# US 2021/0344459 A1 · Techniques for on-demand soft ack/nack in a wireless communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0344459 A1 - Document ID: US20210344459A1 - Status: Published application - Kind: A1 - Application number: 17/302,072 - Filed: 2021-04-22 - Published: 2021-11-04 - Earliest claimed: 2020-04-30 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Yan Zhou; Qian Zhang; Tao Luo - Web page: https://patentgrep.com/patent/US20210344459A1 ## CPC - H04L 1/1861: {Physical mapping arrangements (for ACK signaling see also H04L5/0053)} - H04L 1/1896: {ARQ related signaling} - H04B 17/309: Measuring or estimating channel quality parameters - H04B 17/336: Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] - H04L 1/0003: {by switching between different modulation schemes} - H04L 1/0026: {Transmission of channel quality indication} - H04L 1/1671: {the supervisory signal being transmitted together with control information} - H04L 1/1825: Adaptation of specific ARQ protocol parameters according to transmission conditions - H04L 1/1864: {ARQ related signaling (H04L1/1607 takes precedence)} - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04W 72/542: using measured or perceived quality - H04L 1/20: using signal quality detector - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - 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 Aspects described herein relate to on-demand soft acknowledgement (ACK)/negative acknowledgement (NACK) in radio access and other wireless networks, such as fifth generation new radio (5G NR), 3GPP Long Term Evolution (LTE), 3GPP LTE-Advanced (LTE-A), Wi-Fi, and the like. In an example, the aspects may include receiving, from a network entity, a request to enable soft ACK/NACK feedback; enabling the soft ACK/NACK feedback based on the request, where the soft ACK/NACK feedback comprises at least a link quality metric per diversity branch; and transmitting, to the network entity, the soft ACK/NACK feedback based on a determination to enable the soft ACK/NACK feedback. ## Claims ### Claim 1 A method of wireless communication at a user equipment (UE), comprising: receiving, from a network entity, a request to enable soft acknowledge (ACK)/negative acknowledgement (NACK) feedback; enabling the soft ACK/NACK feedback based on the request, wherein the soft ACK/NACK feedback comprises at least a link quality metric per diversity branch; and transmitting, to the network entity, the soft ACK/NACK feedback based on a determination to enable the soft ACK/NACK feedback. ### Claim 2 (depends on 1) The method of claim 1, wherein the link quality metric per diversity branch corresponds to an individual physical downlink shared channel (PDSCH) quality per at least one of a beam and a transmission reception point (TRP). ### Claim 3 (depends on 2) The method of claim 2, wherein the link quality metric per diversity branch includes ACK/NACK based on at least one of individual decoding, log-likelihood ratio (LLR), signal-to-interference-noise ratio (SINR), reference signal received power (RSRP), channel quality indicator (CQI), or a recommended modulation coding scheme (MCS) per layer number. ### Claim 4 (depends on 2) The method of claim 2, wherein the diversity branch corresponds to at least a subset of branches used for at least one of downlink (DL) reception associated with the soft ACK/NACK and one or more candidate branches for potential future reception. ### Claim 5 (depends on 1) The method of claim 1, wherein receiving the request further comprises receiving the request in at least one of an indicator in a downlink control information (DCI), a medium access control (MAC) control element (CE), or a radio resource control (RRC). ### Claim 6 (depends on 5) The method of claim 5, wherein the indicator corresponds to a single bit requesting the soft ACK/NACK feedback. ### Claim 7 (depends on 5) The method of claim 5, wherein the soft ACK/NACK feedback is configured via at least one of the RRC or the MAC CE. ### Claim 8 (depends on 5) The method of claim 5, further comprising enabling the soft ACK/NACK feedback for subsequent ACK/NACK transmissions following at least one of the DCI, the MAC CE, or the RRC. ### Claim 9 (depends on 5) The method of claim 5, further comprising enabling a subset of subsequent ACK/NACK transmissions following at least one of the DCI, the MAC CE, or the RRC. ### Claim 10 (depends on 1) The method of claim 1, wherein the soft ACK/NACK feedback is applied to one or more types of ACK/NACK codebook. ### Claim 11 A method of wireless communication at a network entity, comprising: determining whether to enable soft acknowledge (ACK)/negative acknowledgement (NACK) feedback; transmitting, to a user equipment (UE), a request to enable the soft ACK/NACK feedback based on a determination to enable the soft ACK/NACK feedback; and receiving, from the UE, a soft ACK/NACK transmission in response to transmitting the request. ### Claim 12 (depends on 11) The method of claim 11, wherein determining whether to enable further comprises at least one of: detecting an increase in errors for recent physical downlink shared channel (PDSCH) receptions; or determining whether a current link quality for one or more beams/transmission reception points (TRPs) fails to satisfy a quality threshold. ### Claim 13 (depends on 12) The method of claim 12, wherein transmitting the request to enable the soft ACK/NACK feedback based on the