OVSF码对码分多址系统信号峰平功率比的影响  

Influence of OVSF code on peak-to-average power ratio in code-division multiple access systems

作　　者：刘中立[1] 黄爱苹[1] 

机构地区：[1]浙江大学信息与通信工程研究所,浙江杭州310027

出　　处：《浙江大学学报（工学版）》2006年第12期2134-2138,共5页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(60472080);华为高校科技基金资助项目(YJCB2004021WL)

摘　　要：为了降低码分多址(CDMA)系统中的信号峰平功率比(PAPR),研究了正交可变扩频因子(OVSF)码对下行链路PAPR的影响.推导了使用OVSF码的CDMA系统下行链路信号瞬时功率表达式,分析了OVSF码构成的最大游程长度不小于8的组合码个数对信号PAPR的影响.归纳出组合码最大游程长度与OVSF码下标之间的关系,导出构成最大游程长度不小于8的组合码的码长条件及下标条件.根据3GPP2标准的cdma2000 1x物理层参数,对不同的OVSF码集合进行了仿真.仿真结果表明,信号PAPR随最大游程长度不小于8的组合码个数增加而增大,该规律为CDMA系统中低PAPR的OVSF码分配算法设计提供了理论依据.To reduce the signal peak-to-average power ratio （PAPR） in code-division multiple access （CDMA） system, the effects of orthogonal variable spreading factor （OVSF） codes on PAPR at the down link transmitter were investigated. The expression of down link signal instantaneous power in CDMA systems was deduced, and the influences of the number of the combined codes with maximum run length of 8 or longer on PAPR were observed. After the relationship between the maximum run-length of the combined codes and the index of OVSF codes was concluded, the length and the subscript conditions of combined codes with maximum run-length of 8 or longer were obtained, and different OVSF code sets were simulated according to cdma2000 lx physical layer parameters of 3GPP2 standard. Simulation results show that signal PAPR increases with increasing number of combined codes with maximum run-length of 8 or longer, the proposed conditions can provide theoretical foundation for algorithmic design of OVSF assignment with low PAPR for CDMA systems.

关 键 词：正交可变扩频因子码 峰平功率比 码分多址系统 

分 类 号：TN929.533[电子电信—通信与信息系统]