一种LDPC编码慢跳频系统迭代信道估计译码算法

低密度奇偶校验码(LDPC, Low Density Parity Check)的和积译码算法(SPA, Sum-product Algorithm)在加性高斯白噪声信道中具有很好的译码性能,但需要已知信道状态信息。提出了一种在部分频带干扰条件下LDPC编码慢跳频(SFH, Slow Frequency Hopping)系统的迭代信道估计译码算法。该算法利用迭代译码过程中产生的比特后验信息作为信道估计器的先验信息辅助信道估计,进而更新下一次译码的初始信息。仿真结果显示,该算法性能逼近已知信道信息时的性能,而且每跳所含的符号数很少,不需要插入导频,增大了传输功率效率。另外,相对于SPA算法运算量增加不大,实现简单。

A Decoding Algorithm with Iterative Channel Estimation in LDPC Coded SFH System

LDPC (Low Density Parity Check) code and SPA (Sum-Product Algorithm) both enjoy excellent decoding performance in AWGN (Additive White Gaussian Noise) channels, and however, channel state information is required. In this paper, a decoding algorithm with iterative channel estimation and partial band jamming in LDPC coded SFH system is proposed.In this algorithm,the bit posteriori information obtained from iterative decoding process is used as the assitant apriori information of channel estimator, and then updating the initial information in the next iteration process is updated. Simulation results indicate that the performance of the proposed algorithm is quite close to that of the algorithms with perfect estimation of channel-state information. What’s more, only a few symbols per hop are needed and no pilot carrier is required in this algorithm, thus it improves the efficiency of transmission power is improved. In addition, this algorithm is similar to the SPA algorithm in complexity, and therefore is easy to implement.