WO2012169799A2 - Système de communication sans fil à antennes réparties et procédé associé - Google Patents

Système de communication sans fil à antennes réparties et procédé associé Download PDF

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Publication number
WO2012169799A2
WO2012169799A2 PCT/KR2012/004495 KR2012004495W WO2012169799A2 WO 2012169799 A2 WO2012169799 A2 WO 2012169799A2 KR 2012004495 W KR2012004495 W KR 2012004495W WO 2012169799 A2 WO2012169799 A2 WO 2012169799A2
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Prior art keywords
terminal
base station
crs
cell
csi
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PCT/KR2012/004495
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English (en)
Korean (ko)
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WO2012169799A3 (fr
WO2012169799A9 (fr
Inventor
고영조
노태균
서방원
안재영
Original Assignee
한국전자통신연구원
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Priority claimed from KR1020120059324A external-priority patent/KR101840642B1/ko
Application filed by 한국전자통신연구원 filed Critical 한국전자통신연구원
Priority to US14/124,433 priority Critical patent/US9712298B2/en
Publication of WO2012169799A2 publication Critical patent/WO2012169799A2/fr
Publication of WO2012169799A3 publication Critical patent/WO2012169799A3/fr
Publication of WO2012169799A9 publication Critical patent/WO2012169799A9/fr

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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
    • 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
    • H04L5/005—Allocation of pilot signals, i.e. of signals known to the receiver of common pilots, i.e. pilots destined for multiple users or terminals

Definitions

  • the present invention relates to a wireless communication system, and more particularly, to a distributed antenna wireless communication system and a method which can be applied to a wireless communication system having a plurality of transmission points geographically separated from each other in a cell.
  • wireless communication systems are accelerating data rates.
  • the CoMP transmission / reception method represents a transmission / reception operation between two or more points (site, cell, base station, distributed antenna, etc.) and one or more terminals.
  • the CoMP transmission / reception method may be classified into uplink CoMP transmission and downlink CoMP reception.
  • Uplink CoMP reception is a method in which a predetermined terminal transmits a signal to a plurality of points geographically separated from each other, and joint reception of a signal received from the terminal at the plurality of points.
  • the UE does not need to know from which network node a signal is transmitted or what processing is performed on the received signal, and only needs to know what downlink signaling is provided in connection with the uplink transmission. . Therefore, uplink CoMP reception can be introduced without major changes in the specification of the air interface.
  • Downlink CoMP transmission is a method in which a plurality of geographically separated points collaborate to transmit signals to one or more terminals.
  • the downlink CoMP category is jointly processed (JP: Joint Processing) and cooperative beamforming / Coordinated Scheduling (CB / CS: Coordinated Beamforming / Coordinated Scheduling), and Joint Processing (JP) again performs simultaneous PDSCH (Physical Downlink Shared CHannel) transmission at multiple points. Joint transmission) and a case of performing PDSCH transmission at one point are divided into dynamic point selection (DPS).
  • JP Joint Processing
  • DPS dynamic point selection
  • JT Joint transmission
  • the dynamic point selection (DPS) method is a method of PDSCH transmission at one point in a CoMP cooperative set at a specific moment.
  • the transmission point may be dynamically changed and performance may be degraded due to a feedback delay.
  • the cooperative beamforming / cooperative scheduling (CB / CS) method is a method of transmitting data to a terminal only at a serving point at a specific moment, and is a passive method of avoiding interference between transmission points, and thus a large capacity increase can be expected.
  • No backhaul may be used when user scheduling / beamforming requires information exchange between base stations having different point-to-point cooperation corresponding to CoMP cooperation sets.
  • PCIs physical layer cell IDs
  • the above-described conventional standards have a problem that cannot be applied in a multi-point transmission environment in which a plurality of points belong to the same cell and have the same physical layer cell ID.
  • An object of the present invention for overcoming the above-mentioned disadvantages is to provide a plurality of points in a network environment where a plurality of points belong to the same cell and have the same physical layer cell ID, or a network environment where a plurality of points have different physical layer cell IDs.
  • Disclosed is a distributed antenna wireless communication system and method for enabling efficient communication using points.
  • a distributed antenna wireless communication method including a base station, a first point, and a second point, wherein each of the base stations includes at least one terminal. And allocating a virtual cell ID for generating an uplink signal of each UE and providing virtual cell ID information allocated by the base station for each UE.
  • the step of the base station to allocate the virtual cell ID for generating the uplink signal for each terminal the base station allocates the same virtual cell ID in the downlink and uplink for each terminal, or the base station for downlink and In the uplink, different virtual cell IDs may be allocated.
  • the base station uses virtual cell ID information for downlink and virtual for uplink for each terminal. Cell ID information may be independently signaled.
  • the terminal obtaining a virtual cell ID from the base station and the terminal of the demodulation reference signal for demodulation of the uplink signal Setting a base sequence and cyclic shift hopping of the demodulation reference signal using the virtual cell ID for setting.
  • the step of assigning, by the base station, an initialization parameter for generating a pseudo random sequence to each of the at least one terminal is performed by the base station according to a CSI channel state information reference signal (RS) pattern set to each of the at least one terminal.
  • RS channel state information reference signal
  • the same initialization parameter may be mapped in the link and the uplink, or the base station may map different initialization parameters in the uplink and the downlink for each of the at least one terminal.
  • the distributed antenna wireless communication method for achieving the object of the present invention in the distributed antenna wireless communication method comprising a base station and at least one point, the base station to each of at least one terminal Allocating different physical layer cell IDs and setting, by the base station, information for generating uplink demodulation reference signals of each of the at least one terminal for each terminal.
  • the step of the base station to set the information for generating the uplink demodulation reference signal of each of the at least one terminal for each terminal the base station (a) for each terminal base sequence index (base sequence index) and sequence Set the group hopping information to be the same, or (b) set the base sequence index to be different for each terminal and the sequence group hopping information to be the same, or (c) the base sequence index to be identical for each terminal and sequence group hopping.
  • the information can be set differently.
  • the distributed antenna wireless communication method for achieving the object of the present invention in the distributed antenna wireless communication method comprising a base station and a plurality of points, the base station is used for demodulation of the downlink signal And allocating a virtual cell ID for initializing a demodulation reference signal to the terminal and providing the terminal with the allocated virtual cell ID information.
  • the distributed antenna wireless communication method for achieving the object of the present invention is a sequence of the downlink signal demodulation reference signal by applying a virtual cell ID allocated from the base station in place of the physical layer cell ID And demodulating a downlink signal based on the sequence of the demodulation reference signal acquired by the terminal.
  • CRS Cell-specific Reference Signal
  • EPRE Energy Per Resource Element
  • the distributed antenna wireless communication method for achieving the object of the present invention is a terminal cell-specific reference signal (CRS) Energy Per Resource Element (EPRE) is set equally at a plurality of points from the base station Receiving information, the terminal estimating a downlink path loss based on the CRS EPRE information, and the terminal acquiring an uplink path loss based on the downlink path loss.
  • CRS cell-specific reference signal
  • EPRE Energy Per Resource Element
  • the distributed antenna wireless communication method for achieving the object of the present invention in the distributed antenna wireless communication method comprising a base station and a plurality of points, the base station is a CRS (Cell-specific Reference Signal) ) EPRE (Energy Per Resource Element), CSI RS EPRE for each of at least one Channel State Information (CSI) RS pattern, ratio of Physical Downlink Shared Channel (PDSCH) EPRE and CRS EPRE, PDSCH EPRE for each CSI RS pattern And CSI RS EPRE, at least one CSI RS EPRE for each of the at least one CSI RS pattern, CRS EPRE, the ratio of the CRS EPRE to the CRE EPRS and the CRS EPRE, or at least one CSI RS CSI RS-based PDSCH for each of the patterns transmits at least one of the ratio of the EPRE of the RS-based PDSCH and the EPRE of the CSI.
  • CRS Cell-specific Reference Signal
  • EPRE Energy Per Resource Element
  • the distributed antenna wireless communication method for achieving the object of the present invention in a distributed antenna wireless communication method comprising a base station and a plurality of points, at a point and a terminal for transmitting a downlink signal If the points for receiving the transmitted uplink signal are the same, the terminal acquires the downlink path loss based on the reference signal pattern provided from the base station, and receives the point for transmitting the downlink signal and the uplink signal transmitted from the terminal. Obtaining a downlink path loss based on the reference signal pattern provided from the base station and energy information of resources constituting the reference signal pattern when the points to be different are different from each other; and uplink based on the downlink path loss obtained by the terminal. Obtaining a link path loss and the obtained uplink Performing uplink power control based on the large path loss.
  • the distributed antenna wireless communication method for achieving the object of the present invention in a distributed antenna wireless communication method comprising a base station and a plurality of points, the terminal transmits and receives a control channel and a data channel If the points are different from each other, the base station provides the terminal with system information including cell ID information of the point at which the base station transmits and receives a data channel.
  • the base station when a point at which the terminal transmits / receives an uplink data channel and a downlink data channel is different from each other, the base station has a cell ID of each point of transmitting and receiving an uplink data channel and a point of transmitting and receiving a downlink data channel.
  • a distributed antenna wireless communication method comprising providing system information including information to the terminal.
  • the distributed antenna wireless communication method for achieving the object of the present invention in a distributed antenna wireless communication method comprising a base station and a plurality of points, the base station is an uplink signal transmitted by the terminal Signaling information for detecting a cell-specific reference signal (CRS) set in each of a plurality of points for receiving the signal and energy information of resources constituting the CRS patterns to the terminal or each of the plurality of points for receiving the uplink signal Information for detecting the CSI RS (Channel State Information Reference Signal) and energy information constituting the CSI RS patterns may be signaled to the terminal.
  • CRS cell-specific reference signal
  • CSI RS Channel State Information Reference Signal
  • the distributed antenna wireless communication method for achieving the object of the present invention in the distributed antenna wireless communication method comprising a plurality of points, each point participating in the cooperative transmission does not include the CRS And setting any one of the unsubframe and the subframe of the anchor cell as a reference subframe and generating a downlink data channel based on the reference subframe in which each point is set.
  • a physical channel and reference signal transmission / reception method for downlink and uplink communication using points is provided.
  • the present invention provides a method of transmitting a physical channel and a reference signal in uplink and downlink by introducing a virtual cell ID, thereby enabling efficient transmission using a plurality of points while minimizing a change to an existing standard.
  • FIG. 1 is a conceptual diagram illustrating a distributed antenna wireless communication system according to an embodiment of the present invention.
  • FIG. 2 illustrates a downlink communication method of a distributed antenna wireless communication system according to an embodiment of the present invention.
  • FIG. 3 is a flowchart illustrating an example of using VCI in a downlink communication method using a distributed antenna according to an embodiment of the present invention.
  • FIG. 4 is a flowchart illustrating a CSI RS based measurement process in a downlink communication method using a distributed antenna according to an embodiment of the present invention.
  • FIG. 5 is a flowchart illustrating a process of performing CoMP transmission in a downlink communication method using a distributed antenna according to an embodiment of the present invention.
