WO2013027947A2 - Procédé et appareil d'émission de signal de commande, et procédé et appareil de réception de données associés - Google Patents

Procédé et appareil d'émission de signal de commande, et procédé et appareil de réception de données associés Download PDF

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Publication number
WO2013027947A2
WO2013027947A2 PCT/KR2012/006283 KR2012006283W WO2013027947A2 WO 2013027947 A2 WO2013027947 A2 WO 2013027947A2 KR 2012006283 W KR2012006283 W KR 2012006283W WO 2013027947 A2 WO2013027947 A2 WO 2013027947A2
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data
comp
transmission
pdsch
information
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PCT/KR2012/006283
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English (en)
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WO2013027947A3 (fr
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Jian Jun Li
Sung Jun Yoon
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Pantech Co., Ltd.
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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
    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J11/00—Orthogonal multiplex systems, e.g. using WALSH codes
    • H04J11/0023—Interference mitigation or co-ordination
    • H04J11/005—Interference mitigation or co-ordination of intercell interference
    • H04J11/0053—Interference mitigation or co-ordination of intercell interference using co-ordinated multipoint transmission/reception
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2602—Signal structure
    • 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
    • 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
    • H04L5/0044—Arrangements for allocating sub-channels of the transmission path allocation of payload
    • 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

Definitions

  • the present invention relates to CoMP (Coordinated Multi-Points) in a wireless communication system and, more particularly, to a method and apparatus for transmitting control information in downlink CoMP and a method and apparatus for receiving data using the same.
  • CoMP Coordinatd Multi-Points
  • CoMP is a technique of coordinating or combining signals transmitted from multiple points, and by applying CoMP, a data transfer rate can be increased and high quality and high throughput can be obtained.
  • a CoMP applied terminal (hereinafter, referred to as a ‘terminal operating in a CoMP mode’) as a terminal supporting CoMP in a CoMP environment (hereinafter, a system supporting CoMP or employing CoMP will be referred to as a ‘CoMP environment’) to which CoMP is applied
  • the terminal aims at receiving data simultaneously from a CoMP set in consideration of a channel environment of each cell constituting the CoMP set or aims at receiving data by minimizing an interference influence among the CoMP cooperation set, so it is required to measure channel information regarding each cell and reported to a serving cell of the corresponding cell.
  • the CoMP set is a set of points which directly/indirectly participate in a data transmission (and geographically separated) in a certain time-frequency domain with respect to a single user equipment (UE).
  • directly participating in a data transmission refers to that the points actually transmit data to the UE in a corresponding time-frequency resource
  • indirectly participating in a data transmission refers to that the points do not actually transmit data in the corresponding time-frequency resource but contribute to determining regarding user scheduling/beamforming.
  • reference information e.g., a reference signal
  • pertinent information is required to be shared between a terminal and a base station.
  • an object of the present invention is to provide a method for allowing a user equipment (UE) to accurately receive data in a CoMP (Coordinated Multi-Points) environment.
  • UE user equipment
  • Another object of the present invention is to provide a method for allowing a UE to accurately receive data even when a cell ID of each transmission point is different in a CoMP environment.
  • Another object of the present invention is to provide a method for preventing an occurrence of interference between a data channel and a control channel transmitted from respective transmission points even when cell IDs of the respective transmission points are different in a CoMP environment.
  • Another object of the present invention is to provide a method for preventing an occurrence of interference between a data channel and a reference signal transmitted from respective transmission points even when cell IDs of the respective transmission points are different in a CoMP environment.
  • Another object of the present invention is to provide a method for transferring control information for avoiding interference between a data channel and a control channel transmitted from respective transmission points and control information for avoiding interference between a data channel and a reference signal to a UE at a time in a CoMP environment.
  • Another object of the present invention is to provide a method for reducing overhead of control information transferred to a UE in a CoMP environment.
  • a method for transmitting downlink control information in a CoMP (Coordinated Multi-Points) system including: controlling data channels transmitted from transmission points of a CoMP set in a subframe of the same transmission time interval (TTI) with respect to control signals and reference signals transmitted from the transmission points; and configuring downlink control information including information regarding the controlled data channels.
  • CoMP Coordinatd Multi-Points
  • starting positions of the data channels transmitted from the transmission points may be aligned, symbols of the data channels are mapped by avoiding resources to which the reference signals transmitted from the transmission points are mapped, and the information regarding the controlled data channels may be an indicator indicating the starting positions of the data channels and resource regions to which data channels are not mapped in the subframe.
  • the indicator may be an index indicating starting positions of the data channels and regions to which data channels are not mapped in the subframe in the table comprised of information regarding starting positions of data channels and data channel mapping
  • symbols of the data channels may be mapped by avoiding resources to which symbols of the control channels transmitted from the transmission points are mapped, and also, symbols of data channels may be mapped by avoiding resources to which reference signals transmitted from the transmission points are mapped, and the information regarding the controlled data channels maybe an indicator indicating resource regions to which data channels are not mapped in the subframe.
  • the indicator may be an index indicating regions to which data channels are not mapped in the subframe in the table comprised of information regarding resources to which symbols of data channels are not allocated.
  • the different transmission points may have different cell IDs.
  • a method for receiving data of a user equipment (UE) in a CoMP (Coordinated Multi-Points) system including: receiving data on data channels from transmission points of a CoMP set in a subframe of the same transmission time interval (TTI); and combining the received data based on information regarding the data channels included in downlink control information received from control information transmission points among the transmission points, wherein the information regarding data channels include information regarding controlling of data channels configured in the subframe with respect to control channels and reference signals transmitted from the transmission points.
  • CoMP Coordinatd Multi-Points
  • data received from the transmission points are combined based on information regarding the data channels, information regarding starting positions of data channels in the subframe indicated by control formation information received from a serving point among the transmission points and resources to which symbols of the data channels are not mapped in the subframe indicated through the information regarding the data channels, and the control format information may indicate regions of control channels in the subframe.
  • the information regarding the channel channels may be an index indicating starting positions of the data channels and regions to which data channels are not mapped in the subframe in a table comprised of information regarding starting positions of data channels and data channel mapping.
  • data received from the transmission points may be combined based on information regarding resources to which symbols of the data channels are not mapped in the subframe indicated through information regarding the data channels.
  • the information regarding the data channels may be an index indicating regions to which data channels are not mapped in the subframe in a table comprised of information regarding resources to which symbols of data channels are not mapped.
  • cell IDs of the transmission points may be different.
  • a UE can accurately receive data in a CoMP environment.
  • control information for avoiding interference between a data channel and a control channel transmitted from respective transmission points and control information for avoiding interference between a data channel and a reference signal can be transferred to a UE at a time in a CoMP environment.
  • overhead of control information transferred to a UE can be reduced in a CoMP environment.
  • FIG. 1 is a view schematically showing an example of a radio frame structure in a system to which the present invention is applied.
  • FIG. 2 is a schematic flow chart illustrating an example of data processing between an eNodeB and a UE in a multi-antenna system.
  • FIG. 3 is a view schematically showing an example in which CRSs are mapped to resource elements (REs) in case of a normal CP.
  • REs resource elements
  • FIG. 4 is a view schematically showing an example in which CRSs are mapped to REs in case of an extended CP.
