DS-CDMA系统多普勒、时延及信道的联合估计方法

Jointly Estimation for Delay,Doppler and Channel Parameters in the DS-CDMA Systems

针对多用户长码、带限DS-CDMA上行链路系统中存在的大多普勒频偏、多径时延及多径信道复增益等参数的联合估计问题,推导出基于根升余弦成型的多普勒、时延、多径衰落信道共同作用下的长码、带限多用户DSCDMA上行链路接收信号模型,将信号表示为仅由导频及多普勒决定的可逆矩阵以及由时延和信道复增益决定的带限多普勒加权复合信道响应.提出一种基于此模型的非结构化间接估计算法即导频辅助下波形匹配-最小二乘并多级网格搜索算法,估计多普勒频偏及复合信道响应,并通过复合信道响应及基于波形匹配的贪婪算法估计时延和信道复增益.对本文算法进行蒙特卡洛仿真,仿真结果表明,在大多普勒条件下,本文算法可对时延、多普勒、信道复增益有良好的估计性能.

In this paper,the problem of estimating the large Doppler frequency offset,delay,and channel parameters in the asynchronous band-limited long-code-based uplink of direct sequence-code division multiple access（DS-CDMA）system was considered.The receiving signal model was established that was shaping by square root-raised cosine wave as two parts,one was composition of guide pilot and Doppler,the other was including the delay and complex gain of the multiple channel.Then proposed an unstructured indirect estimating algorithm,that used wave matched-least squares and multiple grade grid searching based on pilot assistance to estimate Doppler and used wave matched greed to estimate the others parameters.The simulation results based on Monte Carlo method show that the model and methods proposed perform well upon the scenario of the large Doppler frequency offset.