  • FIG. 6 is a conceptual diagram illustrating a need for improving uplink PUCCH in a distributed antenna wireless communication system.
  • FIG. 7 is a conceptual diagram illustrating a PUCCH resource allocation method applied to a distributed antenna wireless communication system according to an embodiment of the present invention.
  • FIG. 8 is a conceptual diagram illustrating a wireless communication system using a distributed antenna according to another embodiment of the present invention.
  • FIG. 9 is a conceptual diagram illustrating a wireless communication system using a distributed antenna according to another embodiment of the present invention.
  • FIG. 10 is a conceptual diagram illustrating CRS resource mapping in a CoMP transmission environment according to an embodiment of the present invention.
  • FIG. 11 is a conceptual diagram illustrating a PDSCH transmission method according to an embodiment of the present invention.
  • FIG. 12 is a conceptual diagram illustrating a PDSCH transmission method according to another embodiment of the present invention.
  • FIG. 13 is a conceptual diagram illustrating a PDSCH RE mapping pattern according to an embodiment of the present invention.
  • FIG. 14 is a conceptual diagram illustrating basic muting / CRS patterns according to an embodiment of the present invention.
  • 15 is a conceptual diagram illustrating a muting / CRS pattern according to a control field value according to an embodiment of the present invention.
  • FIG. 16 is a conceptual diagram illustrating subframes in which PUCCH feedback is performed and contents of feedback when wideband CQI / PMI reporting is set according to an embodiment of the present invention.
  • FIG. 17 is a conceptual diagram illustrating the content of a subframe and feedback in which PUCCH feedback is performed when wideband CQI / PMI and subband CQI / PMI reporting are configured according to an embodiment of the present invention.
  • terminal used in the present application is a mobile station (MS), a mobile terminal (MT), a user terminal, a user equipment (UE), a user terminal (UT: User Terminal), a wireless terminal, Access Terminal (AT), Subscriber Unit, Subscriber Station (SS), Wireless Device, Wireless Communication Device, Wireless Transmit / Receive Unit (WTRU), Mobile Node, Mobile Or other terms.
  • MS mobile station
  • MT mobile terminal
  • UE user equipment
  • UT User Terminal
  • AT Access Terminal
  • SS Subscriber Unit
  • Wireless Device Wireless Communication Device
  • WTRU Wireless Transmit / Receive Unit
  • the 'base station' used in the present application generally refers to a fixed point for communicating with a terminal, and includes a base station, a Node-B, an eNode-B, and a BTS. It may be called other terms such as (Base Transceiver System), Access Point.
  • the 'point' used in the present application is a transmitting and receiving device having at least one transmitting and receiving antenna and connected to the base station through an optical fiber, a microwave, and the like to exchange information with the base station, RRH (Remote Radio Head) It may be referred to as a remote radio unit (RRU), a site, a distributed antenna, or the like.
  • RRU Remote Radio Unit
  • a point may be referred to as a transmission point or a transmission point when transmitting a signal, and may be referred to as a reception point when receiving a signal.
  • FIG. 1 is a conceptual diagram illustrating a distributed antenna wireless communication system according to an embodiment of the present invention.
  • a distributed antenna wireless communication system may include a base station 110, a wide area point 130, and a narrow area point 150, and includes a wide area point 130 and at least one.
  • the narrow point 150 of may be located in the cell 111 operated by the base station 110.
  • the wide area point 130 forms a wide coverage 131 using high transmit power, and the narrow point 150 transmits the wide area point 130 using lower transmit power than the wide area point 130.
  • the transmission region 151 narrower than the region 131 may be formed.
  • each of the narrow narrow points 150 may be arranged to be included in the transmission region 131 of the wide area point 130, and the plurality of narrow narrow points are wide area points. It is connected to the 130 by wireless or wired to send and receive control information and / or data.
  • the plurality of narrow point 150 and the wide point 130 may be connected to the base station 110 through the optical fiber, microwave, etc. to exchange information with the base station 110, and different from the base station 110 You can also exchange information with points.
  • PCI physical layer cell IDs
  • all points 130 and 150 are allocated to have different PCIs, and each point 130 and 150 configures its own cell coverage.
  • the 3GPP LTE Release-8, Release-9, and LTE-Advanced Release-10 standards may be applied to the first scheme.
  • the second PCI allocation scheme is a scheme of allocating the same PCI to all the points 130 and 150 belonging to the same cell, and the above-described conventional 3GPP LTE or LTE-Advanced standard cannot be applied to the second scheme.
  • a downlink communication method and an uplink communication method for communication of points are provided. to provide.
  • the communication between the base station and the terminal in the embodiment of the present invention conforms to the 3GPP LTE-Advanced Release-10 standard.
  • FIG. 2 illustrates a downlink communication method of a distributed antenna wireless communication system according to an embodiment of the present invention.
  • a synchronization signal and a cell-specific reference signal are transmitted.
  • the CRS is used for estimating the downlink channel by the terminal and demodulating the received signal.
  • one of the points transmits a synchronization signal and a CRS corresponding to PCI using a transmission antenna provided by the user, and other points (for example, narrow point).
  • S is a method in which the specific point does not transmit a signal using the radio resources used to transmit the synchronization signal and the CRS.
  • the second method is a method in which all points simultaneously transmit a synchronization signal corresponding to PCI and a CRS using the same radio resource.
  • the radio resource means a resource element (RE) of the time-frequency space defined in 3GPP LTE and LTE-Advanced standards.
  • Each point may transmit its own CSI RS (Channel State Information Reference Signal, hereinafter abbreviated as 'CSI RS').
  • CSI RS Channel State Information Reference Signal
  • the CSI RS is a reference signal used by the UE to measure the quality of the downlink channel, and the configuration of the CSI RS transmitted by each point and the mapping of the corresponding radio resource may be different.
  • a CSI RS sequence used by each point to transmit its own CSI RS may be generated using PCI.
  • Each point belonging to the same cell may transmit the PMCH using the same radio resource.
  • the PMCH refers to a physical channel used for a multicast-broadcast single frequency network (MBSFN) operation.
  • the PBCH is a physical channel used to transmit system information required for the UE to access a network.
  • two methods for transmitting a PBCH are provided.
  • a wide area point transmits a PBCH.
  • the wide area point uses PCI as a method defined in the LTE and LTE-Advanced standards for generating a scrambling sequence for bit-level scrambling in PBCH transmission.
  • at least one narrow point does not transmit a signal using radio resources that the wide area point uses to transmit the PBCH.
  • the second method is a method in which all points belonging to the same cell simultaneously transmit the same PBCH using the same radio resource.
  • each point uses PCI as the method defined in the LTE and LTE-Advanced standards for generating a scrambling sequence for bit-by-bit scrambling during PBCH transmission.
  • the PCFICH is a downlink physical channel used to provide UEs with information necessary for decoding a physical downlink control channel (PDCCH), and transmits the PCFICH in a downlink communication method using a distributed antenna according to an embodiment of the present invention. There are two ways to do this.
  • a wide area point transmits a PCFICH.
  • the wide area point uses PCI as defined in the LTE and LTE-Advanced standards for generating radio resource mapping for PCFICH transmission and scrambling sequence for bit-scrambling.
  • at least one narrow point does not transmit a signal using radio resources that the wide point uses to transmit the PCFICH.
  • the second method is a method in which all points belonging to the same cell simultaneously transmit the same PCFICH using the same radio resource.
  • each point uses PCI as the method defined in the LTE and LTE-Advanced standard for generating a scrambling sequence for bit-scrambled in PCFICH transmission.
  • the PDCCH includes information such as downlink control information such as scheduling assignment required for reception of a Physical Downlink Shared Channel (PDSCH) and information such as scheduling grant for transmitting a Physical Uplink Shared Channel (PUSCH) of the UE.
  • Downlink physical channel used for transmission is information such as downlink control information such as scheduling assignment required for reception of a Physical Downlink Shared Channel (PDSCH) and information such as scheduling grant for transmitting a Physical Uplink Shared Channel (PUSCH) of the UE.
  • PDSCH Physical Downlink Shared Channel
  • PUSCH Physical Uplink Shared Channel
  • the downlink communication method using a distributed antenna provides two methods for transmitting a PDCCH.
  • a wide area point transmits a PDCCH.
  • the wide area point uses PCI as a method defined in the LTE and LTE-Advanced standards for generating a scrambling sequence for mapping a radio resource and generating bit-by-bit scrambling during PDCCH transmission.
  • at least one narrow point does not transmit a signal using radio resources that the wide point uses to transmit the PDCCH.
  • the second method is a method in which all points belonging to the same cell simultaneously transmit the same PDCCH using the same radio resource.
  • each point uses PCI as a method defined in the LTE and LTE-Advanced standards to generate a scrambling sequence for bit-scrambled PDCCH transmission.
  • the PHICH is a downlink physical channel used for transmitting a HARQ acknowledgment for informing the terminal whether to retransmit a transport block.
  • the downlink communication method using a distributed antenna provides two methods for transmitting a PHICH.
  • a wide area point transmits PHICH.
  • the wide area point uses PCI as the method defined in the LTE and LTE-Advanced standards for generating a cell-specific scrambling sequence during PHICH transmission.
  • the at least one narrow point does not transmit a signal using radio resources that the wide point uses to transmit the PHICH.
  • the second method is a method in which all points belonging to the same cell simultaneously transmit the same PHICH using the same radio resource.
  • each point uses PCI as a method defined in the LTE and LTE-Advanced standards to generate a scrambling sequence for bit-by-bit scrambling during PHICH transmission.
  • the MBSFN Reference Signal is a reference signal used for the UE to measure a composite channel of each point for transmitting MBSFN data.
  • each point may transmit an MBSFN reference signal.
  • the sequence and the radio resource that each point is used to transmit the MBSFN reference signal may be the same.
  • Positioning reference signal is a signal transmitted by the base station and / or points to effectively perform the position estimation of the terminal, the terminal measures the position reference signal and calculates its position based on the measured value By transmitting to the base station and / or points to the base station, or by transmitting information necessary to calculate the position of the terminal so that the base station and / or points to determine the position of the terminal.
  • the downlink communication method using a distributed antenna provides two methods of transmitting a location reference signal.
  • a wide area point transmits a location reference signal.
  • the wide area point uses PCI as a method defined in the LTE-Advanced standard for sequence generation of the location reference signal and radio resource mapping of the location reference signal.
  • at least one narrow point does not transmit a signal using radio resources that the wide point uses to transmit the location reference signal.
  • the second method is a method in which all points belonging to the same cell simultaneously transmit the same location reference signal using the same radio resource.
  • each point uses PCI as a method defined in the LTE-Advanced standard for sequence generation of the location reference signal and radio resource mapping of the location reference signal.
  • VCI Virtual Cell Identity
  • a virtual cell in a network deployment environment in which a plurality of points belong to the same cell for a terminal supporting LTE-Advanced Release-11 or later standard specification An ID (hereinafter referred to as 'VCI') is introduced.
