WO2016018100A1 - 채널 상태 보고를 위한 방법 및 이를 위한 장치 - Google Patents
채널 상태 보고를 위한 방법 및 이를 위한 장치 Download PDFInfo
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- WO2016018100A1 WO2016018100A1 PCT/KR2015/007995 KR2015007995W WO2016018100A1 WO 2016018100 A1 WO2016018100 A1 WO 2016018100A1 KR 2015007995 W KR2015007995 W KR 2015007995W WO 2016018100 A1 WO2016018100 A1 WO 2016018100A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0053—Allocation of signaling, i.e. of overhead other than pilot signals
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/003—Arrangements for allocating sub-channels of the transmission path
- H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
- 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
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
- H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
- H04B7/0686—Hybrid systems, i.e. switching and simultaneous transmission
- H04B7/0691—Hybrid systems, i.e. switching and simultaneous transmission using subgroups of transmit antennas
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/0001—Arrangements for dividing the transmission path
- H04L5/0003—Two-dimensional division
- H04L5/0005—Time-frequency
- H04L5/0007—Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/0091—Signaling for the administration of the divided path
- H04L5/0094—Indication of how sub-channels of the path are allocated
Definitions
- the present invention relates to a wireless communication system, and more particularly, to a method for channel state reporting and an apparatus therefor.
- a node is a fixed point capable of transmitting / receiving a radio signal with a user device having one or more antennas.
- a communication system having a high density of nodes can provide higher performance communication services to user equipment by cooperation between nodes.
- This multi-node cooperative communication method in which a plurality of nodes communicate with a user equipment using the same time-frequency resources, is more efficient than a conventional communication method in which each node operates as an independent base station and communicates with the user equipment without mutual cooperation. It has much better performance in data throughput.
- each node cooperates using a plurality of nodes, acting as base stations or access points, antennas, antenna groups, radio remote headers (RRHs), radio remote units (RRUs). Perform communication.
- the plurality of nodes are typically located more than a certain distance apart.
- the plurality of nodes may be managed by one or more base stations or base station controllers that control the operation of each node or schedule data to be transmitted / received through each node.
- Each node is connected to a base station or base station controller that manages the node through a cable or dedicated line.
- Such a multi-node system can be viewed as a kind of multiple input multiple output (MIMO) system in that distributed nodes can simultaneously communicate with a single or multiple user devices by transmitting and receiving different streams.
- MIMO multiple input multiple output
- the multi-node system transmits signals using nodes distributed in various locations, the transmission area that each antenna should cover is reduced as compared to the antennas provided in the existing centralized antenna system. Therefore, compared to the existing system implementing the MIMO technology in the centralized antenna system, in the multi-node system, the transmission power required for each antenna to transmit a signal can be reduced.
- the transmission distance between the antenna and the user equipment is shortened, path loss is reduced, and high-speed data transmission is possible.
- the transmission capacity and power efficiency of the cellular system can be increased, and communication performance of relatively uniform quality can be satisfied regardless of the position of the user equipment in the cell.
- the base station (s) or base station controller (s) connected to the plurality of nodes cooperate with data transmission / reception, signal loss occurring in the transmission process is reduced.
- the correlation (correlation) and interference between the antennas are reduced. Therefore, according to the multi-node cooperative communication scheme, a high signal to interference-plus-noise ratio (SINR) can be obtained.
- SINR signal to interference-plus-noise ratio
- the multi-node system is designed to reduce the cost of base station expansion and backhaul network maintenance in the next generation mobile communication system, and to increase service coverage and channel capacity and SINR. In parallel with or in place of a centralized antenna system, it is emerging as a new foundation for cellular communication.
- the present invention proposes a method for channel state reporting, and in particular, a two-dimensional array of antenna elements is used for downlink transmission, and a codebook for the antenna element is expressed as a Kronecker product of a horizontal antenna precoding matrix and a vertical antenna precoding matrix.
- the following describes a channel state reporting method when a codebook is used.
- a method for channel state reporting for a downlink channel transmitted through N t antenna ports arranged in two dimensions is proposed, and the method is performed by a terminal and the N t
- Each antenna port is mapped to all antenna elements belonging to a specific antenna element group, and each antenna port of the antenna port group corresponding to a reference signal (RS) transmitted in the same OFDM symbol is mapped to a different antenna element group.
- CSI-RS channel state information-reference signal
- the state information may include a precoding matrix for antenna port group selection and a precoding matrix to be applied to the selected antenna port group.
- the precoding matrix for antenna port group selection may be selected in the antenna port group selection codebook.
- the precoding matrix to be applied to the selected antenna port group may be selected from a constant modulus codebook.
- the method may further include receiving information from the serving cell indicating whether transmission of the CSI-RS is activated or deactivated for each antenna port group.
- the precoding matrix for selecting the deactivated antenna port group may be excluded from the channel state information.
- the method may comprise receiving information from the serving cell about a rank limit of precoding for the antenna port group selection or a rank limit of precoding to be applied to the selected antenna port group.
- a terminal configured to report a channel state of a downlink channel transmitted through N t antenna ports arranged in two dimensions
- the terminal includes a radio frequency (RF) Unit and a processor configured to control the RF unit, wherein each of the N t antenna ports is mapped to all antenna elements belonging to a specific antenna element group and is transmitted in a same OFDM symbol with a reference signal (RS)
- RS reference signal
- Each antenna port of the antenna port group corresponding to is configured to be mapped to a different antenna element group
- the processor is configured to refer to a channel state information-reference signal (CSI-RS) for channel state reporting for the antenna port group.
- CSI-RS channel state information-reference signal
- the channel state information for the link channel is calculated and reported to the serving cell.
- the reported channel state information may include a precoding matrix for antenna port group selection and a precoding matrix to be applied to the selected antenna port group.
- the precoding matrix for antenna port group selection may be selected in the antenna port group selection codebook.
- the precoding matrix to be applied to the selected antenna port group may be selected from a constant modulus codebook.
- the processor may be configured to receive, from the serving cell, information indicating whether transmission of the CSI-RS is activated or deactivated for each antenna port group.
- the precoding matrix for selecting the deactivated antenna port group may be excluded from the channel state information.
- the processor may be configured to receive information from the serving cell about a rank limit of precoding for the antenna port group selection or a rank limit of precoding to be applied to the selected antenna port group.
- FIG. 1 illustrates an example of a radio frame structure used in a wireless communication system.
- FIG. 2 illustrates an example of a downlink / uplink (DL / UL) slot structure in a wireless communication system.
- FIG 3 illustrates a downlink (DL) subframe structure used in a 3GPP LTE / LTE-A system.
- FIG. 4 illustrates an example of an uplink (UL) subframe structure used in a 3GPP LTE / LTE-A system.
- FIG. 6 shows a transmittable pattern of CSI-RS having 8 antenna ports in an RB composed of 12 subcarriers in an LTE-A system.
- FIG. 7 shows transmission patterns of two-port, four-port, and eight-port CSI-RSs.
- FIG. 9 shows a three-dimensional beam pattern through a two-dimensional antenna array.
- ERE energy per resource element
- 11 and 12 illustrate antenna port groups.
- FIG. 13 shows a mapping relationship between an antenna port group and an antenna element group.
- 15 shows a block diagram of an apparatus for implementing an embodiment (s) of the present invention.
- a user equipment may be fixed or mobile, and various devices which transmit and receive user data and / or various control information by communicating with a base station (BS) belong to this.
- the UE may be a terminal equipment (MS), a mobile station (MS), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, a personal digital assistant (PDA), or a wireless modem. It may be called a modem, a handheld device, or the like.
- a BS generally refers to a fixed station communicating with the UE and / or another BS, and communicates with the UE and another BS to exchange various data and control information.
- BS includes Advanced Base Station (ABS), Node-B (NB), evolved-NodeB (eNB), Base Transceiver System (BTS), Access Point, Processing Server (PS), Transmission Point (TP) May be called in other terms.
- ABS Advanced Base Station
- NB Node-B
- eNB evolved-NodeB
- BTS Base Transceiver System
- PS Processing Server
- TP Transmission Point
- BS is collectively referred to as eNB.
- a node refers to a fixed point capable of transmitting / receiving a radio signal by communicating with a user equipment.
- Various forms of eNBs may be used as nodes regardless of their name.
- the node may be a BS, an NB, an eNB, a pico-cell eNB (PeNB), a home eNB (HeNB), a relay, a repeater, and the like.
- the node may not be an eNB.
- it may be a radio remote head (RRH), a radio remote unit (RRU).
- RRHs, RRUs, etc. generally have a power level lower than the power level of the eNB.
- RRH or RRU, RRH / RRU is generally connected to an eNB by a dedicated line such as an optical cable
- RRH / RRU and eNB are generally compared to cooperative communication by eNBs connected by a wireless line.
- cooperative communication can be performed smoothly.
- At least one antenna is installed at one node.
- the antenna may mean a physical antenna or may mean an antenna port, a virtual antenna, or an antenna group.
- Nodes are also called points. Unlike conventional centralized antenna systems (ie, single node systems) where antennas are centrally located at base stations and controlled by one eNB controller, in a multi-node system A plurality of nodes are typically located farther apart than a predetermined interval.