  • FIG. 5 is a view schematically showing a first CoMP scenario.
  • FIG. 6 is a view schematically showing a second CoMP scenario.
  • FIG. 7 is a view schematically showing third and fourth CoMP scenarios.
  • FIG. 8 is a view schematically showing an example in which positions of OFDM symbols from which PDSCH region starts do not match up among cells in case of JT CoMP.
  • FIG. 9 is a view schematically showing an example in which interference (collision) occurs between a PDSCH and a CRS transmitted from different cells in the case of JT-CoMP.
  • FIG. 10 is a view schematically showing puncturing and muting.
  • FIG. 11 is a view schematically showing cases of muting available within one subframe with respect to a normal CP.
  • FIG. 12 is a view schematically showing cases of muting available within one subframe with respect to an extended CP.
  • FIG. 13 is a flow chart schematically illustrating an operation of an eNodeB in the system to which the present invention is applied.
  • FIG. 14 is a view schematically showing an operation of a UE in the system to which the present invention is applied.
  • FIG. 15 is a view schematically showing a structure of a UE in the system to which the present invention is applied.
  • FIG. 16 is a view schematically showing an operation of an eNodeB in a view schematically showing an operation of a UE in the system to which the present invention is applied.
  • a wireless communication network will be described, and an operation performed in a wireless communication network may be performed in a process of controlling a network and transmitting data by a system (e.g., a base station) that administers a corresponding wireless communication network or a terminal coupled to the corresponding wireless network.
  • a system e.g., a base station
  • a user equipment may be fixed or mobile, and may be called by other names such as MS (mobile station), MT (mobile terminal), UT (user terminal), SS (subscriber station), wireless device, PDA (personal digital assistant), wireless modem, handheld device, or the like.
  • MS mobile station
  • MT mobile terminal
  • UT user terminal
  • SS subscriber station
  • wireless device PDA (personal digital assistant)
  • PDA personal digital assistant
  • a base station generally refers to a fixed station communicating with a UE, and may be called by other names such as eNodeB (evolved-NodeB), BTS (Base Transceiver System), access point, or the like.
  • eNodeB evolved-NodeB
  • BTS Base Transceiver System
  • Each BS provides a communication service to a particular geographical area (which is generally called a cell).
  • a BS may be divided into a plurality of regions (which is called sectors). Also, a plurality of transmitters may constitute a single cell.
  • FIG. 1 schematically shows an example of a radio frame structure in a system to which the present invention is applied.
  • One radio frame includes 20 slots (#0 ⁇ #19).
  • One subframe includes two slots.
  • a time (length) during which a single subframe is transmitted is called a TTI (transmission time interval).
  • TTI transmission time interval
  • One slot may include a plurality of symbols in a time domain.
  • the symbol when OFDMA (Orthogonal Frequency Division Multiple Access) is used in downlink (DL), the symbol may be an OFDM (Orthogonal Frequency Division Multiplexing) symbol.
  • an expression of a symbol period in a time domain is not limited to a multi-access scheme or name.
  • a plurality of symbols may be SC-FDMA (Single Carrier-Frequency Division Multiple Access) symbols, symbol period, or the like.
  • the number of symbols included in one slot may vary according to a length of a cyclic prefix (CP). For example, in case of a normal CP, one slot includes seven symbols, an in case of an extended CP, one slot may include six or three symbols.
  • CP cyclic prefix
  • RE Resource element
  • 'PRB' Physical Resource Block
  • One PRB includes a plurality of REs contiguous in the time-frequency domain, and a plurality of PRBs are defined in one subframe.
  • 'VRB' Virtual Resource Block
  • 'VRB' Virtual Resource Block
  • the number of REs included in a single VRB is equal to the number of REs included in a single PRB.
  • one VRB may be mapped to one PRB or one VRB may be mapped to a plurality of PRBs in a distributed manner.
  • a downlink subframe may be divided into a control region and a data region in the time domain.
  • the control region may include a maximum of four front OFDM symbols in the first slot of the subframe.
  • the number of OFDM symbols included in the control region may vary.
  • a control channel such as a PDCCH, or the like, is allocated to the control region, and a data transmission channel such as PDSCH is allocated to the data region.
  • a PCFICH transmitted in the first OFDM symbol of the subframe carries a CFI (Control Format Indicator) indicating the number of OFDM symbols (i.e., the size of the control region) used to transmit control channels within the subframe.
  • CFI Control Format Indicator
  • a UE may first receive the CFI on the PCFICH and monitor the PDCCH.
  • the PCFICH may be transmitted through a fixed PCFICH resource of the subframe.
  • a PHICH Physical Hybrid ARQ Indicator CHannel
  • ACK positive-acknowledgement
  • NACK negative-acknowledgement
  • a PBCH Physical Broadcast Channel
  • the PBCH carries system information essential for the UE to communicate with a base station (BS).
  • System information transmitted via the PBCH is called an MIB (Master Information Block).
  • SIB System Information Block
  • MIB Master Information Block
  • SIB System Information Block
  • DCI Downlink control information
  • DCI may include a resource allocation (this is also called a downlink grant) of a PDSCH, a resource allocation (this is also called an uplink grant) of a PUSCH, a set of transmission power control commands with respect to individual UEs of a certain UE group and/or an activation of VoIP (Voice over Internet Protocol).
  • the control region of the subframe includes a plurality of CCEs (control channel elements).
  • the CCE is a logical allocation unit used to provide a coding rate according to a state of a radio channel to the PDCCH.
  • the CCEs correspond to a plurality of REGs (resource element groups).
  • the format of the PDCCH and the number of bits of the PDCCH are determined according to correlation between the number of CCEs and the coding rate provided by the CCEs.
  • REs may be aggregated to constitute an REG and REGs may be aggregated to constitute a CCE.
  • REG includes four REs
  • one CCE includes 9 REGs.
  • ⁇ 1, 2, 4, 8 ⁇ number of CCEs may be used, and here, each element within the aggregate ⁇ 1, 2, 4, 8 ⁇ is called a CCE set level.
  • a control channel comprised of one or more CCEs performs interleaving by REGs, and after a cyclic shift based on a cell ID (Identifier) is performed, the control channel is mapped to physical resource.
  • blind decoding In order to detect a PDCCH, blind decoding may be used. Blind decoding may also be called blind detection. Blind decoding is a method of descrambling a desired identifier in a CRC of a received PDCCH (which is called a candidate PDCCH) and checking a CRC error to determine whether or not the corresponding PDCCH is a control channel thereof or not.
  • a plurality of PDCCHs may be transmitted in a single subframe.
  • a UE monitors a plurality of PDCCHs in every subframe.
  • monitoring refers to that a UE attempts to decode by the UE according to a format of a target PDCCH.
  • a MIMO (Multi-Input Multi-Output) system also called a multi-antenna system, enhances transmission/reception data transmission efficiency by using multiple transmission antennas and multiple reception antennas.
  • a MIMO technique includes transmit diversity, spatial multiplexing, beamforming, and the like.
  • the transmit diversity is a technique that transmits the same data from respective antennas constituting multiple transmission antennas to thus enhance a transmission reliability.
  • Spatial multiplexing is a technique that simultaneously transmits different data from multiple transmission antennas to thus transmit high speed data without increasing a bandwidth of a system.
