# US 2018/0324801 A1 · Access point managed channel correlation for mu-mimo > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0324801 A1 - Document ID: US20180324801A1 - Status: Published application - Kind: A1 - Application number: 15/585,099 - Filed: 2017-05-02 - Published: 2018-11-08 - Earliest claimed: 2017-05-02 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: BadriSrinivasan Sampathkumar; Madhan Jaganathan; Ahmed Ragab Elsherif - Web page: https://patentgrep.com/patent/US20180324801A1 ## CPC - H04B 1/38: Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving - H04B 7/0452: Multi-user MIMO systems - H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]} - H04W 52/386: {centralized, e.g. when the radio network controller or equivalent takes part in the power control} - H04W 84/12: WLAN [Wireless Local Area Networks] - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Apparatuses and methods for reducing channel correlation between wireless nodes are disclosed. An apparatus may receive channel state information (CSI) from each of a plurality of wireless nodes and determine, for each of the plurality of wireless nodes, a level of channel correlation with other wireless nodes based, at least in part, on the received CSI. The apparatus may identify one or more of the plurality of wireless nodes for which the determined level of channel correlation is greater than or equal to a value, and then generate, for at least one of the identified wireless nodes, an instruction requesting at least one of the identified wireless nodes to adjust a parameter by an amount based on the determined level of channel correlation. The apparatus may provide the instruction for transmission to the at least one of the identified wireless nodes. ## Claims ### Claim 1 An apparatus for wireless communication, comprising: an interface configured to receive channel state information (CSI) from each of a plurality of wireless nodes; and a processing system configured to: determine, for each of the plurality of wireless nodes, a level of channel correlation with other wireless nodes based, at least in part, on the received CSI; identify one or more of the plurality of wireless nodes for which the determined level of channel correlation is greater than or equal to a value; and generate an instruction requesting at least one of the identified wireless nodes to adjust a parameter by an amount based on the determined level of channel correlation, wherein the interface is further configured to provide the instruction for transmission to the at least one of the identified wireless nodes. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the determination is further based on a correlation tree structure. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the parameter comprises a cyclic shift diversity (CSD) value. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the parameter comprises an attenuation value, and the instruction requests the at least one of the identified wireless nodes to generate an attenuated signal by applying the attenuation value to a signal. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein the instruction requests the at least one of the identified wireless nodes to generate an artificial multipath signal based on the signal and the attenuated signal. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein: the processing system is further configured to generate an action frame containing the instruction; and the interface is further configured to provide the action frame for transmission to the at least one of the identified wireless nodes. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein: the processing system is further configured to select one or more of the plurality of wireless nodes to form a group based on at least one determined level of channel correlation and to generate multi-user multiple-input multiple-output (MU-MIMO) data for the group; and the interface is further configured to provide the MU-MIMO data for transmission to the group. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein: the interface is further configured to receive, from the selected wireless nodes, updated CSI; and the processing system is further configured to: determine, for each of the selected wireless nodes, an updated level of channel correlation with other wireless nodes based, at least in part, on the updated CSI; identify one or more of the selected wireless nodes for which the updated level of channel correlation is greater than or equal to the value; and remove the identified one or more of the selected wireless nodes from the group. ### Claim 9 (canceled) ### Claim 10 (canceled) ### Claim 11 (canceled) ### Claim 12 (canceled) ### Claim 13 (canceled) ### Claim 14 (canceled) ### Claim 15 (canceled) ### Claim 16 (canceled) ### Claim 17 (canceled) ### Claim 18 (canceled) ### Claim 19 (canceled) ### Claim 20 (canceled) ### Claim 21 (canceled) ### Claim 22 (canceled) ### Claim 23 (canceled) ### Claim 24 (canceled) ### Claim 25 (canceled) ### Claim 26 An apparatus, comprising: an interface configured to receive an instruction requesting the apparatus to adjust a parameter by an amount based on a level of channel correlation between the apparatus and a number of wireless nodes; and a processing system configured to adjust the parameter by the amount. ### Claim 27 (depends on 26) The apparatus of claim 26, wherein the parameter comprises a cyclic shift diversity (CSD) value, and the processing system is further configured to adjust the CSD associated with one or more receive chains of the apparatus based on the CSD value. ### Claim 28 (depends on 26) The apparatus of claim 26, wherein the parameter comprises an attenuation value, and the processing system is further configured to generate an attenuated signal by applying the attenuation value to a signal. ### Claim 29 (depends on 28) The apparatus of claim 28, wherein the processing system is further configured to generate an artificial multipath signal based on the signal and the attenuated signal. ### Claim 30 (depends on 29) The apparatus of claim 29, wherein the processing system is further configured to introduce the artificial multipath signal into a receive path of the apparatus. ### Claim 31 (canceled) ### Claim 32 (canceled) ### Claim 33 (canceled) ### Claim 34 (canceled) ### Claim 35 (canceled) ### Claim 36 (canceled) ### Claim 37 (canceled) ### Claim 38 (canceled) ### Claim 39 (canceled) ### Claim 40 (canceled) ### Claim 41 (canceled) ### Claim 42 (canceled) ### Claim 43 An access point, comprising: a transceiver configured to receive channel state information (CSI) from each of a plurality of wireless devices; and a processing system configured to: determine, for each of the plurality of wireless devices, a level of channel correlation with other wireless devices based, at least in part, on the received CSI; identify one or more of the plurality of wireless devices for which the determined level of channel correlation is greater than or equal to a value; and generate an instruction requesting at least one of the identified wireless devices to adjust a parameter by an amount based on the determined level of channel correlation, wherein the transceiver is further configured to transmit the instruction to the at least one of the identified wireless devices. ### Claim 44 (depends on 26) The apparatus of claim 26, further comprising at least one antenna via which the instruction is received, wherein the apparatus is configured as a wireless node.