- the plurality of nodes may be managed by one or more eNBs or eNB controllers that control the operation of each node or schedule data to be transmitted / received through each node.
- Each node may be connected to the eNB or eNB controller that manages the node through a cable or dedicated line.
- the same cell identifier (ID) may be used or different cell IDs may be used for signal transmission / reception to / from a plurality of nodes.
- ID cell identifier
- each of the plurality of nodes behaves like some antenna group of one cell.
- a multi-node system may be regarded as a multi-cell (eg, macro-cell / femto-cell / pico-cell) system.
- the network formed by the multiple cells is particularly called a multi-tier network.
- the cell ID of the RRH / RRU and the cell ID of the eNB may be the same or may be different.
- both the RRH / RRU and the eNB operate as independent base stations.
- one or more eNB or eNB controllers connected with a plurality of nodes may control the plurality of nodes to simultaneously transmit or receive signals to the UE via some or all of the plurality of nodes.
- multi-node systems depending on the identity of each node, the implementation of each node, etc., these multi-nodes in that multiple nodes together participate in providing communication services to the UE on a given time-frequency resource.
- the systems are different from single node systems (eg CAS, conventional MIMO system, conventional relay system, conventional repeater system, etc.).
- embodiments of the present invention regarding a method for performing data cooperative transmission using some or all of a plurality of nodes may be applied to various kinds of multi-node systems.
- a node generally refers to an antenna group spaced apart from another node by a predetermined distance or more
- embodiments of the present invention described later may be applied even when the node means any antenna group regardless of the interval.
- the eNB may control the node configured as the H-pol antenna and the node configured as the V-pol antenna, and thus embodiments of the present invention may be applied. .
- a communication scheme that enables different nodes to receive the uplink signal is called multi-eNB MIMO or CoMP (Coordinated Multi-Point TX / RX).
- Cooperative transmission schemes among such cooperative communication between nodes can be largely classified into joint processing (JP) and scheduling coordination.
- the former may be divided into joint transmission (JT) / joint reception (JR) and dynamic point selection (DPS), and the latter may be divided into coordinated scheduling (CS) and coordinated beamforming (CB).
- DPS is also called dynamic cell selection (DCS).
- JP Joint Processing Protocol
- JR refers to a communication scheme in which a plurality of nodes receive the same stream from the UE.
- the UE / eNB combines the signals received from the plurality of nodes to recover the stream.
- the reliability of signal transmission may be improved by transmit diversity.
- DPS in JP refers to a communication technique in which a signal is transmitted / received through one node selected according to a specific rule among a plurality of nodes.
- DPS since a node having a good channel condition between the UE and the node will be selected as a communication node, the reliability of signal transmission can be improved.
- a cell refers to a certain geographic area in which one or more nodes provide a communication service. Therefore, in the present invention, communication with a specific cell may mean communication with an eNB or a node that provides a communication service to the specific cell.
- the downlink / uplink signal of a specific cell means a downlink / uplink signal from / to an eNB or a node that provides a communication service to the specific cell.
- the cell providing uplink / downlink communication service to the UE is particularly called a serving cell.
- the channel state / quality of a specific cell means a channel state / quality of a channel or communication link formed between an eNB or a node providing a communication service to the specific cell and a UE.
- a UE transmits a downlink channel state from a specific node on a channel CSI-RS (Channel State Information Reference Signal) resource to which the antenna port (s) of the specific node is assigned to the specific node. Can be measured using CSI-RS (s).
- CSI-RS Channel State Information Reference Signal
- adjacent nodes transmit corresponding CSI-RS resources on CSI-RS resources orthogonal to each other.
- Orthogonality of CSI-RS resources means that the CSI-RS is allocated by CSI-RS resource configuration, subframe offset, and transmission period that specify symbols and subcarriers carrying the CSI-RS. This means that at least one of a subframe configuration and a CSI-RS sequence for specifying the specified subframes are different from each other.
- Physical Downlink Control CHannel / Physical Control Format Indicator CHannel (PCFICH) / PHICH (Physical Hybrid automatic retransmit request Indicator CHannel) / PDSCH (Physical Downlink Shared CHannel) are respectively DCI (Downlink Control Information) / CFI ( Means a set of time-frequency resources or a set of resource elements that carry downlink format ACK / ACK / NACK (ACKnowlegement / Negative ACK) / downlink data, and also a Physical Uplink Control CHannel (PUCCH) / Physical (PUSCH) Uplink Shared CHannel / PACH (Physical Random Access CHannel) means a set of time-frequency resources or a set of resource elements that carry uplink control information (UCI) / uplink data / random access signals, respectively.
- DCI Downlink Control Information
- CFI Means a set of time-frequency resources or a set of resource elements that carry downlink format ACK / ACK
- the PDCCH / PCFICH / PHICH / PDSCH / PUCCH / PUSCH / PRACH resource is referred to below:
- the expression that the user equipment transmits the PUCCH / PUSCH / PRACH is hereinafter referred to as uplink control information / uplink on or through PUSCH / PUCCH / PRACH, respectively.
- PDCCH / PCFICH / PHICH / PDSCH is used for downlink data / control information on or through PDCCH / PCFICH / PHICH / PDSCH, respectively. It is used in the same sense as sending it.
- Figure 1 illustrates an example of a radio frame structure used in a wireless communication system.
- Figure 1 (a) shows a frame structure for frequency division duplex (FDD) used in the 3GPP LTE / LTE-A system
- Figure 1 (b) is used in the 3GPP LTE / LTE-A system
- the frame structure for time division duplex (TDD) is shown.
- a radio frame used in a 3GPP LTE / LTE-A system has a length of 10 ms (307200 Ts), and is composed of 10 equally sized subframes (SF). Numbers may be assigned to 10 subframes in one radio frame.
- Each subframe has a length of 1 ms and consists of two slots. 20 slots in one radio frame may be sequentially numbered from 0 to 19. Each slot is 0.5ms long.
- the time for transmitting one subframe is defined as a transmission time interval (TTI).
- the time resource may be classified by a radio frame number (also called a radio frame index), a subframe number (also called a subframe number), a slot number (or slot index), and the like.
- the radio frame may be configured differently according to the duplex mode. For example, in the FDD mode, since downlink transmission and uplink transmission are divided by frequency, a radio frame includes only one of a downlink subframe or an uplink subframe for a specific frequency band. In the TDD mode, since downlink transmission and uplink transmission are separated by time, a radio frame includes both a downlink subframe and an uplink subframe for a specific frequency band.
- Table 1 illustrates a DL-UL configuration of subframes in a radio frame in the TDD mode.
- D represents a downlink subframe
- U represents an uplink subframe
- S represents a special subframe.
- the singular subframe includes three fields of Downlink Pilot TimeSlot (DwPTS), Guard Period (GP), and Uplink Pilot TimeSlot (UpPTS).
- DwPTS is a time interval reserved for downlink transmission
- UpPTS is a time interval reserved for uplink transmission.
- Table 2 illustrates the configuration of a singular frame.
- FIG. 2 illustrates an example of a downlink / uplink (DL / UL) slot structure in a wireless communication system.
- FIG. 2 shows a structure of a resource grid of a 3GPP LTE / LTE-A system. There is one resource grid per antenna port.
- a slot includes a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain.
- OFDM symbol may mean a symbol period.
- the signal transmitted in each slot is * Subcarriers and It may be represented by a resource grid composed of OFDM symbols.
- Represents the number of resource blocks (RBs) in the downlink slot Represents the number of RBs in the UL slot.
- Wow Depends on the DL transmission bandwidth and the UL transmission bandwidth, respectively.
- Denotes the number of OFDM symbols in the downlink slot Denotes the number of OFDM symbols in the UL slot.
- the OFDM symbol may be called an OFDM symbol, a Single Carrier Frequency Division Multiplexing (SC-FDM) symbol, or the like according to a multiple access scheme.
- the number of OFDM symbols included in one slot may vary depending on the channel bandwidth and the length of the cyclic prefix (CP). For example, in case of a normal CP, one slot includes 7 OFDM symbols, whereas in case of an extended CP, one slot includes 6 OFDM symbols.
- FIG. 2 illustrates a subframe in which one slot includes 7 OFDM symbols for convenience of description, embodiments of the present invention can be applied to subframes having other numbers of OFDM symbols in the same manner. 2, each OFDM symbol, in the frequency domain, * Subcarriers are included.
- the types of subcarriers may be divided into data subcarriers for data transmission, reference signal subcarriers for transmission of reference signals, null subcarriers for guard band, and direct current (DC) components.
- the null subcarrier for the DC component is a subcarrier left unused and is mapped to a carrier frequency f0 during an OFDM signal generation process or a frequency upconversion process.
- the carrier frequency is also called the center frequency.
- 1 RB in the time domain It is defined as (eg, seven) consecutive OFDM symbols, and is defined by c (for example 12) consecutive subcarriers in the frequency domain.
- a resource composed of one OFDM symbol and one subcarrier is called a resource element (RE) or tone. Therefore, one RB is * It consists of three resource elements.
- Each resource element in the resource grid may be uniquely defined by an index pair (k, 1) in one slot. k is from 0 in the frequency domain * Index given up to -1, where l is from 0 in the time domain Index given up to -1.
- Two RBs one in each of two slots of the subframe, occupying the same consecutive subcarriers, are called a physical resource block (PRB) pair.
