# US 9,438,325 B2 · Method for signaling MU-MIMO parameters > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,438,325 B2 - Document ID: US9438325B2 - Status: Granted - Kind: B2 - Application number: 14/659,219 - Filed: 2015-03-16 - Published: 2015-07-09 - Granted: 2016-09-06 - Earliest claimed: 2008-09-23 - Assignees: InterDigital Patent Holdings, Inc. - Applicants: Interdigital Patent Holdings, Inc. - Inventors: Kyle Jung-Lin Pan; Guodong Zhang; Donald M. Grieco; Phillip J. Pietraski - Web page: https://patentgrep.com/patent/US9438325B2 ## CPC - H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting - 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 7/0452: Multi-user MIMO systems - H04B 7/0665: {Feed forward of transmit weights to the receiver} - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - 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 Methods for signaling multi-user multiple-input multiple output (MU-MIMO) parameters for Evolved-UTRA (E-UTRA) are disclosed. Example signaling format methods are presented that allow use of distributed virtual resource blocks (DVRB) or support of four wireless transmit/receive units (WTRUs) but maintaining a predetermined signal format size. A signaling format is also presented that signals transmission precoding matrix indexes used by all co-scheduled WTRUs. ## Claims ### Claim 1 A method for signaling multi-user multiple-input multiple-output (MU-MIMO) transmission parameters, the method comprising: receiving a first downlink control information message with a distributed virtual resource block (DVRB) flag, a power share bit, and transmission precoding matrix index (TPMI) bits conveying a first set of transmission parameters on a condition of a two transmitting antenna configuration, wherein the TPMI bits are configured to indicate TPMIs of wireless transmit receive units (WTRUs) co-scheduled using the two transmitting antenna configuration; processing the first downlink control information message and applying the first set of transmission parameters to perform MU-MIMO reception in accordance with the two transmitting antenna configuration; receiving a second downlink control information message with a DVRB flag and additional TPMI bits conveying a second set of transmission parameters on a condition of a four transmitting antenna configuration, wherein the additional TPMI bits for the four transmitting antenna configuration comprise more TPMI bits than are used for the two transmitting antenna configuration, wherein the additional TPMI bits are configured to indicate TPMIs of WTRUs scheduled using the four transmitting antenna configuration, and wherein power sharing for the four transmitting antenna configuration is configured to be obtained from the additional TPMI bits; and processing the second downlink control information message and applying the second set of transmission parameters to perform MU-MIMO reception for the four transmitting antenna configuration. ### Claim 2 (depends on 1) The method as in claim 1, wherein the first downlink control information associated with the two transmitting antenna configuration and the second downlink control information associated with the four transmitting antenna configuration match a predetermined downlink control information format size. ### Claim 3 (depends on 2) The method as in claim 2, wherein the power share bit or the additional TPMI bits from which power sharing is configured to be obtained allows a wireless transmit/receive unit to correctly and dynamically interpret a ratio between its data power and a resource block power. ### Claim 4 (depends on 1) The method as in claim 1, wherein the power share bit or the additional TPMI bits from which power sharing is configured to be obtained signal whether at least two wireless transmit/receive units are sharing resource blocks. ### Claim 5 (depends on 1) The method as in claim 1, further comprising receiving a third downlink control information message with further TPMI bits conveying a third set of transmission parameters on a condition of an eight transmitting antenna configuration. ### Claim 6 A method for signaling multi-user multiple-input multiple-output (MU-MIMO) transmission parameters, the method comprising: receiving a first downlink control information message with transmission precoding matrix index (TPMI) bits and a power share bit conveying a first set of transmission parameters on a condition of a two transmitting antenna configuration, wherein the TPMI bits are configured to indicate TPMIs of wireless transmit receive units (WTRUs) co-scheduled using the two transmitting antenna configuration; processing the first downlink control information message and applying the first set of transmission parameters to perform MU-MIMO reception in accordance with the two transmitting antenna configuration; receiving a second downlink control information message with additional TPMI bits conveying a second set of transmission parameters on a condition of a four transmitting antenna configuration, wherein the additional TPMI bits for the four transmitting antenna configuration comprise more TPMI bits than are used for the two transmitting antenna configuration, wherein the additional TPMI bits are configured to indicate TPMIs of WTRUs scheduled using the four transmitting antenna configuration, and wherein power sharing for the four transmitting antenna configuration is configured to be obtained from the additional TPMI bits; and processing the second downlink control information message and applying the second set of transmission parameters to perform MU-MIMO reception for the four transmitting antenna configuration. ### Claim 7 (depends on 6) The method as in claim 6, wherein the first downlink control information message further comprises a distributed virtual resource block flag for the two transmitting antenna configuration. ### Claim 8 (depends on 6) The method as in claim 6, wherein the second downlink control information message further comprises a distributed virtual resource block flag for the four transmitting antenna configuration. ### Claim 9 (depends on 6) The method as in claim 6, wherein the power share bit signals whether at least two wireless transmit/receive units are sharing resource blocks. ### Claim 10 (depends on 6) The method as in claim 6, further comprising receiving a third downlink control information message with additional bits conveying a third set of transmission parameters on a condition of an eight transmitting antenna configuration. ### Claim 11 (depends on 6) The method as in claim 6, wherein unitary precoding is used. ### Claim 12 A wireless transmit/receive unit for receiving multi-user multiple-input multiple-output (MU-MIMO) transmission parameters, comprising: a receiver configured to receive a first downlink control information message with a distributed virtual resource block (DVRB) flag, a power share bit, and transmission precoding matrix index (TPMI) bits conveying a first set of transmission parameters on a condition of a two transmitting antenna configuration, a processor configured to process the first downlink control information message and applying the first set of transmission parameters to perform MU-MIMO reception in accordance with the two transmitting antenna configuration, the receiver configured to receive a second downlink control information message with a DVRB flag and additional TPMI bits conveying a second set of transmission parameters on a condition of a four transmitting antenna configuration, wherein the TPMI bits are configured to indicate TPMIs of wireless transmit receive units (WTRUs) co-scheduled using the two transmitting antenna configuration, wherein the additional TPMI bits for the four transmitting antenna configuration comprise more TPMI bits than are used for the two transmitting antenna configuration, wherein the additional TPMI bits are configured to indicate TPMIs of WTRUs scheduled using the four transmitting antenna configuration, and wherein power sharing for the four transmitting antenna configuration is configured to be obtained from the additional TPMI bits; and the processor configured to process the second downlink control information message and apply the second set of transmission parameters to perform MU-MIMO reception for the four transmitting antenna configuration. ### Claim 13 (depends on 12) The WTRU as in claim 12, wherein the first downlink control information associated with the two transmitting antenna configuration and the second downlink control information associated with the four transmitting antenna configuration match a predetermined downlink control information format size. ### Claim 14 (depends on 12) The WTRU as in claim 12, wherein the power share bit or TPMI bits from which power sharing is configured to be obtained signal whether at least two wireless transmit/receive units are sharing resource blocks. ### Claim 15 (depends on 12) The WTRU as in claim 12, wherein the power share bit or the additional TPMI bits from which power sharing is configured to be obtained allows the wireless transmit/receive unit to correctly and dynamically interpret a ratio between its data power and a resource block power. ### Claim 16 (depends on 12) The WTRU as in claim 12, wherein the receiver is further configured to receive a third downlink control information message with further TPMI bits conveying a third set of transmission parameters on a condition of an eight transmitting antenna configuration.