BEM OTFS Receiver with EKF-based Channel Estimation and Interference Cancellation for High-Mobility Communications

In this paper, we design a new receiver scheme for the basis expansion model (BEM)-based orthogonal time frequency space (OTFS) system, which includes an extended Kalman filter (EKF)-based channel estimation and a reliable space (RS)-based interference cancellation (IC). First, the initial channel estimation is obtained by using the pilot-aided method, and the RS is established after the message passing equalizer. Then, based on the channel correlation, the EKF is used to optimize the estimated channel information. Finally, the received symbols are updated by subtracting the interference caused by the symbols in the RS through the optimized estimated channel information. The symbols that are not in the RS are reserved for further equalization. The concept of the RS can be applied to other receivers featuring optimized or iterative channel estimation to enhance the bit error rate (BER) performance and reduce the complexity of the equalization. Simulation results show that the proposed BEM OTFS receiver exhibits higher channel estimation accuracy and better BER performance.