調グループを決定するためにフィードバックするサブバンドの測定結果を取捨選択する、
請求項1に記載の無線通信装置。 - 前記測定結果評価部は、各サブバンドの品質を評価し、
前記測定結果選択部は、品質の良くない方から所定数のサブバンドの測定結果を含むように、フィードバックすべき所定数のサブバンドの測定結果を選択する、
請求項9に記載の無線通信装置。 - 前記測定結果評価部は、サブバンド毎に、測定結果をフィードバックした場合に前記協調グループが更新されることによる品質の向上の期待値を予測し、
前記測定結果選択部は、予測した期待値に基づいて、フィードバックすべき所定数のサブバンドの測定結果を選択する、
請求項9に記載の無線通信装置。 - サブバンド毎に、測定結果をフィードバックすることにより前記協調グループがどのように決定されるかを予測し、予測した結果に基づいて前記リファレンス信号測定部による測定対象とする基地局を選択する測定対象決定部をさらに備え、
前記測定結果評価部は、予測した前記協調グループによる品質の向上の期待値を予測する、
請求項11に記載の無線通信装置。 - 前記測定結果評価部は、サブバンド毎に、測定結果をフィードバックした場合に前記協調グループから無駄な基地局が取り除かれるか否かを評価し、
前記測定結果選択部は、無駄な基地局が取り除かれる可能性に基づいて、フィードバックすべき所定数のサブバンドの測定結果を選択する、
請求項9に記載の無線通信装置。 - サブバンド毎に、測定結果をフィードバックすることにより前記協調グループがどのように決定されるかを予測し、予測した結果に基づいて前記リファレンス信号測定部による測定対象とする基地局を選択する測定対象決定部をさらに備え、
前記測定結果評価部は、予測した前記協調グループにより無駄な基地局がいくつ取り除かれるかを評価する、
請求項13に記載の無線通信装置。 - 前記測定結果選択部は、周波数方向に連続し且つ前記協調グループを構成する基地局の組合せが同一となるサブバンドの集団をサブバンド・グループとしてグループ化し、サブバンド・グループ単位でフィードバックするよう、測定結果を取捨選択する、
請求項1に記載の無線通信装置。 - システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、各基地局から送信されるリファレンス信号の測定とフィードバックを行なう範囲を決定するための情報を端末局に通知する通知部と、
端末局からフィードバックされた情報に基づいて、ワイドバンド及び各サブバンドで前記端末局に対して多地点協調送受信を行なう基地局の協調グループを決定する協調グループ決定部と、
を具備する無線通信装置。 - 前記通知部は、前記協調グループ決定部がサブバンド毎に決定した協調グループに関する情報を端末局に通知する、
請求項16に記載の無線通信装置。 - 前記通知部は、端末局に通知する情報を、測定する可能性がある範囲を示す情報、最も良く使用されている範囲を示す情報、サブバンド毎に追加的に使用されている基地局の範囲を示す情報の3種類に分け、情報毎に異なる更新頻度で通知する、
請求項16に記載の無線通信装置。 - システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、ワイドバンド及び各サブバンドで、各基地局から送信されるリファレンス信号の測定を行なうリファレンス信号測定ステップと、
前記リファレンス信号測定ステップによりワイドバンド及び各サブバンドで得られた測定結果のうち、自装置に対して多地点協調送受信を行なう基地局の協調グループを決定するためにフィードバックするものを取捨選択する測定結果選択ステップと、
前記測定結果選択ステップで選択した測定結果を基地局にフィードバックするフィードバック・ステップと、
を有する無線通信方法。 - システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、各基地局から送信されるリファレンス信号の測定とフィードバックを行なう範囲を決定するための情報を端末局に通知する通知ステップと、
端末局からフィードバックされた情報に基づいて、ワイドバンド及び各サブバンドで前記端末局に対して多地点協調送受信を行なう基地局の協調グループを決定する協調グループ決定ステップと、
を有する無線通信方法。 - リファレンス信号を送信する複数の基地局と、
基地局からのリファレンス信号を受信して、自局のための多地点協調送受信を行なう協調グループの決定用の測定を行なう端末局と、
を具備し、
前記端末局は、システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、ワイドバンド及び各サブバンドで、各基地局から送信されるリファレンス信号の測定を行ない、自装置に対して多地点協調送受信を行なう基地局の協調グループを決定するために必要な測定結果を取捨選択してフィードバックする、
無線通信システム。 - リファレンス信号を送信する複数の基地局と、
基地局からのリファレンス信号を受信して、自局のための多地点協調送受信を行なう基地局の協調グループの決定用の測定及びフィードバックを行なう端末局と、
を具備し、
少なくとも1つの基地局は、システム帯域全体をワイドバンドとして使用するとともに、システム帯域を複数のサブバンドに分割して使用する通信環境下で、各基地局から送信されるリファレンス信号の測定とフィードバックを行なう範囲を決定するための情報を端末局に通知する、
無線通信システム。
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- 2012-11-02 JP JP2013555125A patent/JP5835356B2/ja not_active Expired - Fee Related
- 2012-11-02 EP EP12866795.3A patent/EP2809101B1/en not_active Not-in-force
- 2012-11-02 BR BR112014017110A patent/BR112014017110A8/pt not_active Application Discontinuation
- 2012-11-02 US US14/372,855 patent/US9571244B2/en active Active
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EP3177060A4 (en) * | 2014-08-21 | 2017-07-19 | Huawei Technologies Co., Ltd. | Coordinated multi-point transmission method and apparatus |
CN106465359A (zh) * | 2014-09-05 | 2017-02-22 | 华为技术有限公司 | 传输数据的方法、系统及设备 |
EP3179797A4 (en) * | 2014-09-05 | 2017-08-23 | Huawei Technologies Co., Ltd. | Data transmission method, system and device |
US10432285B2 (en) | 2014-09-05 | 2019-10-01 | Huawei Technologies Co., Ltd. | Data transmission method, system, and device |
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Also Published As
Publication number | Publication date |
---|---|
BR112014017110A2 (pt) | 2017-06-13 |
JPWO2013111412A1 (ja) | 2015-05-11 |
US20150009924A1 (en) | 2015-01-08 |
CN104081809B (zh) | 2018-03-30 |
US9571244B2 (en) | 2017-02-14 |
EP2809101B1 (en) | 2017-01-04 |
JP5835356B2 (ja) | 2015-12-24 |
CN104081809A (zh) | 2014-10-01 |
EP2809101A4 (en) | 2016-01-20 |
RU2014129460A (ru) | 2016-02-10 |
BR112014017110A8 (pt) | 2017-07-04 |
EP2809101A1 (en) | 2014-12-03 |
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