  • a reference signal sequence used for a UE-specific reference signal is defined as a pseudo random sequence, and an initialization value used to generate a pseudo random sequence is different according to PCI. . Therefore, cells having different PCIs use different pseudo random sequences as reference signal sequences. The reason why different cells generate different pseudo random sequences using different PCIs is to alleviate inter-cell interference. In particular, in the case of the reference signals corresponding to antenna ports 7, 8, 9, 10, 11, 12, 13, 14, all cells use the same radio resources, so as to mitigate interference due to reference signals transmitted from neighbor cells. It is necessary to use different reference signal sequences between adjacent cells.
  • each transmission point in order for the transmission points to use different reference signals, it is preferable to use different initialization values when each transmission point generates a pseudo random sequence used for generating a UE-specific reference signal sequence.
  • FIG. 3 is a flowchart illustrating an example of using VCI in a downlink communication method using a distributed antenna according to an embodiment of the present invention.
  • the base station 110 informs the VCI for each terminal 171, 173 (step S310).
  • the base station 110 generates a pseudo signal sequence by applying VCI instead of PCI to generate a reference signal sequence (step S320), and generates a unique reference signal of each terminal 171 or 173 using the generated reference signal sequence.
  • the unique reference signals of the generated terminals 171 and 173 are transmitted to the corresponding terminal (step S340).
  • the VCI may be assigned a different value for each terminal.
  • Each terminal 171, 173 generates a reference signal sequence using the VCI allocated from the base station 110 (step S350), and detects the terminal specific reference signal using the generated reference signal sequence (step S360).
  • the base station may generate a pseudo random sequence by applying VCI instead of PCI to generate a scrambling sequence used for bit scrambling of each codeword.
  • the UE generates the scrambling sequence using the VCI allocated from the base station and then performs PDSCH detection using the generated scrambling sequence.
  • the scrambling sequence used for bit scrambling of each codeword generates a scrambling sequence by generating a pseudo random sequence using PCI. .
  • a VCI is allocated to a terminal that uses a VCI instead of PCI to generate a scrambling sequence.
  • the scrambling sequence may be generated using the PCI.
  • the terminal has not yet been allocated the VCI, so the base station generates a scrambling sequence by applying PCI to the response and message transmission of the random access of the terminal. After that, bit-by-bit scrambling of the encoded codeword is performed using the generated scrambling sequence.
  • the downlink communication method using a distributed antenna provides two methods for transmitting a PDSCH.
  • a wide area point transmits a PDSCH.
  • the UE may demodulate the PDSCH received from the wide area point by using the CRS or the UE-specific reference signal according to a transmission mode.
  • At least one narrow point is a PDSCH to the terminal when the terminal is set to the transmission mode to obtain channel estimation and CQI (Channel Quality Indicator) information using the CSI RS and performs data demodulation using the UE-specific reference signal And a UE-specific reference signal can be transmitted.
  • CQI Channel Quality Indicator
  • the PDSCH is not transmitted to the corresponding UE. This is because the first method does not transmit the CRS to the terminal at least one narrow point.
  • each point belonging to the same cell is transmitted to the UE.
  • Each point belonging to the same cell may transmit a UE-specific reference signal together with the PDSCH.
  • each point generates and transmits a UE-specific reference signal sequence using VCI instead of PCI to the UE to which the VCI is allocated, and the UE receiving the UE uses the reference signal sequence generated using the assigned VCI to refer to the UE-specific reference. Detect the signal.
  • each point generates and transmits a UE-specific reference signal sequence using VCI instead of PCI to the UE to which VCI is allocated, and the UE, which receives the UE, generates a reference signal sequence to detect the UE-specific reference signal. .
  • each point uses radio resources determined by using VCI instead of PCI for radio resource mapping of a signal (for example, UE-specific reference signal) transmitted to antenna port 5 to a terminal to which VCI is allocated.
  • a signal for example, UE-specific reference signal
  • each point generates and transmits a UE-specific reference signal sequence using a PCI to a UE that has not been assigned a VCI, and the UE, which receives the UE, detects the UE-specific reference signal using a reference signal sequence generated using the PCI. do.
  • each point uses radio resources determined by using PCI for radio resource mapping for a signal transmitted to antenna port 5 to a terminal not assigned a VCI.
  • each point belonging to the same cell may perform a new physical channel capable of performing the functions of PDCCH and PHICH defined in the LTE or LTE-Advanced standard, respectively.
  • a new physical channel capable of performing the function of the PDCCH is called an e-PDCCH
  • a new physical channel capable of performing the PHICH function is called an e-PHICH.
  • Each point belonging to the same cell transmits the e-PDCCH and the e-PHICH together with the UE-specific reference signal so that the UE can demodulate the e-PDCCH and the e-PHICH.
  • the e-PDCCH and the e-PHICH may be transmitted using some of radio resources that a wide area point can use for PDSCH transmission.
  • each point may use the VCI for mapping the e-PDCCH and the e-PHICH to radio resources and generating a scrambling sequence for bit-by-bit scrambling.
  • a new reference signal is introduced to increase the positioning accuracy of the terminal.
  • the new reference signal is referred to as RRH-PRS.
  • a plurality of points belonging to the same cell may transmit RRH-PRS for positioning of the terminal.
  • each point may use the VCI for sequence generation of the RRH-PRS and radio resource mapping of the RRH-PRS.
  • CSI RS-based measurement is performed.
  • FIG. 4 is a flowchart illustrating a CSI RS based measurement process in a downlink communication method using a distributed antenna according to an embodiment of the present invention.
  • the base station 110 transmits CSI RS measurement information for each terminal (step S410).
  • the CSI RS measurement information may include configuration information corresponding to all or some CSI RSs of the CSI RSs transmitted from each point, and the CSI RS is configured by the terminal 170 from the configuration information according to a predefined mapping rule.
  • the radio resource pattern information of the time-frequency space is set to be known.
  • the terminal 170 Upon receiving the information for the CSI RS measurement transmitted from the base station 110, the terminal 170 performs measurement on the CSI RSs included in the CSI RS measurement information (step S420), and transmits the measurement result to the base station 110. Transmit (step S430).
  • the base station 110 determines the CSI RS pattern or the CSI RS patterns to be measured by the terminal 170 based on the measurement result received from the terminal 170 (step S440), and determines the determined CSI RS pattern or the CSI RS patterns. It transmits to 170 (step S450).
  • the terminal 170 acquires CSI for link adaptation using the CSI RS pattern or the CSI RS patterns received from the base station 110 (step S460), and reports the obtained CSI to the base station 110. (Step S470).
  • the base station 110 performs link adaptation based on the CSI received from the terminal 170 (step S480).
  • the CSI RS pattern or the CSI RS patterns set by the base station 110 to the terminal 170 may belong to one or a plurality of points.
  • the terminal 170 acquires the CSI using the set CSI RS and transmits the obtained CSI to the base station 110. At this time, the terminal 170 assumes that the PDSCH is not transmitted in the REs to which the CSI RS is transmitted. That is, the base station 170 maps resources such that the resource elements for CSI RS transmission and the resource elements for PDSCH transmission do not overlap each other.
  • a base station may perform cooperative multi-point transmission using a plurality of transmission points to transmit data or control information to a terminal.
  • a set of a plurality of transmission points for performing cooperative transmission with respect to a terminal is referred to as a 'cooperative point set'.
  • FIG. 5 is a flowchart illustrating a process of performing cooperative multi-point transmission in a downlink communication method using a distributed antenna according to an embodiment of the present invention.
  • the base station 110 receives channel state information from each terminal 170 (step S510).
  • the base station 110 determines a cooperative point set for performing cooperative multipoint transmission for the terminal 170 based on the received channel state information (step S520). That is, the cooperative point set may be set differently for each terminal 170 according to the channel environment of each terminal 170.
  • step S530 After the plurality of transmission points 152 and 154 included in the cooperative point set for performing the cooperative multi-point transmission with respect to the terminal 170 generate the transmission signal to transmit the same data to the terminal 170 using the same radio resource, In operation S530, the generated transmission signal and the terminal specific reference signal for demodulation of the terminal 170 are transmitted to the terminal 170 together (step S540).
  • a plurality of transmission points performing cooperative multi-point transmission should simultaneously transmit the UE-specific reference signals and use the same reference signal sequence.
  • a plurality of transmission points performing cooperative multi-point transmission transmit a PDSCH and a UE-specific reference signal sequence generated using the VCI informed by the base station.
  • a UE performs a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), a physical random access channel (PRACH), and a DM RS through uplink.
  • PUSCH physical uplink shared channel
  • PUCCH physical uplink control channel
  • PRACH physical random access channel
  • DM RS DM RS through uplink.
  • Demodulation Reference Signal and SRS (Sounding Reference Signal) can be transmitted.
  • Bit-scrambling sequence generation in PUCCH format 3 cell-specific Single Carrier-Frequency Division Multiple Access (SC-FDMA) symbol-based cyclic shift hopping (cell-specific cyclic shift hopping), cell-specific SC-FDMA symbolic scrambling
  • SC-FDMA Single Carrier-Frequency Division Multiple Access
  • the terminals supporting the LTE Release-8 / 9/10 standard Since the terminals supporting the LTE Release-8 / 9/10 standard generate signals according to the corresponding supporting standards, the terminals generate and transmit the signals using the same PCI.
  • the resources used by the terminal may be reused according to the position of the terminal in order to increase the frequency utilization efficiency. That is, the terminals having relatively little influence of interference may transmit the above signals using the same resource.
  • the resource used by the terminal may be reused based on a reception point for receiving a signal transmitted from the terminal in order to spatially reuse the frequency resource to increase the frequency utilization efficiency.
  • a terminal provides a method of performing uplink transmission using VCI.
  • the terminal receives the VCI from the base station, generates the partial or all uplink channels and signals (for example, PUSCH, PUCCH, DM RS, SRS) by applying the assigned VCI instead of PCI, and generates the generated signal send.
  • the VCI for example, PUSCH, PUCCH, DM RS, SRS
  • each of the reception points forms a cell having a unique PCI. That is, terminals belonging to different reception points belonging to the same cell have an effect belonging to different cells.
  • the uplink communication method using the distributed antenna according to the embodiment of the present invention described above may be introduced to the LTE-Advanced Release-11 standard standard or later and applied to terminals supporting the standard standard. Can be.
  • the terminal that has not been allocated the VCI may generate the above-described channels and signals using PCI.
  • PCI may be used for random access message transmission and PUCCH ACK / NAK transmission.
  • VCI can be applied to both a case where a plurality of points have different PCIs and a case where a plurality of points belong to the same cell and have the same PCI.
  • the VCI may be set identically in downlink and uplink or may be configured differently.
  • the base station may independently signal the VCI for the downlink and the VCI for the uplink to the UE.
  • the uplink / downlink communication method using VCI instead of PCI has been described.
  • PCI is used as it is and new parameters are initialized for generating a pseudo random sequence. Can also be used as a parameter.
  • the base station may inform the terminal of the initialization parameter.
  • the newly added initialization parameter may be the same parameter used in the downlink and uplink, or different parameters may be used.
  • the VCI or the newly added initialization parameter value may allow the terminal to recognize through various methods.
