Performance Comparison of LDPC Block and Spatially Coupled Codes over GF(q)

In this paper, we compare the finite-length performance of protograph-based spatially coupled lowdensity parity-check (SC-LDPC) codes and LDPC block codes (LDPC-BCs) over GF(q). In order to reduce computational complexity and latency, a sliding window decoder with a stopping rule based on a soft bit-error-rate (BER) estimate is used for the q-ary SC-LDPC codes. Two regimes are considered: one when the constraint length of q-ary SC-LDPC codes is equal to the block length of q-ary LDPCBCs and the other when the two decoding latencies are equal. Simulation results confirm that, in both regimes, (3, 6)-, (3, 9)-, and (3, 12)-regular non-binary SC-LDPC codes can significantly outperform both binary and non-binary LDPC-BCs and binary SC-LDPC codes. Finally, we present a computational complexity comparison of q-ary SC-LDPC codes and q-ary LDPC-BCs under equal decoding latency and equal decoding performance assumptions. This work was partially supported by the Joint Ph.D. Fellowship Program of the China Scholarship Council, the 973 Program (No. 2012CB316100), the China NSF (No. 61172082), and the U.S. NSF (No. CCF-1161754). This work was performed while K. Huang was visiting the University of Notre Dame. The material in this paper was presented in part at the Information Theory and Applications Workshop, San Diego, CA, Feb. 2014, and in part at the IEEE International Symposium on Information Theory, Honolulu, HI, July 2014. K. Huang and X. Ma are with the Department of Electronics and Communication Engineering, Sun Yat-sen University, Guangzhou, GD 510006, China (e-mail: [email protected]; [email protected]). K. Huang is also with the Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA. D. G. M. Mitchell, L. Wei, and D. J. Costello, Jr. are with the Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA (e-mail: [email protected]; [email protected]; [email protected]). IEEE TRANS. COMMUN. (SUBMITTED PAPER) 2 Index Terms Decoding latency, LDPC block codes, LDPC convolutional codes, protograph-based codes, q-ary LDPC codes, spatially coupled codes.