# US 2022/0045902 A1 · Configuring measurement reference signals for mimo > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0045902 A1 - Document ID: US20220045902A1 - Status: Published application - Kind: A1 - Application number: 17/404,813 - Filed: 2021-08-17 - Published: 2022-02-10 - Earliest claimed: 2015-05-14 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget Lm Ericsson (Publ) - Inventors: Mattias Frenne; Shiwei Gao; Robert Mark Harrison; Siva Muruganathan - Web page: https://patentgrep.com/patent/US20220045902A1 ## CPC - H04L 41/0803: Configuration setting - 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)} - H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION ## Abstract Systems and methods relating to 6-port and/or greater than 8-port Channel State Information Reference Signal (CSI-RS) configurations are disclosed. In some embodiments, a method of operation of a radio access node in a cellular communications network comprises configuring a plurality of CSI-RS ports for a wireless device, where the plurality of CSI-RS ports is six CSI-RS ports, ten CSI-RS ports, twelve CSI-RS ports, fourteen CSI-RS ports, or sixteen CSI-RS ports, depending on the embodiment. The method further comprises transmitting CSI-RS on at least a subset of the plurality of CSI-RS ports configured for the wireless device. In this manner, support for, e.g., an increased number of antenna ports and/or support for two-dimensional (2D) antenna arrays is provided. ## Claims ### Claim 1 A method of operation of a radio access node in a cellular communications network, comprising: configuring a plurality of Channel State Information Reference Signal (CSI-RS) ports for a wireless device, the plurality of CSI-RS ports comprising at least one 8-port configuration, wherein the plurality of CSI-RS ports is allocated in a subset of Resource Elements (REs) contained in a Resource Block (RB); and transmitting CSI-RS on the plurality of CSI-RS ports, wherein the plurality of CSI-RS ports are configured such that there is an corresponding number of CSI-RS REs in each Orthogonal Frequency Division Multiplexing (OFDM) symbol of the RB in which CSI-RS is present, wherein the plurality of CSI-RS ports containing CSI-RS transmission satisfy uniform power boosting across the CSI-RS ports containing the CSI-RS transmission, and wherein a group of four CSI-RS ports of the plurality of CSI-RS ports configured for the wireless device are mapped to a group of four CSI-RS REs and transmitting the CSI-RS comprises multiplexing CSI-RS for the group of four CSI-RS ports onto the group of four CSI-RS REs using respective length-4 OCCs. ### Claim 2 (depends on 1) The method of claim 1, wherein the plurality of CSI-RS ports containing the CSI-RS transmission satisfies Signal to Interference plus Noise Ratio, SINR, improvement of at least 3 decibels, dB, for each of the CSI-RS ports containing the CSI-RS transmission over a case where two CSI-RS ports are multiplexed onto two CSI-RS REs using length-2 Orthogonal Cover Codes (OCCs). ### Claim 3 (canceled) ### Claim 4 (depends on 1) The method of claim 1, wherein the group of four CSI-RS REs are in two Orthogonal Frequency Division Multiplexing (OFDM) symbols on two subcarriers. ### Claim 5 (depends on 4) The method of claim 4, wherein multiplexing CSI-RS for the group of four CSI-RS ports onto the group of four CSI-RS REs using respective length-4 OCCs comprises, for each of the two subcarriers, applying a first length-2 OCC on the two OFDM symbols and for each of the two OFDM symbols, applying a second length-2 OCC on the two subcarriers, the first length-2 OCC being an OCC used across OFDM symbols for CSI-RS configurations of 2, 4, or 8 ports. ### Claim 6 (depends on 4) The method of claim 4, wherein the two OFDM symbols are adjacent in time and the two subcarriers are adjacent in frequency. ### Claim 7 (depends on 1) The method of claim 1, wherein: there is a plurality of predefined CSI-RS configurations comprising multiple predefined 8-port CSI-RS configurations, multiple predefined 4-port CSI-RS configurations, and multiple predefined 2-port CSI-RS configurations; and configuring the plurality of CSI-RS ports for the wireless device comprises configuring a merger of two or more of the plurality of predefined CSI-RS configurations for the wireless device, wherein the two or more of the plurality of predefined CSI-RS configurations for the merger are limited to combinations of two or more of a plurality of predefined CSI-RS configurations that result in at least four CSI-RS REs per Physical Resource Block, PRB, per Orthogonal Frequency Division Multiplexing, OFDM, symbol that contains CSI-RS. ### Claim 8 (depends on 7) The method of claim 7, wherein the two or more predefined CSI-RS configurations comprise two predefined 8-port CSI-RS configurations such that the f CSI-RS ports configured for the wireless device is sixteen CSI-RS ports. ### Claim 9 (depends on 1) The method of claim 1, wherein the CSI-RS ports configured for the wireless device comprises more than eight CSI-RS ports, and configuring the CSI-RS ports for the wireless device comprises signaling one of two or more predefined 16-port CSI-RS configurations to the wireless device. ### Claim 10 A radio access node for a cellular communications network, comprising: a transceiver; a processor; and memory storing software instructions executable by the processor whereby the radio access node is operable to: configure a plurality of Channel State Information Reference Signal (CSI-RS) ports for a wireless device, the plurality of CSI-RS ports comprising at least one 8-port configuration, wherein the plurality of CSI-RS ports is allocated in a subset of Resource Elements (REs) contained in a Resource Block (RB); and transmit CSI-RS on the plurality of CSI-RS ports, wherein the plurality of CSI-RS ports are configured such that there is an corresponding number