Mobility adaptation in OFDM systems over rapidly time-varying fading channels

Due to the rapidly time-varying nature of wireless channels, it is not possible to obtain accurate instantaneous channel state information (CSI). However, predicting and obtaining the velocity of the moving terminals is not difficult, where the velocity (mobility) can be considered as a large scale metric. A new concept called mobility adaptation is proposed for OFDM systems under rapidly time-varying channels to combat intercarrier interference (ICI) by adjusting system parameters based on the estimated velocity of the terminals, without need to know instantaneous CSI. As examples of mobility adaptation, two kinds of adaptation based on velocity are presented. Our analysis and simulation results show that the proposed mobility schemes based on velocity are quite effective to improve the performance of OFDM systems over rapidly time-varying fading channels.