Design and implementation of an LDPC encoder for satellite navigation system

Abstract

In this work, a low-complexity encoder is designed and implemented for LDPC codes in the GPS-L1C standard. By using the structural properties of parity-check matrices, we propose a backward substitution encoding method based on look-up-tables for calculating parity-check bits, which avoids the storage of the inverse matrices recommended by the GPS-L1C standard. As a result, the storage requirement and the encoding delay are reduced. The implementation results in 65 nm process indicate that the designed encoder circuit area is 5869.44µm², the number of equivalent gates is 2006, the storage is 600 bits, and the delay is 60 cycles.