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Cyclic redundancy check‐based detection algorithms for automatic identification system signals received by satellite
Author(s) -
Prévost Raoul,
Coulon Martial,
Bonacci David,
LeMaitre Julia,
Millerioux JeanPierre,
Tourneret JeanYves
Publication year - 2013
Publication title -
international journal of satellite communications and networking
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.388
H-Index - 39
eISSN - 1542-0981
pISSN - 1542-0973
DOI - 10.1002/sat.1030
Subject(s) - algorithm , computer science , viterbi algorithm , demodulation , cyclic redundancy check , redundancy (engineering) , phase shift keying , trellis (graph) , keying , decoding methods , bit error rate , channel (broadcasting) , telecommunications , operating system
SUMMARY This paper addresses the problem of demodulating signals transmitted in the automatic identification system. The main characteristics of such signals consist of two points: (i) they are modulated using a trellis‐coded modulation, more precisely a Gaussian minimum shift keying modulation; and (ii) they are submitted to a bit stuffing procedure, which makes more difficult the detection of the transmitted information bits. This paper presents several demodulation algorithms developed in different contexts: mono‐user and multi‐user transmissions, and known/unknown phase shift. The proposed receiver uses the cyclic redundancy check (CRC) present in the automatic identification system signals for error correction and not for error detection only. By using this CRC, a particular Viterbi algorithm, on the basis of a so‐called extended trellis, is developed. This trellis is defined by extended states composed of a trellis code state and a CRC state. Moreover, specific conditional transitions are defined to take into account the possible presence of stuffing bits. The algorithms proposed in the multi‐user scenario present a small increase of computation complexity with respect to the mono‐user algorithms. Some performance results are presented for several scenarios in the context of the automatic identification system and compared with those of existing techniques developed in similar scenarios. Copyright © 2013 John Wiley & Sons, Ltd.