  • the VCI or added initialization parameter may be configured to map according to the CSI RS pattern. That is, when the base station sets the CSI RS pattern to the terminal, it can be configured to determine the VCI or additional initialization parameter value for the terminal according to a predetermined rule. This method can be applied when using the same initialization parameter in the downlink and uplink.
  • the initialization parameters used for the downlink are mapped by the base station using the CSI RS pattern corresponding to the initialization parameters as described above, so that the UE can recognize the initialization parameters.
  • the initialization parameter used for uplink may be mapped in another way or configured so that the base station directly informs the terminal of the initialization parameter value.
  • the point-to-point interference is randomized, and the base sequence and cyclic shift of the PUSCH DM RS are used for orthogonalization between points. Allows cyclic shift hopping to be set independently.
  • VCI for Base Sequence Configuration of PUSCH DM RS To introduce Use Also, a parameter used for initiating hopping pattern generation for PUSCH DM RS cyclic shift hopping configuration. Set. here, Wow Is used in the same meaning as defined in Section 5.5.1.3 and Section 5.5.1.4 of 3GPP TS 36.211, Means parameters used in Section 5.5.2.1.1 of TS 36.211.
  • the sequence group number u in slot n s is a group hopping pattern as shown in Equation 1.
  • Equation 2 group hopping pattern for PUSCH DM RS when group hopping is used is pseudo random sequence
  • Equation 2 is used in the present invention to initialize a pseudo-random sequence generator. That is, in the present invention, as shown in Equation 2, VCI instead of conventional PCI Use to perform initialization at the beginning of every radio frame.
  • Equation 3 The value is transmitted by the base station to the corresponding terminal through signaling for each terminal.
  • cyclic shift of a DM RS sequence in PUSCH DM RS sequence generation is changed through cell-specific hopping as the slot number is changed.
  • Such cyclic shift hopping The amount is determined by Equation 4 according to the slot number n s .
  • Equation 5 the conventional pseudorandom sequence Equation 5 was used for the initialization and the value was determined for each cell.
  • the signal is individually signaled to the terminal.
  • the base station through the terminal-specific signaling , ,
  • the value is transmitted to each terminal.
  • the base station first sets the following two parameter sets to the terminal through RRC signaling.
  • the base station adds a 1-bit control field in the DCI format (Downlink Control Information format) 4, and informs the terminal of the usage parameter set as shown in Table 1 using the added control field.
  • DCI format Downlink Control Information format
  • the UE recognizes the indicated usage parameter set through the control field, generates a PUSCH DM RS using the indicated parameter set, and transmits the same to the base station.
  • the PUSCH DM RS is generated using the existing LTE Rel-10 scheme.
  • an area separation gain is obtained or orthogonality between terminals is maintained.
  • the present invention uses a method of differently setting the BSI of each terminal to obtain an area splitting gain between terminals belonging to different points.
  • the following methods may be used to allow orthogonality of the DM RSs of terminals allocated with partially or totally overlapping resources.
  • the Orthogonal Cover Code OCC
  • SGH Sequence Group Hopping
  • DM RS orthogonality is given using OCC and Cyclic Shift (CS).
  • BSI is different but CSH is set to be the same. That is, DM RS orthogonality is given using OCC.
  • BSI is set to be the same but CSH is different.
  • CS is used to impart DM RS orthogonality.
  • Method 2 of granting orthogonality of DM RSs using OCC among the method of granting orthogonal DM RS orthogonality may provide better orthogonality than Method 1.
  • method 3 when applying orthogonality of DM RS by applying different CS to each terminal, it is difficult to maintain orthogonality of DM RS between terminals if two CSs collide or are located close by CSH. Do.
  • terminals belonging to different points set BSI differently in order to simultaneously obtain area separation gain and orthogonality between terminals. .
  • Terminals located on the boundary of adjacent points may grant DM RS orthogonality using one of the above three methods for granting orthogonal DM RS.
  • DM RS orthogonality may be granted between legacy terminals for paring with MU MIMO (Multi User-Multiple Input Multiple Output).
  • the PUCCH region determined by the e-PDCCH may be configured to overlap each other between reception points for region separation gain, and in this case, different PUCCH randomization for each transmission point. It is necessary to mitigate the interference between the transmission points using.
  • FIG. 6 is a conceptual diagram illustrating a need for improving uplink PUCCH in a distributed antenna wireless communication system.
  • a transmission point for transmitting a downlink PDCCH according to a terminal and The receiving point receiving the PUCCH may not match.
  • the 3GPP Release-11 terminal 175 and the legacy terminal 176 receive the PDCCH from the same wide area point 130, the Release-11 terminal 175 transmits the PUCCH to the narrow reception point 150, The legacy terminal 176 may occur when transmitting the PUCCH to the wide area point 130.
  • the PUCCH transmitted by the legacy terminal 176 belonging to the wide area point 130 at high power may act as a large interference to the PUCCH transmitted by the Release-11 terminal 175.
  • the e-PDCCH when the e-PDCCH is introduced, it is necessary to allocate the PUCCH resource region determined by the e-PDCCH to a position which does not overlap with the dynamic PUCCH resource region allocated to the legacy terminal.
  • VCI for PUCCH Using PUCCH DM RS base sequence generation and cyclic shift hopping pattern is generated.
  • VCI for PUCCH And VCI for PUSCH DM RS are set independently of each other.
  • the transmission resource of the PUCCH format 1a / 1b used to transmit the HARQ-ACK is the lowest CCE (Control Channel Element) index and parameters of the PDCCH Determined by
  • the PUCCH resource region can be set to match the channel situation for each terminal. This may be particularly used for PUCCH resource allocation with orthogonality between reception points.
  • FIG. 7 is a conceptual diagram illustrating a PUCCH resource allocation method applied to a distributed antenna wireless communication system according to an embodiment of the present invention, in which orthogonality between reception points and interference between reception points of a PUCCH in which resources are set by RRC signaling are illustrated.
  • An example of a PUCCH resource allocation method for accomplishing this is illustrated.
  • Points TP0, TP1, and TP1 that operate as receiving points by allocating resources 1-2 as PUCCH transmission resources of terminals located inside the areas of points TP0, TP1, and TP2, respectively. Interference randomization between the points TP2 can be obtained.
  • PUCCH resource 2 may be jointly allocated to the PUCCH transmission resources of the terminal located between the point TP1 and the area of the point TP2, and the resources used by the terminals may be set to be orthogonal to each other.
  • the PUCCH resource 3 may be used as an orthogonal resource of a point TP0, a point TP1, and a point TP2 operating as a reception point.
  • the legacy terminal cannot grant the VCI, the legacy terminal and the terminal on which the VCI is configured (for example, 3GPP Release-11 or later terminal) cannot be multiplexed on the same PUCCH resource.
  • UEs using PUCCH resource 2 can multiplex to the same PUCCH resource by setting the same VCI regardless of whether the point receiving the PUCCH is a point TP1 and / or a point TP2.
  • UEs using the PUCCH resource 2 for randomization of the interference between the reception points with the point TP0 are allocated to the VCI different from the VCI used in the PUCCH resource 1-1.
  • PUCCH resource 3 can be used as an orthogonal resource between points TP0, points TP1, and points TP2, which are reception points, and terminals using existing PCI can use the same resource without setting VCI. Can be assigned to maintain orthogonality.
  • the PUCCH resource 1-0, the PUCCH resource 1-1, and the PUCCH resource 1-2 are randomized to receive point-to-point interference using different PCIs without VCI setting.
  • UEs using PUCCH resource 2 can multiplex to the same PUCCH resource by setting the same VCI regardless of whether the point receiving the PUCCH is a point TP1 and / or a point TP2.
  • UEs using the PUCCH resource 2 for randomization of the interference between the reception points with the point TP0 are allocated to the VCI different from the VCI used in the PUCCH resource 1-1. It is preferable.
  • the base station may be determined by signaling to the terminal or through implicit mapping.
  • the terminal detects the e-PDCCH and acquires control information contained in the e-PDCCH, and then receives and demodulates the PDSCH, the terminal needs to know the DM RS sequence used for e-PDCCH demodulation to demodulate the e-PDCCH. Can be.
  • the UE may use Equation 7 to initialize the DM RS sequence generation.
  • the base station determines the Is set to the terminal, the terminal is PCI (i.e., Assigns the VCI value instead DM RS sequence for e-PDCCH demodulation can be obtained by using. here, May use a fixed value (eg, 0) without being set by the base station.
  • PCI i.e., Assigns the VCI value instead DM RS sequence for e-PDCCH demodulation can be obtained by using.
  • the UE needs to know a DM RS sequence used for PDSCH demodulation.
  • the base station may inform the UE of the DM RS sequence initial value setting through the RRC configuration and the e-PDCCH. That is, the base station sets one or a plurality of VCI values to the terminal through RRC signaling, and then uses the Downlink Control Information (DCI) field included in the PDCCH or e-PDCCH to allow the terminal to initialize the DM RS sequence. Value and You can tell the value dynamically.
  • DCI Downlink Control Information
  • the base station transmits two VCI values to the terminal through RRC signaling. Can be set, Assuming that the value can take two values, the base station uses a two-bit control information N_init included in the PDCCH or the e-PDCCH transmitted to the UE, and the VCI value to be used to initialize the DM RS sequence for PDSCH demodulation. The value can be informed to the terminal as shown in Table 2.
  • the base station has two VCI values and Is set to the UE through RRC signaling, and 1 bit is added to DCI Format 2B and Format 2C in DCI to inform the VCI value to be used by the UE as shown in Table 3.
  • DCI Formats 2B and 2C are the same as described in 3GPP TS 36.212.
  • the base station and the terminal are each PCI (i.e., Create a sequence by assigning a VCI value instead.
  • This method uses one of two VCI values If set to, there is an advantage that can be used to perform the MU MIMO pairing (paring) using the legacy terminal and orthogonal RS using this. On the other hand, if the VCI is not set in the terminal Can be used to generate a sequence.
  • the range of VCI values preferably includes a range of existing PCI values.
  • the PCI value may currently have an integer value between 0 and 503.
  • the VCI may have an integer value ranging from 0 to Max_VCI, and the Max_VCI may have an integer value of 503 or more than 503. If the VCI value is set above the range of the existing PCI value, it is advantageous to randomize inter-cell interference.
  • the VCI value is set to the existing PCI value, there is an advantage in that DM RS ports orthogonal to each other are allocated between legacy terminals that do not receive VCI and terminals that have VCI set.
  • Equation 8 Another example of an initial value setting method for generating a DM RS sequence used by a UE to demodulate an e-PDCCH is shown in Equation 8.
  • the base station to the terminal Value (or ) can be set.
  • the base station is configured to randomize the interference of the DM RS for e-PDCCH demodulation.
  • the terminal is set to DM RS sequence initialization Assign a value and set it to itself
  • the value may be used to obtain a DM RS sequence for e-PDCCH demodulation.
  • the UE needs to know a DM RS sequence used for PDSCH demodulation.