- PRB physical resource block
- Two RBs constituting a PRB pair have the same PRB number (or also referred to as a PRB index).
- VRB is a kind of logical resource allocation unit introduced for resource allocation.
- VRB has the same size as PRB.
- FIG 3 illustrates a downlink (DL) subframe structure used in a 3GPP LTE / LTE-A system.
- a DL subframe is divided into a control region and a data region in the time domain.
- up to three (or four) OFDM symbols located in the first slot of a subframe correspond to a control region to which a control channel is allocated.
- a resource region available for PDCCH transmission in a DL subframe is called a PDCCH region.
- the remaining OFDM symbols other than the OFDM symbol (s) used as the control region correspond to a data region to which a Physical Downlink Shared CHannel (PDSCH) is allocated.
- PDSCH Physical Downlink Shared CHannel
- a resource region available for PDSCH transmission in a DL subframe is called a PDSCH region.
- Examples of DL control channels used in 3GPP LTE include a physical control format indicator channel (PCFICH), a physical downlink control channel (PDCCH), a physical hybrid ARQ indicator channel (PHICH), and the like.
- the PCFICH is transmitted in the first OFDM symbol of a subframe and carries information about the number of OFDM symbols used for transmission of a control channel within the subframe.
- the PHICH carries a Hybrid Automatic Repeat Request (HARQ) ACK / NACK (acknowledgment / negative-acknowledgment) signal in response to the UL transmission.
- HARQ Hybrid Automatic Repeat Request
- DCI downlink control information
- DL-SCH downlink shared channel
- UL-SCH uplink shared channel
- paging channel a downlink shared channel
- the transmission format and resource allocation information of a downlink shared channel may also be called DL scheduling information or a DL grant, and may be referred to as an uplink shared channel (UL-SCH).
- the transmission format and resource allocation information is also called UL scheduling information or UL grant.
- the DCI carried by one PDCCH has a different size and use depending on the DCI format, and its size may vary depending on a coding rate.
- various formats such as formats 0 and 4 for uplink and formats 1, 1A, 1B, 1C, 1D, 2, 2A, 2B, 2C, 3, and 3A are defined for uplink.
- Hopping flag RB allocation, modulation coding scheme (MCS), redundancy version (RV), new data indicator (NDI), transmit power control (TPC), and cyclic shift DMRS Control information such as shift demodulation reference signal (UL), UL index, CQI request, DL assignment index, HARQ process number, transmitted precoding matrix indicator (TPMI), and precoding matrix indicator (PMI) information
- MCS modulation coding scheme
- RV redundancy version
- NDI new data indicator
- TPC transmit power control
- cyclic shift DMRS Control information such as shift demodulation reference signal (UL), UL index, CQI request, DL assignment index, HARQ process number, transmitted precoding matrix indicator (TPMI), and precoding matrix indicator (PMI) information
- UL shift demodulation reference signal
- CQI request UL assignment index
- HARQ process number transmitted precoding matrix indicator
- PMI precoding matrix indicator
- the DCI format that can be transmitted to the UE depends on the transmission mode (TM) configured in the UE.
- TM transmission mode
- not all DCI formats may be used for a UE configured in a specific transmission mode, but only certain DCI format (s) corresponding to the specific transmission mode may be used.
- the PDCCH is transmitted on an aggregation of one or a plurality of consecutive control channel elements (CCEs).
- CCE is a logical allocation unit used to provide a PDCCH with a coding rate based on radio channel conditions.
- the CCE corresponds to a plurality of resource element groups (REGs). For example, one CCE corresponds to nine REGs and one REG corresponds to four REs.
- REGs resource element groups
- a CCE set in which a PDCCH can be located is defined for each UE.
- the set of CCEs in which a UE can discover its PDCCH is referred to as a PDCCH search space, simply a search space (SS).
- SS search space
- An individual resource to which a PDCCH can be transmitted in a search space is called a PDCCH candidate.
- the collection of PDCCH candidates that the UE will monitor is defined as a search space.
- a search space for each DCI format may have a different size, and a dedicated search space and a common search space are defined.
- the dedicated search space is a UE-specific search space and is configured for each individual UE.
- the common search space is configured for a plurality of UEs.
- An aggregation level defining the search space is as follows.
- One PDCCH candidate corresponds to 1, 2, 4 or 8 CCEs depending on the CCE aggregation level.
- the eNB sends the actual PDCCH (DCI) on any PDCCH candidate in the search space, and the UE monitors the search space to find the PDCCH (DCI).
- monitoring means attempting decoding of each PDCCH in a corresponding search space according to all monitored DCI formats.
- the UE may detect its own PDCCH by monitoring the plurality of PDCCHs. Basically, since the UE does not know where its PDCCH is transmitted, every Pframe attempts to decode the PDCCH until every PDCCH of the corresponding DCI format has detected a PDCCH having its own identifier. It is called blind detection (blind decoding).
- the eNB may transmit data for the UE or the UE group through the data area.
- Data transmitted through the data area is also called user data.
- a physical downlink shared channel (PDSCH) may be allocated to the data area.
- Paging channel (PCH) and downlink-shared channel (DL-SCH) are transmitted through PDSCH.
- the UE may read data transmitted through the PDSCH by decoding control information transmitted through the PDCCH.
- Information indicating to which UE or UE group data of the PDSCH is transmitted, how the UE or UE group should receive and decode PDSCH data, and the like are included in the PDCCH and transmitted.
- a specific PDCCH is masked with a cyclic redundancy check (CRC) with a Radio Network Temporary Identity (RNTI) of "A", a radio resource (eg, a frequency location) of "B” and a transmission of "C".
- CRC cyclic redundancy check
- RNTI Radio Network Temporary Identity
- format information eg, transport block size, modulation scheme, coding information, etc.
- a reference signal reference signal For demodulation of the signal received by the UE from the eNB, a reference signal reference signal (RS) to be compared with the data signal is required.
- the reference signal refers to a signal of a predetermined special waveform that the eNB and the UE know each other, which the eNB transmits to the UE or the eNB, and is also called a pilot.
- Reference signals are divided into a cell-specific RS shared by all UEs in a cell and a demodulation RS (DM RS) dedicated to a specific UE.
- the DM RS transmitted by the eNB for demodulation of downlink data for a specific UE may be specifically referred to as a UE-specific RS.
- the DM RS and the CRS may be transmitted together, but only one of the two may be transmitted.
- the DM RS transmitted by applying the same precoder as the data may be used only for demodulation purposes, and thus RS for channel measurement should be separately provided.
- an additional measurement RS, CSI-RS is transmitted to the UE.
- the CSI-RS is transmitted every predetermined transmission period consisting of a plurality of subframes, unlike the CRS transmitted every subframe, based on the fact that the channel state is relatively not changed over time.
- FIG. 4 illustrates an example of an uplink (UL) subframe structure used in a 3GPP LTE / LTE-A system.
- the UL subframe may be divided into a control region and a data region in the frequency domain.
- One or several physical uplink control channels may be allocated to the control region to carry uplink control information (UCI).
- One or several physical uplink shared channels may be allocated to a data region of a UL subframe to carry user data.
- subcarriers having a long distance based on a direct current (DC) subcarrier are used as a control region.
- subcarriers located at both ends of the UL transmission bandwidth are allocated for transmission of uplink control information.
- the DC subcarrier is a component that is not used for signal transmission and is mapped to a carrier frequency f0 during frequency upconversion.
- the PUCCH for one UE is allocated to an RB pair belonging to resources operating at one carrier frequency in one subframe, and the RBs belonging to the RB pair occupy different subcarriers in two slots.
- the PUCCH allocated in this way is expressed as that the RB pair allocated to the PUCCH is frequency hopped at the slot boundary. However, if frequency hopping is not applied, RB pairs occupy the same subcarrier.
- PUCCH may be used to transmit the following control information.
- SR Service Request: Information used for requesting an uplink UL-SCH resource. It is transmitted using OOK (On-Off Keying) method.
- HARQ-ACK A response to a PDCCH and / or a response to a downlink data packet (eg, codeword) on a PDSCH. This indicates whether the PDCCH or PDSCH is successfully received.
- One bit of HARQ-ACK is transmitted in response to a single downlink codeword, and two bits of HARQ-ACK are transmitted in response to two downlink codewords.
- HARQ-ACK response includes a positive ACK (simple, ACK), negative ACK (hereinafter, NACK), DTX (Discontinuous Transmission) or NACK / DTX.
- the term HARQ-ACK is mixed with HARQ ACK / NACK, ACK / NACK.
- CSI Channel State Information
- MIMO Multiple Input Multiple Output
- RI rank indicator
- PMI precoding matrix indicator
- the amount of uplink control information (UCI) that a UE can transmit in a subframe depends on the number of SC-FDMA available for control information transmission.
- SC-FDMA available for UCI means the remaining SC-FDMA symbol except for the SC-FDMA symbol for transmitting the reference signal in the subframe, and in the case of a subframe including a Sounding Reference Signal (SRS), the last SC of the subframe
- SRS Sounding Reference Signal
- the -FDMA symbol is also excluded.
- the reference signal is used for coherent detection of the PUCCH.
- PUCCH supports various formats according to the transmitted information.