  • Beamforming is used to increase a signal to interference plus noise ratio (SINR) of a signal by adding a weight value according to a channel state at multiple antennas.
  • the weight value may be represented by a weight vector or a weight matrix, and it is called a precoding vector or a precoding matrix.
  • Spatial multiplexing includes spatial multiplexing for a single user and spatial multiplexing for multiple users.
  • the spatial multiplexing for a single user is called a single user MIMO (SU-MIMO), and the spatial multiplexing for multiple users is called spatial division multiple access (SDMA) or multi-user MIMO (MU-MIMO).
  • SDMA spatial division multiple access
  • MU-MIMO multi-user MIMO
  • the MIMO channel may be disintegrated into independent channels. If the number of transmission antennas is Nt and the number of reception antennas is Nr, the number of independent channels Ni is Ni ⁇ min ⁇ Nt, Nr ⁇ . Each independent channel may be a spatial layer.
  • a rank is the number of non-zero eigen value of the MIMO channel, which may be defined as the number of spatial streams that can be multiplexed.
  • the codebook-based precoding scheme is a scheme of preprocessing data by using a precoding matrix most similar to a MIMO channel among previously determined precoding matrices.
  • a PMI Precoding Matrix Indicator
  • a codebook is comprised of a codebook set that may represent a spatial channel. In order to enhance a data transfer rate, the number of antennas is required to be increased, and here, as the number of antennas is increased, the codebook should include more codebook sets.
  • FIG. 2 is a schematic flow chart illustrating an example of data processing between an eNodeB and a UE in a multi-antenna system.
  • an eNodeB (or eNB) transmits data to a UE (S210).
  • the eNodeB may perform precoding on input symbols by using a precoding matrix including a plurality of rows and columns and transmit the precoded symbols, namely, data.
  • the eNodeB may select a precoding matrix by using a codebook including at least one precoding matrix.
  • the eNodeB may include a scheduler, a channel encoder/mapper, a MIMO encoder, an OFDM modulator, or the like.
  • the eNodeB may include Nt (Nt>1) number of transmission antennas.
  • the scheduler receives data from N number of users and outputs K number of streams to be transmitted at a time.
  • the scheduler determines a user to which transmission is made with available radio resource by using channel information regarding each user or transmitted from each user, and a transfer rate.
  • the scheduler may extract channel information from feedback information and select a code rate, a modulation and coding scheme (MCS), or the like.
  • MCS modulation and coding scheme
  • the feedback information may include control information such as CQI (Channel Quality Indicator), CSI (Channel State Information), CCM (Channel Covariance Matrix), PW (Precoding Weight), CR (Channel Rank), and the like.
  • CQI Channel Quality Indicator
  • CSI Channel State Information
  • CCM Channel Covariance Matrix
  • PW Precoding Weight
  • CR Channel Rank
  • the CSI may include a channel matrix, a channel correlation matrix, a quantized channel matrix, or a quantized channel correlation matrix, a PMI, and the like, between a transmitter and a receiver.
  • the CQI may be a signal-to-noise ratio (SNR), a signal-to-interference and noise ratio (SINR), or the like between a transmitter and a receiver.
  • the channel encoder/mapper encodes an input stream according to a determined coding scheme to form coded data, and maps the coded data to symbols representing a position on a signal constellation.
  • the MIMO encoder performs precoding on input symbols.
  • Precoding is a scheme of preprocessing a symbol to be transmitted, and among the precoding schemes are RBF (random beamforming), ZFBF (zero forcing beamforming), and the like, which generates a symbol by applying a weight vector, a precoding matrix, or the like.
  • the OFDM modulator allocates input symbols to an appropriate subcarrier and transmits the same via a transmission antenna.
  • the UE transmits feedback with respect to the data received from the eNodeB (S220).
  • the UE may include an OFDM demodulator, a channel estimator, a MIMO decoder, a channel decoder/demapper, a feedback information acquirer, and the like.
  • the UE may include Nr (Nr>1) number of reception antennas.
  • a signal received from a reception antenna is demodulated by the OFDM demodulator, the channel estimator estimates a channel, and a MIMO decoder performs postprocessing corresponding to the MIMO encoder.
  • the decoder/demapper demaps the input symbols into encoded data and decodes encoded data to restore the original data.
  • the feedback information acquirer generates user information including a CSI, a CQI, a PMI, and the like.
  • the generated user information may be configured as feedback data and transmitted to the eNodeB.
  • control information such as a CQI, a CSI, a channel covariance matrix, a precoding weight, a channel rank, and the like, may be required.
  • control information are feedback information that may be reported via a feedback channel.
  • the precoding scheme is a MIMO scheme of preprocessing a transmission data stream by using a preprocessing weight and transmitting the same. Equation 1 below shows a precoding scheme of preprocessing a transmission data stream x by using a preprocessing weight.
  • W(i) is a precoding matrix
  • the UE may retain a codebook including a precoding matrix previously determined between the UE and the eNodeB.
  • the UE may estimate a channel and determine the most appropriate precoding matrix.
  • the UE may select a precoding matrix that maximizes channel performance, select a precoding matrix indicator (PMI) with respect to the selected precoding matrix, and report the same.
  • PMI precoding matrix indicator
  • a precoding matrix that is able to maximize average throughput of resources of a certain band may be selected.
  • a precoding matrix that maximizes reception power in a receiver may be selected.
  • a precoding matrix that maximizes an SINR Signal to Interference plus Noise Ratio
  • the UE feeds back the index (PMI) indicating the determined precoding matrix to the eNodeB.
  • the eNodeB may select the precoding matrix indicated by the feedback PMI from the codebook and use the same for a data transmission.
  • a scheme of using a precoding weight according to a channel state is called a CL (Closed-Loop) MIMO scheme.
  • a transmitter e.g., the eNodeB copes with a channel situation by utilizing channel state information (CSI) as feedback information transmitted from a receiver, e.g., the UE.
  • the CSI may include the PMI and be transmitted.
  • a scheme of using a precoding weight according to a certain rule irrespective of a channel state is called an OL (Open-Loop) MIMO scheme.
  • step S210 is performed by the eNodeB and the operation described in step S220 is performed by the UE, but the present invention is not limited thereto and the operation described in step S210 may be performed by the UE and the operation described in step S220 may be performed by the eNodeB.
  • an uplink channel or a downlink channel is required to be estimated for a data transmission/reception, system synchronization acquirement, channel information feedback, or the like.
  • a process of compensating for distortion of a signal caused by a rapid change in an environment to restore a transmission signal is called a channel estimation.
  • a channel state with respect to a cell to which the UE belongs or a different cell may also be required to be measured.
  • a reference signal (RS) known by a transmitter and receiver is used.
  • the receiver may estimate a channel based on the reference signal of the received signal and compensate for a channel value to accurately obtain data transmitted from the transmitter.
  • the reference signal transmitted by the transmitter is p
  • channel information undergone by the reference signal during a transmission is h
  • thermal noise generated from the receiver is n
  • a signal received by the receiver is y
  • y h ⁇ p + n .
  • the receiver already knows the reference signal p, when an LS (Least Square) scheme is used, the channel information can be estimated.