  • the base station may inform the terminal of the DM RS sequence initial value setting through the RRC configuration and the PDCCH or e-PDCCH. That is, the base station is one or a plurality of terminals to the terminal by RRC signaling
  • the UE uses the Downlink Control Information (DCI) field included in the PDCCH or e-PDCCH to be used for the UE to initialize the DM RS sequence. Value and You can tell the value dynamically.
  • DCI Downlink Control Information
  • the base station provides two UEs to the UE through RRC signaling. Two to set the value value Can be set, Assuming that the value can take two values, the base station uses the 2-bit control information N_init included in the PDCCH or e-PDCCH transmitted to the UE to use for initialization of the DM RS sequence for PDSCH demodulation. Value and The value can be informed to the terminal as shown in Table 4.
  • the method of dynamically configuring the VCI in the uplink may use a method in which the base station informs the terminal of information about a predetermined number of VCIs in advance through RRC signaling and indirectly informs the VCI of the terminal to be used for transmission through a control field in the DCI. Can be.
  • the base station displays the VCI index in the control field in the DCI
  • the terminal obtains the VCI index from the received DCI
  • the base station may designate a VCI index in DCI for uplink scheduling grant
  • the PUCCH may designate a VCI index in DCI for downlink scheduling assignment.
  • the UE estimates a radio channel using the CRS for demodulation of the PDCCH and then performs demodulation based thereon.
  • the terminal demodulates the PDSCH using DM RS or CRS according to the configured transmission mode.
  • uplink power control according to an embodiment of the present invention will be described with assuming that the UE is set to a transmission mode for estimating CSI using CRS and performing PDSCH demodulation.
  • the power control scheme for uplink power control of a terminal is largely composed of an open-loop scheme and a closed-loop scheme.
  • the UE For open loop power control, the UE must estimate uplink pathloss. In order to estimate the uplink path loss, the UE estimates the path loss of the downlink and regards it as the path loss of the uplink.
  • the base station informs the terminal of the 'referenceSignalPower' parameter so that the terminal can estimate the downlink path loss.
  • the referenceSingnalPower value is a value expressed in dBm of the CRS EPRE (Energy Per Resource Element).
  • path loss PL c is defined as follows.
  • the serving cell chosen as the reference serving cell and used for determining referenceSignalPower and higher layer filtered RSRP is configured by the higher layer parameter pathlossReferenceLinking.
  • referenceSinganlPower means CRS EPRE
  • higher layer filtered RSRP can be obtained from the CRS received by the UE. That is, the terminal calculates a downlink path loss from the CRS EPRE and the received CRS.
  • the first method of the uplink power control method based on the CRS is to transmit the same CRS by using the same resource for both the wide area point and the narrow point.
  • the following problem may occur in estimating path loss.
  • Er_UE which is an EPRE of the CRS received by the UE, may be expressed as in Equation 9.
  • Equation 9 a denotes a loss coefficient indicating a path loss between a wide area point and a terminal, and b denotes a loss coefficient indicating a path loss between a narrow point and a terminal.
  • the power ratio DL_PL of the transmission power E_total and the reception power Er_UE corresponding to the downlink path loss may be expressed as in Equation 10.
  • a path loss can be obtained as follows.
  • the path loss between the wide area point and the terminal and the path loss between the narrow point and the terminal are the same in downlink and uplink.
  • Equation (11) the total received energy Er_eNB received by the base station may be expressed as in Equation (11).
  • the power ratio UL_PL of the transmission power and the reception power corresponding to the uplink path loss may be expressed by Equation 12.
  • Equation 12 Comparing Equation 12 with Equation 10, it can be seen that the path loss of the downlink does not match the path loss of the uplink.
  • the existing 3GPP LTE Release-8 / 9/10 UEs consider the downlink path loss obtained through the EPRE of the CRS as the uplink path loss, the path loss mismatch between the downlink and the uplink hink as described above It causes inefficiency of uplink power control.
  • the terminal estimates the downlink path loss using the CRS EPRE value signaled from the base station, so that the downlink path loss can be obtained as shown in Equation 13.
  • the estimated downlink path loss is equal to the actual uplink path loss. Therefore, all points transmitting the CRS should each set the CRS EPRE to the same value, and the base station signals the CRS EPRE value to the UE.
  • a second method of the uplink power control method based on the CRS according to an embodiment of the present invention is to transmit only the wide area point CRS.
  • the second method since only the wide point transmits the CRS and the narrow point does not transmit the CRS, there is no problem of inconsistency between the downlink path loss and the uplink path loss.
  • the UE is set to a transmission mode in which the UE estimates the CSI by measuring the CSI RS and performs PDSCH demodulation using the DM RS. Assume This transmission mode corresponds to transmission mode 9 of 3GPP LTE Release-10 standard.
  • the base station informs the terminal of the CSI RS pattern transmitted at the point for the PDSCH transmission to the terminal.
  • the terminal may calculate the downlink path loss based on the CSI RS pattern set to the terminal.
  • the UE should be able to know the EPRE value of the corresponding CSI RS in order to calculate the downlink path loss.
  • the base station should perform signaling so that the UE can know the EPRE value of the CSI RS.
  • the UE may estimate downlink path loss from the received CSI RS and the EPRE values of the CSI RS, and may perform the uplink power control by considering it as an uplink path loss.
  • the base station informs the UE of the following values.
  • the base station signals the ratio of PDSCH EPRE and CRS EPRE and the ratio of PDSCH EPRE and CSI RS EPRE for each terminal. Accordingly, the UE can know the CSI RS EPRE for the CSI RS pattern set to the UE and can use it for downlink path loss estimation.
  • the base station may signal the following values to the terminal.
  • the base station should allow the UE to know the following values.
  • TP_set ⁇ TP_0, TP_1,... , TP_ (L-1) ⁇ .
  • TP_i means a predetermined transmission point included in the set of transmission points.
  • Each transmission point has a unique CSI RS pattern, and the base station may set one or more CSI RS patterns for the terminal.
  • the base station may set one or more CSI RS patterns for the terminal.
  • the base station should inform the UE of the ratio of PDSCH EPRE and CSI RS EPRE for each CSI RS pattern of transmission points belonging to TP_set through RRC signaling for each UE.
  • the UE calculates the downlink CSI using the ratio of the signaled PDSCH EPRE and the CSI RS EPRE.
  • RP_i means a predetermined reception point included in the set of reception points.
  • the total received power Pr received by the RP_set may be expressed by Equation (14).
  • Equation 14 if the terminal can estimate (a_0 + a_1 + .. + a_ (N-1)), the terminal can estimate a reception power value corresponding to the given transmission power.
  • a_i 0,1, ... N-1) for all reception points belonging to the RP_set, (a_0 + a_1 + .. + a_ (N-1)) is estimated. can do. If the UE knows the transmit power of the CSI RS belonging to the reception point RP_i, the received power of the CSI RS can be measured to know the downlink power attenuation rate, and this value can be used as the uplink power attenuation rate a_i.
  • the uplink path loss is expressed by Equation 15.
  • the base station should allow the terminal to know information necessary for the terminal to detect the CSI RS, such as a pattern in the time-frequency space of the CSI RSs set in each of the reception points RP_i belonging to the RP_set, and the transmission power of each CSI RS pattern.
  • the base station enables the terminal to know or estimate the corresponding CSI RS EPRE value together with the CSI RS information of each reception point belonging to the RP_set of the terminal by using any one of methods A to C described below. Can be.
  • the base station directly informs the EPRE value of the CSI RS through RRC signaling.
  • the base station directly informs the UE of the EPRE value of the CSI RS corresponding to the CSI RS pattern of each reception point by RRC signaling.
  • the base station informs the EPRE value of the CRS, the EPRE ratio of the CSI RS and the CRS through RRC signaling for each terminal.
  • the base station additionally informs the terminal of the EPRE ratio of the CSI RS and the CRS for the CSI RS pattern of each of the reception points, and the terminal estimates the EPRE of the CSI RS based on this.
  • the base station informs the following values (1) and (2) through RRC signaling for each terminal.
  • the base station informs the UE of the CRS EPRE value through RRC signaling.
  • the base station has two parameters to the terminal Wow Informs via RRC signaling.
  • Wow Denotes the ratio of PDSCH EPRE and CRS EPRE among PDSCH resource elements. From this, the UE can know the EPRE ratio of PDSCH and CRS in each OFDM symbol.
  • the base station performs RRC signaling on the UE of the EPRE ratio values of PDSCH and CSI RS for one CSI RS pattern, and the UE extracts CSI on the assumption of EPRE ratios of PDSCH and CSI RS.
  • the base station When configuring a plurality of CSI RS patterns in the UE, the base station signals the EPRE ratio of the PDSCH and the CSI RS for each CSI RS pattern in the same manner as described above.
  • the UE may estimate the EPRE value of each CSI RS pattern from the information of (1) and (2).
  • the point for transmitting the e-PDCCH to the terminal and the point for receiving the PUCCH transmitted by the terminal are preferably the same point. The following description assumes this.
  • the UE When the UE receives a downlink assignment by the e-PDCCH, it describes a method for the UE to transmit ACK / NACK for the corresponding PDSCH.
  • the ACK / NAK resource used by the terminal is preferably implicitly mapped by the resource location of the e-PDCCH that has been successfully received. Accordingly, the terminal transmits ACK / NAK using a PUCCH resource and a PUCCH format determined according to a predetermined appointment.
  • the terminal may calculate the path loss from the EPRE of the CSI RS transmitted by the point transmitting the e-PDCCH for power control of the PUCCH.
  • the terminal assigned the VCI from the base station to the assigned VCI instead of PCI to generate and transmit a PUCCH.
  • PCI may be used as it is, or PUCCH may be generated by introducing different additional initialization parameters according to reception points.
  • Physical channels used for communication between the terminal and the base station may be classified as follows.
  • 'downlink control channel' PCFICH, PHICH, PDCCH, PBCH, synchronization signal, CRS, PRS in LTE / LET-Advanced
  • Downlink data channel PDSCH, PMCH in LTE / LET-Advanced
  • Uplink control channel and signal (hereinafter, abbreviated as 'uplink control channel'): PUCCH, PRACH, demodulation reference signal (DM RS), sounding reference signal (Sounding RS) in LTE / LTE-Advanced
  • Uplink data channel PUSCH in LTE / LET-Advanced
  • a terminal belongs to one cell and receives and transmits all channels and signals based on the cell to which the terminal belongs.
  • a cell for transmitting and receiving a control channel and a data channel may be configured differently for effective communication.
  • FIG. 9 is a conceptual diagram illustrating a wireless communication system using a distributed antenna according to another embodiment of the present invention.
  • FIG. 9 illustrates an example in which a cell transmitting and receiving an uplink data channel and a downlink data channel are different from each other.
  • a second terminal transmits and receives a control channel with the macro cell 211, receives downlink data from the base station 210, and transmits uplink data to the second RRH cell 253.
  • the base station needs to inform the user equipment of a cell for transmitting a downlink data channel and a cell for receiving an uplink data channel.
  • a cell for transmitting a downlink data channel is referred to as a downlink data channel reference cell
  • a cell for receiving an uplink data channel is referred to as an uplink data channel reference cell.
