# US 2014/0192917 A1 · Channel State Information Feedback Design in Advanced Wireless Communication Systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192917 A1 - Document ID: US20140192917A1 - Status: Published application - Kind: A1 - Application number: 14/149,436 - Filed: 2014-01-07 - Published: 2014-07-10 - Earliest claimed: 2013-01-08 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Young-Han Nam; Yang Li; Boon Loong Ng - Web page: https://patentgrep.com/patent/US20140192917A1 ## CPC - H04B 7/0417: Feedback systems - H04B 7/0632: {Channel quality parameters, e.g. channel quality indicator [CQI]} - H04L 1/0026: {Transmission of channel quality indication} - H04L 5/0023: {Time-frequency-space} - H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals} - H04B 7/063: {Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection} - H04B 7/0639: {Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection} - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Methods and apparatuses for providing feedback by a UE. A method includes receiving a first set of CSI-RS and a second set of CSI-RS, calculating a CQI using a received power of the first set of CSI-RS and a channel matrix estimated based on the second set of CSI-RS, and sending feedback based on the calculated CQI. A method includes measuring signals received on a plurality of CSI-RS ports; calculating CQI values for each of applications of precoding matrixes to each of the selected combinations of CSI-RS ports; selecting a SPN, a SPI, a PMI, and a RI that yields a highest CQI from among the calculated CQI values; and sending feedback indicating the SPI, the highest CQI value, the PMI, and at least one of the SPN or the RI. ## Claims ### Claim 1 A method for providing feedback by a user equipment (UE) in a wireless communication system, the method comprising: receiving a first set of channel state information reference signals (CSI-RS) and a second set of CSI-RS; calculating a channel quality indicator (CQI) using a received power of the first set of CSI-RS and a channel matrix estimated based on the second set of CSI-RS; and sending feedback based on the calculated CQI. ### Claim 2 (depends on 1) The method of claim 1, wherein calculating the CQI comprises: calculating the CQI according to: √{square root over (PE-CSI-RS(e))}·HAz, wherein PE-CSI-RS(e) is the received power on the first set of CSI-RS, and HAz is the channel matrix based on the second set of CSI-RS. ### Claim 3 (depends on 1) The method of claim 1, wherein channel direction information is a precoder matrix associated with a state of precoding matrix indicator (PMI) selected based on the second set of CSI-RS. ### Claim 4 (depends on 1) The method of claim 1, wherein a N number of CSI-RS comprising the first set of CSI-RS are transmitted on beams steered to the N number of angles in an elevation domain, a M number of CSI-RS comprising the second set of CSI-RS are transmitted on beams steered to a same angle in an azimuth domain. ### Claim 5 An apparatus in a user equipment (UE) configured to provide feedback in a wireless communication system, the apparatus comprising: a receiver configured to receive a first set of channel state information reference signal (CSI-RS) and a second set of CSI-RS; a controller configured to calculate a channel quality indicator (CQI) using a received power of the first set of CSI-RS and a channel matrix estimated based on the second set of CSI-RS; and a transmitter configured to send feedback based on the calculated CQI. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the controller is configured to calculate the CQI according to: √{square root over (PE-CSI-RS(e))}·HAz, wherein PE-CSI-RS(e) is the received power on the first set of CSI-RS, and HAz is the channel matrix based on the second set of CSI-RS. ### Claim 7 (depends on 5) The apparatus of claim 5, wherein channel direction information is a precoder matrix associated with a state of precoding matrix indicator (PMI) selected based on the second set of CSI-RS. ### Claim 8 (depends on 5) The apparatus of claim 5, wherein a N number of CSI-RS comprising the first set of CSI-RS are transmitted on beams steered to the N number of angles in an elevation domain, a M number of CSI-RS comprising the second set of CSI-RS are transmitted on beams steered to a same angle in an azimuth domain. ### Claim 9 An apparatus in a base station (BS) configured to receive feedback in a wireless communication system, the apparatus comprising: a controller configured to control generation and transmission of a first set of channel state information reference signal (CSI-RS) and a second set of CSI-RS; and a receiver configured to receive feedback based on a channel quality indicator (CQI) calculated using a received power of the first set of CSI-RS and a channel matrix estimated based on the second set of CSI-RS. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the CQI is calculated according to: √{square root over (PE-CSI-RS(e))}·HAz, wherein PE-CSI-RS(e) is the received power on the first set of CSI-RS, and HAz is the channel matrix based on the second set of CSI-RS. ### Claim 11 (depends on 9) The apparatus of claim 9, wherein channel direction information is a precoder matrix associated with a state of precoding matrix indicator (PMI) selected based on the second set of CSI-RS. ### Claim 12 (depends on 9) The apparatus of claim 9, wherein a N number of CSI-RS comprising the first set of CSI-RS are transmitted on beams steered to the N number of angles in an elevation domain, a M number of CSI-RS comprising the second set of CSI-RS are transmitted on beams steered to a same angle in an azimuth domain. ### Claim 13 A method for providing feedback by a user equipment (UE) in a wireless communication system, the method comprising: measuring signals received on a plurality of channel state information reference signal (CSI-RS) ports; selecting a plurality of combinations of the CSI-RS ports; applying a plurality of precoding matrixes to each of the selected combinations of CSI-RS ports; calculating channel quality indicator (CQI) values for each of the applications of precoding matrixes to each of the selected combinations of CSI-RS ports; selecting a selected port number (SPN), a selected port index (SPI), a