Self-adjustable offset min-sum algorithm for ISDB-S2 LDPC decoder

Abstract

Abstract:In this paper, a novel self-adjustable offset min-sum LDPC decoding algorithm is proposed for ISDB-S2 application. We present for the first time a uniform approximation of the check node operation through mathematical induction on Jacobian logarithm and theoretically shows that the offset value is mainly dependent on the difference of the two most unreliable inputs from the bit nodes, which makes the offset value adjustable during the iterative decoding procedure. Simulation results for all 11 code rates of ISDB-S2 demonstrate that the proposed method can achieve an average of 0.15 dB gain compared to the Min-sum based algorithms, and consumes only 1.21% computation complexity compared to BP-based algorithms in the best case. Keywords: LDPC decoding algorithm, ISDB-S2 Classification: Integrated circuits References[1] A. Hashimoto and Y. Suzuki, "A new transmission system for the advanced satellite broadcast," IEEE Trans.

Iteration-Aware LDPC Code Design for Low-Power Optical Communications

“…Note that the decoding iteration can be terminated earlier than N ite to avoid unnecessary iterations and to save power consumption once the soft decision provides a valid codeword, which passes a syndrome check. Since the CND requires arithmetic multiplications and nonlinear functions in (3), a number of simplified versions such as min-sum algorithm have been investigated [47]. In order to improve convergence speed of iterative BP decoding, several scheduling methods [48] have also been proposed.…”

“…5 have a lower average number of iterations than the conventional code for the whole SNR regime when early termination with syndrome checking at every iteration is carried out. Although we consider SPA decoding for LDPC code design, it is expected that the designed codes still have a great advantage over the conventional code for various simplified algorithms [47] because those algorithms have relatively small penalty from SPA. In Fig.…”

“…In Fig. 6, we compare BER performance of our iteration-aware optimized code and the conventional code optimized by the curve fitting for N ite = 8 using different decoding algorithms; SPA, min-sum (MS), offset min-sum (OMS), and delta-min (DM) [47]. The LDPC codes are the same ones used in Fig.…”

A New PWL Approximation for the &quotSelf-Adjustable Offset Min-Sum&quot Decoding with a highly Reduced-Complexity

“…In order to reduce more the performance degradation, several other approaches have been proposed, such the Degree Matched Min-Sum (DMMS) [8] in which the degree of the check node and offset factor are associated and the Adaptive Offset Min-Sum (AOMS) [9] which adapts the offset factor according to the minimum magnitude output from the check node. Among the other works, the Self-Adjustable Offset Min-Sum algorithm (SAOMS) have been proposed for the Integrated Service Digital Broadcasting via Satellite-Second Generation (ISDB-S2) LDPC decoder [10]. This works shows that the offset value is mainly dependent on the difference between the second and the first minimum magnitude of the incoming messages to the check node, thus the offset value is made adjustable during the iterative decoding process.…”

“…This works shows that the offset value is mainly dependent on the difference between the second and the first minimum magnitude of the incoming messages to the check node, thus the offset value is made adjustable during the iterative decoding process. A performances comparison of the BP, NMS, OMS, DMMS, AOMS and SAOMS algorithms shows that the latter is an efficient candidate for the ISDB-S2 [10]. Then, it was proposed that the non-linear function f (x) = ln 1 + e −|x| should be computed to update the check nodes.…”