基于非信令TD-SCDMA信号EVM指标算法的研究

Study of EVM algorithm based on non-signaling signal of TD-SCDMA

针对非信令情况下TD-SCDMA信号EVM测量实时性差、测量精度不高的问题,提出一种基于符号同步、载波频偏估计和初始相位估计的算法,该算法可以快速、精确测量EVM。该算法不需要对基带信号进行解调、还原码流、生成相应的参考信号,而是直接通过载波频偏估计和初始相位估计来准确恢复参考信号,并最终实现EVM的测量。把使用该算法得到的结果与国外先进仪表非信令解调测试结果相比较,比较结果表明本算法的实时性、精确度完全可以作为非信令测试仪表的关键、可靠算法。

For the problem of low real time and low demodulate precision in the condition of non-signaling demodulation,aquick and accurate algorithm that measure the index of modulation in the condition of non-signaling demodulation is proposed,the algorithm is based on symbol synchronization,carrier frequency offset estimate and original phase estimate.The algorithm use symbol synchronization,carrier frequency offset estimate and original phase estimate to resume the reference signal quickly and accurately,but don＇t need to demodulate baseband signal,restore code stream.Through comparing to the measuring result of foreign instrument,the algorithm can be taken as the reliable and key algorithm of non-signaling measuring instrument.