  • the channel estimation value estimaed by using the reference signal P relies on the value , so in order to accurately estiamed the h value, is required to be converged on 0 so as to minimize an influence thereof.
  • the OFDM system there are a scheme of allocating the reference signal to every subcarrier and a scheme of allocating the reference signal between data subcarriers transmitting data.
  • a signal comprised of only the reference signal is used in order to obtain a gain of channel estimation performance.
  • channel estimation performance can be improved in comparison to a scheme of allocating the reference signal between data subcarriers.
  • the scheme of allocating the reference signal between data subcarriers may be used to increase the amount of data transmission.
  • the reference signal is transmitted by generating a signal from a sequence of the reference signal.
  • the reference signal sequence one or more of various sequences having excellent correlation characteristics may be used.
  • a CAZAC Constant Amplitude Zero Auto-Correlation
  • ZC Zero Auto-Chu
  • a PN pseudo-noise sequence
  • m-sequence a gold sequence
  • Kasami sequence a Kasami sequence
  • various other sequences having excellent correlation characteristics may be used according to a system context.
  • the reference signal sequence may be cyclic-extended or truncated to be used in order to adjust a length of a sequence, and may be modulated in various forms through BPSK (Binary Phase Shift Keying) or QPSK (Quadrature Phase Shift Keying) so as to be mapped to a resource element (RE).
  • BPSK Binary Phase Shift Keying
  • QPSK Quadrature Phase Shift Keying
  • Downlink references signal include a cell-specific reference signal (CRS), an MBSFN (Multimedia Broadcast and multicast Single Frequency Network) reference signal, a UE-specific RS, a positioning RS, a channel state information reference signal (CSI-RS), and the like.
  • CRS cell-specific reference signal
  • MBSFN Multimedia Broadcast and multicast Single Frequency Network
  • UE-specific RS a UE-specific RS
  • positioning RS a positioning RS
  • CSI-RS channel state information reference signal
  • the CRS a reference signal transmitted to every UE within a cell, is used to estimate a channel.
  • the CRS may be transmitted in every downlink subframe within a cell supporting a PDSCH transmission.
  • the MBSFN RS may be transmitted in a subframe allocated for an MBSFN transmission.
  • MBMS Multimedia Broadcast Multicast Service
  • the PRS may be used to measure a location of a UE.
  • the PRS may be transmitted only through a resource block within a downlink subframe allocated to transmit the PRS.
  • the CSI-RS may be used to estimate channel state information.
  • the CSI-RS is relatively sparsely disposed in the frequency domain or the time domain and transmitted in a subframe having a certain period.
  • a CQI Channel Quality Indicator
  • PMI Precoding Matrix Indicator
  • RI Rank Indicator
  • the UE-specific RS is a reference signal received by a particular UE or a particular UE group within a cell. Since the UE-specific RS is largely used for data modulation of a particular UE or a particular UE group, it may also be called a DM-RS (Demodulation RS).
  • DM-RS Demodulation RS
  • the CRS may be transmitted in every downlink subframe in a cell supporting a PDSCH transmission. Also, the CRS may be transmitted through one or more of 0 to 3 antenna ports.
  • a reference signal sequence used for generating a CRS is defined as shwon in Equation 3 below.
  • n s is the number of slots within a radio frame, and 1 is the number of OFDM symbols within a slot. Also, indicates a maximum number of downlink resource blocks.
  • N CP has a value 1 in the case of a normal CP (Cyclic Prefix) and has a value 0 in the case of an extended CP.
  • N cell ID indicates a cell ID in a physical layer (physical layer cell ID).
  • the reference signal sequence is mapped to a complex modulation symbol with respect to an antenna port p of the slot n s .
  • a mapping relationship between and is expressed as shown in Equation 5 below.
  • N DL RB indicates the number of downlink resource blocks. Also, the values v and v shift can be obtained as expressed in Equation 6 below.
  • the CRS is generated based on a cell ID.
  • Resource elements (REs) (k,l) used for transmitting the generated CRS to an antenna port within a slot are not used for a transmission made in a different antenna port within the same slot.
  • FIG. 3 is a view schematically showing an example in which CRSs are mapped to REs in case of the normal CP according to the foregoing description.
  • R p is an RE used for a CRS transmission in an antenna port p.
  • FIG. 4 is a view schematically showing an example in which CRSs are mapped to REs in case of an extended CP. As shown in FIGS. 3 and 4, the CRSs are mapped to REs in a certain pattern.
  • a transmission and reception may be performed between a UE and a multi-cell and/or Multi-Points by employing a CoMP (Coordinated Multi Point) scheme.
  • a CoMP system is also called a cooperation type multi-transmission and reception system.
  • points are a set of geographically co-located transmission antennas. Sectors may correspond to different points although they are sectors of the same site.
  • a serving point is a point through which a UE receives a PBCH.
  • a plurality of serving points may exist. When a plurality of serving points exist, they may form a set.
  • the serving point may include a concept of a serving cell.
  • a control signaling point is a point through which a UE receives a UE-specific control signal, and a plurality of control signaling points may exist. When a plurality of control signaling points exist, they may form a set.
  • the control signaling point also includes a concept of a serving cell. Points used for transmitting a PDSCH to a particular UE may be serving points of a UE and/or control signaling points or may not.
  • CoMP scenarios include first to fourth CoMP scenarios as follows.
  • FIG. 5 is a view schematically showing a first CoMP scenario.
  • the first CoMP scenario relates to a homogeneous network with intra-site CoMP.
  • a CoMP set is configured among three different cells (or sectors) configured by an eNodeB.
  • the CoMP set refers to a set of (geographically separated) points that directly/indirectly participating in a data transmission with respect to a certain UE in a certain time-frequency resource.
  • the CoMP set may be transparent or not with respect to a corresponding UE.
  • directly participating in a data transmission refers to that a corresponding point actually transmits data in a corresponding time-frequency resource.
  • Indirectly participating in a data transmission refers to that corresponding point, as a candidate point with respect to a data transmission, does not actually transmit data in the corresponding time-frequency resource but contributes to determining scheduling/beamforming, or the like.
  • FIG. 6 is a view schematically showing a second CoMP scenario.
  • the second CoMP scenario relates to a homogeneous network with high Tx Power RRH (Remote Radio Head).
  • the RRH is a device configured to have only an RF (Radio Frequency) part by dividing eNodeB equipment into the RF part and a baseband part.
  • the RRH may include an A/D converter (Analog to Digital Converter), an up/down converter, in addition to an RF circuitry. Since the RRH has a small size by having only the RF part, it can extend coverage without an installation of a base station.
  • the RRH may be connected to the eNodeB through an optical fiber, or the like.
  • a CoMP set is configured between eNodeBs, and the eNodeBs may share data required for operating the CoMP system through a wired/wireless network (e.g., an optical fiber) connecting the eNodeBs.
  • eNodeBs are taken as an example for the convenience of explanation, but points constituting a CoMP set in the second CoMP scenario may also include RRHs as well as eNodeBs.
  • a wired network is established between the eNodeB and the RRHs, and information required for operating the CoMP system may be s hared through the wired network.
  • FIG. 7 is a view schematically showing third and fourth CoMP scenarios.
  • the third CoMP scenario relates to a heterogeneous network with low power RRHs within the macro cell coverage.
