DocumentCode :
2910475
Title :
An efficient tail-biting MAP decoder for convolutional turbo codes in OFDM systems
Author :
Im, Se-Bin ; Kim, Min-Gu ; Choi, Hyung-Jin
Author_Institution :
Dept. of Inf. & Commun. Eng., Sung Kyun Kwan Univ., Suwon, South Korea
Volume :
B
fYear :
2004
fDate :
21-24 Nov. 2004
Firstpage :
589
Abstract :
In this paper, we consider an efficient tail-biting MAP (Maximum a posteriori probability) decoding algorithm for CTC (Convolutional Turbo Codes) specified in IEEE 802.16a/e OFDM. For short block lengths, the CTC encoder uses tail-biting scheme instead of inserting tail bits for path termination. To process a tail-biting codeword, the decoder begins with estimating the circulation states. But this estimation procedure increases the computational complexity. We first describe the CTC decoding process based on the MAP algorithm of the nonbinary codes. Using a suboptimal iterative decoding method, we propose an efficient circulation states estimation algorithm. The BER (Bit Error Rate) performance of the proposed algorithm is evaluated using computer simulations. The results show that the proposed algorithm performs close to the ideal case with known circulation states information.
Keywords :
OFDM modulation; convolutional codes; error statistics; iterative decoding; maximum likelihood decoding; maximum likelihood estimation; metropolitan area networks; radio access networks; state estimation; turbo codes; BER; CTC; IEEE 802.16a; IEEE 802.16e; OFDM system; bit error rate; circulation state estimation; computational complexity; convolutional turbo code; efficient tail-biting MAP decoder; maximum a posteriori probability algorithm; metropolitan area network; nonbinary code; orthogonal frequency division multiplexing; short block length; suboptimal iterative decoding method; wireless MAN; Bit error rate; Computational complexity; Computer simulation; Convolutional codes; Iterative algorithms; Iterative decoding; OFDM; State estimation; Tail; Turbo codes;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
TENCON 2004. 2004 IEEE Region 10 Conference
Print_ISBN :
0-7803-8560-8
Type :
conf
DOI :
10.1109/TENCON.2004.1414664
Filename :
1414664
Link To Document :
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