determination to enable the soft ACK/NACK feedback further comprises transmitting the request to enable the soft ACK/NACK feedback based on detecting the increase in errors for the recent PDSCH receptions and based on a determination that the current link quality for the one or more beams/TRPs fails to satisfy the quality threshold. ### Claim 14 (depends on 11) The method of claim 11, wherein the request corresponds to an on-demand dynamic soft ACK/NACK feedback. ### Claim 15 (depends on 11) The method of claim 11, further comprising continuing ACK/NACK feedback procedures with the UE based on a determination not to enable the soft ACK/NACK feedback. ### Claim 16 (depends on 11) The method of claim 11, wherein the soft ACK/NACK feedback includes at least a link quality metric per diversity branch. ### Claim 17 (depends on 16) The method of claim 16, wherein the link quality metric per diversity branch corresponds to an individual physical downlink shared channel (PDSCH) quality per at least one a beam and transmission reception point (TRP). ### Claim 18 (depends on 16) The method of claim 16, wherein the link quality metric per diversity branch includes ACK/NACK based on at least one of individual decoding, log-likelihood ratio (LLR), signal-to-interference-noise ratio (SINR), reference signal received power (RSRP), channel quality indicator (CQI), and recommended modulation coding scheme (MCS) per layer number. ### Claim 19 (depends on 16) The method of claim 16, wherein the diversity branch corresponds to at least a subset of branches used for at least one of downlink (DL) reception associated with the soft ACK/NACK and one or more candidate branches for potential future reception. ### Claim 20 (depends on 11) The method of claim 11, wherein transmitting the request further comprises transmitting the request in at least one of an indicator in a downlink control information (DCI), a medium access control (MAC) control element (CE), or a radio resource control (RRC). ### Claim 21 An apparatus for wireless communication, the apparatus being a user equipment (UE), comprising: a memory; and at least one processor coupled to the memory and configured to: receive, from a network entity, a request to enable soft acknowledge (ACK)/negative acknowledgement (NACK) feedback; determine to enable the soft ACK/NACK feedback based on the request; and transmit, to the network entity, the soft ACK/NACK feedback based on a determination to enable the soft ACK/NACK feedback. ### Claim 22 (depends on 21) The apparatus of claim 21, wherein the soft ACK/NACK feedback comprises at least a link quality metric per diversity branch, and the link quality metric per diversity branch corresponds to an individual physical downlink shared channel (PDSCH) quality per at least one of a beam and a transmission reception point (TRP). ### Claim 23 (depends on 22) The apparatus of claim 22, wherein the link quality metric per diversity branch includes ACK/NACK based on at least one of individual decoding, log-likelihood ratio (LLR), signal-to-interference-noise ratio (SINR), reference signal received power (RSRP), channel quality indicator (CQI), or a recommended modulation coding scheme (MCS) per layer number. ### Claim 24 (depends on 22) The apparatus of claim 22, wherein the diversity branch corresponds to at least a subset of branches used for at least one of downlink (DL) reception associated with the soft ACK/NACK and one or more candidate branches for potential future reception. ### Claim 25 (depends on 21) The apparatus of claim 21, wherein receiving the request further comprises receiving the request in at least one of an indicator in a downlink control information (DCI), a medium access control (MAC) control element (CE), or a radio resource control (RRC). ### Claim 26 An apparatus for wireless communication, the apparatus being a network entity, comprising: a memory; and at least one processor coupled to the memory and configured to: determine whether to enable soft acknowledge (ACK)/negative acknowledgement (NACK) feedback; transmit, to a user equipment (UE), a request to enable the soft ACK/NACK feedback based on a determination to enable the soft ACK/NACK feedback; and receive, from the UE, a soft ACK/NACK transmission in response to transmitting the request. ### Claim 27 (depends on 26) The apparatus of claim 26, wherein to determine whether to enable soft ACK/NACK, the at least one processor is configured to: detect an increase in errors for recent physical downlink shared channel (PDSCH) receptions; and determine whether a current link quality for one or more beams/transmission reception points (TRPs) fails to satisfy a quality threshold. ### Claim 28 (depends on 27) The apparatus of claim 27, wherein transmitting the request to enable the soft ACK/NACK feedback based on the determination to enable the soft ACK/NACK feedback further comprises transmitting the request to enable the soft ACK/NACK feedback based on detecting the increase in errors for the recent PDSCH receptions and based on a determination that the current link quality for the one or more beams/TRPs fails to satisfy the quality threshold. ### Claim 29 (depends on 26) The apparatus of claim 26, wherein the request corresponds to an on-demand dynamic soft ACK/NACK feedback. ### Claim 30 (depends on 26) The apparatus of claim 26, wherein the soft ACK/NACK feedback includes at least a link quality metric per diversity branch.