  • the transmission/reception points generated by the RRHs have cell IDs different from that of a macro cell.
  • the fourth CoMP scenario also relates to a heterogeneous network with low power RRHs within the macro cell coverage, but unlike the third CoMP scenario, transmission/reception points generated by RRHs have the same cell ID as that of a macro cell.
  • the CoMP transmission point(s) refers to a point or a set of points transmitting data to a certain UE
  • the CoMP reception point(s) refers to a point or a set of points receiving data from a certain UE.
  • a category of the CoMP includes joint processing (JP) and coordinated scheduling/beamforming (CS/CB), and here, JP and CS/CB may be mixed.
  • JP data with respect to a UE is available in at least one point of a CoMP set in a certain time-frequency resource.
  • JP includes a joint transmission (JT) and dynamic point selection (DPS).
  • JT refers to performing a data transmission from Multi-Points belonging to a CoMP to one UE or a plurality of UEs in a time-frequency resource.
  • DPS a data transmission is performed from one point of a CoMP set in a time-domain resource, and here, a transmission point may be changed in every subframe, and it includes a transmission point changing over a resource block pair within a subframe. Transmitted data may be simultaneously used in a plurality of points.
  • DPS includes a dynamic cell selection (DCS).
  • DCS dynamic cell selection
  • CS/CB data is transmitted from one point of a CoMP set with respect to a time-frequency resource.
  • User scheduling/beamforming is determined through coordination between points of a corresponding CoMP set.
  • a used point is dynamically or semi-statically.
  • dynamically selecting a point a transmission is performed from one point at a time, and here, a transmission point may be changed in every subframe and it includes a transmission points changing over an RB pair within a subframe.
  • selecting a point semi-statically a transmission is performed from only one point at a time and a transmission point may be changed only in a semi-static manner.
  • JP and CS/CB may be mixed.
  • some points of a CoMP set may transmit data to a target UE according to JP, while the other points of the CoMP set may perform CS/CB.
  • a PDCCH may be transmitted in first one to three OFDM symbols, a maximum of four OFDM symbols, in a downlink subframe.
  • the transmission points e.g., RRHs
  • the different cells may have different PDCCH regions, so there may be REs that may not be used for downlink JT-CoMP.
  • PDSCH regions e.g., starting positions of the PDSCH, are different in the downlink transmission of each cell, making it difficult for the UE to combine received signals.
  • FIG. 8 is a view schematically showing an example in which positions of OFDM symbols from which PDSCH region starts do not match up among cells in case of JT CoMP.
  • JP-CoMP in case of a first cell among cells constituting a CoMP set, a first OFDM symbol of a subframe is used for a PDCCH transmission, and in case of a second cell having a cell ID different from that of the first cell, first three OFDM symbols of a subframe are used for a PDCCH transmission.
  • CRS since a reference signal sequence is generated based on a cell ID, when cell IDs are different, the patterns of CRSs transmitted to downlink are different.
  • a CRS and a PDSCH transmitted from different transmission points in the corresponding subframe may collide and REs, which may not be used for downlink JT-CoMP, may be generated.
  • FIG. 9 is a view schematically showing an example in which interference (collision) occurs between a PDSCH and a CRS transmitted from different cells in the case of the JT-CoMP.
  • interference collision
  • FIG. 9 in the case of JP-CoMP, a pattern of CRSs transmitted by the first cell among cells constituting a CoMP set and a pattern of CRSs transmitted by a second cell having a cell ID different from that of the first cell are different.
  • the cell IDs of the transmission points e.g., the RRHs
  • cell-specific CRS frequency shifts namely, v shift in Equation 6
  • the patterns of the CRSs transmitted from the different transmission points are different.
  • interference may occur between the PDSCHs and the CRSs transmitted from different transmission points.
  • JP-CoMP when the state in which the starting positions of the PDSCHs transmitted from the different transmission points are not aligned in one subframe or the PDSCHs are interfered is neglected or left as it is, communication performance is greatly degraded. Thus, information regarding the situation is required to be transferred to a UE, and controlling such as muting PDSCHs and/or CRSs or recovering PDCCH regions, or the like, is required in the downlink transmission.
  • PDCCHs from the respective RRHs may have different regions. Namely, PDCCHs from respective RRHs may be transmitted by using different numbers of OFDM symbols. How many OFDM symbols are to be used for a PDCCH transmission may be dynamically changed according to a value of CFI (Control Format Indicator) transmitted on a PCFICH (Physical Control Format Indicator Channel).
  • CFI Control Format Indicator
  • PCFICH Physical Control Format Indicator Channel
  • Table 1 below shows an example of CFI values and CFI codewords.
  • CFI values indicate the number of OFDM symbols used for a PDCCH transmission.
  • the number of downlink RBs is more than 10, when the CFI value is 1, one OFDM symbol is used for a PDCCH transmission, when the CFI value is 2, two OFDM symbols are used for a PDCCH transmission, and when the CFI value is 3, three OFDM symbols are used for a PDCCH transmission.
  • the number of downlink RBs is 10 or smaller, when the CFI value is 1, two OFDM symbols are used for a PDCCH transmission, when the CFI value is 2, three OFDM symbols are used for a PDCCH transmission, and when the CFI value is 3, four OFDM symbols are used for a PDCCH transmission.
  • the CFI value 4 is reserved, rather than being used.
  • CRSs transmitted from cells having different cell IDs may have different CRS patterns due to different frequency shifts.
  • mapping of data to resource elements (REs) in the PDSCH region may be affected by the CRS patterns so as to be changed between transmission points having different cell IDs.
  • the PDSCHs in the second and OFDM symbols of the first cell may be muted. This may be considered that the PDSCHs are muted from viewpoint of the first cell in which the starting positions of the PDSCHs are changed.
  • the starting positions of the PDSCHs may be aligned by conforming the PDSCH starting position 2 of the second cell to the PDSCH starting position S1 of the first cell. This may be expressed such that the PDSCHs are recovered in the PDCCH region from the viewpoint of the second cell in which the starting positions of the PDSCHs are changed.
  • muting refers to not mapping data (symbol) to a resource to be muted, unlike puncturing in which after data is mapped to resource, symbols allocated to the corresponding to the resource are weeded out.
  • FIG. 10 is a view schematically showing puncturing and muting.
  • puncturing after symbols S1, S2, ... are allocated to respective resources, puncturing is performed.
  • FIG. 10(a) when a symbol desired to be punctured is mapped to RE2, the symbol S2 is punctured after being mapped to RE2.
  • muting a symbol is not mapped to an RE desired to be muted.
  • FIG. 10(b) when an RE desired to be muted is RE2, a symbol is not mapped to RE2 but mapped to a next RE.
  • PDSCHs are muted with respect to a portion corresponding to CSI-RSs of the second cell in the transmission from the first cell, and PDSCHs are muted with respect to a portion corresponding to CSI-RSs of the first cell in the transmission from the second cell.
  • CRSs similarly, when a collision with CRSs transmitted from different transmission points occurs, the collision may be prevented by muting the PDSCHs.
  • a method for transferring together muting information for the PDSCHs regarding the PDCCHs and muting information for the PDSCHs regarding the CRSs.