- Table 4 shows a mapping relationship between PUCCH format and UCI in LTE / LTE-A system.
- the PUCCH format 1 series is mainly used to transmit ACK / NACK information
- the PUCCH format 2 series is mainly used to carry channel state information (CSI) such as CQI / PMI / RI
- the PUCCH format 3 series is mainly used to transmit ACK / NACK information.
- precoding may be applied to appropriately distribute transmission information to each antenna according to channel conditions.
- a set of precoding matrices are determined in advance at a transmitting end and a receiving end, and the receiving end measures channel information from the transmitting end to determine the most suitable precoding matrix (ie, a precoding matrix index).
- PMI Precoding Matrix Index
- the transmitting end is a technique of applying the appropriate precoding to the signal transmission based on the PMI, since a method of selecting an appropriate precoding matrix from a predetermined set of precoding matrices.
- PMI Precoding Matrix Index
- 5 is a diagram illustrating a basic concept of codebook based precoding.
- the transmitter and the receiver share codebook information including a predetermined number of precoding matrices predetermined according to a transmission rank, the number of antennas, and the like. That is, when the feedback information is finite, the precoding-based codebook method may be used.
- the receiving end may measure the channel state through the received signal, and feed back a finite number of preferred precoding matrix information (that is, an index of the corresponding precoding matrix) to the transmitting end based on the above-described codebook information.
- the receiver may select an optimal precoding matrix by measuring the received signal in a maximum likelihood (ML) or minimum mean square error (MMSE) method.
- FIG. 5 illustrates that the receiving end transmits precoding matrix information for each codeword to the transmitting end, the present invention is not limited thereto.
- the transmitter receiving feedback information from the receiver may select a specific precoding matrix from the codebook based on the received information.
- the transmitter that selects the precoding matrix performs precoding by multiplying the number of layer signals corresponding to the transmission rank by the selected precoding matrix, and transmits the precoded transmission signal through a plurality of antennas.
- the number of rows in the precoding matrix is equal to the number of antennas, and the number of columns is equal to the rank value. Since the rank value is equal to the number of layers, the number of columns is equal to the number of layers.
- the precoding matrix may be configured by a 4by2 matrix. Information transmitted through each layer may be mapped to each antenna through a precoding matrix.
- the receiving end receiving the signal precoded and transmitted by the transmitting end may restore the received signal by performing reverse processing of the precoding performed by the transmitting end.
- the inverse processing of the precoding described above is a Hermit of the precoding matrix P used for the precoding of the transmitter. (Hermit) matrix (P H ) can be made by multiplying the received signal.
- Table 5 shows codebooks used for downlink transmission using a 2-tx (transmit) antenna in 3GPP LTE Release-8 / 9, and Table 6 shows 4- in 3GPP LTE Release-8 / 9.
- the codebook for the two transmit antennas has a total of seven precoding vectors / matrices, where a single matrix is for an open-loop system, loop) There are a total of 6 precoding vectors / matrix for precoding of the system.
- the codebook for four transmission antennas as shown in Table 6 has a total of 64 precoding vectors / matrices.
- the codebook as described above has common characteristics such as constant modulus (CM) characteristics, nested properties, and constrained alphabet.
- CM characteristic is a characteristic that each element of all precoding matrices in the codebook does not include '0' and is configured to have the same size.
- the nested characteristic means that the low rank precoding matrix is designed to consist of a subset of a particular column of the high rank precoding matrix.
- the restricted alphabetic feature means that each element of every precoding matrix in the codebook is limited. For example, each element of the precoding matrix is limited to only one element ( ⁇ 1) used for Binary Phase Shift Keying (BPSK) or only one element ( ⁇ 1, ⁇ j) used for Quadrature Phase Shift Keying (QPSK). Elements restricted or used in 8-PSK ( Can be limited to In the codebook example of Table 5, the alphabet of each element of every precoding matrix in the codebook Because it is composed of, it can be expressed as having a limited alphabet characteristics.
- BPSK Binary Phase Shift
- the transmitted packet is transmitted through a wireless channel
- signal distortion may occur during the transmission process.
- the distortion In order to correctly receive the distorted signal at the receiving end, the distortion must be corrected in the received signal using the channel information.
- a method of transmitting the signal known to both the transmitting side and the receiving side and finding the channel information with the distortion degree when the signal is received through the channel is mainly used.
- the signal is called a pilot signal or a reference signal.
- the reference signal may be divided into an uplink reference signal and a downlink reference signal.
- an uplink reference signal as an uplink reference signal,
- DM-RS Demodulation-Reference Signal
- SRS sounding reference signal
- DM-RS Demodulation-Reference Signal
- CSI-RS Channel State Information Reference Signal
- MBSFN Multimedia Broadcast Single Frequency Network
- Reference signals can be classified into two types according to their purpose. There is a reference signal for obtaining channel information and a reference signal used for data demodulation. In the former, since the UE can acquire channel information on the downlink, it should be transmitted over a wide band, and even if the UE does not receive downlink data in a specific subframe, it should receive the reference signal. It is also used in situations such as handover.
- the latter is a reference signal transmitted together with a corresponding resource when the base station transmits a downlink, and the terminal can demodulate data by performing channel measurement by receiving the reference signal. This reference signal should be transmitted in the area where data is transmitted.
- a cell-specific RS CRS
- a UE-specific RS a UE-specific RS
- the UE-specific RS is used only for data demodulation, and the CRS is used not only for data demodulation but also for RRM measurement such as CSI acquisition and handover.
- the CRS is transmitted every subframe for the entire system band, and RS for up to four antenna ports is transmitted according to the number of transmit antennas of the base station. For example, if the number of transmitting antennas of the base station is two, CRSs for antenna ports 0 and 1 are transmitted, and if four, CRSs for antenna ports 0 to 3 are transmitted.
- the LTE-A system up to eight transmit antennas are supported as a downlink of the base station.
- the RS for up to eight transmit antennas are transmitted in every subframe in the same manner as the CRS of the existing LTE, the RS overhead becomes excessively large. Therefore, in the LTE-A system, two RSs are added, separated into CSI-RS for CSI measurement and DM-RS for data demodulation for selecting MCS and PMI.
- the CSI-RS can be used for purposes such as RRM measurement, but is designed for the purpose of obtaining CSI. Since the CSI-RS is not used for data demodulation, it does not need to be transmitted every subframe.
- the DM-RS is transmitted to the UE scheduled in the corresponding time-frequency domain. That is, the DM-RS of a specific UE is transmitted only in a region where the UE is scheduled, that is, a time-frequency region in which data is received.
- FIG. 6 shows a transmittable pattern of a CSI-RS having 8 antenna ports in an RB composed of 12 subcarriers in an LTE-A system.
- the RS for one antenna port is spread over two OFDM symbols.
- the two RSs share two REs and are separated using orthogonal codes.
- REs represented by the numbers 0 and 1 mean two REs through which CSI-RS ports 0 and 1 are transmitted.
- expressions such as CSI-RS ports 0 and 1 are used, and CSI-RS ports 0 and 1 are port 15, CSI-RS for distinguishing them from other types of RS such as CRS or UE-specific RS. It may have an index such as 16.
- the CSI-RS may be configured to have 1, 2, and 4 ports in addition to 8 ports.
- Table 7 shows the location of the transmission RE of the N-port CSI-RS in the transmission scheme of the normal CP as the subcarrier index k, the OFDM symbol index l, and the slot index n s in the RB.
- the 8-port CSI-RS has only 5 transmission patterns in one subframe. 7 shows transmission patterns of two-port, four-port, and eight-port CSI-RSs.
- the CSI-RS configuration is composed of antennaPortsCount, subframeConfig, resourceConfig, etc., and how many antenna ports CSI-RS is transmitted and how the period and offset of the subframe to which the CSI-RS is transmitted And tells which RE position (frequency and OFDM symbol index) is transmitted in the corresponding subframe.
- the base station delivers the following information when delivering a specific CSI-RS configuration to the UE.
- antennaPortsCount a parameter indicating the number of antenna ports used for transmission of CSI reference signals (e.g., 1 CSI-RS port, 2 CSI-RS port, 4 CSI-RS port or 8 CSI-RS port)
- resourceConfig Parameter about location of CSI-RS allocated resource
- subframeConfig Parameter about subframe period and offset to which CSI-RS will be transmitted
- Pc may have values in the range of [-8, 15] dB with 1 dB step size when the UE derives the CSI feedback. When present, it corresponds to the ratio of CSI-RS EPRE to PDSCH energy per resource element (EPRE).
- zeroTxPowerResourceConfigList Parameters for zero-power CSI-RS configuration
- zeroTxPowerSubframeConfig Parameter about subframe period and offset to which zero power CSI-RS will be transmitted.
- AAS active antenna system
- each antenna includes an active element such as an amplifier.
- the AAS does not require a separate cable, connector, or other hardware for connecting the amplifier and the antenna according to the use of the active antenna, and thus has high efficiency in terms of energy and operation cost.
- the AAS supports an electronic beam control scheme for each antenna, thereby enabling an advanced MIMO technology such as forming a precise beam pattern or a three-dimensional beam pattern in consideration of the beam direction and the beam width.
- a large scale MIMO structure having a plurality of input / output antennas and a multi-dimensional antenna structure is also considered.
