# US 12,114,359 B2 · Rules for redundant subcarrier collision with reference signal for UW-OFDM > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,114,359 B2 - Document ID: US12114359B2 - Status: Granted - Kind: B2 - Application number: 17/649,035 - Filed: 2022-01-26 - Published: 2023-07-27 - Granted: 2024-10-08 - Earliest claimed: 2022-01-26 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Iyab Issam Sakhnini; Hemant Saggar; Tao Luo - Web page: https://patentgrep.com/patent/US12114359B2 ## CPC - 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)} - H04W 74/0816: with collision avoidance - H04L 5/0058: {Allocation criteria} - H04L 27/2605: {Symbol extensions, e.g. Zero Tail, Unique Word [UW]} - H04L 27/261: {Details of reference signals} - H04L 5/0023: {Time-frequency-space} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A wireless device (e.g., a UE or a base station) may identify a first subcarrier mapping associated with one or more redundant subcarriers. The one or more redundant subcarriers may correspond to one or more UWs in a UW-OFDM waveform. The wireless device may identify a second subcarrier mapping associated with one or more reference signals. A simultaneous application of the first subcarrier mapping and the second subcarrier mapping may be associated with one or more collisions. The wireless device may modify at least one of the first subcarrier mapping or the second subcarrier mapping to eliminate the one or more collisions. The wireless device may generate the UW-OFDM waveform based on the modified at least one of the first subcarrier mapping or the second subcarrier mapping. The wireless device may transmit a signal based on the generated UW-OFDM waveform. ## Claims ### Claim 1 An apparatus for wireless communication at a user equipment (UE), comprising: a memory; and at least one processor coupled to the memory and configured to: identify a first subcarrier mapping associated with one or more redundant subcarriers, the one or more redundant subcarriers corresponding to one or more unique words (UWs) in a UW—orthogonal frequency-division multiplexing (OFDM) (UW-OFDM) waveform; identify a second subcarrier mapping associated with one or more reference signals, a simultaneous application of the first subcarrier mapping and the second subcarrier mapping being associated with one or more collisions, each collision in the one or more collisions corresponding to a mapping of a redundant subcarrier of the one or more redundant subcarriers to a corresponding resource element based on the first subcarrier mapping and a mapping of a reference signal of the one or more reference signals to the corresponding resource element based on the second subcarrier mapping; modify at least one of the first subcarrier mapping or the second subcarrier mapping to eliminate the one or more collisions; generate the UW-OFDM waveform based on the modified at least one of the first subcarrier mapping or the second subcarrier mapping; and transmit a signal based on the generated UW-OFDM waveform. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the one or more reference signals correspond to one or more demodulation reference signals (DMRSs), channel state information (CSI)—reference signals (RSs) (CSI-RSs), or sounding reference signals (SRSs). ### Claim 3 (depends on 1) The apparatus of claim 1, wherein to modify the at least one of the first subcarrier mapping or the second subcarrier mapping to eliminate the one or more collisions, the at least one processor is further configured to: modify the first subcarrier mapping, such that the one or more redundant subcarriers are shifted by a number of subcarriers based on the modified first subcarrier mapping and, subsequent to the shifting, do not collide with the one or more reference signals based on the second subcarrier mapping. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein to modify the at least one of the first subcarrier mapping or the second subcarrier mapping to eliminate the one or more collisions, the at least one processor is further configured to: modify the first subcarrier mapping, such that based on the modified first subcarrier mapping, the mapping of the redundant subcarrier to the resource element corresponding to each collision in the one or more collisions is canceled. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein to modify the at least one of the first subcarrier mapping or the second subcarrier mapping to eliminate the one or more collisions, the at least one processor is further configured to: modify the second subcarrier mapping, such that based on the modified second subcarrier mapping, the mapping of the reference signal to the resource element corresponding to each collision in the one or more collisions is canceled. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein a number of antenna ports associated with the one or more reference signals is greater than a threshold. ### Claim 7 (depends on 6) The apparatus of claim 6, wherein each subset of at least one subset of reference signals in the one or more reference signals is associated with a same symbol and two or more contiguous tones, and some but not all reference signals in each subset of the at least one subset of reference signals are associated with the one or more collisions. