Gradient Projection Decoding of LDPC Codes

Abstract-A new practical method for decoding Low-Density Parity Check (LDPC) codes is presented. The followed approach involves reformulating the parity check equations using nonlinear functions of a specific form, defined over ρ , where ρ denotes the check node degree. By constraining the inputs to these functions in the closed convex subset [0

Link between Sum-Product and Gradient Projection Decoding of LDPC codes: an Intermediate Algorithm

Abstract-This paper investigates the connection between the classical Sum-Product (SP) decoder for Low Density Parity Check (LDPC) codes and the recently proposed Gradient Projection (GP) decoding scheme presented in [1]. A graphical model for GP is exhibited based on which we derive an intermediate algorithm which establishes a bridge between graphical based algorithms (SP and variants) and an optimization based algorithm (GP). A more practical decoding algorithm with improved performance and reduced complexity is also proposed. A complexity analysis is provided and performance are studied through Monte-Carlo simulations