# US 2021/0176104 A1 · Techniques for generating signal sequences for wireless communications > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0176104 A1 - Document ID: US20210176104A1 - Status: Published application - Kind: A1 - Application number: 16/709,621 - Filed: 2019-12-10 - Published: 2021-06-10 - Earliest claimed: 2019-12-10 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Wei YANG; Seyong PARK; Yi HUANG; Peter GAAL - Web page: https://patentgrep.com/patent/US20210176104A1 ## CPC - H04L 27/2613: {Structure of the reference signals} - H04J 13/0062: {Zadoff-Chu} - H04L 27/2607: {Cyclic extensions} - H04L 27/2614: {Peak power aspects} - H04L 27/2634: {Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) ## Abstract Some aspects described herein relate to determining a length for a sequence for communicating a signal, determining a reduced length as a largest prime number that is smaller than a fraction of the length, generating a Zadoff-Chu sequence based on the reduced length, extending the Zadoff-Chu sequence to be of the length to generate the sequence of the length, and communicating the signal based on the generated sequence. ## Claims ### Claim 1 A method of wireless communication, comprising: determining a length for a sequence; determining a reduced length as a largest prime number that is smaller than a fraction of the length; generating a Zadoff-Chu sequence based on the reduced length; extending the Zadoff-Chu sequence to be of the length to generate the sequence having the length; and communicating a signal based on the generated sequence. ### Claim 2 (depends on 1) The method of claim 1, wherein at least one of determining the reduced length or generating the Zadoff-Chu sequence based on the reduced length is based at least in part on determining that the length achieves a threshold. ### Claim 3 (depends on 1) The method of claim 1, wherein determining the reduced length comprises at least one of: determining, based on determining that the length achieves a first threshold, the reduced length as the largest prime number that is smaller than a first fraction; or determining, based on determining that the length achieves a second threshold, the reduced length as the largest prime number that is smaller than a second fraction. ### Claim 4 (depends on 1) The method of claim 1, wherein the fraction of the length is two-thirds of the length. ### Claim 5 (depends on 1) The method of claim 1, wherein extending the Zadoff-Chu sequence comprises cyclically extending the Zadoff-Chu sequence based on the reduced length until the length is achieved. ### Claim 6 (depends on 1) The method of claim 1, wherein communicating the signal comprises transmitting the signal based on the generated sequence. ### Claim 7 (depends on 6) The method of claim 6, further comprising applying, before communicating the signal, a frequency domain single-carrier spread (FDSS) filter to the generated sequence. ### Claim 8 (depends on 7) The method of claim 7, wherein the FDSS filter relates to a time domain filter with up to three significant taps. ### Claim 9 (depends on 6) The method of claim 6, wherein transmitting the signal comprises transmitting, by a base station, a downlink positioning reference signal, a downlink demodulation reference signal (DMRS), or a downlink channel state information reference signal (CSI-RS). ### Claim 10 (depends on 6) The method of claim 6, wherein transmitting the signal comprises transmitting, by a user equipment (UE), a sounding reference signal (SRS), an uplink demodulation reference signal (DMRS), or a random access preamble. ### Claim 11 (depends on 1) The method of claim 1, further comprising receiving the signal based on the generated sequence, and further comprising detecting the signal based on the generated sequence. ### Claim 12 (depends on 11) The method of claim 11, wherein receiving the signal comprises receiving, from a base station, a downlink positioning reference signal, a downlink demodulation reference signal (DMRS), or a downlink channel state information reference signal (CSI-RS). ### Claim 13 (depends on 11) The method of claim 11, wherein receiving the signal comprises receiving, from a user equipment (UE), a sounding reference signal (SRS) or an uplink demodulation reference signal (DMRS). ### Claim 14 An apparatus for wireless communication, comprising: a transceiver; a memory configured to store instructions; and one or more processors communicatively coupled with the transceiver and the memory, wherein the one or more processors are configured to: determine a length for a sequence; determine a reduced length as a largest prime number that is smaller than a fraction of the length; generate a Zadoff-Chu sequence based on the reduced length; extend the Zadoff-Chu sequence to be of the length to generate the sequence having the length; and communicate a signal based on the generated sequence. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein the one or more processors are configured to at least one of determine the reduced length or generate the Zadoff-Chu sequence based on the reduced length based at least in part on determining that the length achieves a threshold. ### Claim 16 (depends on 14) The apparatus of claim 14, wherein the one or more processors are configured to determine the reduced length at least in part by: determining, based on determining that the length achieves a first threshold, the reduced length as the largest prime number that is smaller than a first fraction; or determining, based on determining that the length achieves a second threshold, the reduced length as the largest prime number that is smaller than a second fraction. ### Claim 17 (depends on 14) The apparatus of claim 14, wherein the fraction of the length is two-thirds of the length. ### Claim 18 (depends on 14) The apparatus of claim 14, wherein the one or more processors are configured to extend the Zadoff-Chu sequence at least in part by cyclically extending the Zadoff-Chu sequence based on the reduced length until the length is achieved. ### Claim 19 (depends on 14) The apparatus of claim 14, wherein the one or more processors are configured to communicate the signal at least in part by transmitting the signal based on the generated sequence. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein the one or more processors are further configured to apply, before communicating the signal, a frequency domain single-carrier spread (FDSS) filter to the generated sequence. ### Claim 21 (depends on 20) The apparatus of claim 20, wherein the FDSS filter relates to a time domain filter with up to three significant taps. ### Claim 22 (depends on 19) The apparatus of claim 19, wherein the one or more processors are configured to transmit the signal as a downlink positioning reference signal, a downlink demodulation reference signal (DMRS), or a downlink channel state information reference signal (CSI-RS). ### Claim 23 (depends on 19) The apparatus of claim 19, wherein the one or more processors are configured to transmit the signal as a sounding reference signal (SRS), an uplink demodulation reference signal (DMRS), or a random access preamble. ### Claim 24 (depends on 14) The apparatus of claim 14, wherein the one or more processors are further configured to receive the signal based on the generated sequence, and to detect the signal based on the generated sequence. ### Claim 25 (depends on 24) The apparatus of claim 24, wherein the one or more processors are configured to receive the signal, from a base station, as a downlink positioning reference signal, a downlink demodulation reference signal (DMRS), or a downlink channel state information reference signal (CSI-RS). ### Claim 26 (depends on 24) The apparatus of claim 24, wherein the one or more processors are configured to receive the signal, from a user equipment (UE), as a sounding reference signal (SRS) or an uplink demodulation reference signal (DMRS). ### Claim 27 An apparatus for wireless communication, comprising: means for determining a length for a sequence; means for determining a reduced length as a largest prime number that is smaller than a fraction of the length; means for generating a Zadoff-Chu sequence based on the reduced length; means for extending the Zadoff-Chu sequence to be of the length to generate the sequence having the length; and means for communicating a signal based on the generated sequence. ### Claim 28 (depends on 27) The apparatus of claim 27, wherein at least one of the means for determining the reduced length or the means for generating the Zadoff-Chu sequence are based on the reduced length is based at least in part on determining that the length achieves a threshold. ### Claim 29 A non-transitory computer-readable medium, comprising code executable by one or more processors for wireless communication, the code comprising code for: determining a length for a sequence; determining a reduced length as a largest prime number that is smaller than a fraction of the length; generating a Zadoff-Chu sequence based on the reduced length; extending the Zadoff-Chu sequence to be of the length to generate the sequence having the length; and communicating a signal based on the generated sequence. ### Claim 30 (depends on 29) The non-transitory computer-readable medium of claim 29, wherein at least one of the code for determining the reduced length or the code for generating the Zadoff-Chu sequence are based on the reduced length is based at least in part on determining that the length achieves a threshold.