  • FIG. 11 is a view schematically showing cases of muting available within one subframe with respect to a normal CP.
  • positions of OFDM symbols 1110, 1140, 1150, and 1170 in which CRSs are positioned may be checked, and when the transmission point performs 4Tx transmission, positions of OFDM symbols 1120 and 1160 in which CRSs are positioned may be checked in addition.
  • FIG. 12 is a view schematically showing cases of muting available within one subframe with respect to an extended CP.
  • positions of OFDM symbols 1210, 1240, 1250, and 1270 in which CRSs are positioned may be checked, and when the transmission point performs 4Tx transmission, positions of OFDM symbols 1220 and 1260 in which CRSs are positioned may be checked in addition.
  • a collision occurs between channels and/or reference signals transmitted from respective transmission points within one subframe as follows: (1) Collision between PDCCH and PDSCH, (2) collision between PDSCH and CRS
  • JP(Joint Process)-CoMP in a downlink transmission from a transmission point of a first cell and a transmission point of a second cell, the number of OFDM symbols used for a PDCCH transmission, in other words, starting positions of PDSCH regions, within each subframe which is the same transmission time interval (TTI) may differ.
  • TTI transmission time interval
  • the collision problem may be solved by aligning transmission timing of the PDSCHs transmitted from the transmission points constituting a CoMP set.
  • the PDSCH starting positions (OFDM symbols from which PDSCH transmission starts) within the same subframe may be conformed as the latest PDSCH staring position.
  • a PDSCH transmission starts from the second OFDM symbol of the subframe, and in the transmission from a transmission point of the second cell, the PDSCH transmission starts from a fourth OFDM symbol.
  • PDSCHs in the second and third OFDM symbols are muted, namely, the PDSCHs are not mapped to the second and third OFDM symbols, thereby aligning the transmission from the second cell and the starting positions of the PDSCHs.
  • PDSCH starting positions may be aligned to the earliest PDSCH starting position.
  • the starting positions of the PDSCHs are changed to the second OFDM symbol, thereby aligning the starting positions of the PDSCHs in the transmission from the first cell and the starting positions of the PDSCHs in the transmission from the second cell.
  • the second cell it may be regarded that the PDSCHs are recovered in the PDCCH regions.
  • the PDSCH starting positions may be determined through a wired/wireless network between the respective transmission points constituting the CoMP set.
  • the points that transmit the control information e.g., the foregoing control signaling points, may inform the user about the starting position of the PDSCH or in what OFDM symbol the PDSCH is muted through a DCI (Downlink Control Information).
  • DCI Downlink Control Information
  • JP(Joint Process)-CoMP when the cell IDs of the transmission points constituting the CoMP set are different, the patterns of the CRSs in the downlink transmission from the respective transmission points are different. In this case, CRSs and PDSCHs may collide in the same resource positions, and the UE to which the JP-CoMP is applied cannot accurately combine information received from the respective transmission points.
  • the RE of the fifth OFDM symbol allocated to transmit a CRS in the first cell is allocated for a transmission of a PDSCH in the second cell.
  • the PDSCH is muted to prevent a collision between the PDSCH and the CRS.
  • the PDSCHs in the fifth OFDM symbols in the transmission from the first cell and the transmission from the second cell are muted to thus solve the collision between the CRS and the PDSCH.
  • the OFDM symbols in which the PDSCHs are muted may be determined through a wired/wireless network between the respective transmission points constituting the CoMP set.
  • a point that transmits control information e.g., the foregoing control signaling point or a serving point, may inform the user about the OFDM symbols in which the PDSCHs are muted on the downlink control channel, namely, a DCI.
  • information regarding muting of the PDSCHs with respect to the collisions (the collision between the PDCCH and the PDSCH and the collision between the PDSCH and the CRS) of the foregoing two cases within one subframe is transmitted together or simultaneously to the UE.
  • the point that transmits control information transmits information regarding muting of the PDSCH or avoiding the collision between the PDCCH and the PDSCH and the information regarding muting of the PDSCH for avoiding the collision between the CRS and the PDSCH separately to the UE, overhead in transmissions would further increase.
  • the information regarding the muting of the PDSCH with respect to the PDCCH and the CRS is jointly encoded and transmitted, thus greatly reducing overhead.
  • FIG. 9 it may be checked that there are PDSCH symbols commonly muted with respect to the PDCCH and the CRS. Since there is a region in which the PDSCH can be commonly muted with respect to the PDCCH and the CRS, overhead can be further reduced by jointly encoding the information regarding the muting of the PDSCH with respect to the PDCCH and the information regarding muting of the PDSCH with respect to the CRS.
  • a method of dynamically signaling muting information to the UE by adding a muting information index indicating the information regarding the muting of the PDSCH with respect to the PDCCH and the CRS in the DCI (Downlink Control Information) may be considered.
  • the muting information index indicates the information regarding muting of the PDSCH with respect to the PDCCH and the CRS in a muting information table.
  • a muting information table allowing for the use of muting information index, a table showing starting position of the PDSCH of a corresponding subframe and information regarding muting of the PDSCH with respect to the CRS may be configured.
  • a table showing information regarding OFDM symbols in which the PDSCH is muted in the downlink subframe from the transmission points may be configured.
  • the muting information table may be used.
  • the muting information table may be comprised of (1) the number of OFDM symbols that may be used by the PDCCH, namely, the OFDM symbols that may become PDSCH starting position, (2) OFDM symbols in which the CRS is positioned, namely, the OFDM symbols in which the CRS may be positioned in case of 2Tx and 4Tx, and (3) muting information index indicating a combination of (1) and (2).
  • Table 2 shows an example of muting information table for simultaneously transferring information regarding a starting position of the PDSCH within a corresponding subframe and information regarding PDSCH muted with respect to the CRS simultaneously by three bits.
  • Table 2 information regarding the starting positions of the PDSCHs within a corresponding subframe and information regarding PDSCHs muted with respect to the CRS are jointly indicated.
  • Table 2 may be previously stored in the UE and the transmission points, or may be determined among transmission points and transferred to the UE through a higher layer message.
  • an index indicating the starting positions of the PDSCHs and the PDSCHs muted with respect to the CRS may be transferred to the UE through the DCI in the physical control channel.
  • the starting positions of the PDSCHs indicated by the muting information index and the muted PDSCHs may be the starting positions of the PDSCHs and the muted PDSCHs in the subframe in which the corresponding muting information index was transmitted.
  • the information regarding the starting position of the PDSCH is information indicating an OFDM symbol in which the PDSCH starts in the downlink transmission from the respective transmission points.
  • the information regarding the starting position of the PDSCH may also be information indicating that the PDSCHs transmitted from the respective transmission points start from one indicated OFDM symbol within the subframe by muting some of PDSCHs from different transmission points or recovering the PDSCHs in the PDCCH regions.
  • the PDSCH muting with respect to 2Tx indicates muting of the PDSCH with respect to the OFDM symbol in which the CRS is positioned
  • the PDSCH muting with respect to 4Tx indicates muting of the PDSCH with respect to the OFDM symbol in which the CRS is positioned
  • the muting information index transferred in the DCI when the muting information index transferred in the DCI is 000, it indicates that the PDSCHs transmitted to the UE from the respective transmission points start from the second OFDM symbol and there is no PDSCH muted with respect to the CRS.