of CSI-RS REs in each Orthogonal Frequency Division Multiplexing (OFDM) symbol of the RB in which CSI-RS is present, and wherein the plurality of CSI-RS ports containing CSI-RS transmission satisfy uniform power boosting across the CSI-RS ports containing the CSI-RS transmission, and wherein a group of four CSI-RS ports of the plurality of CSI-RS ports configured for the wireless device are mapped to a group of four CSI-RS REs and transmitting the CSI-RS comprises multiplexing CSI-RS for the group of four CSI-RS ports onto the group of four CSI-RS REs using respective length-4 OCCs. ### Claim 11 (depends on 10) The radio access node of claim 10, wherein the plurality of CSI-RS ports containing the CSI-RS transmission satisfies Signal to Interference plus Noise Ratio, SINR, improvement of at least 3 decibels, dB, for each of the CSI-RS ports containing the CSI-RS transmission over a case where two CSI-RS ports are multiplexed onto two CSI-RS REs using length-2 Orthogonal Cover Codes (OCCs). ### Claim 12 (depends on 10) The radio access node of claim 10, wherein the group of four CSI-RS REs are in two Orthogonal Frequency Division Multiplexing (OFDM) symbols on two subcarriers. ### Claim 13 (canceled) ### Claim 13 (depends on 10) The radio access node of claim 10, wherein the two or more predefined CSI-RS configurations comprise two predefined 8-port CSI-RS configurations such that the plurality of CSI-RS ports configured for the wireless device is sixteen CSI-RS ports. ### Claim 14 A method comprising: receiving, from a radio access node, a configuration of a plurality of sixteen Channel State Information Reference Signal (CSI-RS) ports from a radio access node, wherein the CSI-RS ports are allocated in a subset of Resource Elements (REs) contained in a Resource Block (RB) and the CSI-RS ports are configured such that there is an equal number of CSI-RS REs in each Orthogonal Frequency Division Multiplexing (OFDM) symbol of the RB in which the CSI-RS is present; wherein the plurality of CSI-RS ports containing the CSI-RS transmission satisfy uniform power boosting across the plurality of CSI-RS ports containing the CSI-RS transmission. ### Claim 15 (depends on 14) The method of claim 14, wherein the plurality of CSI-RS ports containing the CSI-RS transmission satisfies Signal to Interference plus Noise Ratio, SINR, improvement of at least 3 decibels, dB, for each of the CSI-RS ports containing the CSI-RS transmission over a case where two CSI-RS ports are multiplexed onto two CSI-RS REs using length-2 Orthogonal Cover Codes, OCCs. ### Claim 16 (depends on 14) The method of claim 14, further comprising: performing measurements on the plurality of CSI-RS ports configured for the wireless device; and transmitting a Channel State Information (CSI) report to the radio access node based on the measurements. ### Claim 17 (depends on 14) The method of claim 14, wherein a group of four CSI-RS ports of the plurality of CSI-RS ports configured for the wireless device are mapped to a group of four CSI-RS REs and CSI-RS for the group of four CSI-RS ports are multiplexed onto the group of four CSI-RS REs using respective length-4 OCCs. ### Claim 18 (depends on 14) The method of claim 14, wherein the group of four CSI-RS REs are in two Orthogonal Frequency Division Multiplexing (OFDM) symbols on two subcarriers. ### Claim 19 (depends on 14) The method of claim 14, wherein receiving configuration of the CSI-RS ports comprises receiving a bit map that is an indication of which of a plurality of predefined CSI-RS resources contain CSI-RS. ### Claim 20 A wireless device for a cellular communications network, comprising: a transceiver; a processor; and memory storing software instructions executable by the processor whereby the wireless device is operable to: receive, from a radio access node, a configuration comprising at least one set of 8 Channel State Information Reference Signal (CSI-RS) ports from a radio access node, wherein the CSI-RS ports are allocated in a subset of Resource Elements (REs) contained in a Resource Block (RB) and the CSI-RS ports are configured such that there is an corresponding number of CSI-RS REs in each Orthogonal Frequency Division Multiplexing (OFDM) symbol of the RB in which the CSI-RS is present; wherein the plurality of CSI-RS ports containing the CSI-RS transmission satisfy uniform power boosting across the plurality of CSI-RS ports containing the CSI-RS transmission, and wherein a group of four CSI-RS ports of the plurality of CSI-RS ports configured for the wireless device are mapped to a group of four CSI-RS REs and CSI-RS for the group of four CSI-RS ports are multiplexed onto the group of four CSI-RS REs using respective length-4 OCCs. ### Claim 21 (depends on 20) The wireless device of claim 20, wherein the CSI-RS ports containing the CSI-RS transmission satisfies Signal to Interference plus Noise Ratio (SINR) improvement of at least 3 decibels for each of the CSI-RS ports containing the CSI-RS transmission over a case where two CSI-RS ports are multiplexed onto two CSI-RS REs using length-2 Orthogonal Cover Codes (OCCs). ### Claim 22 (depends on 20) The wireless device of claim 20, wherein by execution of the software instructions, the wireless device is further operable to: perform measurements on the plurality of CSI-RS ports configured for the wireless device; and transmit a Channel State Information (CSI) report to the radio access node based on the measurements. ### Claim 23 (canceled) ### Claim 24 (depends on 20) The wireless device of claim 20, wherein the group of four CSI-RS REs are in two Orthogonal Frequency Division Multiplexing (OFDM) symbols on two subcarriers. ### Claim 25 (depends on 20) The wireless device of claim 20, wherein receiving configuration of the CSI-RS ports comprises receiving a bit map that is an indication of which of a plurality of predefined CSI-RS resources contain CSI-RS.