Error performance of short-block-length LDPC codes built on scale-free networks

X. Zheng, Francis C. M. Lau, Chi Kong Tse +2 more

Study of complex networks has been conducted across many fields of science, including computer networks, biological networks and social networks. Characteristics of different types of complex networks such as random networks, regular-coupled networks, small-world networks and scale-free networks have been discovered by researchers. Application of such network properties to solve engineering problems, however, is still at the infancy stage. In this study, we make one of the first attempts in applying complex network theories to communications engineering. In particular, inspired by the shortest-average-path-length property of scale-free networks, we design short-length low-density-parity-check (LDPC) codes with an aim to shortening the average distance between any two variable nodes. We will also compare the error performance, both theoretically and by simulations, of the proposed codes with those of other well-known LDPC codes.

Xiao Zheng, Francis C. M. Lau, Chi Kong Tse +1 more

Devichand P. Rathod, Raval N. Awale, Sanjiv Vedu Bonde

Performance of medium length LDPC codes is directly proportional to error floor .In these codes, error floor can be mainly improved through elimination of short cycles.Hence, for effective elimination of short cycles, it is customary to use a girth conditioning in random construction process.Various accurate techniques, such as, density evolution and EXIT chart are developed for performance prediction of large block length, iteratively decoded LDPC codes.However, for medium block length, this method evolved with erroneous results.Even though, the medium block length LDPC codes have many application, short cycles degrades the performance and adds computational complexity in decoding process.

Stefan Laendner, Thorsten Hehn, Olgica Milenković +1 more

Bruce E. Moision

Abdelilah Kadi, Hajar El Ouakili, Rachid El Alami +1 more

Recently, short block codes are in great demand due to the emergent applications requiring the transmission of a short data unit and can guarantee speedy communication, with a minimum of latency and complexity which are among the technical challenges in today’s wireless services and systems. In the context of channel coding using low density parity check (LDPC) codes, the shorter length LDPC block codes are more likely to have short cycles with lengths of 4 and 6. The effect of the cycle with the minimum size is that this one prevents the propagation of the information in the Tanner graph during the iterative process. Therefore, the message decoded by short block code is assumed to be of poor quality due to short cycles. In this work, we present a study of the evolution of the messages on check nodes during the iterative decoding process when using the LDPC decoding algorithm normalized min sum (NMS), to see the destructive effect of short cycles and justify the effectiveness of the girth aware normalized min sum (GA-NMS) decoding LDPC codes algorithm in terms of correction of the errors, particularly for the codes with short cycles 4 and 6. In addition to this, the GA-NMS algorithm is evaluated in terms of bit error rate performance and convergence behavior, using wireless regional area networks (WRAN) LDPC code, which is considered as a short block code.