Research On Codec Technology Of The High-speed Of Free-space Laser Communication System

In the free-space laser communication system,transmission of information is affected by detector noise、optical platform jitter and other factors,thus resulting in the generation of the error code. In order to increase the reliability of communication system, it is necessary to introduce the appropriate error correction coding. Reed-Solomon code is the preferred code.This article first introduces RS encoding and decoding algorithm,with an emphasis on the Euclidean and its improved algorithms. In the implementation of the RS codec,the curable matrix cell structure is used to form the multiplier,and the algorithm pipelined recursive modified Euclidean (PrME) is used to solve the key equation module,which are the difficulty and innovation of this paper,respectively. Then the works are proceeded,which about writing the code of the codec by the Verilog HDL,the function simulation of the tested pseudo-random sequence, downloading the written code by JTAG,and testing and verifying the code.We can see that the signals observed by Signal Tap Ⅱ are consistent with the results of the matlab simulation,so the correctness of the codec functions is verified.Finally,through the System joint commissioning under the Laboratory optical platform with the622Mb/s transmition rate of analog channel.received optical power of-39dBm,using codec the bit error rate could be increased from2.67×10-3to1.42×10-7,coding gain is close to4dB.