  • the base station transmits system information including the cell ID of the downlink data channel reference cell to the terminal.
  • the base station transmits system information including the cell ID of the uplink data channel reference cell to the terminal.
  • the UE regards the signaled downlink data channel reference cell as a cell for receiving downlink data channel. That is, the reception of the downlink data channel is treated as if the terminal belongs to the downlink data channel reference cell.
  • the UE regards the signaled uplink data reference cell as a cell for uplink data channel transmission. That is, the transmission of the uplink data channel is treated as if the terminal belongs to the uplink data reference cell.
  • control channels for one terminal are configured such that both uplink and downlink belong to the same cell.
  • the cell transmitting / receiving the control channel with the terminal may select the cell having the strongest signal as the reference cell of the control channel when the terminal is in the idle mode, and handover after the RRC connection is established.
  • the base station may change the reference cell of the control channel according to the reason.
  • the terminal performs uplink power control based on a cell that transmits and receives a control channel.
  • the terminal belongs to one cell and receives and transmits all channels based on the cell to which the terminal belongs, but the base station receives the receiving cell or the receiving cell in order to perform effective uplink power control. Information of these can be informed to the terminal.
  • the UE can calculate the downlink path loss by measuring the CRS for each of the receiving cells or each of the receiving cells, and regards the calculated downlink path loss of each receiving cell as the uplink path loss of each receiving cell.
  • the UE may perform power control in consideration of the path loss of the receiving cell or the receiving cells without assuming that the control channel reference cell receives.
  • an uplink power control method in the case where one or more receiving cells receives an uplink signal transmitted from a predetermined terminal.
  • RC_i means the i-th receiving cell included in the set of receiving cells.
  • Equation 16 the total received power Pr received by RC_set
  • Equation 15 if the UE can estimate (a_0 + a_1 + .. + a_ (N-1)), the UE can estimate a reception power value corresponding to a given transmission power.
  • a terminal can estimate a_i with respect to a received cell RC_i belonging to RC_set, (a_0 + a_1 + .. + a_ (N-1)) can be estimated. If the UE knows the transmission power of the CRS belonging to the reception cell RC_i, it can measure the reception power of the CRS to know the downlink power attenuation rate and use this value as the uplink power attenuation rate a_i.
  • the uplink path loss is expressed by Equation 17.
  • the base station must signal to the terminal so that the terminal can know the information necessary for CRS detection, such as the pattern in the time-frequency space of the CRSs set in each of the reception cells RC_i belonging to RC_set and the transmission power of each CRS pattern.
  • the base station may signal the cell ID of the receiving cells and the CRS EPRE value of each cell to the terminal.
  • the CSI RS may be configured to take the role of the CRS. That is, when the UE knows the transmission power of the CSI RS belonging to the reception cell RC_i, it is possible to know the downlink power attenuation rate by measuring the reception power of the CSI RS, and using this value as the uplink power attenuation rate a_i, the uplink The path loss is expressed by Equation 18.
  • the base station In order for the UE to estimate the path loss using the CSI RS, the base station needs to detect CSI RS such as a pattern in the time-frequency space of the CSI RSs set in each of the reception cells RC_i belonging to RC_set and each CSI RS pattern.
  • the UE should signal the UE so that the UE knows its transmit power.
  • the base station may signal the cell ID of the receiving cells and the CSI RS EPRE value of each cell to the UE.
  • CoMP Coordinatd Multi Point
  • CoMP cooperating set means a set of transmission points that directly or indirectly participate in downlink data transmission.
  • CoMP transmission point (CoMP transmission point (s)) may be composed of some or all of the transmission points belonging to the CoMP cooperation set, and are points that actually transmit the downlink data to the terminal.
  • the CoMP reporting set is a set of transmission points at which the UE performs CSI reporting to the base station.
  • Downlink CoMP transmission is classified into Joint Processing (JP) and Coordinated Scheduling / Beamforming (CS / CB).
  • JP Joint Processing
  • CS / CB Coordinated Scheduling / Beamforming
  • JP CoMP transmission a plurality of geographically separated transmission points share data to be transmitted to the terminal.
  • Joint transmission (JT) in JP CoMP transmits the same data to the UE by multiple transmission points using the same resource at the same time.
  • Dynamic Cell Selection (DCS) is a method in which one transmission point transmits data at a time, but the transmission points can be changed dynamically.
  • the serving cell In the CS / CB CoMP transmission, only the serving cell has data, and the interference of the cell boundary terminal is reduced by cooperating with neighboring cells for scheduling and beamforming.
  • the CoMP transmission point and the CoMP transmission cell can be regarded as the same meaning.
  • cells may have different CRS configurations.
  • the UE needs to know CRS configuration of CoMP transmission cells.
  • FIG. 10 is a conceptual diagram illustrating CRS resource mapping in a CoMP transmission environment according to an embodiment of the present invention.
  • the first transmission cell (or first transmission point) and the second transmission cell (or second transmission point) belong to the CoMP cooperative set of the terminal.
  • the first transmission cell and the second transmission cell may have different positions of REs to which the CRS is transmitted. Therefore, in order to demodulate the PDSCH transmitted from the first transmission cell and the second transmission cell, the terminal needs to know CRS configuration information of each transmission cell.
  • the UE may receive PDSCH transmitted simultaneously from a plurality of cells.
  • each CoMP transmission cell may transmit the PDSCH by any of the following methods (1) to (3B).
  • Each transmitting cell sends a CRS to the RE sending the CRS.
  • Method (2) All the transmitting cells simultaneously transmit the same data to the RE at the same position in the REs which transmit only the PDSCH. That is, for REs in which no transmission cell transmits a downlink physical channel and a signal (a reference signal and a synchronization signal), all the transmission cells simultaneously transmit the same PDSCH data to the RE at the same location.
  • Each transmitting cell transmits a PDSCH in the corresponding RE even when the RE transmitting the PDSCH collides with the RE transmitting the CRS of another transmitting cell.
  • Each transmitting cell transmits nothing in that RE if the RE transmitting the PDSCH collides with the RE transmitting the CRS of another transmitting cell.
  • the method of (3A) or (3B) may be used for JT transmission.
  • the JT transmission it is preferable to set a reference subframe for each cell to perform rate matching and mapping to the RE for PDSCH transmission.
  • the following transmission methods can be considered.
  • a subframe without CRS (eg, MBSFN subframe) has a structure of a reference subframe.
  • FIG. 11 is a conceptual diagram illustrating a PDSCH transmission method according to an embodiment of the present invention, and illustrates a PDSCH and CRS transmission method when a subframe structure without CRS is defined as a reference subframe.
  • each transmitting cell generates data to be transmitted to the PDSCH RE based on the reference subframe (FIG. 11 (a)), and then transmits the data as it is in the PDSCH RE thereof,
  • CRS is transmitted instead of PDSCH data (FIG. 11B). That is, data is punctured in its CRS RE.
  • the corresponding RE transmits the PDSCH. This corresponds to the PDSCH transmission method 3A described above.
  • a subframe of an anchor cell is referred to as a reference subframe.
  • FIG. 12 is a conceptual diagram illustrating a PDSCH transmission method according to another embodiment of the present invention, and illustrates a PDSCH and CRS transmission method when a subframe of an anchor cell is defined as a reference subframe.
  • the anchor cell when the anchor cell is a transmission cell, the anchor cell generates and transmits a PDSCH by applying a single cell transmission (Non-CoMP transmission) method as it is (FIG. 12A). This case corresponds to the PDSCH transmission method 3A described above.
  • the transmission cell other than the anchor cell transmits nothing in the RE where the PDSCH RE of the anchor cell and the CRS RE of the anchor cell overlap (muted RE) (FIG. 12B). This corresponds to the PDSCH transmission method 3B described above.
  • a transmission cell other than the anchor cell transmits the same data as that sent by the anchor cell in the RE where the PDSCH RE of the anchor cell overlaps with its PDSCH RE.
  • the anchor cell may be a cell in which the terminal exchanges control information.
  • the anchor cell may be the lowest or highest cell index among the transmission cells indicated by the DCI.
  • control channel regions of transmission cells may not coincide with each other.
  • the PDSCH is transmitted from the next OFDM symbol of the control channel region in consideration of the control channel region of the cell having the largest control channel region among the cells participating in the transmission.
  • the base station may directly signal the position of the OFDM symbol at which the PDSCH starts to the terminal.
  • the UE needs to know the CRS configuration of the CoMP transmission cells.
  • a transmission cell using a given subframe may be one of cells belonging to a CoMP cooperative set.
  • the UE knows the CRS configuration information of the transmitting cell, it can know the RE to which the PDSCH is transmitted and can use it for PDSCH demodulation.
  • the UE needs to know CRS configuration information of the transmission cell (s).
  • the CRS configuration information may include the number of CRS ports, a cell-specific frequency shift of the CRS, and a CRS sequence.
  • the frequency shift and the CRS sequence of the CRS are determined by the PCI. Therefore, the UE needs to know the number of CRS ports and PCI of the transmitting cell.
  • the UE when the UE knows the number of CRS ports and the frequency shift of the CRS as well as the CRS sequence, the UE can use an interference cancellation technique that detects the CRS and extracts it from the received signal, thereby improving performance. This can be
  • the base station informs the terminal of general configuration information about cells belonging to a CoMP cooperative set through UE-specific RRC signaling.
  • the general configuration information includes CRS configuration information.
  • the base station includes information indicating the presence or absence of the CRS of the CoMP transmission cell (s) in the DCI transmitted using the PDCCH or e-PDCCH channel.
  • the base station may place a bitmap in the DCI to dynamically inform the CRS information of the transmitting cells participating in the actual transmission in the subframe in which the DCI is transmitted.
  • the size of the bitmap may be the number of cells belonging to a CoMP reporting set or may be fixed to a specific size.
  • the base station may indicate a transmitting cell using a bitmap composed of 5 bits in the DCI.
  • bit '0' indicates that the CRS of the cell does not exist in the subframe in which DCI is transmitted
  • bit '1' indicates that the cell participates in transmission and that the CRS of the cell exists.
  • the cell participating in the transmission and whether there is a CRS of the cell may be indicated as follows.
  • the bitmap when the first cell participates in CoMP transmission and the CRS of the first cell exists, the bitmap may be set to '10000', and the first cell and the third cell participate in CoMP transmission, If the CRS of the third cell exists, the bitmap may be set to '10100'.
  • the bitmap when no CRS exists in all cells participating in CoMP transmission (for example, all of the transmitting cells correspond to MBSFN subframes), the bitmap may be set to '00000'.
  • the DM RS sequence may be transmitted in the following two ways.
  • Method 1 A method of generating a DM RS sequence using PCI of a cell transmitting control information to a terminal
  • Method 2 A method of generating a DM RS sequence using PCI of a transmitting cell transmitting data to a terminal
  • the DM RS sequence in the JT CoMP transmission may be generated by using the PCI of the cell to which the terminal sends control information.
  • the base station may indirectly inform a transmission parameter to be used for transmission by the UE by placing a control field in the DCI.