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the second subcarrier mapping is modified, such that based on the modified second subcarrier mapping, a mapping of all reference signals in the at least one subset of reference signals is canceled. ### Claim 9 (depends on 7) The apparatus of claim 7, wherein one or more first reference signals in the at least one subset of reference signals are associated with the one or more collisions, and one or more second reference signals in the at least one subset of reference signals are not associated with the one or more collisions, and the second subcarrier mapping is modified, such that based on the modified second subcarrier mapping, a mapping of the one or more first reference signals is canceled, and a mapping of the one or more second reference signals is maintained. ### Claim 10 (depends on 1) The apparatus of claim 1, the at least one processor being further configured to: receive, from a base station, an indication associated with eliminating the one or more collisions. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein the at least one of the first subcarrier mapping or the second subcarrier mapping is modified based on the indication. ### Claim 12 (depends on 10) The apparatus of claim 10, wherein the indication is based on at least one of a scheduling specification, an available bandwidth, or a peak to average power ratio (PAPR) specification. ### Claim 13 (depends on 1) The apparatus of claim 1, wherein the at least one of the first subcarrier mapping or the second subcarrier mapping is modified based on at least one of a UE request, a UE recommendation, a UE capability, a UE supported bandwidth, a predefined rule, an allocated bandwidth, a channel type, a reference signal type, a preconfigured maximum percentage of canceled references signals, a preconfigured maximum percentage of canceled redundant subcarriers, a performance specification, a user input, or a number of ports associated with the one or more reference signals. ### Claim 14 (depends on 1) The apparatus of claim 1, further comprising a transceiver coupled to the at least one processor. ### Claim 15 A method of wireless communication at a user equipment (UE), comprising: identifying a first subcarrier mapping associated with one or more redundant subcarriers, the one or more redundant subcarriers corresponding to one or more unique words (UWs) in a UW—orthogonal frequency-division multiplexing (OFDM) (UW-OFDM) waveform; identifying a second subcarrier mapping associated with one or more reference signals, a simultaneous application of the first subcarrier mapping and the second subcarrier mapping being associated with one or more collisions, each collision in the one or more collisions corresponding to a mapping of a redundant subcarrier of the one or more redundant subcarriers to a corresponding resource element based on the first subcarrier mapping and a mapping of a reference signal of the one or more reference signals to the corresponding resource element based on the second subcarrier mapping; modifying at least one of the first subcarrier mapping or the second subcarrier mapping to eliminate the one or more collisions; generating the UW-OFDM waveform based on the modified at least one of the first subcarrier mapping or the second subcarrier mapping; and transmitting a signal based on the generated UW-OFDM waveform. ### Claim 16 An apparatus for wireless communication at a base station, comprising: a memory; and at least one processor coupled to the memory and configured to: identify a first subcarrier mapping associated with one or more redundant subcarriers, the one or more redundant subcarriers corresponding to one or more unique words (UWs) in a UW—orthogonal frequency-division multiplexing (OFDM) (UW-OFDM) waveform; identify a second subcarrier mapping associated with one or more reference signals, a simultaneous application of the first subcarrier mapping and the second subcarrier mapping being associated with one or more collisions, each collision in the one or more collisions corresponding to a mapping of a redundant subcarrier of the one or more redundant subcarriers to a corresponding resource element based on the first subcarrier mapping and a mapping of a reference signal of the one or more reference signals to the corresponding resource element based on the second subcarrier mapping; modify at least one of the first subcarrier mapping or the second subcarrier mapping to eliminate the one or more collisions; generate the UW-OFDM waveform based on the modified at least one of the first subcarrier mapping or the second subcarrier mapping; and transmit a signal based on the generated UW-OFDM waveform. ### Claim 17 (depends on 16) The apparatus of claim 16, wherein the one or more reference signals correspond to one or more demodulation reference signals (DMRSs), channel state information (CSI)—reference signals (RSs) (CSI-RSs), or sounding reference signals (SRSs). ### Claim 18 (depends on 16) The apparatus of claim 16, wherein to modify the at least one of the first subcarrier mapping or the second subcarrier mapping to eliminate the one or more collisions, the at least one processor is further configured to: modify the first subcarrier mapping, such