A Turbo-Hadamard Encoder/Decoder System with Hundreds of Mbps Throughput

A turbo-Hadamard code (THC) is a type of low-rate channel code with capacity approaching the ultimate Shannon limit, i.e., −1.6 dB. In this paper, we investigate the hardware implementation of a turbo-Hadamard encoder/decoder system. In particular, we study THC systems with rates 0.0114 and 0.0143. With channel messages quantized into 6 bits, we show that the degradation compared with floating-point computation is within 0.15 dB. The entire system has been implemented on a FPGA board. When the code rate equals 0.0143, a bit error rate (BER) of 10−5 can be achieved at around Eb/N0 = −0.3 dB with a throughput of about 600 Mbps.