Mixed-signal implementation of differential decoding using binary message passing algorithms

This paper presents the mixed-signal circuit implementation of reduced complexity algorithms for decoding low-density parity check (LDPC) codes. Based on modified differential decoding using binary message passing (MDD-BMP), binary addition using discrete-time digital circuits is replaced by continuous-time analog-current summation. Potential degradation due to the mismatch between current sources, P/N strength mismatch and inverter-threshold mismatch is considered in behavioural simulation and shown to be tolerable. Area estimates suggest a reduction from 0.27 mm² to 0.11 mm² for the FG(273, 191) code. Finally, transistor level simulation of the FG(273, 191) code using TSMC 65 nm technology shows an efficiency of 0.56 pJ/bit.