TD-SCDMA HSDPA中使用比特重排的HARQ性能

HARQ performance with bit rearrangement in TD-SCDMA HSDPA

分析了高阶调制不同层次比特可靠性的差异,论证了在高阶调制重传中使用比特重排的意义,并根据各个层次比特可靠性设计了HARQ比特重排方案,该重排方案能够均衡各个层次比特的可靠性,然后综合分析了不同HARQ类型和比特重排组合在TD-SCDMA HSDPA中的重传性能.仿真结果表明,对于HARQ类型I,比特重排有很大的性能增益,而对于HARQ类型II,比特重排没有增益,而且,调制阶次越高,编码速率越高,比特重排增益越大.

This paper analyzes the difference of bit reliabilities for high level modulation. The theoretical analysis results show that it is significant to utilize the technology of bit rearrangement. The scheme of bit rearrangement, which averages the bit reliability, is put forward based on different reliability levels. Then the performance of combination of different HARQ types and bit rearrangement schemes in TD-SCDMA HSDPA is investigated. There is great performance gain with bit rearrangement for HARQ Type Ⅰ, however, little gain for HARQ Type Ⅱ. Furthermore, the higher are the modulation and coding rate, the more gain can be obtained with bit rearrangement.