高速铁路环境下TD-SCDMA系统的多普勒频偏校正算法

Doppler frequency offset compensation in high speed railways for TD-SCDMA systems

高速铁路环境带来的大多普勒频偏会严重破坏移动通信系统性能.为消除大多普勒频偏的影响并且不增加终端的设备复杂度,本文提出一种低运算复杂度的TD-SCDMA系统多普勒(Doppler)频偏校正方案.方案首先利用系统上行时隙中训练序列(Midamble)的结构特点估计多普勒频偏.然后,根据时分复用系统的特点,利用上行时隙的多普勒频偏估计结果在基站端对下行时隙进行多普勒频偏预校正.仿真结果表明,所提出的多普勒频偏校正方案在高速铁路环境下可以取得良好的性能.

Under high-speed railway environments,the performance of wireless communications systems is severely degraded due to large Doppler frequency offset.In order to mitigate the effect of significant Doppler frequency offset,a performance enhanced pre-offset compensation strategy is presented with Doppler frequency offset estimation and precorrection in TD-SCDMA systems.Specifically,by using the structural characteristics of the uplink midamble,the proposed method estimates Doppler frequency offset in the uplink timeslot.Then,the base station precorrects the Doppler frequency offset of the downlink timeslot based on the reciprocity property of TD-SCDMA systems.Simulation results demonstrate that the proposed algorithm significantly improves the performance of high speed railway wireless communication systems.