  • the base station indicates a cell index in a control field in the DCI, and the terminal uses the transmission parameter (PCI, etc.) used in the cell as if belonging to the cell based on the cell index to the PUSCH and DM RS Can transmit
  • control channel regions of transmission cells may not coincide with each other. Accordingly, in the present invention, in consideration of the control channel region of the cell having the largest control channel region among the cells participating in the transmission, the PDSCH is transmitted from the next OFDM symbol of the control channel region or the location of the OFDM symbol at which the base station starts the PDSCH. Assume that is directly signaled to the terminal.
  • the PDSCH RE mapping of the cell is determined according to the CRS port setting and the MBSFN subframe setting of the cell.
  • the frequency shift of the CRS port is determined by PCI, and a total of six shifts are possible.
  • a cell using one CRS port has six different PDSCH RE mapping patterns.
  • a cell using two CRS ports may have three different PDSCH RE mapping patterns due to six frequency shifts.
  • a total of three different PDSCH RE mapping patterns may be generated by six frequency shifts.
  • mapping patterns may be generated according to the configuration of the CRS port from the PDSCH RE mapping point of view.
  • the PDSCH RE mapping pattern in the MBSFN subframe there are a total of 13 different mapping patterns. Therefore, a 4-bit control field is required to indicate which PDSCH RE mapping is used.
  • the performance gain can be sufficiently obtained. Informing some candidates and indicating which of the candidate mapping patterns are dynamically used through the DCI is advantageous in reducing the signaling overhead of the DCI.
  • the base station configures a plurality of PDSCH RE mapping patterns in the terminal using RRC signaling.
  • the information on the mapping patterns of the PDSCH RE may include MBSFN subframe information (corresponding to FIG. 11A), PDSCH RE mapping patterns according to the number of CRS ports and the frequency displacement value.
  • the frequency shift is a variable defined in 3GPP LTE specification TS 36.211 Section 6.10.1.2. Can be used.
  • the base station may set the following four PDSCH RE mapping patterns to the terminal through RRC signaling in consideration of the CRS port configuration of cells around the terminal.
  • Pattern 2a Number of CRS ports 2, frequency shift 0
  • Pattern 3a Number of CRS ports 2, frequency shift 1
  • Pattern 4a Number of CRS Ports 2, Frequency Shift 2
  • FIG. 13 is a conceptual diagram illustrating a PDSCH RE mapping pattern according to an embodiment of the present invention.
  • FIG. 13A illustrates an example of the pattern 1a
  • FIG. 13B illustrates an example of the pattern 2A
  • 13 (c) shows an example of the pattern 3a
  • FIG. 13 (d) shows an example of the pattern 4a.
  • the RE region in which the PDCCH (or PDCCH and e-PDCCH) are transmitted is not indicated, but the PDSCH REs are not mapped to the REs used by the PDCCH and the e-PDCCH existing in the subframe. That is, the UE should know the REs used by the PDCCH and the e-PDCCH in advance and it should be understood that these REs do not correspond to the PDSCH REs.
  • the base station may inform the terminal of the location of the OFDM symbol starting the PDSCH through separate signaling.
  • the UE should be understood that the PDSCH RE is mapped to the REs to which the e-PDCCH and the CRS port are not transmitted among the REs after the OFDM symbol at which the PDSCH starts.
  • these REs should be excluded from PDSCH RE mapping.
  • the base station is used to obtain the CRS sequence generation initialization and the frequency displacement value in the pattern information It can also be used to tell a value to use.
  • the base station may inform the terminal of the following pattern 1b to 4b information instead of the above pattern 1a to pattern 4a information.
  • Pattern 2b number of CRS ports 2
  • Pattern 3b number of CRS ports 2,
  • Pattern 4b Number of CRS Ports 2,
  • the terminal when the base station informs the terminal of the pattern 1b to pattern 4b information, the terminal is a frequency shift equation. And CRS sequence generation initialization expressions on To Instead, it can be substituted to obtain the frequency shift value and the CRS sequence of each CRS pattern.
  • a reception technique for detecting and removing a CRS acting as an interference in the JT transmission can be applied, thereby improving reception performance.
  • the base station informs the terminal of which PDSCH RE mapping of the patterns 1b to 4b is used by using a control field composed of 2 bits in the PDCCH or the e-PDCCH transmitted to the terminal.
  • the UE determines how the PDSCH resources allocated to the UE are mapped in the time-frequency space according to the mapping patterns configured with the RRC and the DCI value.
  • the above scheme can be used in both the JT and DCS transmission schemes.
  • the base station may select the RDSCH RE mapping in consideration of the CRS port of the transmitting cell or the transmitting cells to perform PDSCH transmission and inform the terminal of the PDSCH RE mapping information used through the DCI.
  • the UE acquires PDSCH RE mapping information obtained through RRC and DCI, demodulates after receiving the PDSCH.
  • control channel regions of transmission cells may not coincide with each other.
  • PDSCH is transmitted from the next OFDM symbol of the control channel region or the base station directly signals the position of the OFDM symbol at which the PDSCH starts.
  • the PDSCH RE mapping of the cell is determined according to the CRS port setting and the MBSFN subframe setting of the cell.
  • the PDSCH RE mapping scheme may use the following two mapping schemes.
  • the base station informs the terminal of the PDSCH RE muting pattern.
  • REs corresponding to the muting pattern are not used for PDSCH transmission.
  • the muting pattern corresponds to the CRS pattern of the transmitting cells.
  • the base station informs the terminal of the CRS patterns of the transmission cells.
  • Each cell may use the remaining REs except for the REs corresponding to its CRS pattern for PDSCH transmission or some may not participate in the transmission. Detailed description of the PDSCH RE mapping associated with this will be described later.
  • the base station and the terminal should know in advance which of the two methods is used.
  • the base station may signal which of the two methods is used to the terminal through RRC signaling.
  • [Method 1] and [Method 2] differ in terms of the mapping of PDSCH RE, but since the muting pattern is generated by a combination of the CRS patterns of the transmitting cells, signaling for informing the UE of the muting pattern and the CRS pattern may take the same method. have.
  • the frequency shift of the CRS port is determined by PCI, and a total of six shifts are possible.
  • a total of six different CRS mapping patterns are generated.
  • a total of three different CRS mapping patterns may be generated by six frequency shifts.
  • a total of three different CRS mapping patterns may be generated by six frequency shifts.
  • the base station sets a plurality of basic muting / CRS patterns to the terminal using RRC signaling.
  • Each basic muting / CRS pattern preferably corresponds to one CRS pattern defined according to the number of CRS ports and the frequency shift.
  • a CRS pattern made of a combination of two or more CRS patterns may be set as a basic muting / CRS pattern.
  • the frequency displacement is a variable defined in 3GPP LTE specification TS 36.211 Section 6.10.1.2 Can be used.
  • the base station may set the following three basic muting / CRS patterns to the terminal through RRC signaling in consideration of the CRS port configuration of cells around the terminal.
  • FIG. 14 is a conceptual diagram illustrating basic muting / CRS patterns according to an embodiment of the present invention, and illustrates the three basic muting / CRS patterns described above.
  • FIG. 14A illustrates an example of the basic muting / CRS pattern 1a
  • FIG. 14B illustrates an example of the basic muting / CRS pattern 2a
  • FIG. 14C illustrates the basic muting / CRS.
  • An example of the pattern 3a is shown.
  • the muting / CRS pattern used in the actual subframe is determined by a combination of basic muting / CRS patterns.
  • the base station informs the terminal of the muting / CRS pattern used for PDSCH transmission in the corresponding subframe using the DCI control field included in the PDCCH or the e-PDCCH transmitted to the terminal, and the muting / CRS pattern used at this time is the basic muting Determined by a combination of / CRS patterns.
  • the control field of the DCI for muting / CRS pattern display may be configured with 3 bits.
  • each bit corresponds to one basic muting / CRS pattern set to RRC as described above, and a bit value may indicate whether a corresponding basic muting / CRS pattern exists in a subframe in which DCI is transmitted.
  • bit '0' may indicate that there is no corresponding pattern
  • bit '1' indicates that there is a corresponding pattern.
  • the base station may inform the terminal of the following information according to the control field (a b c) value consisting of three bits.
  • (1 1 1) means that the pattern obtained by the union of the basic muting / CRS pattern 1a, the basic muting / CRS pattern 2a, and the basic muting / CRS pattern 3a is a muting / CRS pattern.
  • FIG. 15 is a conceptual diagram illustrating a muting / CRS pattern according to a control field value according to an embodiment of the present invention.
  • FIG. 15A illustrates a case in which the control field in the DCI is (0 0 0).
  • FIG. 15C illustrates the muting / CRS pattern when the control field is 111, for example.
  • the transmission cell (s) uses REs excluding the REs and the control region corresponding to the muting / CRS pattern for PDSCH transmission.
  • the transmission cell (s) uses REs excluding the REs and the control region corresponding to the muting / CRS pattern for PDSCH transmission.
  • the scheme 2 may consider the PDSCH RE mapping scheme of the scheme 2a or the scheme 2b.
  • a subframe (for example, MBSFN subframe) structure without CRS is used as a reference subframe.
  • each transmitting cell generates data to be transmitted to the PDSCH RE based on the reference subframe, and then transmits the data as it is to the PDSCH RE, and transmits the CRS instead of the PDSCH data to the RE to which the CRS is transmitted. That is, data is puncturing in its CRS RE.
  • This case corresponds to FIG. 11 described above.
  • the corresponding RE transmits the PDSCH.
  • One of the basic muting / CRS patterns is used as the reference pattern.
  • a cell transmitting a CRS corresponding to a reference pattern generates and transmits a PDSCH by applying a single cell transmission (Non-CoMP transmission) method as it is.
  • a transmitting cell that does not transmit the reference pattern CRS transmits nothing in the RE where its PDSCH RE collides with the reference pattern CRS RE, and transmits the reference pattern CRS in the RE where the CRS of the reference pattern does not collide with its PDSCH RE.
  • the reference pattern may be designated as the lowest or highest index among the basic muting / CRS patterns indicated as present in the DCI (ie, indicated by '1' in the bitmap).
  • [Method 2a] and [Method 2b] have an advantage of increasing reception performance when the terminal applies a receiver method of detecting and canceling a CRS pattern.
  • the PDSCH RE mapping method of [Method 1] is a method of muting REs colliding with CRS patterns, and thus, it is preferable to apply it when the UE does not perform CRS pattern detection and cancellation.
  • the base station and the terminal should know which of the [method 1], [method 2a], and [method 2b] to use.
  • the base station may inform the method of using the terminal through the signaling.
  • the UE may grasp how the PDSCH resource allocated to the RMA is mapped in the time-frequency space from the basic muting / CRS patterns configured with RRC and the DCI control field, and may demodulate the PDSCH using this information.
  • the RE region in which the PDCCH (or PDCCH and e-PDCCH) are transmitted is not indicated, but the PDSCH REs are not mapped to the REs used by the PDCCH and the e-PDCCH existing in the subframe. That is, the UE must know in advance the REs used by the PDCCH and the e-PDCCH, and these REs are regarded as not corresponding to the PDSCH RE.
