【摘要】 将分块传输系统和码合并技术相结合构造了新型hybrid autom atic repeat request(HARQ)系统.根据code d ivision mu ltip le access(CDMA)系统重传次数等于信噪比增加倍数的特性,计算出达到要求误帧率的重传次数,进而计算出新型HARQ的最佳方案.将每帧数据多次重传合并转化在一帧的多个分块之间进行信息合并,不需要重传;使接收数据在解扩之前合并,避免了常用Ⅰ型HARQ因为扩频和存储器的限制使接收信息不能充分合并;各子块添加归零,使性能进一步提高.新型HARQ保证数据的实时通信,省去了常用Ⅰ型HARQ中必须采用的收发端复杂的反馈重传控制和庞大的存储器.更多还原

【Abstract】 A new hybrid automatic repeat request(HARQ) system is constructed by combining the sub-packet scheme with the averaged diversity combining technique.The optimal number of sub-packets of the new HARQ system is evaluated according to the characteristics that the signal to noise ratio is increased by a factor equal to the retransmission times in the Code Division Multiple Access(CDMA) system.In the new HARQ system the diversity combination of data packet and its copies in the retransmissions is converted to the diversity combination of the same sub-packets in the one data packet and no retransmission is needed,which brings the advantages of real time communication,omitting the complicated retransmission control and a mass of memory.Also the method of making combination before being despread avoids the inefficient combination due to the spread and restriction of memory in type-Ⅰ HARQ.In addition,the method of adding tail bits to each sub-packet improves the performance of the new HARQ.Numerical and simulation results show the new HARQ system has a much higher throughput than the type-Ⅰ HARQ and the evaluated optimal number of sub-packets is in agreement with the simulated results.更多还原