ICI Mitigation by Doppler Frequency Shift Estimation and Pre-Compensation in LTE-R Systems
Inter-Carrier Interference (ICI) caused by high Doppler frequency shift has severe impact on link performance and capacity for High-Speed Railway (HSR) communications. In this paper, the authors investigate the ICI mitigation scheme by utilizing the estimation and pre-compensation of high Doppler shifts in Long Term Evolution for Railway (LTE-R) systems with distributed Remote Radio Units (RRU). They propose several schemes to estimate and mitigate ICI caused by Doppler frequency shifts. In addition, they propose to use Cellular Cyclic Delay Diversity (C-CDD) technique for Mobile Relay Station (MRS) on the roof of HSR. Additional frequency diversity gain can be obtained when MRS lies within coverage area of two RRUs so that the communication quality is improved.