A high throughput LDPC decoder in CMMB based on virtual radio

LDPC (Low Density Parity Check) is widely used in many telecommunication systems due to its excellent performance. However, real-time LDPC decoder in virtual radio system is difficult to realize. Taking CMMB (China Mobile Multimedia Broadcasting) for instance, this paper proposes a method to achieve high throughput decoder based on x86 processors which support SIMD (Single Instruction Multiple Data) instructions. By utilizing Normalized Min Sum decoding algorithm, normalized parameter as well as bit width of input variables and intermediate variables are determined. Then taking advantages of SIMD instructions, updating progress of variable nodes and check nodes in LDPC decoding algorithm is parallelized. Meanwhile, memory access operations are optimized as well. Tested on Intel Core i7-3960X, the throughput of the LDPC decoder using multithread processing can reach 92Mbps ~ 722Mbps.