precoding matrix indicator (PMI) corresponding to one of the plurality of precoding matrixes, and a rank indicator (RI) that yields a highest CQI from among the calculated CQI values, wherein the SPN is a number of selected CSI-RS ports and is equal to the RI, and wherein the SPI includes indices of the selected CSI-RS ports; and sending feedback indicating the SPI, the highest CQI value, the PMI, and at least one of the SPN or the RI. ### Claim 14 (depends on 13) The method of claim 13 further comprising determining the SPN as the number of CSI-RS ports to select based on at least one of the calculated CQI values or a grouping of the CSI-RS ports. ### Claim 15 (depends on 13) The method of claim 13, wherein selecting the SPN and the SPI comprises: when the SPN and the SPI are calculated by the UE, selecting a number of CSI-RS ports whose signal power exceeds a threshold, selecting a number of CSI-RS ports whose total sum power exceed a threshold, or selecting a number of CSI-RS ports where each port is from a group of CSI-RS ports and received power exceed a threshold, wherein the UE is configured to calculate the CQI values based on the selected SPN and the SPI, and wherein the threshold is determined by the UE or configured by a base station. ### Claim 16 (depends on 13) The method of claim 13, wherein: the UE is configured to calculate the CQI values based on each of the plurality of the CSI-RS ports selection and select the CQI/PMI/SPN/SPI associated with a particular CQI, or calculate the CQI values and the PMI based on each of the plurality of possible combinations of CSI-RS ports whose received power exceeds the threshold and select the CQI/PMI/SPN/SPI associated with the highest CQI value, and the threshold is determined by the UE or configured by a base station. ### Claim 17 (depends on 13) The method of claim 13, wherein when the SPN is configured for the UE, selecting the number of the CSI-RS ports comprises selecting the number of the CSI-RS ports according to a value of the SPN configured for the UE. ### Claim 18 (depends on 13) The method of claim 13, wherein when SPN/SPI sets are configured for the UE, selecting the number of the CSI-RS ports comprises selecting a SPN/SPI set from the configured SPN/SPI sets based on the calculated CQI values. ### Claim 19 (depends on 13) The method of claim 13, wherein sending the feedback comprises sending the feedback including both the SPN and the SPI for each of the selected CSI-RS ports. ### Claim 20 (depends on 13) The method of claim 13, wherein sending the feedback indicating at least the SPI for each of the selected CSI-RS ports comprises: jointly encoding the SPN and the SPI using a selected port number and index (SPNI) index; and sending the feedback including the SPNI index, wherein the SPN is fed back implicitly based on the SPN being equal to the RI. ### Claim 21 An apparatus in a user equipment (UE) configured to provide feedback in a wireless communication system, the apparatus comprising: a controller configured to measure signals received on a plurality of channel state information reference signal (CSI-RS) ports; select a plurality of combinations of the CSI-RS ports; apply a plurality of precoding matrixes to each of the selected combinations of CSI-RS ports; calculate channel quality indicator (CQI) values for each of the applications of precoding matrixes to each of the selected combinations of CSI-RS ports selection; and select a selected port number (SPN), a selected port index (SPI), a precoding matrix indicator (PMI) corresponding to one of the plurality of precoding matrixes, and a rank indicator (RI) that yields a highest CQI from among the calculated CQI values, wherein the SPN is a number of selected CSI-RS ports and is equal to the RI, and wherein the SPI includes indices of the selected CSI-RS ports; and a transmitter configured to send feedback indicating the SPI, the CQI, the PMI and at least one of the SPN or the RI. ### Claim 22 (depends on 21) The apparatus of claim 21, wherein the controller is configured to determine the SPN as the number of CSI-RS ports to select based on at least one of the calculated CQI values or a grouping of the CSI-RS ports. ### Claim 23 (depends on 21) The apparatus of claim 21, wherein: when the SPN and the SPI are calculated by the UE, the controller is configured to select a number of CSI-RS ports whose signal power exceeds a threshold, select a number of CSI-RS ports whose total sum power exceed a threshold, or select a number of CSI-RS ports where each port is from a group of CSI-RS ports and received power exceed a threshold, the controller is configured to calculate the CQI values based on the selected SPN and the SPI, and the threshold is determined by the UE or configured by a base station. ### Claim 24 (depends on 21) The apparatus of claim 21, wherein: the controller is configured to calculate the CQI values based on each of the plurality of the CSI-RS ports selection and select the CQI/PMI/SPN/SPI associated with a particular CQI, or calculate the CQI values based on each of the plurality of possible combinations of CSI-RS ports whose received power exceeds the threshold and select the CQI/PMI/SPN/SPI associated with the highest CQI value, and the threshold is determined by the UE or configured by a base station. ### Claim 25 (depends on 21) The apparatus of claim 21, wherein when the SPN is configured for the UE, the controller is configured to select the number of the CSI-RS ports according to a value of the SPN configured for the UE. ### Claim 26 (depends on 21) The apparatus of claim 21, wherein when SPN/SPI sets are configured for the UE, the controller is configured to select a SPN/SPI set from the configured SPN/SPI sets based on the calculated CQI values. ### Claim 27 (depends on 21) The apparatus of claim 21, wherein the transmitter is configured to send the feedback including the SPN and the SPI for each of the selected CSI-RS ports. ### Claim 28 (depends on 21) The apparatus of claim 21, wherein: the controller is configured to control joint encoding of the SPN and the SPI according to a selected port number and index (SPNI) index; the transmitter is configured to send the feedback including the SPNI index; and the SPN is fed back implicitly based on the SPN being equal to the RI.