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Code Optimization and Iterative Decoding of QC-LDPC Coded OFDM System


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Code Optimization and Iterative Decoding of QC-LDPC Coded OFDM System
LIU Bin-bin1BAI Dong2GE Qi-hong1MEI Shun-liang1
1.Department of Electronic Engineering,Tsinghua University,Beijing 100084,China;2.Department of Electronics,Peking University,Beijing 100871,China
orthogonal frequency division multiplexing channel coding telecommunication channels low density parity check codes code optimization iterative decoding degree distribution Gaussian approximation
In the multi-paths environment,since the performance of orthogonal frequency division multiplexing(OFDM) system may be severely degraded by the sub-carriers in deep fading,powerful error-correcting codes have to be applied to OFDM.This paper presents a novel quasi-cyclic low density parity check(QC-LDPC) coded OFDM system.In this system,the redundant bits of codeword are mapped to higher-order constellation,and a group shuffled message passing scheduling is used in the iterative decoding.According to the mapping scheme,the QC-LDPC code is optimized by density evolution based on group shuffled message passing with Gaussian approximation.Simulation results show that the proposed system can achieve better error rate performance and faster decoding convergence than conventional approaches on both additive white Gaussian noise(AWGN) and Rayleigh fading channels.


[ 1] M acKay D J C. Good error-correc ting codes based on very sparsem atrices[ J]. IEEE Transactions on Inform ation Theo ry, 1999, 45( 2): 399- 431.
[ 2] L i ZW, Chen L, Zeng L Q, et a .l E ffic ient encoding of quas-i cyc lic LDPC codes[ J]. IEEE Transac tions on Communications, 2005, 54( 1): 71- 81.
[ 3] Futak iH, Oh tsuk iT. Perfo rm ance o f low-density par-i ty- check ( LDPC ) coded OFDM system s [ A ]. IEEE Internationa lConference on Comm unications[ C]. New York, USA: IEEE, 2002. 1696- 1700.
[ 4] Le iM, H a rada H. Low-density parity-check ( LDPC ) coded u ltra h igh-da ta-rate OFDM system in frequencyse lective fad ing [ A]. IEEE Vehicu la rTechno logy Confe rence-Spr ing [ C ]. Stockho lm, Sw eden: IEEE, 2005. 1590- 1594.
[ 5] R ichardson T J, Urbanke R L. The capac ity of lowdensity par ity- check codes unde r message-passing decod ing[ J]. IEEE Transactions on In fo rm ation Theory, 2001, 47( 2): 599- 618.
[ 6] R ichardson T J, Shokro llahiM A, Urbanke R L. Design o f capacity approach ing irregu lar low-density par-i ty- check codes[ J] . IEEE Transac tions on Inform ation Theory, 2001, 47( 2): 399- 431.
[ 7] Chung S, R ichardson T J, U rbanke R L. Analysis o f sum-product decoding o f low-density parity- check codes using a gaussian approx ima tion [ J ]. IEEE Transactions on In fo rm ation Theo ry, 2001, 47 ( 2): 657- 670.
[ 8] Zhang J, Fo sso rierM. Shuffled be lief propagation decod ing [ J]. IEEE T ransactions on Comm un ications, 2005, 53( 2): 209- 213.
[ 9] H o ltzm an JM. A s imp le, accura tem ethod to calculate spread spectrum m ultiple-access error probabilities [ J] . IEEE Transac tions on Communications, 1992, 40 ( 3) : 461- 464.
[ 10] Fosso rierM P C. Quas-i cyclic low-density parity- check codes from circu lant perm utation m atrices[ J]. IEEE Transac tions on In fo rm ation Theo ry, 2004, 50 ( 8): 1788- 1793.


Last Update: 2012-11-19