  • the muting information index transferred in the DCI when the muting information index transferred in the DCI is 100, it indicates that the PDSCHs transmitted to the UE from the respective transmission points start from the third OFDM symbol and PDSCH is muted only with respect to the CRS transmitted by 2Tx.
  • the first OFDM symbol is used for a PDCCH transmission all the time, and PDSCHs are muted in the OFDM symbols 1140, 1150, and 1170 in which 2Tx CRS are positioned.
  • the muting information index transferred in the DCI when the muting information index transferred in the DCI is 111, it indicates that the PDSCHs transmitted to the UE from the respective transmission points start from the fourth OFDM symbol and PDSCH is muted with respect to the CRS transmitted by 4Tx.
  • CRSs are positioned in the OFDM symbols 1120 and 1160 in addition to the pattern of the 2Tx CRS.
  • the PDSCHs are muted in the OFDM symbols 1120, 1140, 1150, 1160, and 1170.
  • Table 2 can be applied upon be dynamically switched among all the CoMP schemes, namely, between JP (Joint Processing) and CS/CB (Coordinated Scheduling/Beamforming). For example, muting of PDSCH with respect to CRS is applied in case of the JP, the muting information indices 000, 011, and 101 may be applied to a scheme other than JP, namely, to CS/CB.
  • Table 2 may also be applied to PDSCH recovery in the PDCCH region. For example, a transmission is performed from the first transmission point in the first subframe, the CFI is 3 and a PDSCH transmission is performed from the fourth OFDM symbol, but according to the DPS result, transmission is performed from the second transmission point in the second subframe.
  • muting information index of 011 may be transmitted to the UE to indicate that a PDSCH transmission from the third OFDM symbol.
  • the CFI is 3
  • PDSCH is restored in the PDCCH region.
  • muting information regarding 4Tx CRS when the second OFDM symbol is used for a PDCCH transmission namely, when the PDSCH transmission starts from the third OFDM symbol.
  • the muting regarding the 4Tx CRS when the PDSCH transmission starts from the third OFDM symbol has the same muting result, i.e., the same muting pattern, as that of the muting regarding the 4Tx CRS when the PDSCH transmission starts from the second OFDM symbol.
  • muting information regarding the 4Tx CRS when the PDSCH transmission starts from the third OFDM symbol and the muting information regarding the 4Tx CRS when the PDSCH transmission starts from the second OFDM symbol may be indicated by the same index.
  • the information regarding the two cases are indicated by the same index 010.
  • a different muting information table may be used.
  • the muting information used in this case may include the respective cases that can be derived in FIG. 11 and the muting information indexes indicating them like the embodiment regarding Table 2, but in this case, unlike the cases of Table 2, the muting information index is configured to indicate only the OFDM symbol in which a PDSCH is muted.
  • Table 3 shows an example of a muting information table for transferring information regarding PDSCH by 3 bits.
  • muting information of PDSCH to avoid a collision with PDCCH and muting information of PDSCH to avoid a collision with CRS are transferred together, but the UE is not required to discriminate whether or not corresponding PDSCH muting is related to PDCCH or CRS.
  • Table 3 only information of a muted PDSCH is transferred without discriminating whether or not it is related to PDCCH or CRS.
  • Table 3 shows an example when the number of normal CPs and the entire downlink RBs is greater than 10, and OFDM symbols in which PDSCHs are muted among from #0 OFDM symbol to #13 OFDM symbol of one subframe.
  • the OFDM symbols indicated for muting PDSCHs by the muting information index may be OFDM symbols of a subframe to which a corresponding muting information index has been transmitted.
  • Table 3 shows each case of OFDM symbol numbers in which PDSCH is muted substantially according to the meaning of each muting information index. Based on this, Table 3 can be derived. Thus, Table 3 may be an example of expressing OFDM symbol numbers in which PDSCH is substantially muted according to each muting information index in Table 2.
  • the case in which the number of entire downlink RBs is greater than 10 is described as an example, but the present invention can be also applicable to a case in which the number of entire downlink RBs is 10 or smaller.
  • the number of entire downlink RBs is 10 or smaller.
  • Table 2 when the number of entire downlink RBs is 10 or smaller, PDSCH starting positions may be changed to the third, fourth, and fifth symbols in the second, third, and fourth symbols.
  • FIG. 13 is a flow chart schematically illustrating an operation of an eNodeB in the system to which the present invention is applied.
  • a point transmitting control information determines a PDSCH to be muted in a corresponding subframe (S1310).
  • the PDSCH to be muted may be specified by a starting position of PDSCH (OFDM symbol in which PDSCH starts) and an OFDM in which PDSCH is muted with respect to CRS.
  • the PDSCH to be muted may be specified by only OFDM symbols in which PDSCH is muted. The muted PDSCH has been described in detail above.
  • a point or a serving point for transmitting control information may determine a CFI.
  • the CFI indicates the number of OFDM symbols used for a PDCCH transmission
  • an actual starting position of a PDCCH may be determined by the number of OFDM symbols indicated by the CFI and the OFDM symbols in which the PDSCH is muted.
  • a point transmitting control information may determine recovery of a PDSCH in the PDCCH region in case of the DCS (Dynamic Cell selection).
  • the PDSCH to be muted in the corresponding subframe may be determined through a wired/wireless network between transmission points constituting a CoMP set.
  • the point transmitting control information configures downlink control information (DCI) including muting information of the PDSCH determined in step S1310 (S1320).
  • the muting information included in the DCI may be a muting information index indicating a muting state of the corresponding subframe in the muting information table.
  • the muting information may be a table including OFDM symbols in which PDSCH is muted with respect to the starting positions of the PDSCHs and CRS, for example, the table such as Table 2.
  • the muting information table may be a table including OFDM symbols in which PDSCH is muted, such as, for example, Table 3.
  • the muting information table may be previously stored in the point transmitting the control information and the UE, or may be transferred from the point transmitting the control information to the UE through higher layer signaling.
  • the point or serving point transmitting the control information transmits the DCI including the muting information of the PDSCH to the UE to which CoMP is applied (S1330).
  • the UE may be a UE to which JP-CoMP is applied, or a UE to which CS/CB, other than JP, is applied.
  • the muting information table according to an embodiment of the present invention may support dynamically indicating the CoMP scheme besides JP-CoMP.
  • the mute information index included in the DCI is not limited to the JP-CoMP and may dynamically indicate the CS/CB
  • FIG. 14 is a view schematically showing an operation of a UE in the system to which the present invention is applied.
  • the UE receives downlink transmissions from respective transmission points and receives the DCI from the point or serving point transmitting the control information (S1410).
  • the control information S1410
  • cell IDs of the respective transmission points constituting a CoMP set are different
  • JP-CoMP JP-CoMP is performed, starting points of the PDSCHs transmitted from the respective transmission points are required to be aligned or a collision between CRS and PDSCH is required to be prevented.
  • the UE checks muting information of the PDSCHs included in the received DCI (S1420). As described above, the DCI received by the UE includes muting information of the PDSCHs.
  • the muting information of the PDSCHs included in the DCI may be a muting information index indicating muting state of the corresponding subframe in the muting information table.
