# US 2014/0153526 A1 · Method and apparatus for channel measurements for coordinated multipoint transmission > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153526 A1 - Document ID: US20140153526A1 - Status: Published application - Kind: A1 - Application number: 14/176,222 - Filed: 2014-02-10 - Published: 2014-06-05 - Earliest claimed: 2011-08-08 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: David MAZZARESE - Web page: https://patentgrep.com/patent/US20140153526A1 ## CPC - 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 7/0626: {Channel coefficients, e.g. channel state information [CSI]} - H04L 5/0057: {Physical resource allocation for CQI} - H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals} - H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal} - Y02D 30/70: in wireless communication networks - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract The present invention relates to a method for configuring reference signals and measurement sets to support coordinated multipoint transmission with distributed antennas. A first set of reference signal patterns is used for measuring and reporting received signal power from different transmission points, and a second set of reference signal patterns is used for measuring and reporting channel state information from different transmission points. The method allows to minimize power consumption and feedback overhead, while still being flexible in the configuration and re-configuration of the measurement sets. ## Claims ### Claim 1 A method for channel measurements for coordinated multipoint transmission in a wireless communication system, comprising: obtaining, by a receiver, a first set of channel state information reference signals (CSI-RS) and a second set of CSI-RS from a transmitter; deriving, by the receiver, at least one value of channel state information (CSI) based on the first set of CSI-RS; deriving, by the receiver, at least one value of CSI reference signal received power (CSI-RSRP) based on the second set of CSI-RS; and sending, by the receiver, the at least one value of CSI and the at least one value of CSI-RSRP to the transmitter. ### Claim 2 (depends on 1) The method of claim 1, wherein the obtaining, by the receiver, the first set of CSI-RS and the second set of CSI-RS from the transmitter comprises: receiving, by the receiver, configuration of at least one CSI-RS pattern from the transmitter; receiving, by the receiver, at least one CSI-RS transmitted by the transmitter according to the at least one CSI-RS pattern; and obtaining, by the receiver, the first set of CSI-RS and the second set of CSI-RS from the received at least one CSI-RS according to the configuration. ### Claim 3 (depends on 2) The method of claim 2, the configuration comprises a CSI measurements flag for each CSI-RS pattern; wherein the first set of CSI-RS comprises a first set of CSI-RS patterns for which the CSI measurements flag takes value 1; the second set of CSI-RS comprises a second set of CSI-RS patterns for which the CSI measurements flag takes value 1 and value 0; and the CSI measurements flag with value 1 indicates that the receiver takes CSI measurements. ### Claim 4 (depends on 2) The method of claim 2, the configuration comprises a CSI measurement flag for each CSI-RS pattern and a radio resource management (RRM) flag for each CSI-RS pattern; wherein the first set of CSI-RS comprises a first set of CSI-RS patterns for which the CSI measurement flag takes value 1; the second set of CSI-RS comprises a second set of CSI-RS patterns for which the RRM flag takes value 1; the CSI measurements flag with value 1 indicates that the receiver takes CSI measurements; and the RRM measurement flag with value 1 indicates that the receiver takes RRM measurements of CSI-RSRP. ### Claim 5 (depends on 4) The method of claim 4, further comprising: obtaining, by the receiver, a third set of CSI-RS from the transmitter; wherein the third set of CSI-RS comprises a third set of CSI-RS patterns for which the RRM measurements flag and the CSI measurements flag take value 0; and a CSI-RS of the third set of CSI-RS is used by the receiver for rate matching a physical downlink shared channel (PDSCH) around resource elements occupied by the CSI-RS of the third set of CSI-RS. ### Claim 6 (depends on 1) The method of claim 1, wherein all of the obtained CSI-RS are used by the receiver for rate matching a physical downlink shared channel (PDSCH) around resource elements occupied by these CSI-RS. ### Claim 7 A method for channel measurements for coordinated multipoint transmission in a wireless communication system, comprising: sending, by a transmitter, a first set of channel state information reference signals (CSI-RS) according to a first set of CSI-RS patterns and a second set of CSI-RS according to a second set of CSI-RS patterns, to a receiver; receiving, by the transmitter, at least one value of channel state information (CSI) derived by the receiver based on the first set of CSI-RS; receiving, by the transmitter, at least one value of CSI reference signal received power (CSI-RSRP) derived by the receiver based on the second set of CSI-RS; determining, by the transmitter, based on the at least one value of CSI, a precoder for precoding data; and configuring, by the transmitter, the first set of CSI-RS patterns based on the at least one value of CSI-RSRP. ### Claim 8 (depends on 7) The method of claim 7, further comprising: sending, by the transmitter, configuration of at least one CSI-RS pattern to the receiver; wherein the at least one CSI-RS pattern comprises the first set of CSI-RS patterns and the second set of CSI-RS patterns. ### Claim 9 (depends on 8) The method of claim 8, the configuration comprises a CSI measurements flag for each CSI-RS pattern; wherein the first set of CSI-RS comprises the first set of CSI-RS patterns for which the RLM measurements flag takes value 1; the second set of CSI-RS comprises the second set of CSI-RS patterns for which the RLM measurements flag takes value 1 and value 0; and the CSI measurements flag with value 1 indicates that the receiver takes CSI measurements. ### Claim 10 (depends on 8) The method of claim 8, the configuration comprises a CSI measurement flag for each CSI-RS pattern and a radio resource