# US 9,438,395 B2 · Method for feeding back channel state information in wireless communication system and apparatus therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,438,395 B2 - Document ID: US9438395B2 - Status: Granted - Kind: B2 - Application number: 14/383,220 - Filed: 2013-10-22 - Published: 2015-01-22 - Granted: 2016-09-06 - Earliest claimed: 2012-10-23 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Hyungtae Kim; Jonghyun Park; Kijun Kim - Web page: https://patentgrep.com/patent/US9438395B2 ## CPC - H04W 24/10: Scheduling measurement reports {; Arrangements for measurement reports} - H04B 7/04: using two or more spaced independent antennas - H04B 7/0417: Feedback systems - H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]} - H04L 5/0023: {Time-frequency-space} - H04L 5/0035: {Resource allocation in a cooperative multipoint environment} - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04L 5/0057: {Physical resource allocation for CQI} - H04L 5/0073: {Allocation arrangements that take into account other cell interferences} - H04L 5/0082: {at predetermined intervals} - H04L 5/0091: {Signalling for the administration of the divided path, e.g. signalling of configuration information} - H04L 5/0094: {Indication of how sub-channels of the path are allocated} - H04W 76/27: Transitions between radio resource control [RRC] states - H04B 7/024: Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems - H04B 7/0658: {Feedback reduction} - H04W 88/08: Access point devices - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract The present invention relates to a method for receiving a reference CSI configuration information and a following CSI configuration information which is configured to report a same RI (Rank Indicator) as the reference CSI configuration information, receiving a first CSI-RS (Channel State Information-Resource Signal) configuration information associated with the reference CSI configuration and a second CSI-RS configuration information associated with the following CSI configuration, number of CSI-RS antenna ports according to the second CSI-RS configuration information is same as number of CSI-RS antenna ports according to the first CSI-RS configuration information; and transmitting CSI determined based on at least one of the first CSI-RS configuration information and the second CSI-RS configuration information. ## Claims ### Claim 1 A method for transmitting CSI (Channel State Information) in a wireless access system, the method performed by a user equipment and comprising: configuring a first CSI process associated with a first CSI-RS (Channel State Information-Resource Signal) and a second CSI process associated with a second CSI-RS; and transmitting the CSI based on at least one of the first CSI process and the second CSI process, wherein a second RI (Rank Indicator) of the second CSI process is configured the same as a first RI of the first CSI process, and wherein a number of a first CSI-RS antenna ports of the first CSI process is the same as a number of a second CSI-RS antenna ports of the second CSI process. ### Claim 2 (depends on 1) The method of claim 1, wherein the first CSI-RS and the second CSI-RS are related to CSI-RS of non-zero transmission power. ### Claim 3 (depends on 1) The method of claim 1, further comprising: receiving first CSI-RS configuration information and second CSI-RS configuration information using RRC (Radio Resource Control) signaling. ### Claim 4 (depends on 1) The method of claim 1, wherein the CSI includes at least one of a RI, a PMI (Precoding Matrix Indicator), and a CQI (Channel Quality Indicator). ### Claim 5 A method for receiving CSI (Channel State Information) in a wireless access system, the method performed by a base station and comprising: transmitting first configuration information of a first CSI process associated with a first CSI-RS (Channel State Information-Resource Signal) and second configuration information of a second CSI process associated with a second CSI-RS; and receiving the CSI based on at least one of the first CSI process and the second CSI process, wherein a second RI (Rank Indicator) of the second CSI process is configured the same as a first RI of the first CSI process, and wherein a number of a first CSI-RS antenna ports of the first CSI process is the same as a number of a second CSI-RS antenna ports of the second CSI process. ### Claim 6 (depends on 5) The method of claim 5, wherein the first CSI-RS and the second CSI-RS are related to CSI-RS of non-zero transmission power. ### Claim 7 (depends on 5) The method of claim 5, further comprising: transmitting first CSI-RS configuration information and second CSI-RS configuration information using RRC (Radio Resource Control) signaling. ### Claim 8 (depends on 5) The method of claim 5, wherein the CSI includes at least one of a RI, a PMI (Precoding Matrix Indicator), and a CQI (Channel Quality Indicator). ### Claim 9 A user equipment for transmitting CSI (Channel State Information) in a wireless access system, the user equipment comprising: a RF (Radio Frequency) module; and a processor which is configured to: configure a first CSI process associated with a first CSI-RS (Channel State Information-Resource Signal) and a second CSI process associated with a second CSI-RS; and transmit the CSI based on at least one of the first CSI process and the second CSI process, wherein a second RI (Rank Indicator) of the second CSI process is configured the same as a first RI of the first CSI process, and wherein a number of a first CSI-RS antenna ports of the first CSI process is the same as a number of a second CSI-RS antenna ports of the second CSI process. ### Claim 10 A base station for receiving CSI (Channel State Information) in a wireless access system, the base station comprising: a RF (Radio Frequency) module; and a processor which is configured to: transmit first configuration information of a first CSI process associated with a first CSI-RS (Channel State Information-Resource Signal) and second configuration information of a second CSI process associated with a second CSI-RS; and receive the CSI based on at least one of the first CSI process and the second CSI process, wherein a second RI (Rank Indicator) of the second CSI process is configured the same as a first RI of the first CSI process, and wherein a number of a first CSI-RS antenna ports of the first CSI process is the same as a number of a second CSI-RS antenna ports of the second CSI process.