that the one or more redundant subcarriers are shifted by a number of subcarriers based on the modified first subcarrier mapping and, subsequent to the shifting, do not collide with the one or more reference signals based on the second subcarrier mapping. ### Claim 19 (depends on 16) The apparatus of claim 16, wherein to modify the at least one of the first subcarrier mapping or the second subcarrier mapping to eliminate the one or more collisions, the at least one processor is further configured to: modify the first subcarrier mapping, such that based on the modified first subcarrier mapping, the mapping of the redundant subcarrier to the resource element corresponding to each collision in the one or more collisions is canceled. ### Claim 20 (depends on 16) The apparatus of claim 16, wherein to modify the at least one of the first subcarrier mapping or the second subcarrier mapping to eliminate the one or more collisions, the at least one processor is further configured to: modify the second subcarrier mapping, such that based on the modified second subcarrier mapping, the mapping of the reference signal to the resource element corresponding to each collision in the one or more collisions is canceled. ### Claim 21 (depends on 20) The apparatus of claim 20, wherein a number of antenna ports associated with the one or more reference signals is greater than a threshold. ### Claim 22 (depends on 21) The apparatus of claim 21, wherein each subset of at least one subset of reference signals in the one or more reference signals is associated with a same symbol and two or more contiguous tones, and some but not all reference signals in each subset of the at least one subset of reference signals are associated with the one or more collisions. ### Claim 23 (depends on 22) The apparatus of claim 22, wherein the second subcarrier mapping is modified, such that based on the modified second subcarrier mapping, a mapping of all reference signals in the at least one subset of reference signals is canceled. ### Claim 24 (depends on 22) The apparatus of claim 22, wherein one or more first reference signals in the at least one subset of reference signals are associated with the one or more collisions, and one or more second reference signals in the at least one subset of reference signals are not associated with the one or more collisions, and the second subcarrier mapping is modified, such that based on the modified second subcarrier mapping, a mapping of the one or more first reference signals is canceled, and a mapping of the one or more second reference signals is maintained. ### Claim 25 (depends on 16) The apparatus of claim 16, the at least one processor being further configured to: transmit, to a user equipment (UE), an indication associated with elimination of one or more second collisions at the UE. ### Claim 26 (depends on 25) The apparatus of claim 25, wherein the indication is based on at least one of a scheduling specification, an available bandwidth, or a peak to average power ratio (PAPR) specification. ### Claim 27 (depends on 16) The apparatus of claim 16, wherein the at least one of the first subcarrier mapping or the second subcarrier mapping is modified based on at least one of a user equipment (UE) request, a UE recommendation, a UE capability, a UE supported bandwidth, a predefined rule, an allocated bandwidth, a channel type, a reference signal type, a preconfigured maximum percentage of canceled references signals, a preconfigured maximum percentage of canceled redundant subcarriers, a performance specification, a user input, or a number of ports associated with the one or more reference signals. ### Claim 28 (depends on 16) The apparatus of claim 16, further comprising a transceiver coupled to the at least one processor. ### Claim 29 A method of wireless communication at a base station, comprising: identifying a first subcarrier mapping associated with one or more redundant subcarriers, the one or more redundant subcarriers corresponding to one or more unique words (UWs) in a UW—orthogonal frequency-division multiplexing (OFDM) (UW-OFDM) waveform; identifying a second subcarrier mapping associated with one or more reference signals, a simultaneous application of the first subcarrier mapping and the second subcarrier mapping being associated with one or more collisions, each collision in the one or more collisions corresponding to a mapping of a redundant subcarrier of the one or more redundant subcarriers to a corresponding resource element based on the first subcarrier mapping and a mapping of a reference signal of the one or more reference signals to the corresponding resource element based on the second subcarrier mapping; modifying at least one of the first subcarrier mapping or the second subcarrier mapping to eliminate the one or more collisions; generating the UW-OFDM waveform based on the modified at least one of the first subcarrier mapping or the second subcarrier mapping; and transmitting a signal based on the generated UW-OFDM waveform. ### Claim 30 (depends on 29) The method of claim 29, wherein the one or more reference signals correspond to one or more demodulation reference signals (DMRSs), channel state information (CSI)—reference signals (RSs) (CSI-RSs), or sounding reference signals (SRSs).