For short-packet, low-latency communications over random access channels, piloting overhead significantly reduces spectral efficiency. Therefore, pilotless systems recently gained attraction. While blind phase estimation algorithms such as Viterbi-Viterbi Phase Estimation (VVPE) can correct a phase offset using only payload symbols, a phase ambiguity remains. We first show that the remaining phase rotations in a polar coded quadrature amplitude modulation (QAM) transmission with gray labeling are combinations of bit-flips and code automorphisms. Therefore, the decoder is equivariant to such phase rotations and, by smartly selecting the frozen bits, one can jointly decode and resolve the phase ambiguity, without the need for pilot symbols or an outer code. Our proposed system outperforms pilot-assisted transmissions by up to 0.8 dB and 2 dB for quaternary phase shift keying (QPSK) and 16-QAM, respectively.
%0 Conference Paper
%1 10273501
%A Geiselhart, Marvin
%A Gauger, Marc
%A Krieg, Felix
%A Clausius, Jannis
%A ten Brink, Stephan
%B 2023 12th International Symposium on Topics in Coding (ISTC)
%D 2023
%K
%P 1-5
%R 10.1109/ISTC57237.2023.10273501
%T Phase-Equivariant Polar Coded Modulation
%X For short-packet, low-latency communications over random access channels, piloting overhead significantly reduces spectral efficiency. Therefore, pilotless systems recently gained attraction. While blind phase estimation algorithms such as Viterbi-Viterbi Phase Estimation (VVPE) can correct a phase offset using only payload symbols, a phase ambiguity remains. We first show that the remaining phase rotations in a polar coded quadrature amplitude modulation (QAM) transmission with gray labeling are combinations of bit-flips and code automorphisms. Therefore, the decoder is equivariant to such phase rotations and, by smartly selecting the frozen bits, one can jointly decode and resolve the phase ambiguity, without the need for pilot symbols or an outer code. Our proposed system outperforms pilot-assisted transmissions by up to 0.8 dB and 2 dB for quaternary phase shift keying (QPSK) and 16-QAM, respectively.
@inproceedings{10273501,
abstract = {For short-packet, low-latency communications over random access channels, piloting overhead significantly reduces spectral efficiency. Therefore, pilotless systems recently gained attraction. While blind phase estimation algorithms such as Viterbi-Viterbi Phase Estimation (VVPE) can correct a phase offset using only payload symbols, a phase ambiguity remains. We first show that the remaining phase rotations in a polar coded quadrature amplitude modulation (QAM) transmission with gray labeling are combinations of bit-flips and code automorphisms. Therefore, the decoder is equivariant to such phase rotations and, by smartly selecting the frozen bits, one can jointly decode and resolve the phase ambiguity, without the need for pilot symbols or an outer code. Our proposed system outperforms pilot-assisted transmissions by up to 0.8 dB and 2 dB for quaternary phase shift keying (QPSK) and 16-QAM, respectively.},
added-at = {2024-01-12T09:06:32.000+0100},
author = {Geiselhart, Marvin and Gauger, Marc and Krieg, Felix and Clausius, Jannis and ten Brink, Stephan},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2c1153efeb9cc9f83eff6768263813c21/inue},
booktitle = {2023 12th International Symposium on Topics in Coding (ISTC)},
description = {Phase-Equivariant Polar Coded Modulation | IEEE Conference Publication | IEEE Xplore},
doi = {10.1109/ISTC57237.2023.10273501},
interhash = {95bd110cec5a0fddf3e74756761156bc},
intrahash = {c1153efeb9cc9f83eff6768263813c21},
keywords = {},
month = {Sep.},
pages = {1-5},
timestamp = {2024-01-12T09:06:32.000+0100},
title = {Phase-Equivariant Polar Coded Modulation},
year = 2023
}