  • the muting information table may be a table including OFDM symbols in which PDSCH is muted with respect to the starting positions of the PDSCHs and the CRS, such as, for example, such as Table 2.
  • the muting information table may be a table including OFDM symbols in which PDSCHs are muted, such as, for example, Table 3.
  • the muting information table may be previously stored in the point transmitting the control information and the UE, or may be transferred from the point transmitting the control information to the UE through higher layer signaling.
  • the UE combines data received in downlink (S1430).
  • the UE aligns starting positions of the PDSCHs received from the respective transmission points of the CoMP set based on the muting information of the PDSCH and avoid a collision between CRS and PDSCH.
  • the UE can successfully combines the data received from the respective transmission points.
  • FIG. 15 is a view schematically showing a structure of a UE in the system to which the present invention is applied.
  • the UE 1510 includes an RF unit 1520, a memory 1530, and a processor 1540.
  • the UE 1510 performs communication through an RF unit 1520.
  • the RF unit 1520 may include multiple antennas and support MIMO (Multi Input Multi Output) and CoMP.
  • the memory 1530 may store information required for the UE to perform communication.
  • the memory 1530 may store channel measurement information, a precoding matrix indicator, a codebook, and the like. Also, the memory 1530 may store the foregoing muting information table.
  • the processor 1540 implements the function, process, and/or method proposed in the present disclosure. For example, as described above, the processor 1540 may combine data received from the respective transmission points of the CoMP set based on muting information received through a DCI.
  • the processor 1540 may include a muting information detecting unit 1550 and a data combining unit 1560.
  • the muting information detecting unit 1550 may detect muting information regarding a corresponding subframe from the received DCI.
  • the data combining unit 1560 may successfully combine data received from the respective transmission points in the corresponding subframe based on the detected muting information.
  • FIG. 16 is a view schematically showing an operation of an eNodeB in a view schematically showing an operation of a UE in the system to which the present invention is applied.
  • a point 1610 transmitting control information includes a communication unit 1620, a memory 1630,and a processor 1640.
  • the point 1610 transmitting control information performs required communication through the communication unit 1620.
  • the communication unit 1620 may include multiple antennas and perform communication with a UE therethrough.
  • the multiple antennas of the communication unit 1620 may support MIMO and CoMP.
  • the communication unit 1620 may be connected to transmission points, e.g., RRHs, constituting a CoMP set through a wired/wireless network to transmit and receive required information.
  • the memory 1630 may store information required for communication.
  • the memory 1630 may store received measurement information, a codebook for determining a precoding matrix, and the like. Also, the memory 1630 may store the foregoing muting information table.
  • the processor 1640 implements the function, process, and/or method proposed in the present disclosure. For example, as described above, the processor 1640 may determine muting information, configure a DCI including the muting information, and transfer the muting information to the UE.
  • the processor 640 may include a muting information determining unit 1650 and a DCI configuring unit 1660.
  • the muting information determining unit 1650 may determine a PDSCH to be muted in a corresponding subframe.
  • the information regarding the PDSCH to be muted may include information regarding a starting position of the PDSCH and/or information regarding recovery of the PDSCH in a PDCCH region.
  • the muting information may be an index indicating a corresponding muting state in the muting information table.
  • the DCI configuring unit 1660 may configure a DCI including the muting information determined by the muting information determining unit 1650.
  • the methods are described based on the flow chart by sequential steps or blocks, but the present invention is not limited to the order of the steps, and a step may be performed in different order from another step as described above or simultaneously performed. It would be understood by a skilled person in the art that the steps are not exclusive, a different step may be included, or one or more of the steps of the flow chart may be deleted without affecting the scope of the present invention.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

L'invention porte sur un procédé et sur un appareil de transmission d'informations de commande en transmission CoMP (multipoints coordonnés) de liaison descendante, ainsi que sur un procédé et sur un appareil de réception de données associés. Le procédé de transmission d'informations de commande dans un système CoMP consiste à commander des canaux de données émis par des points d'émission d'un ensemble CoMP par rapport à des canaux de commande et des signaux de référence émis par les points d'émission ; à configurer des informations de commande de liaison descendante comprenant des informations concernant les canaux de données commandés. Dans l'environnement CoMP, des informations de commande servant à éviter un brouillage entre canaux de données et canaux de commande émis par des points d'émission respectifs et des informations de commande servant à éviter un brouillage entre canaux de données et signaux de référence sont transférées à un UE en une fois, ce qui réduit ainsi le surdébit d'informations de commande transférées à l'UE.
PCT/KR2012/006283 2011-08-19 2012-08-08 Procédé et appareil d'émission de signal de commande, et procédé et appareil de réception de données associés WO2013027947A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR10-2011-0083145 2011-08-19
KR1020110083145A KR20130020487A (ko) 2011-08-19 2011-08-19 제어 정보 전송 방법 및 장치와 이를 이용한 데이터 수신 방법 및 장치

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WO2013027947A2 true WO2013027947A2 (fr) 2013-02-28
WO2013027947A3 WO2013027947A3 (fr) 2013-05-16

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WO2018014964A1 (fr) * 2016-07-21 2018-01-25 Telefonaktiebolaget Lm Ericsson (Publ) Indication flexible de la position de départ du canal de données
US11700532B2 (en) 2016-08-10 2023-07-11 Huawei Technologies Co., Ltd. Data channel sending and receiving methods, network device, and terminal
US11997044B2 (en) 2023-05-04 2024-05-28 Telefonaktiebolaget Lm Ericsson (Publ) Flexible indication for start position of data channel

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US20160128022A1 (en) * 2013-05-31 2016-05-05 Lg Electronics Inc. Method and apparatus for receiving control information for removing interference of adjacent cell in wireless access system
KR102186144B1 (ko) * 2014-02-21 2020-12-03 삼성전자주식회사 다중 입력 다중 출력 시스템에서 채널 관련 정보 송/수신 장치 및 방법
US10492201B2 (en) 2015-12-06 2019-11-26 Lg Electronics Inc. Method and apparatus for communication using multiple TTI structures

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WO2010110588A2 (fr) * 2009-03-23 2010-09-30 엘지전자주식회사 Procédé et appareil permettant de transmettre un signal de référence dans un système à plusieurs antennes
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WO2018014964A1 (fr) * 2016-07-21 2018-01-25 Telefonaktiebolaget Lm Ericsson (Publ) Indication flexible de la position de départ du canal de données
US11038651B2 (en) 2016-07-21 2021-06-15 Telefonaktiebolaget Lm Ericsson (Publ) Flexible indication for start position of data channel
US11683143B2 (en) 2016-07-21 2023-06-20 Telefonaktiebolaget Lm Ericsson (Publ) Flexible indication for start position of data channel
US11700532B2 (en) 2016-08-10 2023-07-11 Huawei Technologies Co., Ltd. Data channel sending and receiving methods, network device, and terminal
EP3490286B1 (fr) * 2016-08-10 2024-01-24 Huawei Technologies Co., Ltd. Procédé d'envoi et de réception de canal de données, dispositif de réseau et terminal
US11997044B2 (en) 2023-05-04 2024-05-28 Telefonaktiebolaget Lm Ericsson (Publ) Flexible indication for start position of data channel

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WO2013027947A3 (fr) 2013-05-16

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