# US 12,010,616 B2 · Controlling MIMO layers for UE power saving > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,010,616 B2 - Document ID: US12010616B2 - Status: Granted - Kind: B2 - Application number: 16/564,018 - Filed: 2019-09-09 - Published: 2020-03-26 - Granted: 2024-06-11 - Earliest claimed: 2018-09-25 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Yuchul Kim; Haitong Sun; Wei Zeng; Dawei Zhang - Web page: https://patentgrep.com/patent/US12010616B2 ## CPC - H04W 52/0212: {managed by the network, e.g. network or access point is leader and terminal is follower} - H04W 52/028: {switching on or off only a part of the equipment circuit blocks} - H04B 7/046: {taking physical layer constraints into account} - H04W 52/0203: {in the radio access network or backbone network of wireless communication networks} - H04W 52/0216: {using a pre-established activity schedule, e.g. traffic indication frame} - H04W 52/0235: {where the received signal is a power saving command} - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04W 76/10: Connection setup - H04W 76/28: Discontinuous transmission [DTX]; Discontinuous reception [DRX] - H04W 72/0466: {the resource being a scrambling code} - Y02D 30/70: in wireless communication networks - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION - 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 This disclosure relates to techniques for dynamically adjusting a number of active receiver chains of a wireless device. Based on communication parameters exchanged with a base station, a device may determine a maximum number of receiver chains needed for data reception during one or more time periods. Such dynamic adjustment may enable power savings. ## Claims ### Claim 1 A method, comprising: at a base station: establishing a wireless communication link with a user equipment device (UE); receiving, from the UE, a preference for a maximum number of multiple-input multiple-output (MIMO) layers for power savings at the UE; configuring a first Bandwidth Part (BWP), wherein a configuration of the first BWP includes a first maximum number of MIMO layers specific to the first BWP; configuring a second BWP, wherein a configuration of the second BWP includes a second maximum number of MIMO layers specific to the second BWP, wherein the second maximum number of MIMO layers is less than the first maximum number of MIMO layers; transmitting, to the UE, data using the first BWP and using a first number of MIMO layers less than or equal to the first maximum number of MIMO layers; transmitting, to the UE, an indication to switch to the second BWP configured with the second maximum number of MIMO layers to enable the power savings at the UE; transmitting, to the UE, downlink control information, wherein the downlink control information indicates an actual number of MIMO layers less than or equal to the second maximum number of MIMO layers; and transmitting data to the UE using the actual number of MIMO layers. ### Claim 2 (depends on 1) The method of claim 1, wherein the first bandwidth part is a default bandwidth part, wherein the first maximum number of MIMO layers is equal to one. ### Claim 3 (depends on 1) The method of claim 1, the method further comprising transmitting a second communication parameter to the UE, wherein the second communication parameter comprises a maximum number of layers to receive during a connected mode discontinuous reception (CDRX) on duration. ### Claim 4 (depends on 1) The method of claim 1, wherein the second maximum number of MIMO layers is less than or equal to the maximum number of layers for power savings at the UE. ### Claim 5 (depends on 1) The method of claim 1, the method further comprising transmitting a second communication parameter to the UE, wherein the second communication parameter comprises a media access control (MAC) control element (CE), wherein said transmitting the indication to switch to the second BWP is based at least in part on channel conditions. ### Claim 6 (depends on 5) The method of claim 5, wherein the MAC CE is transmitted to the UE during a first slot, wherein the second maximum number of MIMO layers is applicable to one or more second slots after the first slot, the method further comprising: determining a third maximum number of MIMO layers for communication with the UE, wherein the third maximum number of MIMO layers is determined based at least in part on a change in channel conditions; transmitting a third communication parameter to the UE, wherein the third communication parameter indicates the third maximum number of MIMO layers, wherein the third maximum number of MIMO layers is applicable to one or more third slots after the one or more second slots; transmitting, to the UE, second downlink control information indicating a second actual number of MIMO layers less than or equal to the third maximum number of MIMO layers; and transmitting data to the UE using the second actual number of MIMO layers during the one or more third slots. ### Claim 7 An apparatus, comprising: a processor configured to cause a user equipment device (UE) to: establish communication with a base station; transmit, to the base station, a preference for a maximum number of multiple-input multiple-output (MIMO) layers