management (RRM) flag for each CSI-RS pattern; wherein the first set of CSI-RS comprises the first set of CSI-RS patterns for which the CSI measurement flag takes value 1; the second set of CSI-RS comprises the second set of CSI-RS patterns for which the RRM flag takes value 1; the CSI measurements flag with value 1 indicates that the receiver takes CSI measurements; and the RRM measurement flag with value 1 indicates that the receiver takes RRM measurements of CSI-RSRP. ### Claim 11 (depends on 10) The method of claim 10, further comprising: sending, by the transmitter, a third set of CSI-RS to the receiver; wherein the third set of CSI-RS comprises a third set of CSI-RS patterns for which the RRM measurements flag and the CSI measurements flag take value 0, and a CSI-RS of the third set of CSI-RS is used by the receiver for rate matching a physical downlink shared channel (PDSCH) around resource elements occupied by the CSI-RS of the third set of CSI-RS. ### Claim 12 A receiver for channel measurements for coordinated multipoint transmission in a wireless communication system, comprising: a processor module, configured to: obtain a first set of channel state information reference signals (CSI-RS) and a second set of CSI-RS from a transmitter; derive at least one value of channel state information (CSI) based on the first set of CSI-RS; derive at least one value of CSI reference signal received power (CSI-RSRP) based on the second set of CSI-RS; and send the at least one value of CSI and the at least one value of CSI-RSRP to the transmitter. ### Claim 13 (depends on 12) The receiver of claim 12, the processor module is further configured to: receive configuration of at least one CSI-RS pattern from the transmitter; receive at least one CSI-RS transmitted by the transmitter according to the at least one CSI-RS pattern; and obtain the first set of CSI-RS and the second set of CSI-RS from the received at least one CSI-RS according to the configuration. ### Claim 14 (depends on 13) The receiver of claim 13, the configuration comprises a CSI measurements flag for each CSI-RS pattern; wherein the first set of CSI-RS comprises a first set of CSI-RS patterns for which the CSI measurements flag takes value 1; the second set of CSI-RS comprises a second set of CSI-RS patterns for which the CSI measurements flag takes value 1 and value 0; and the CSI measurements flag with value 1 indicates that the receiver takes CSI measurements. ### Claim 15 (depends on 13) The receiver of claim 13, the configuration comprises a CSI measurement flag for each CSI-RS pattern and a radio resource management (RRM) flag for each CSI-RS pattern; wherein the first set of CSI-RS comprises a first set of CSI-RS patterns for which the CSI measurement flag takes value 1; the second set of CSI-RS comprises a second set of CSI-RS patterns for which the RRM flag takes value 1; the CSI measurements flag with value 1 indicates that the receiver takes CSI measurements; and the RRM measurement flag with value 1 indicates that the receiver takes RRM measurements of CSI-RSRP. ### Claim 16 (depends on 15) The receiver of claim 15, the processor module is further configured to obtain a third set of CSI-RS; wherein the third set of CSI-RS comprises a third set of CSI-RS patterns for which the RRM measurements flag and the CSI measurements flag take value 0; and a CSI-RS of the third set of CSI-RS is used by the receiver for rate matching a physical downlink shared channel (PDSCH) around resource elements occupied by the CSI-RS of the third set of CSI-RS. ### Claim 17 A transmitter for channel measurements for coordinated multipoint transmission in a wireless communication system, comprising: a processor module, configured to: send a first set of channel state information reference signals (CSI-RS) according to a first set of CSI-RS patterns and a second set of CSI-RS according to a second set of CSI-RS patterns, to a receiver; receive at least one value of channel state information (CSI) derived by the receiver based on the first set of CSI-RS; receive at least one value of CSI reference signal received power (CSI-RSRP) derived by the receiver based on the second set of CSI-RS; determine a precoder for precoding data based on the at least one value of CSI; and configure the first set of CSI-RS patterns based on the at least one value of CSI-RSRP or the at least one value of RSS. ### Claim 18 (depends on 17) The transmitter of claim 17, the processor module is further configured to: send configuration of at least one CSI-RS pattern to the receiver; wherein the at least one CSI-RS pattern comprises the first set of CSI-RS patterns and the second set of CSI-RS patterns. ### Claim 19 (depends on 18) The transmitter of claim 18, the configuration comprises a CSI measurements flag for each CSI-RS pattern; wherein the first set of CSI-RS comprises the first set of CSI-RS patterns for which the CSI measurements flag takes value 1; the second set of CSI-RS comprises the second set of CSI-RS patterns for which the CSI measurements flag takes value 1 and value 0; and the CSI measurements flag with value 1 indicates that the receiver takes CSI measurements. ### Claim 20 (depends on 18) The transmitter of claim 18, the configuration comprises a CSI measurement flag for each CSI-RS pattern and a radio resource management (RRM) flag for each CSI-RS pattern; wherein the first set of CSI-RS comprises the first set of CSI-RS patterns for which the CSI measurement flag takes value 1; the second set of CSI-RS comprises the second set of CSI-RS patterns for which the RRM flag takes value 1; the CSI measurements flag with value 1 indicates that the receiver takes CSI measurements; and the RRM measurement flag with value 1 indicates that the receiver takes RRM measurements of CSI-RSRP. ### Claim 21 (depends on 20) The transmitter of claim 20, the processor module is further configured to: send a third set of CSI-RS to the receiver; wherein the third set of CSI-RS comprises a third set of CSI-RS patterns for which the RRM measurements flag and the CSI measurements flag take value 0; and a CSI-RS of the third set of CSI-RS is used by the receiver for rate matching a physical downlink shared channel (PDSCH) around resource elements occupied by the CSI-RS of the third set of CSI-RS.