A Reduced-complexity Ldpc Decoding Algorithm with Chebyshev Polynomial Fitting

BP decoding algorithm is a high-performance low-density parity-check (LDPC) code decoding algorithm, but because of its high complexity, it can’t be applied to the high-speed communications systems. So in order to further reduce the implementation complexity with the minimum affection to the system performance, , we proposed a BP algorithm based on Chebyshev polynomial fitting for its good approximation performance in this paper. This method can transform the complicated exponential function into polynomial with the error at 3 10 level in the process of decoding , which can reduce the consumption of memory resources considerably. At the same time, a Chebyshev unit is proposed in the process of implementation with less multiplier; we implemented a semi-parallel LDPC decoder with this method on Altera CycloneII FPGA. The simulation results show that the degradation of this method is only 0.4dB compared with conventional BP algorithm.