577 research outputs found
Successive Cancellation Ordered Search Decoding of Modified -Coset Codes
A tree search algorithm called successive cancellation ordered search (SCOS)
is proposed for -coset codes that implements
maximum-likelihood (ML) decoding with an adaptive complexity for transmission
over binary-input AWGN channels. Unlike bit-flip decoders, no outer code is
needed to terminate decoding; therefore, SCOS also applies to
-coset codes modified with dynamic frozen bits. The average
complexity is close to that of successive cancellation (SC) decoding at
practical frame error rates (FERs) for codes with wide ranges of rate and
lengths up to bits, which perform within dB or less from the
random coding union bound and outperform Reed--Muller codes under ML decoding
by up to dB. Simulations illustrate simultaneous gains for SCOS over
SC-Fano, SC stack (SCS) and SC list (SCL) decoding in FER and the average
complexity at various SNR regimes. SCOS is further extended by forcing it to
look for candidates satisfying a threshold on the likelihood, thereby
outperforming basic SCOS under complexity constraints. The modified SCOS
enables strong error-detection capability without the need for an outer code.
In particular, the PAC code under modified SCOS provides gains in
overall and undetected FER compared to CRC-aided polar codes under SCL/dynamic
SC flip decoding at high SNR.Comment: 14 pages, 9 figures, 3 tables. Submitted to IEEE journal. The revised
version of the first submission. Major changes: 1) No dedicated section for
numerical results. Instead, simulations are provided right after the relevant
section. 2) More simulation results are added to compare all the state of art
polar decoders in terms of the number of arithmetic operations. arXiv admin
note: text overlap with arXiv:2105.0404
Fast shape-based nearest-neighbor search for brain MRIs using hierarchical feature matching
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