  • the base station may inform the terminal of the location of the OFDM symbol starting the PDSCH through separate signaling.
  • the UE considers the PDSCH RE to be mapped to the REs to which the e-PDCCH and the CRS port are not transmitted among the REs after the OFDM symbol at which the PDSCH starts.
  • these REs should be excluded from PDSCH RE mapping.
  • the base station is used to obtain CRS sequence generation initialization and frequency shift value as basic muting / CRS pattern information. It can also be used to tell a value to use. For example, the base station may inform the UE of the following basic muting / CRS pattern 1b to 3b information instead of the basic muting / CRS pattern 1a to pattern 4a information.
  • the base station informs the user equipment of the basic muting / CRS pattern 1b to pattern 3b information
  • the user equipment has a frequency shift equation.
  • a reception technique for detecting and removing a CRS acting as an interference in JT CoMP transmission can be applied. This can improve the reception performance.
  • the periodic CSI reporting method defined in the existing 3GPP LTE Release 8 to 10 specifications is defined in 3GPP TS 36.213 Section 7.2.2, and supports four modes of modes 1-0, 1-1, 2-0, and 2-1. do.
  • feedback for CoMP support is performed while maximally reusing the structure of the modes defined in the above-described standard.
  • the periodic CSI reporting mode using PUCCH for CoMP support is defined as modes 1-0, 1-1, 2-0, and 2-1.
  • CoMP feedback is allowed only when a plurality of CSI-RS resources are configured for the UE. Therefore, in order for the UE to perform CoMP feedback, it is set to transmission mode 9 and PMI (Rank Indicator) reporting (parameter: pmi-RI-Report) must be set. If PMI / RI reporting is not configured, it is set to calculate CQI using CRS.
  • PMI Rank Indicator
  • the periodic CSI reporting mode supported according to the number of CSI-RS ports of CSI-RS resources is as follows.
  • the number of CSI-RS ports in the CSI-RS resources may be set differently for each CSI-RS resource, but CoMP feedback is limited to the above cases.
  • the CSI-RS measurement set M may be expressed as Equation 19.
  • a simplified scheme based on Per-CSI-RS resource is used.
  • the UE configures RI / PMI / CQI feedback for each CSI-RS resource under the assumption that transmission points associated with CSI-RS resources belonging to the CoMP measurement set are transmitted alone.
  • each of the CSI-RS resources has a corresponding transmission point (TP).
  • the terminal configures RI reporting on a CSI-RS resource basis.
  • the terminal selects a preferred RI for each CSI-RS resource belonging to the measurement set. In this case, it is assumed that the transmission occurs only at the corresponding transmission point.
  • the terminal configures a wideband PMI report on a CSI-RS resource basis.
  • the terminal selects a preferred precoding matrix for each CSI-RS resource belonging to the measurement set. In this case, it is assumed that the transmission occurs only at the corresponding transmission point.
  • the wideband PMI refers to a PMI report reflecting a channel state of the entire cell bandwidth.
  • the terminal configures a wideband CQI report in units of CSI-RS resources.
  • the UE estimates the Per-CSI-RS resource CQI by applying a preferred PMI to the CSI-RS resource.
  • the interference is calculated as the sum of the signals from all transmission points that do not belong to the CoMP measurement set.
  • the wideband CQI refers to a CQI report reflecting a channel state for the entire cell bandwidth.
  • Feedback reporting of the UE is performed in the same manner as 3GPP LTE Release-10 except that the CSI-RS resources belonging to the CSI-RS measurement set are alternately performed and the assumption of interference is different. . Parameters not specifically mentioned below are assumed to conform to the definition in 3GPP LTE Release-10 TS 36.213 Section 7.2.2.
  • the UE performs CSI reporting on all CSI-RS resources within the configured measurement set.
  • the CSI-RS measurement set is configured for each terminal through RRC signaling for each terminal.
  • the following UE feedback report is assumed to be defined for one cell and the transmission point corresponding to the cell is indicated as TP 0 .
  • the reporting interval of RI is set to the interval N pd times the integer M RI .
  • RI reporting on TP i is performed in a subframe satisfying Equation 22.
  • FIG. 16 is a conceptual diagram illustrating the content of a subframe and feedback in which PUCCH feedback is performed when wideband CQI / PMI reporting is configured.
  • the terminal alternately performs RI reporting for each of the transmission points TP 0 , TP 1, and TP 2 every N pd ⁇ M RI cycles. Therefore, every report S M ⁇ N pd ⁇ M RI cycle multiplied by the total number of S M of the non-zero-power CSI-RS resource that belongs to the CSI-RS measurement set of N pd ⁇ M RI for all the CSI-RS resources Is repeated.
  • 17 is a conceptual diagram illustrating the contents of a subframe and feedback in which PUCCH feedback is performed when wideband CQI / PMI and subband CQI / PMI reporting are configured.
  • the subband CQI report means a CQI report reflecting channel status for each subband.
  • the J ⁇ K reporting opportunities remaining between two consecutive wideband CQI / wideband PMI (or wideband CQI / wideband second PMI in transmission mode 9) reports are sequentially determined for the bandwidth portions. It is used for subband CQI reporting, which is a report of full cycling of K parts. However, if there are less than J ⁇ K reporting opportunities remaining within the interval between two consecutive wideband CQI / PMI reports (eg, by changing the system frame number to 0), the terminal may have two wideband CQIs. Of the / wideband PMI (or wideband CQI / wideband second PMI) reports, the remaining subband CQI reports not transmitted before the second report time point are omitted (ie, not transmitted).
  • the transmission points targeted by the subband CQI reports reported between the two consecutive wideband CQI / wideband PMI reports (or the wideband CQI / wideband second PMI in transmission mode 9) described above are as shown in FIG. 17. It can be seen that the first report among the consecutive consecutive wideband CQI / wideband PMI (or transmission mode 9 wideband CQI / wideband second PMI) reports is identical to the target transmission point.
  • the traversal of the bandwidth parts is in order of increasing number from the bandwidth part 0 to the bandwidth part J-1.
  • the parameter K is set by the upper layer.
  • the frequency of wideband first PMI reporting is And targets for TP i are performed in subframes satisfying Equation 27 and Equation 30.
  • Equation 27 and Equation 28 H 'is signaled by a higher layer.
  • the remaining reporting opportunities that exist between two consecutive wideband first PMI reports are used for wideband second PMI reporting with wideband CQI.
  • the transmission point targeted by the reports reported between the two consecutive wideband first PMI reports is the same as the transmission point of the first report among the two consecutive wideband first reports.
  • the reporting period of RI is the wideband CQI / PMI reporting period. Is set to an interval multiplied by an integer M RI , and RI is reported using the same PUCCH cyclic shift resource that is used when wideband CQI / PMI and subband CQI reporting are reported together.
  • Interference is calculated as the sum of the signals received from all transmission points that do not belong to the CoMP measurement set. That is, the interference is estimated by assuming that all transmission points belonging to the CoMP measurement set do not contribute to the interference.
  • the CSI format of periodic CSI reporting using PUCCH is the same as defined in 3GPP LTE Release-10.
  • the terminal measures the interference using zero power CSI-RS resources.
  • the method of measuring the interference by the terminal may vary according to the configuration of the zero power CSI-RS resource and the feedback mode.
  • Zero power CSI-RS resource means a resource that is not used for transmission at the corresponding transmission point or transmission points. Therefore, when the UE measures the reception power for REs corresponding to a certain CSI-RS resource, it measures the power of the sum of signals received from other transmission points except for the transmission point or transmission points corresponding to the CSI-RS resource.
  • the base station may set different zero power CSI-RS resources or different zero power CSI-RS resources to transmission points belonging to the CoMP measurement set.
  • the UE can calculate the interference corresponding to the CoMP transmission scheme as follows.
  • CS Coordinated Scheduling
  • DPS Dynamic Point Selection
  • the received power estimated using the zero power CSI-RS resource corresponding to each transmission point is referred to as I CM
  • the received power for the signal at the transmitted point i estimated using the non-zero power CSI-RS resource is referred to as P i. If only the transmission point k transmits data, the interference can be obtained using Equation 30.
  • the interference may be obtained using Equation 31.
  • interference may be obtained as Equation 32 as the sum (I CM ) of the signals received from all transmission points that do not belong to the CoMP measurement set.
  • the UE may calculate the interference corresponding to the CoMP transmission scheme as follows.
  • the CQI is estimated on the assumption that all transmission points in the CoMP measurement set use the same resource at the same time. Interference is calculated as the sum of the signals received from all transmission points that do not belong to the CoMP measurement set.
  • the received power estimated using the zero power CSI-RS resource corresponding to the transmission point k is called I k , and the signal for only the transmission point estimated using the non-zero power CSI-RS resource corresponding to the transmission point k is obtained. If the received power is P k , interference can be obtained as shown in Equation 34.
  • Equation 34 K denotes the number of transmission points in the CoMP measurement set.

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Abstract

La présente invention se rapporte à un système de communication sans fil à antennes réparties et à un procédé associé. La présente invention porte sur un procédé de transmission et de réception d'un canal physique et d'un signal de référence à l'aide d'une pluralité de points dans un environnement de communication sans fil à antennes réparties dans lequel la pluralité de points présentent des identifiants (ID) de cellule de couche physique mutuellement différents ou la pluralité de points appartiennent à une même cellule et présentent le même identifiant de cellule de couche physique ; porte sur un procédé de transmission du canal physique et du signal de référence depuis une liaison montante et une liaison descendante par introduction d'un identifiant de cellule virtuelle ; et peut améliorer l'efficacité de la communication du système de communication sans fil à antennes réparties par utilisation d'un procédé de transmission coordonnée qui utilise la pluralité de points.
PCT/KR2012/004495 2011-06-07 2012-06-07 Système de communication sans fil à antennes réparties et procédé associé WO2012169799A2 (fr)

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KR10-2011-0075024 2011-07-28
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KR20120027182 2012-03-16
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KR1020120059324A KR101840642B1 (ko) 2011-06-07 2012-06-01 분산 안테나 무선 통신 시스템 및 그 방법
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JP2018038047A (ja) * 2014-05-07 2018-03-08 クゥアルコム・インコーポレイテッドＱｕａｌｃｏｍｍ Ｉｎｃｏｒｐｏｒａｔｅｄ Ｌｔｅ（登録商標）におけるスモールセルのための発見基準信号についてのセルｉｄ管理
KR20170077193A (ko) * 2014-10-29 2017-07-05 후아웨이 테크놀러지 컴퍼니 리미티드 자원 스케줄링 방법 및 장치
US11672047B2 (en) * 2017-08-11 2023-06-06 Apple Inc. Network based CRS mitigation
CN112534770A (zh) * 2018-08-09 2021-03-19 Lg 电子株式会社 在支持mtc的无线通信系统中发送或接收mpdcch的方法及其装置
CN112534770B (zh) * 2018-08-09 2024-01-16 Lg 电子株式会社 在支持mtc的无线通信系统中发送或接收mpdcch的方法及其装置

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