- a 3D beam pattern may be formed by an active antenna of the AAS.
- N h represents the number of antenna columns and N v represents the number of antenna rows.
- the base station may receive a signal transmitted from the terminal through a plurality of antennas, and the terminal may set its transmission power very low in consideration of the gain of the large receiving antenna in order to reduce the interference effect.
- antenna ports of RSs (reference signals) transmitted in the same orthogonal frequency division multiplexing (OFDM) symbol in a frequency division multiplexing (FDM) + time division multiplexing (TDM) scheme are grouped, and physical antenna elements are also grouped. Each antenna port in the port group is allowed to be transmitted through multiple antenna elements in different antenna element groups.
- the codebook of the precoding matrix for data transmission and CSI reporting is used by combining a selection codebook for antenna port group selection and a constant modulus codebook for determining a beam pattern to be used in the selected antenna port group. .
- the selection codebook is used to inform the group of antenna port groups to use, and the constant modulus codebook is used to inform the ports in the antenna port group which precoding to apply. do.
- a specific subcarrier of a transmission OFDM symbol of each antenna port is called a resource element (RE), and the RE of the k-th subcarrier of an n-th OFDM symbol of an n-th antenna port is RE (k, l , n).
- the average energy transmitted per RE of each antenna port is called an energy per resource element (EPRE).
- E t T ⁇ P t / K
- EPRE Is E t T ⁇ P a / K. Since K subcarriers are amplified and transmitted by a single amplifier, transmission power exchange between subcarriers is easy. That is, the transmission energy of all K subcarriers in the same OFDM symbol does not have to exceed K ⁇ E a .
- Antenna port is a logical antenna concept and does not mean a real (physical) antenna element. Therefore, antenna ports are sometimes referred to as virtual antennas and antenna elements as physical antennas. The way each logical antenna port is mapped to a physical antenna element is an important factor in designing the entire MIMO system. One-to-one mapping for mapping antenna ports to one antenna element and one-to-many mapping for mapping antenna ports to multiple antenna elements may be considered in the antenna mapping scheme.
- the mapping from the antenna port to the antenna element is represented by the virtualization matrix B in the following equation.
- x denotes a transmission signal at the antenna port
- z denotes a transmission signal at the antenna element.
- the number of antenna ports may be smaller than the number of antenna elements, but for convenience of explanation, the case where the number of antenna ports is also N t is considered.
- b n represents a virtualization vector indicating a relationship in which an nth antenna port is mapped to antenna elements.
- One non-zero element of the virtualization vector b n indicates a one-to-one mapping method, and a plurality of non-zero elements indicates a one-to-many mapping method.
- the transmission data symbol vector is transmitted through each of the N t antennas by precoding, as shown in the following equation, where the precoding matrix W is equal to the maximum power P t .
- the elements have the same size, i.e. Is preferably.
- the number R of data layers transmitted at the same time is also called the number of streams or rank.
- the transmitted signal of Equation 3 is received by a receiver having N r receive antennas after passing through the channel, and the received signal may be represented by the following equation.
- H denotes an N r ⁇ N t channel matrix
- n denotes an N r ⁇ 1 noise vector.
- the effective channels H, B, and W are required for data demodulation, a method of directly estimating an effective channel through DM-RS transmission is also possible. However, in order to determine the precoding matrix W that maximizes transmission efficiency, the channel matrix H ⁇ B must be estimated.
- Effective Channel Matrix Can be expressed as N t channel column vectors, Denotes an effective channel between the n-th transmit antenna port and the N r receive antennas. Estimation of the effective channel matrix is performed by transmitting an independent RS at each antenna port Let be estimated separately. RS requires that RS for each antenna port be transmitted through orthogonal resources for the accuracy of channel estimation. That is, in order to transmit the RS for the 0-th antenna port in Equation 2, the precoding matrix is a column vector of rank 1 and all elements except the first element are 0, that is, , (i ⁇ 0). Where the size of the first element w 0 is This is preferably because the data symbols are transmitted with an energy of N t ⁇ E a so that they are transmitted with the same transmission energy and have the same cell coverage.
- the N t one method for transmitting the FDM the RS for antenna ports RE (k i, l, n i) n i in - n on the second port RS is transmitted in the RE (k j, l, n j) j -
- RE (k i , l, n i ) and RE (k j , l, n j ) are not transmitted, so RE (k i , l, n i ) and RE (k
- the 0-th antenna port may perform a muting operation in which no signal is transmitted so as not to interfere with RS transmitted from another port, and transmit from the corresponding RE.
- the energy is transferred to the RE (2, l, 0) where the RS of the 0-th antenna port is transmitted.
- the EPRE of the RS transmission RE is N t times larger than the EPRE of the data transmission RE in terms of the EPRE per antenna, the RS transmission energy and the data transmission energy are the same in terms of the energy of the sum of the transmission energies of all antennas.
- the RS is repeatedly transmitted at regular intervals on the frequency axis in order to measure the entire band channel. Since at least one RS must be transmitted for each coherence bandwidth BW c of the channel, the spacing of subcarriers through which RS of the same antenna port is transmitted should be set lower than T ⁇ BW c .
- TDM or CDM scheme should be additionally considered.
- 11 illustrates an example of transmitting 16 RSs to a total of 16 REs using four subcarriers and four OFDM symbols in an OFDM resource grid as an example of an FDM + TDM scheme.
- the 0-th antenna port transmits RS to RE (2,2,0), and muting is performed on the RE where the RS of another antenna port is transmitted.
- an antenna port mapping scheme for increasing transmission energy efficiency of the RS transmission scheme of FDM + TDM in a state in which the transmission power limitation of the antenna element amplifier is given will be described.
- the antenna virtualization of Equation 1 is applied so that the transmission energy of RS becomes N t ⁇ E a . It allows a single antenna to the antenna port mapping scheme to be used for both the transmission power of the antenna elements of M t be sent to the antenna elements of M t.
- the RS transmission energy is boosted by M f times by the transmission power exchange between the FDM RSs, and the transmission power is boosted by M t times by one-to-many antenna mapping.
- antenna ports of RSs transmitted in the same OFDM symbol are formed as a group to group the antenna ports in a disjoint manner.
- the group from the i ⁇ M f th antenna port to the (i + 1) ⁇ M f ⁇ 1 th antenna port is called a group T (i).
- N t antenna elements are divided by M t to form M f groups, and the i th antenna element group is called group E (i).
- one antenna port is mapped to all antenna elements belonging to one antenna element group E (i). That is, there is a one-to-one mapping between the antenna port and the antenna element group.
- antenna ports belonging to the same group T (i) are mapped to different antenna element groups.
- the grouping of antenna elements applied to antenna port group T (i) and antenna port group T (j) may be different. However, hereinafter, the description will be limited to the case where the grouping method of the antenna elements is maintained for convenience of description. In particular, a case of grouping the i ⁇ M t th antenna element to the (i + 1) ⁇ M t ⁇ 1 th antenna element into the group E (i) will be described as a representative example. In this case, the antenna ports mapped to the same antenna element group are grouped to define this as the antenna port group F (i).
- the proposed scheme will be described as a feature of the antenna virtualization matrix.
- the antenna virtualization matrix B of Equation 1 is represented by a matrix of M t as in the following equation.
- C n represents a virtualization matrix applied to the nth antenna port group T (n).
- C n may be expressed as an M t ⁇ 1 column vector as in the following equation.
- each row vector has only one non-zero element. This is to ensure that each antenna element is mapped to one antenna port in antenna port group T (n).
- Equations 6 and 7 form the group F (i) because the i th antenna port of the antenna port group T (n) is mapped to the same group E (i).
- group E (i) is composed of M t antenna ports spaced at intervals of M f from the i th antenna port.
- each antenna port belonging to group F (i) is transmitted in another OFDM symbol of the same subcarrier.
- the RSs of the antenna ports forming the group T (n) should be transmitted in the same OFDM symbol, but the RSs of the ports belonging to the group T (n) and the group T (n + 1) are transmitted in successive OFDM symbols. It doesn't have to be.
- This section describes an example of applying the content proposed in the present specification to the 2D AAS of FIG. 12.
- a group of antenna elements to which RS ports are mapped one-to-many may be applied to a group consisting of horizontal antenna rows or a group consisting of vertical antenna columns.
- one antenna port is mapped to N h antenna elements so that N v antenna ports form a group T (n) so that corresponding RSs are transmitted in the same OFDM symbol.
- one antenna port is mapped to N v antenna elements so that N h antenna ports form a group T (n) so that corresponding RSs are transmitted in the same OFDM symbol.
- R is R H
- the set of precoding matrices of the horizontal antenna is defined as the codebook CB (H) (N h ) of the horizontal antenna
- the set of precoding matrices of the vertical antenna is defined as the vertical antenna codebook CB (V) (N v ).
- the selection codebook is used as the horizontal antenna codebook, and the constant modulus codebook is used as the vertical antenna codebook.
- the selection codebook is used as the vertical antenna codebook and the constant modulus codebook is used as the horizontal antenna codebook.
- the selection codebook means a codebook having only a matrix formed of column vectors having one non-zero element as a precoding matrix
- the constant modulus codebook includes a codebook having only a matrix having elements having the same size as a precoding matrix. it means.
