A novel state metric normalization technique for high-throughput maximum-a-posteriori-probability decoder

In this paper, a new state metric normalization technique is proposed for maximum-a-posteriori-probability (MAP) algorithm to enhance the throughput of MAP decoder. Bit-error-rate (BER) performance comparison showed that the MAP algorithm based on the proposed normalization technique has a coding gain of 0.25 dB at a BER of 10^-4 in comparison with MAP algorithm based on the subtractive normalization technique. An architecture for MAP decoder based on the new normalization technique has been proposed with a reduced critical path delay as compared to the contributions in literature. Subsequently, a field-programmable-gate-array (FPGA) implementation of the new MAP decoder is carried out. Thereby, the proposed decoder based on non-parallel radix-2 and radix-4 architectures are able to achieve high throughputs of 514 Mbps and 1.028 Gbps respectively.