OFDM系统中LDPC码度分布的混合ARQ方案

Degree distribution-based HARQ scheme for LDPC coded OFDM system

综合考虑LDPC码的度分布特性和多载波传输系统的信道条件,提出了一种自适应的信道编码传输方案。该方案中LDPC码度数较大的比特具有较高的重传优先级,并被映射到OFDM系统中信道条件较好的子载波上进行传输,为重要比特提供更多保护。使用高斯近似的方法对方案的性能进行了研究,计算和仿真结果表明该方案具有较好的性能且复杂度低。

The new scheme considers the degree distribution property of LDPC （low density parity check） codes and improves the system performance by providing the important bits with more protection. The important bits with large degrees in the scheme have high retransmission priorities and are mapped to the sub-carriers with better CQI（ channel quality indicator） levels in OFDM （orthogonal frequency division multiplexing） system. The performance of the new scheme has been investigated by the Gaussian approximation. The analysis and simulation results prove that the new scheme is practical because it has better performance with low system complexity.