- the configuration of the codebook is such that each element of the final precoding matrix B ⁇ W used in the transmission signal of Equation 3 has the same size.
- the selection codebook informs information on which groups of M t antenna port groups T (n) are used, and the constant modulus codebook indicates which precoding to apply to antenna ports in the antenna port group. Inform the information.
- the antenna port selection codebook of the antenna size N may have the number M of codebooks of rank M selected from N, that is, as many as combination (N, M).
- the antenna ports may be divided into a plurality of antenna port sets, and the rank M codebook may be limited to select M antenna ports in the same antenna port set.
- the rank M codebook is the number of selecting M among the ports N / 2 in the set in each of the two antenna port sets, that is, 2 There may be * combinations (N / 2, M).
- the rank M codebook is the number of selecting M among the N / G ports in the set in each of the G antenna port sets. There may be G * combination (N / G, M) pieces.
- the proposed scheme is applied when the transmission beams of N antenna ports are not all orthogonal.
- only the ports orthogonal to the transmission beams of the antenna ports are configured as a set. That is, the transmission beam is orthogonal between the ports in the antenna port set.
- the transmission beam may not be orthogonal between ports belonging to different antenna port sets. Therefore, rank M codebook allows selecting only antenna ports in the same antenna port set to ensure orthogonality between transport layers.
- the maximum rank of the antenna port selection codebook may be predefined and the codebook that can be used in each rank may be limited by the bitmap indicator of RRC signaling.
- R V is The rank of indicates how many antenna port groups are selected. Is the antenna port selection vector, indicating which antenna port group is selected as the r th antenna. Denotes precoding applied to the selected r-th antenna port group. If the rank of is expressed as R H (r), the rank of the entire precoding is given by
- the rank of total precoding is the sum of the ranks of the precoding matrix applied to each of the selected antenna port groups.
- N t antenna ports CSI-RS using the proposed scheme are grouped into a plurality of groups, and RSs of antenna ports belonging to the same group are transmitted in the same OFDM symbol. That is, antenna ports of RSs transmitted in the same OFDM symbol may form one group, or RSs of a plurality of antenna port groups may be transmitted in the same OFDM symbol.
- the number of RSs belonging to the m th RS group must be defined as M f (m).
- the number of antenna ports per group may be the same.
- M f (m) N t / M t .
- the N t antenna ports CSI-RS applying the proposed scheme are grouped into a plurality of groups, and the CSI-RS of the ports belonging to the same group uses the existing CSI-RS transmission pattern of FIG. 7.
- the number of antenna ports included in one group is selected from 1, 2, 4, or 8.
- CSI-RSs of ports belonging to the same group are transmitted by being multiplexed by the FDM + CDM scheme of FIG. 7.
- RSs of ports belonging to different groups may be transmitted in different OFDM symbols.
- the entire CSI-RS can be said to be transmitted by FDM + CDM + TDM.
- the base station configures the proposed CSI-RS to the UE, the following information is transmitted to the CSI-RS configuration.
- Pc is a ratio of the PDSCH EPRE and the CSI-RS EPRE and is a parameter for the UE to assume CSI reporting and determine the quality of the PDSCH.
- different Pc per antenna port group is applied to enable different transmission power settings between data layers transmitted in each antenna port group.
- the location of the CSI-RS transmission resource per antenna port group can be individually specified through the CSI-RS configuration, but only the location of the CSI-RS transmission resource of the first group and the location of the CSI-RS transmission resource of the remaining group are relative to the first group. It can be specified in advance.
- the CSI-RS transmission period and offset may be set identically for all antenna port groups, but different transmission periods and offsets may be set per antenna port group in order to increase CSI-RS transmission efficiency. In particular, when RSs of all the antenna port groups of the CSI-RS cannot be transmitted in the same subframe due to lack of resources, even if RSs of all the antenna port groups are transmitted in the same period, the offset of the transmission subframe may be specified differently for each antenna port group. do.
- the base station may stop the transmission of the CSI-RS when it is determined that the transmission of the specific CSI-RS is unnecessary to reduce the overhead for the CSI-RS transmission. If the CSI-RS is a CSI-RS configured to UEs in advance, the UEs are informed that the CSI-RS is deactivated through MAC or RRC signaling, so that the CSI estimation for the CSI-RS is no longer performed. Do not do it.
- This method is applied to the CSI-RS configuration consisting of a plurality of antenna port groups so that the base station can inform whether the CSI-RS transmission is activated or deactivated for each antenna port group. That is, when the base station informs the UE of the CSI-RS activation / deactivation command, the base station informs of which antenna port group of which CSI-RS configuration is activated or deactivated.
- the UE allows the antenna port group deactivated by the activation / deactivation command of the base station to be excluded from the antenna port selection. That is, some codebooks of the antenna port selection codebook are automatically limited. As an example, when receiving the command that the fourth antenna port group is deactivated with the CSI-RS configuration consisting of four antenna port groups configured, the UE selects a fourth antenna port group from the antenna port selection codebook shown in Table 8. Is automatically limited so that the UE does not select the corresponding codebook upon CSI reporting.
- This section describes the CSI reporting method for CSI-RS configuration formed of a plurality of antenna port groups.
- the UE reports the information on which antenna port group to select using an antenna port selection codebook.
- the number of antenna port groups selected is the reported antenna port selection precoding matrix. Determined by the rank of.
- the UE determines which precoding matrix for the rth selected antenna port group. Report the information about whether to send the data.
- the precoding matrix applied to the antenna port group is selected from the constant modulus codebook.
- the UE rank R V and precoding matrix for antenna port group selection for CSI reporting R V ranks R H (r) and the precoding matrix for precoding applied to each selected antenna port group. Can report. The UE then reports on the CQI that can be obtained when the reported precoding matrices have been applied.
- the reporting period of each report item may be set differently.
- the reporting period of rank R V is the precoding matrix May be greater than or equal to the reporting period of. That is, if rank R V is reported once every 500 subframes, May be set to be reported once every 100 subframes.
- the precoding matrix The reporting period of rank R H (r) or May be greater than or equal to the reporting period of.
- the reporting period of the rank R H (r) is a precoding matrix May be greater than or equal to the reporting period of.
- an application frequency band of each report item may be set differently. That is, each report item is selected and reported independently by measuring a channel for each band, and the band size of each report item may be set differently.
- the magnitude of the band in which the rank R V is independently determined is the precoding matrix. It may be greater than or equal to the size of the band of. That is, if the rank R V is determined and reported once every 100 RB May be determined and reported once every 20 RBs. Or, rank R V is one value reported across the system band, May be reported for each subband.
- the precoding matrix The decision band of rank is R H (r) or It may be greater than or equal to the crystal band of.
- the determination band of the rank R H (r) is a precoding matrix It may be greater than or equal to the crystal band of.
- the entire precoding matrix is represented by the Kronecker product of Equation 9, where the UE has a rank R V and a precoding matrix for antenna port group selection for CSI reporting. Rank R H and the precoding matrix for precoding applied to the selected antenna port groups. Can report. And, the UE can report on the CQI that can be obtained when the reported precoding matrices are applied. If the reporting period of CSI information X is denoted as Period (X), Period (R V ) ⁇ Period ( ) ⁇ Period (R H ) ⁇ Period ( Can be set to Or Period (R V ) ⁇ Period (R H ) ⁇ Period ( ) ⁇ Period ( Can be set to
- the crystal band of the CSI information X is denoted as Bw (X)
- Bw (R V ) ⁇ Bw ( ) ⁇ Bw (R H ) ⁇ Bw ( Can be set to
- Bw (R V ) ⁇ Bw (R H ) ⁇ Bw ( ) ⁇ Bw ( Can be set to
- the UE is R V , , R H is determined and reported as a single value throughout the system band. To report for each subband. Or, for example, the UE determines and reports R V and R H as one value in the system band as a whole. , To report for each subband.
- Grouped antenna ports of the CSI-RS configuration to which the antenna port grouping proposed by the present invention may be defined as a sub-CSI-RS and configured as a CSI-RS configuration consisting of a plurality of sub-CSI-RSs.
- a scheme of setting a super CSI-RS by combining a plurality of CSI-RS configurations may be considered.
- FIG. 13 A case where the present invention is applied to a 2D AAS having 32 antenna elements will be described with reference to FIG. 13.
- the left side of FIG. 13 represents a physical antenna with 32 antenna elements.
- the right side of FIG. 13 represents a logical antenna with 32 antenna ports. 13 shows a grouping method of an antenna element and a grouping method of an antenna port, and also shows a mapping between the antenna element and the antenna port.
- FIG. 13 corresponds to FIG. 12 (b) which groups the antenna elements into vertical antenna rows, where the antenna elements comprise four groups E (0), E (1), E (2) and E (3). Are divided into The 32 antenna ports are also divided into four groups to form groups F (0), F (1), F (2) and F (3).
- the antenna ports belonging to the group F (i) are virtualized using all antenna elements belonging to the group E (i).
- the virtualization vector of each antenna port belonging to the group F (i) is set differently.
- one port is selected from each antenna port group to form group T (i).
- Each antenna port belonging to group T (i) is mapped to a different antenna element group using the same virtualization vector.
- the RS for each antenna port belonging to the group T (i) is to be transmitted in the same OFDM symbol.
