Performance Analysis of Atmospheric Laser Communication Turbo Code based on Improved MAX-Log-MAP Algorithm

The decoding performance of suboptimal MAX-Log-MAP algorithm is reduced due to neglecting the correction function. To solve the above problem, this paper proposes an optimization method that combines linear fitting of correction functions with the correction factors based on extrinsic information for atmospheric turbulence channels. A piecewise linear fitting correction function is used to reduce the calculation errors of the forward and backward recursion terms in the decoding, and the optimal correction factor is given to obtain accurate extrinsic information so as to achieve the minimum error performance of the system under the given SNR. The simulation results show that the improved algorithm achieves a gain of nearly 0.5dB compared with the Max-Log-MAP algorithm at a bit error rate of 10
^-6
, which verifies the effectiveness of the proposed algorithm and can effectively improve the error correction performance of Turbo code in atmospheric laser communication system.