Efficient high-speed quasi-cyclic LDPC decoder architecture

This paper studies load imbalance problem in the two stages of belief propagation decoding algorithm for LDPC codes and re-distributes computational load between two stages. To further reduce the critical path delay, new look-up-tables (LUT) are developed to replace both conventional LUTs and data format transformation blocks. The adder trees are also reorganized for speed. This novel approach can reduce the critical path delay by 41.0% with negligible increase in the logic core size. This paper also exploits the similarity between these two stages and derives an area efficient design that re-maps the functional units for these two stages onto the same hardware, which can reduce the logic core size by 10.2% and reduce the critical path delay by 16.2%.