- the codebook to be used in the 2D AAS by extending the proposed scheme is to use a Kronecker product of two codebooks as in Equations 8 and 9, or a combination of two types of codebooks as in Equations 10 and 11.
- the codebook uses a constant modulus codebook and another codebook allows the user to select between an antenna port selection codebook and a constant modulus codebook.
- This scheme has the flexibility of selecting and using a codebook according to the CSI-RS transmission scheme of the base station.
- the UE is allowed to specify whether to report CSI using the antenna port selection codebook or CSI using the constant modulus codebook.
- the codebook to be applied may be specified as an antenna port selection codebook or a constant modulus codebook.
- the codebook to be used in the 2D AAS by extending the proposed scheme is to use a Kronecker product of two codebooks as in Equations 8 and 9, or a combination of two types of codebooks as in Equations 10 and 11.
- the codebook uses a constant modulus codebook, and another codebook uses a mixed codebook with a mixture of antenna port selection precoder and constant modulus precoder.
- the base station may apply a codebook restriction to the mixed codebook according to the CSI-RS transmission scheme to use only a specific kind of precoder, that is, an antenna port selection precoder or constant modulus precoder.
- the rank R V for antenna port group selection may be limited to some specific value in advance. That is, the rank R V may be limited to be selected only from 1 and 2.
- the base station may limit the value that the rank R V may have through the RRC signaling for transmitting the MIMO transmission mode.
- the rank R H (r) applied to each of the selected antenna port groups may be limited to some specific value in advance.
- the rank of the entire precoding of Equation 12 may be limited to some specific value in advance.
- the rank of the entire precoding of Equation 12 may be limited so that it cannot be set beyond the number of receive antennas of the terminal or the maximum number of dataators that the terminal can receive.
- the maximum value of rank R H (r) applied to each antenna port group may be limited to a specific value or less by a transmission characteristic of each antenna port group.
- the maximum value of R H (r) and the maximum value of the rank of total precoding applied to each of the antenna port groups may be informed to the UE through RRC signaling in which the base station transmits a MIMO transmission mode.
- This embodiment relates to channel state reporting for downlink channels transmitted through N t antenna ports arranged in two dimensions.
- Each of the N t antenna ports is mapped to all antenna elements belonging to a specific antenna element group, and the antenna port groups corresponding to a reference signal (RS) transmitted in the same OFDM symbol are mapped to different antenna element groups. Is set.
- RS reference signal
- the terminal 141 may receive from the serving cell 142 a channel state report (CSI-RS) configuration for reporting the channel state for the antenna port group (S1410).
- CSI-RS channel state report
- the terminal may calculate channel state information for the downlink channel through the received CSI-RS using the received CSI-RS configuration (S1420).
- the terminal may report the channel state information to the serving cell (S1430).
- the reported channel state information may include a precoding matrix for antenna port group selection and a precoding matrix to be applied to the selected antenna port group.
- the precoding matrix for the antenna port group selection may be selected from an antenna port group selection codebook.
- the precoding matrix to be applied to the selected antenna port group may be selected from a constant modulus codebook.
- the terminal may receive information indicating whether transmission of the CSI-RS is activated or deactivated for each antenna port group from the serving cell.
- the precoding matrix for selecting the deactivated antenna port group may be excluded from the channel state information.
- the terminal may receive information on the rank limit of the precoding for the antenna port group selection or the rank limit of the precoding to be applied to the selected antenna port group from the serving cell.
- the operation of the terminal or the base station illustrated in FIG. 14 may include not only the embodiment described with reference to FIG. 14 but also at least one of the specific embodiments of the present invention described above.
- FIG. 15 is a block diagram illustrating components of a transmitter 10 and a receiver 20 that perform embodiments of the present invention.
- the transmitter 10 and the receiver 20 are radio frequency (RF) units 13 and 23 capable of transmitting or receiving radio signals carrying information and / or data, signals, messages, and the like, and in a wireless communication system.
- the device is operatively connected to components such as the memory 12 and 22 storing the communication related information, the RF units 13 and 23 and the memory 12 and 22, and controls the components.
- a processor 11, 21 configured to control the memory 12, 22 and / or the RF units 13, 23, respectively, to perform at least one of the embodiments of the invention described above.
- the memories 12 and 22 may store a program for processing and controlling the processors 11 and 21, and may temporarily store input / output information.
- the memories 12 and 22 may be utilized as buffers.
- the processors 11 and 21 typically control the overall operation of the various modules in the transmitter or receiver. In particular, the processors 11 and 21 may perform various control functions for carrying out the present invention.
- the processors 11 and 21 may also be called controllers, microcontrollers, microprocessors, microcomputers, or the like.
- the processors 11 and 21 may be implemented by hardware or firmware, software, or a combination thereof.
- firmware or software When implementing the present invention using hardware, application specific integrated circuits (ASICs) or digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), FPGAs ( field programmable gate arrays) may be provided in the processors 11 and 21.
- ASICs application specific integrated circuits
- DSPs digital signal processors
- DSPDs digital signal processing devices
- PLDs programmable logic devices
- FPGAs field programmable gate arrays
- firmware or software may be configured to include a module, a procedure, or a function for performing the functions or operations of the present invention, and configured to perform the present invention.
- the firmware or software may be provided in the processors 11 and 21 or stored in the memory 12 and 22 to be driven by the processors 11 and 21.
- the processor 11 of the transmission apparatus 10 is predetermined from the processor 11 or a scheduler connected to the processor 11 and has a predetermined encoding and modulation on a signal and / or data to be transmitted to the outside. After performing the transmission to the RF unit 13. For example, the processor 11 converts the data sequence to be transmitted into K layers through demultiplexing, channel encoding, scrambling, and modulation.
- the coded data string is also called a codeword and is equivalent to a transport block, which is a data block provided by the MAC layer.
- One transport block (TB) is encoded into one codeword, and each codeword is transmitted to a receiving device in the form of one or more layers.
- the RF unit 13 may include an oscillator for frequency upconversion.
- the RF unit 13 may include Nt transmit antennas (Nt is a positive integer greater than or equal to 1).
- the signal processing of the receiver 20 is the reverse of the signal processing of the transmitter 10.
- the RF unit 23 of the receiving device 20 receives a radio signal transmitted by the transmitting device 10.
- the RF unit 23 may include Nr receive antennas, and the RF unit 23 frequency down-converts each of the signals received through the receive antennas to restore the baseband signal.
- the RF unit 23 may include an oscillator for frequency downconversion.
- the processor 21 may decode and demodulate a radio signal received through a reception antenna to restore data originally transmitted by the transmission apparatus 10.
- the RF units 13, 23 have one or more antennas.
- the antenna transmits a signal processed by the RF units 13 and 23 to the outside under the control of the processors 11 and 21, or receives a radio signal from the outside to receive the RF unit 13. , 23).
- Antennas are also called antenna ports.
- Each antenna may correspond to one physical antenna or may be configured by a combination of more than one physical antenna elements.
- the signal transmitted from each antenna can no longer be decomposed by the receiver 20.
- a reference signal (RS) transmitted in correspondence with the corresponding antenna defines the antenna as viewed from the perspective of the receiver 20, and whether the channel is a single radio channel from one physical antenna or includes the antenna.
- RS reference signal
- the receiver 20 enables channel estimation for the antenna. That is, the antenna is defined such that a channel carrying a symbol on the antenna can be derived from the channel through which another symbol on the same antenna is delivered.
- the antenna In the case of an RF unit supporting a multi-input multi-output (MIMO) function for transmitting and receiving data using a plurality of antennas, two or more antennas may be connected.
- MIMO multi-input multi-output
- the UE operates as the transmitter 10 in the uplink and the receiver 20 in the downlink.
- the eNB operates as the receiving device 20 in the uplink, and operates as the transmitting device 10 in the downlink.
- the transmitter and / or the receiver may perform at least one or a combination of two or more of the embodiments of the present invention described above.
- the present invention can be used in a wireless communication device such as a terminal, a relay, a base station, and the like.
