High throughput LDPC decoder for C-RAN optical fronthaul based on improved bit-flipping algorithm

In this paper we demonstrate the potentiality of the integration of low density parity check (LDPC) codes for a full self-seeded optical architecture dedicated to Cloud Radio Access Network (C-RAN). After comparison, Gradient Decent Bit Flipping algorithm (GDBF) has been retained for this application. We show that improvements can be obtained by using multiple-GDBF or mixed (single + multiple or multiple + single)-GDBF. We demonstrate that it is possible to be in accordance with the requirements (BER=10-9) after LDPC decoder with an input BER of 10-4. We propose a serial FPGA architecture that permits to achieve throughputs up to 500 Mb/s using a 500MHz FPGA. We give the guidelines to increase the rate by parallelizing the architecture. We obtained, by FPGA circuit simulations, up to 2.5 Gb/s with affordable complexity.