US 11,888,661 B2
Demodulating a wireless signal modulated by phase-shift keying
Zhenlan Cheng, Thalwil (CH)
Assigned to u-blox AG, Thalwil (CH)
Filed by u-blox AG, Thalwil (CH)
Filed on Dec. 3, 2021, as Appl. No. 17/457,544.
Claims priority of application No. 20212463 (EP), filed on Dec. 8, 2020.
Prior Publication US 2022/0182270 A1, Jun. 9, 2022
Int. Cl. H04L 27/233 (2006.01); H04L 27/227 (2006.01)
CPC H04L 27/2338 (2013.01) [H04L 27/227 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method of demodulating a wireless signal modulated by phase-shift keying, the wireless signal comprising a plurality of symbols, the method comprising:
obtaining a first sequence of samples based on the wireless signal;
converting the first sequence of samples to a first sequence of frequency domain samples;
selecting, as a decision variable, a sample that has a maximum magnitude among the first sequence of the frequency domain samples; and
identifying a symbol or a symbol-transition based on the decision variable,
wherein the first sequence of samples starts at a start of a symbol period, and the method further comprises:
obtaining a second sequence of samples based on the wireless signal, wherein the second sequence of samples ends at the start of the symbol period;
reversing the second sequence of samples relative to the first sequence of samples;
converting the reversed second sequence of samples to a second sequence of frequency domain samples; and
selecting, as a reference variable, a sample that has a maximum magnitude among the second sequence of frequency domain samples,
wherein the identifying the symbol or the symbol-transition comprises comparing the decision variable with the reference variable.