Abstract
Description
DL-UL configuration | Downlink-to-Uplink Switch-point periodicity | Subframe number | |||||||||
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | ||
0 | 5ms | D | S | U | U | U | D | S | U | U | U |
1 | 5ms | D | S | U | U | D | D | S | U | U | D |
2 | 5ms | D | S | U | D | D | D | S | U | D | D |
3 | 10ms | D | S | U | U | U | D | D | D | D | D |
4 | 10ms | D | S | U | U | D | D | D | D | D | D |
5 | 10ms | D | S | U | D | D | D | D | D | D | D |
6 | 5ms | D | S | U | U | U | D | S | U | U | D |
Special subframe configuration | Normal cyclic prefix in downlink | Extended cyclic prefix in downlink | ||||
DwPTS | UpPTS | DwPTS | UpPTS | |||
Normal cyclic prefix in uplink | Extended cyclic prefix in uplink | Normal cyclic prefix in uplink | Extended cyclic prefix in uplink | |||
0 | 6592·Ts | 2192·Ts | 2560·Ts | 7680·Ts | 2192·Ts | 2560·Ts |
1 | 19760·Ts | 20480·Ts | ||||
2 | 21952·Ts | 23040·Ts | ||||
3 | 24144·Ts | 25600·Ts | ||||
4 | 26336·Ts | 7680·Ts | 4384·Ts | 5120·Ts | ||
5 | 6592·Ts | 4384·Ts | 5120·Ts | 20480·Ts | ||
6 | 19760·Ts | 23040·Ts | ||||
7 | 21952·Ts | 12800·Ts | ||||
8 | 24144·Ts | - | - | - | ||
9 | 13168·Ts | - | - | - |
Search Space SK (L) | Number of PDCCH candidates M(L) | ||
Type | Aggregation Level L | Size[in CCEs] | |
UE-specific | 1 | 6 | 6 |
2 | 12 | 6 | |
4 | 8 | 2 | |
8 | 16 | 2 | |
Common | 4 | 16 | 4 |
8 | 16 | 2 |
PUCCH format | Modulation scheme | Number of bits per subframe | Usage | Etc. |
1 | N/A | N/A (exist or absent) | SR (Scheduling Request) | |
1a | BPSK | 1 | ACK/NACK orSR + ACK/NACK | One codeword |
1b | QPSK | 2 | ACK/NACK orSR + ACK/NACK | Two codeword |
2 | QPSK | 20 | CQI/PMI/RI | Joint coding ACK/NACK (extended CP) |
2a | QPSK+BPSK | 21 | CQI/PMI/RI + ACK/NACK | Normal CP only |
2b | QPSK+QPSK | 22 | CQI/PMI/RI + ACK/NACK | Normal CP only |
3 | QPSK | 48 | ACK/NACK orSR + ACK/NACK orCQI/PMI/RI + ACK/NACK |
CSI-RS configuration | Number of CSI-RSs configured | ||||||
1 or 2 | 4 | 8 | |||||
(k',l') | nsmod2 | (k',l') | nsmod2 | (k',l') | nsmod2 | ||
FS-1 and FS-2 | 0 | (9,5) | 0 | (9,5) | 0 | (9,5) | 0 |
1 | (11,2) | 1 | (11,2) | 1 | (11,2) | 1 | |
2 | (9,2) | 1 | (9,2) | 1 | (9,2) | 1 | |
3 | (7,2) | 1 | (7,2) | 1 | (7,2) | 1 | |
4 | (9,5) | 1 | (9,5) | 1 | (9,5) | 1 | |
5 | (8,5) | 0 | (8,5) | 0 | |||
6 | (10,2) | 1 | (10,2) | 1 | |||
7 | (8,2) | 1 | (8,2) | 1 | |||
8 | (6,2) | 1 | (6,2) | 1 | |||
9 | (8,5) | 1 | (8,5) | 1 | |||
10 | (3,5) | 0 | |||||
11 | (2,5) | 0 | |||||
12 | (5,2) | 1 | |||||
13 | (4,2) | 1 | |||||
14 | (3,2) | 1 | |||||
15 | (2,2) | 1 | |||||
16 | (1,2) | 1 | |||||
17 | (0,2) | 1 | |||||
18 | (3,5) | 1 | |||||
19 | (2,5) | 1 |
Claims (12)
- 2차원으로 배열된 Nt개의 안테나 포트를 통해 전송되는 하향링크 채널에 대한 채널 상태 보고를 위한 방법에 있어서, 상기 방법은 단말에 의해 수행되며,상기 Nt개의 안테나 포트 각각은 특정 안테나 엘리먼트 그룹에 속하는 모든 안테나 엘리먼트에 맵핑되고, 동일한 OFDM 심볼에서 전송되는 참조 신호(reference signal; RS)에 대응하는 안테나 포트 그룹의 각 안테나 포트는 서로 다른 안테나 엘리먼트 그룹에 맵핑되도록 설정되며,상기 안테나 포트 그룹에 대한 채널 상태 보고를 위한 참조 신호(chaneel state information-reference signal; CSI-RS) 설정을 수신하는 단계; 및상기 수신된 CSI-RS 설정을 사용하여 수신된 CSI-RS를 통해 하향링크 채널에 대한 채널 상태 정보를 계산하여 서빙 셀로 보고하는 단계를 포함하고,상기 보고되는 채널 상태 정보는 안테나 포트 그룹 선택을 위한 프리코딩 행렬 및 선택된 안테나 포트 그룹에 적용될 프리코딩 행렬을 포함하는 것을 특징으로 하는, 채널 상태 보고 방법.
- 제1항에 있어서, 상기 안테나 포트 그룹 선택을 위한 프리코딩 행렬은 안테나 포트 그룹 선택 코드북에서 선택되는 것을 특징으로 하는, 채널 상태 보고 방법.
- 제1항에 있어서, 상기 선택된 안테나 포트 그룹에 적용될 프리코딩 행렬은 상수 모듈러스(constant modulus) 코드북에서 선택되는 것을 특징으로 하는, 채널 상태 보고 방법.
- 제1항에 있어서, 안테나 포트 그룹 별로 상기 CSI-RS의 전송이 활성화 또는 비활성화되었는지 여부를 지시하는 정보를 상기 서빙 셀로부터 수신하는 단계를 더 포함하는 것을 특징으로 하는, 채널 상태 보고 방법.
- 제4항에 있어서, 상기 비활성화된 안테나 포트 그룹을 선택하기 위한 프리코딩 행렬은 상기 채널 상태 정보에서 제외되는 것을 특징으로 하는, 채널 상태 보고 방법.
- 제1항에 있어서, 상기 안테나 포트 그룹 선택을 위한 프리코딩의 랭크 제한 또는 상기 선택된 안테나 포트 그룹에 적용될 프리코딩의 랭크 제한에 대한 정보를 상기 서빙 셀로부터 수신하는 단계를 포함하는 것을 특징으로 하는, 채널 상태 보고 방법.
- 2차원으로 배열된 Nt개의 안테나 포트를 통해 전송되는 하향링크 채널에 대한 채널 상태 보고를 하도록 구성된 단말에 있어서,무선 주파수(radio frequency, RF) 유닛; 및상기 RF 유닛을 제어하도록 구성된 프로세서를 포함하되,상기 Nt개의 안테나 포트 각각은 특정 안테나 엘리먼트 그룹에 속하는 모든 안테나 엘리먼트에 맵핑되고, 동일한 OFDM 심볼에서 전송되는 참조 신호(reference signal; RS)에 대응하는 안테나 포트 그룹의 각 안테나 포트는 서로 다른 안테나 엘리먼트 그룹에 맵핑되도록 설정되며,상기 프로세서는 상기 안테나 포트 그룹에 대한 채널 상태 보고를 위한 참조 신호(chaneel state information-reference signal; CSI-RS) 설정을 수신하고, 그리고상기 수신된 CSI-RS 설정을 사용하여 수신된 CSI-RS를 통해 하향링크 채널에 대한 채널 상태 정보를 계산하여 서빙 셀로 보고하도록 구성되며,상기 보고되는 채널 상태 정보는 안테나 포트 그룹 선택을 위한 프리코딩 행렬 및 선택된 안테나 포트 그룹에 적용될 프리코딩 행렬을 포함하는 것을 특징으로 하는, 단말.
- 제7항에 있어서, 상기 안테나 포트 그룹 선택을 위한 프리코딩 행렬은 안테나 포트 그룹 선택 코드북에서 선택되는 것을 특징으로 하는, 단말.
- 제7항에 있어서, 상기 선택된 안테나 포트 그룹에 적용될 프리코딩 행렬은 상수 모듈러스(constant modulus) 코드북에서 선택되는 것을 특징으로 하는, 단말.
- 제7항에 있어서, 상기 프로세서는 안테나 포트 그룹 별로 상기 CSI-RS의 전송이 활성화 또는 비활성화되었는지 여부를 지시하는 정보를 상기 서빙 셀로부터 수신하도록 구성되는 것을 특징으로 하는, 단말.
- 제10항에 있어서, 상기 비활성화된 안테나 포트 그룹을 선택하기 위한 프리코딩 행렬은 상기 채널 상태 정보에서 제외되는 것을 특징으로 하는, 단말.
- 제7항에 있어서, 상기 프로세서는 상기 안테나 포트 그룹 선택을 위한 프리코딩의 랭크 제한 또는 상기 선택된 안테나 포트 그룹에 적용될 프리코딩의 랭크 제한에 대한 정보를 상기 서빙 셀로부터 수신하도록 구성되는 것을 특징으로 하는, 단말.
Priority Applications (3)
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EP15827230.2A EP3185436A4 (en) | 2014-08-01 | 2015-07-30 | Method for reporting channel state, and device therefor |
US15/315,334 US10320546B2 (en) | 2014-08-01 | 2015-07-30 | Method for reporting channel state, and device therefor |
KR1020167032392A KR102333401B1 (ko) | 2014-08-01 | 2015-07-30 | 채널 상태 보고를 위한 방법 및 이를 위한 장치 |
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US201462031876P | 2014-08-01 | 2014-08-01 | |
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US62/132,458 | 2015-03-12 | ||
US201562148718P | 2015-04-16 | 2015-04-16 | |
US62/148,718 | 2015-04-16 |
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US10320546B2 (en) | 2019-06-11 |
EP3185436A4 (en) | 2018-04-18 |
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KR20170038759A (ko) | 2017-04-07 |
EP3185436A1 (en) | 2017-06-28 |
US20170195100A1 (en) | 2017-07-06 |
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