Abstract: An iterative channel estimation algorithm in time-frequency domain based on orthogonal time and frequency space (OTFS) system is proposed for time-frequency dual selection channel environment with high delay and high Doppler offset. Using the property that channel matrix in time-frequency domain can be expressed as the product of Doppler offset matrix, channel complex gain matrix and delay matrix, the estimation results of Doppler offset and delay parameters of each path are updated iteratively to improve the accuracy of each parameter estimation. The channel matrix in the time-frequency domain is calculated according to the parameter estimation results, which is directly used in the time-frequency domain equalizer to reduce the complexity of the receiver. Simulation results show that the proposed algorithm can significantly improve the performance of channel estimation, support more flexible reference signal configuration, and reduce transmission overhead.

Key words: orthogonal time frequency space , channel estimation, reference signal