针对低信噪比和高频偏条件下,CDMA2000用户身份识别的问题,研究了CDMA2000 1x EV-DO反向接入信道的结构,提出了一种利用接入信道物理层分组数据进行获取的方法.首先利用滑动匹配与功率谱分析的方法对接入信道前缀进行捕获,当本地产生的同步序列与接入信号同步时,其功率谱在残余频偏位置会出现一个尖锐的谱峰;然后根据谱峰的幅度和位置获取信号的频偏并对接收信号进行频偏校正;最后根据系统特点获取接入信道物理层分组数据得到用户身份信息.通过仿真验证,该方法识别效果良好.
For the problem of identifying CDMA2000 user's identity in low SNR and high frequency offset conditions,an algorithm is proposed by researching on the structure of CDMA2000 lx EV-DO reverse access channel.This method uses sliding match and power spectrum analysis to capture the access channel preamble.When the local synchronous sequence matches the preamble code,there would be a sharp peak at frequency offset position.Then,by detecting the peak amplitude and its position the frequency offset would be estimated,by which the signal could be Corrected.Finally,according to the characteristics of system,the user identity information could be identified from access channel physical layer packet data.Simulation results show that this algorithm has a good pefformance.