Multi-Stage Threshold Decoding for Self-Orthogonal Convolutional Codes
This paper describes a least complex high speed decoding method named multi stage threshold decoding (MTD DR) Each stage of MTD DR is formed by the traditional threshold decoder with a special shift register called difference register (DR) After flipping each information bit DR helps to shorten the Hamming and the Euclidian distance between a received word and the decoded codeword for hard and soft decoding respectively However the MTD DR with self orthogonal convolutional codes (SOCCs) type 1 in this paper makes an unavoidable error group which depends on the tap connection patterns in the encoder and limits the error performance This paper introduces a class of SOCCs type 2 which can breakdown that error group as a result MTD DR gives better error performance For a shorter code (code length = 4200) hard and soft decoding MTD DR achieves 4 7 dB and 6 5 dB coding gain over the additive white Gaussian noise (AWGN) channel at the bit error rate (BER) 10(-5) respectively In addition hard and soft decoding MTD DR for a longer code (code length = 80000) give 5 3 dB and 7 1 dB coding gain under the same condition respectively The hard and the soft decoding MTD DR experiences error flooring at high E(b)/N(0) region For improving overall error performance of MTD DR this paper proposes parity check codes concatenation with soft decoding MTD DR as well
threshold decoding multi stage threshold decoding difference register error group