Improved Decoding Algorithms of LDPC Codes Based on Reliability Metrics of Variable Nodes

Abstract

The informed dynamic scheduling (IDS) strategies for decoding of low-density parity-check codes obtained superior performance in error correction performance and convergence speed. However, there are still two problems existing in the current IDS algorithms. The first is that the current IDS algorithms only preferentially update the selected unreliable messages, but they do not guarantee the updating is performed with reliable information. In this paper, a two-step message selecting strategy is introduced. On the basis of the two reliability metrics and two types of variable node residuals, the residual belief propagation (BP) decoding algorithm, short for TRM-TVRBP, is proposed. With the algorithm, the reliability of the updatingmessages can be improved. The second is the greediness problem, prevalently existed in the IDS-like algorithms. The problem arises mainly from the fact that the major computing resources are allocated to or concentrated on some nodes and edges. To overcome the problem, the reliability metric-based RBP algorithm (RM-RBP) is proposed, which can force every variable node to contribute its intrinsic information to the iterative decoding. At the same time, the algorithm can force the related variable nodes to be updated, and make every edge have an equal opportunity of being updated. The simulation results show that both the TRM-TVRBP and the RM-RBP have appealing convergence rate and error-correcting performance compared with the previous IDS decoders over the white Gaussian noise (AWGN) channel.INDEX TERMS Low-density parity-check (LDPC) codes, dynamic selection strategies, dynamic updating strategies, residuals of variable nodes.

Low-Complexity LDPC Decoding Algorithm Based on Layered Vicinal Variable Node Scheduling

“…To approach or even outperform the performances of RBP algorithms, some dynamic decoding algorithms based on the residual message and other selection criteria have also been proposed [16][17][18]. In the (RM RBP) [16], a reliability metric is used to define the priority of message updates.…”

“…To approach or even outperform the performances of RBP algorithms, some dynamic decoding algorithms based on the residual message and other selection criteria have also been proposed [16][17][18]. In the (RM RBP) [16], a reliability metric is used to define the priority of message updates. Firstly, the number of unsatisfied parity check equations for each variable node is calculated; then, all variable nodes are divided into two sets based on whether the number of unsatisfied parity check equations is equal to its maximum value or not.…”

Reordered static layered schedule for 5G low‐density parity‐check codes

“…There are two categories of schedules. One is dynamic [8][9][10][11][12][13][14] whose order is determined online, while the other is static [15][16][17][18][19][20] whose order is decided offline and kept fixed during the decoding. Usually dynamic schedules have better error performance and faster convergence speed since the real-time information is used to determine the optimal order.…”

“…Then, we shift to the next (right) entry of e (line 14). Afterward, the former ARD adding and entry shifting operations are performed repeatedly until all entries in the ith BR are traversed (lines [11][12][13][14].…”