Study of LDPC codes built from scale-free networks

Xiu-Cheng Zheng, Francis C. M. Lau, Chi Kong Tse

B. N. Sindhu Tejaswini, Rajendra Prasad Lal, Vadlamudi Ch. Venkaiah

X. Zheng, Francis C. M. Lau, Chi Kong Tse

Low-density parity-check (LDPC) codes with scale-free (SF) symbol-node degree distribution have been shown to provide very good error performance. When the code rate becomes high, however, there will be a lot of degree-2 symbol nodes in the “pure” SF-LDPC codes. As a consequence, when the codes are constructed by connecting the symbol nodes with the check nodes, many small-size cycles will be formed. Such small-cycles will degrade the error performance of the codes. In this paper, we address the issue by imposing a new constraint on the design of high-rate SF-LDPC codes. We will compare the error rates of the constrained SF-LDPC codes and other optimized LDPC codes.

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.

W.E. Ryan, Shu Lin

Bahram Honary