基于高速移动下的TD-SCDMA多普勒频偏估计研究

Research on the Performance for Chase Combining HARQ Scheme in TD-SCDMA

移动终端和基站间的快速相对移动会导致较大的多普勒频偏,从而影响到接收端数据的正确接收,因此进行准确的频偏估计会使数据传输向更可靠的阶段发展。基于TD-SCDMA系统的上行链路,提出了一种"双重矫正"的频偏估计算法。首先在训练序列进行频偏估计的基础上,将一重频偏矫正后的用户数据进行解调,然后用解调得到的用户数据进行二重频偏估计矫正。仿真结果对比表明,在相同信噪比的条件下,该算法具有更低的误码率,提高了系统的通信质量。

The rapid relative displacement between mobile terminal and base station will bring big frequency offset value,as a result,the receiver can not achieve the correct signal demodulation.Therefore,an accurate frequency offset estimation can increase the reliability sensibly during the transmission service.Based on TD-SCDMA uplink,this paper elaborates the principle of doppler frequency offset estimation,and a ＂dual rectification＂ scheme is proposed,in which the midamble sequence is firstly used to estimate frequency offset,the rectified user data is subsequently demodulated and used to estimate frequency offset.It is found from the emulation that under the same condition of SNR,lower bit error rate is achieved at receiving end by using the algorithm and so the communication quality of system is well improved.