HSDPA系统中高码率混合重传协议映射准则优化

Optimization of Mapping Rules in High-Rate Coded Hybrid ARQ Protocol in HSDPA System

针对高速下行分组接入(HSDPA)系统中的混合重传(HARQ)协议,提出适用于高码率Turbo码的全增余(FIR)和部分增余(PIR)型的映射准则优化方法.分析了不同编码比特的重传优先级,通过向高优先级的比特提供高可靠性差错保护实现不等差错优化,并且在优化策略中使不同编码比特在初始传输和重传过程中的可靠性度量尽可能均匀.仿真结果表明,在高码率的全增余和部分增余型HARQ协议中,优化策略能够提高系统性能,而复杂度不会有明显增加.

The optimization of mapping rule in hybrid ARQ （HARQ） protocol of high speed downlink packet access （HSDPA） system is presented, especially for full incremental redundancy （FIR） and partial incremental redundancy （PIR） with high rate Turbo code. The retransmission priorities of various encoded bits are analyzed and the presented scheme provides higher reliabilities to the bits that have higher priorities to achieve unequal error protection optimization. Furthermore, the reliabilities of encoded bits among initial and retransmissions are attempted to be averaged. Simulation results showed that this scheme can achieve performance gain for PIR and FIR with high code rates with only slight increases in complexity.