LT码和q-LDPC码级联方案在深空通信中的应用

Application of the Concatenation of q-LDPC and Luby Transform Codes in Deep Communications

该文针对深空通信对长纠删码的需求,提出了LT(Luby Transform)码和q-LDPC码的级联方案。在综合考虑性能和复杂度的情况下,选取8-LDPC码和8PSK的级联作为等效的删除信道,长度选择灵活、编译码简单的LT码实现纠删功能。文中设计了两种短8-LDPC码,并对整个级联系统的纠错性能进行了仿真。仿真结果表明8-LDPC码的性能优于信源信息速率和码率相同的二进制LDPC码,级联系统在等效包删除概率不超过0.1时,系统误比特率以概率1趋于0。

A concatenated scheme of Luby Transform （LT） code and q-ary Low Density Parity Check （q-LDPC） code is proposed for the requirement of deep space communications long erasure correcting codes.Considering the performance and complexity of the concatenated system,8PSK modulation coded with 8-LDPC codes over AWGN channels is chosen to act as equivalent erasure channels and LT codes with flexible code length and low encoding and decoding complexity correct erasure errors.Two short 8-LDPC codes are designed.Simulations are conducted on the performance of packet error of two 8-LDPC codes and the overall performance of the concatenated system.Simulation results show that both the 8-LDPC codes outperform the corresponding binary LDPC （B-LDPC） codes with the same source rate and code rate and the bit error rate of the concatenated system is null with probability 1 when the packet erasure rate is not more than 0.1.