for power savings at the UE; receive, from the base station, a first communication parameter; determine a maximum number of MIMO layers for a first bandwidth part, BWP, based on the first communication parameter; receive, from the base station, a second communication parameter; determine a second maximum number of MIMO layers for a second BWP based on the second communication parameter; receive, from the base station, an indication to switch to the second BWP configured with the second maximum number of MIMO layers, wherein the switch to the second BWP configured with the second maximum number of MIMO layers enables the power savings at the UE; receive, from the base station, downlink control information (DCI) indicating an actual number of MIMO layers equal to or less than the second maximum number of MIMO layers; and receive, from the base station, downlink data using the actual number of MIMO layers. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the second maximum number of MIMO layers is less than or equal to the maximum number of layers for power savings at the UE. ### Claim 9 (depends on 7) The apparatus of claim 7, wherein the processor is further configured to cause the UE to: indicate to the base station a number of codewords supported by the UE, wherein the first maximum number of MIMO layers is associated with the number of codewords. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the maximum number of MIMO layers for power savings at the UE is based on one or more measurements of channel conditions. ### Claim 11 (depends on 7) The apparatus of claim 7, wherein the processor is further configured to cause the UE to: determine a dynamic maximum number of MIMO layers. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the dynamic maximum number of MIMO layers is further based on at least one inactivity timer, wherein the at least one inactivity timer includes a BWP inactivity timer. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the at least one inactivity timer further includes a discontinuous reception (DRX) inactivity timer, wherein at least one of the first communication parameter and/or the second communication parameter includes a maximum number of layers for a connected mode discontinuous reception (CDRX) on duration. ### Claim 14 (depends on 11) The apparatus of claim 11, wherein the processor is further configured to cause the UE to: receive a further communication parameter from the base station, wherein the further communication parameter is received via a media access control (MAC) control element (CE); and adjust the dynamic maximum number of MIMO layers based on the further communication parameter, wherein the processor is further configured to cause the UE to: depower at least one receiver chain plurality of receiver chains based on the adjustment to the dynamic maximum number of MIMO layers. ### Claim 15 A user equipment device (UE), comprising: a radio; and a processor operably connected to the radio and configured to cause the UE to: establish communication with a base station; transmit, to the base station, a preference for a maximum number of multiple-input multiple-output (MIMO) layers for power savings at the UE; receive, from the base station, a first communication parameter; determine a maximum number of MIMO layers for a first bandwidth part, BWP, based on the first communication parameter; receive, from the base station, a second communication parameter; determine a second maximum number of MIMO layers for a second BWP based on the second communication parameter; receive, from the base station, an indication to switch to the second BWP configured with the second maximum number of MIMO layers, wherein the switch to the second BWP configured with the second maximum number of MIMO layers enables the power savings at the UE; receive, from the base station, downlink control information (DCI) indicating an actual number of MIMO layers equal to or less than the second maximum number of MIMO layers; and receive, from the base station, downlink data using the actual number of MIMO layers. ### Claim 16 (depends on 15) The UE of claim 15, wherein the DCI is received from the base station during a first slot, wherein the processor is further configured to cause the UE to: depower at least one active receiver chain during the first slot, wherein the downlink data is received during the first slot and subsequent to said depowering; and repower the at least one active receiver chain for at least a portion of a subsequent slot. ### Claim 17 (depends on 15) The UE of claim 15, wherein the maximum number of layers for power savings at the UE is greater than or equal to the second maximum number of MIMO layers. ### Claim 18 (depends on 17) The UE of claim 17, wherein the second maximum number of MIMO layers is equal to the maximum number of MIMO layers for power savings at the UE. ### Claim 19 (depends on 15) The UE of claim 15, wherein the processor is further configured to cause the UE to: determine a dynamic maximum number of MIMO layers. ### Claim 20 (depends on 19) The UE of claim 19, wherein the dynamic maximum number of MIMO layers is further based on at least one inactivity timer, wherein the at least one inactivity timer includes a BWP inactivity timer.