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Faculty of Engineering and Information Sciences - Papers: Part A

2008

Codes

Articles 1 - 2 of 2

Full-Text Articles in Social and Behavioral Sciences

Joint Linear Interleaver Design For Concatenated Zigzag Codes, D S. Lin, S Tong, S Q. Li Jan 2008

Joint Linear Interleaver Design For Concatenated Zigzag Codes, D S. Lin, S Tong, S Q. Li

Faculty of Engineering and Information Sciences - Papers: Part A

The design of a class of well-structured low-density parity-check (LDPC) codes, namely linear interleaver based concatenated zigzag (LICZ) codes, is investigated. With summary distances as the design metric, short LICZ codes with large minimum distances can be constructed. Moreover, an efficient cycle-based method is proposed to compute the minimum distances of LICZ codes. Simulation results show that LICZ codes outperform both CZ codes with random interleavers and LDPC codes by the progressive edge growth algorithm.


Tangential Sphere Bounds On The Ensemble Performance Of Ml Decoded Gallager Codes Via Their Exact Ensemble Distance Spectrum, Sheng Tong Jan 2008

Tangential Sphere Bounds On The Ensemble Performance Of Ml Decoded Gallager Codes Via Their Exact Ensemble Distance Spectrum, Sheng Tong

Faculty of Engineering and Information Sciences - Papers: Part A

An efficient numerical approach to the exact ensemble distance spectrum of Gallager codes has been developed by evaluating powers of polynomials. With the exact ensemble distance spectrum of Gallager codes, tangential sphere upper bounds on their maximum likelihood (ML) decoding performance over binary input AWGN channels are investigated. Numerical results indicate improved bounds have been obtained, better than Sason and Shamai's results (which are based on Gallager's upper bound on the ensemble distance spectrum), especially in the error floor region. Furthermore, some critical properties of Gallager codes, including typical minimum distance and the performance tradeoff in the waterfall and error …