US 12,192,038 B2
Systems and methods of phase-tracking reference signal transmission for OFDM
Yushu Zhang, Beijing (CN); Alexei Davydov, Nizhny Novgorod (RU); Gregory Morozov, Nizhny Novgorod (RU); Guotong Wang, Beijing (CN); Dae Won Lee, Portland, OR (US); Gang Xiong, Portland, OR (US); Sameer Pawar, Santa Clara, CA (US); and Jie Zhu, San Jose, CA (US)
Assigned to APPLE INC., Cupertino, CA (US)
Appl. No. 17/418,150
Filed by Apple Inc., Cupertino, CA (US)
PCT Filed Mar. 13, 2020, PCT No. PCT/US2020/022673
§ 371(c)(1), (2) Date Jun. 24, 2021,
PCT Pub. No. WO2020/186179, PCT Pub. Date Sep. 17, 2020.
Claims priority of provisional application 62/818,611, filed on Mar. 14, 2019.
Prior Publication US 2022/0060361 A1, Feb. 24, 2022
Int. Cl. H04J 13/00 (2011.01); H04L 5/00 (2006.01); H04L 27/26 (2006.01)
CPC H04L 27/2613 (2013.01) [H04J 13/0062 (2013.01); H04L 5/0007 (2013.01); H04L 5/0048 (2013.01); H04L 27/2607 (2013.01); H04L 27/2602 (2013.01)] 13 Claims
OG exemplary drawing
 
1. An apparatus for communicating a phase-tracking reference signal (PT-RS) for orthogonal frequency division multiplexing (OFDM) in a wireless communication system, the apparatus comprising:
a processor; and
a memory storing instructions that, when executed by the processor, configure the apparatus to:
determine one or more PT-RS groups of adjacent subcarriers in a resource allocation for a physical uplink shared channel (PUSCH), wherein to determine the one or more PT-RS groups of adjacent subcarriers in the resource allocation is in response to a determination that a modulation and code scheme (MCS) indicated by downlink control information (DCI) is above an MCS threshold;
modulate PT-RS subcarriers within the one or more PT-RS groups of adjacent subcarriers with a predetermined PT-RS modulation sequence, wherein the predetermined PT-RS modulation sequence is based on a Zadoff-Chu sequence;
cyclically extend the Zadoff-Chu sequence to zero-power guard subcarriers, wherein the predetermined PT-RS modulation sequence comprises:

OG Complex Work Unit Math
where q is a root of the Zadoff-Chu sequence, Nzc is a length of the Zadoff-Chu sequence, N is a number of non-zero subcarriers in a PT-RS group, m is an integer between zero and Nzc, and N0 determines a length of a cyclic extension;
encode data to be transmitted by the PUSCH in data subcarriers within the resource allocation for the PUSCH; and
encode phase-tracking reference signals within the one or more PT-RS groups of adjacent subcarriers.