Performance Analysis of OAMP Detection for Orthogonal Time Frequency Space Modulation

The emerging orthogonal time frequency (OTFS) technique has attracted significant research attentions for ensuring link reliability in high-speed mobile communication scenarios. Due to practical sampling constraints, the conventional linear detection algorithms fail to tackle inter-carrier interference (ICI) problems in demodulating OTFS signals. In this paper, we propose an orthogonal approximate message passing (OAMP) algorithm based detector to harvest the time and frequency diversity promised by OTFS modulation. By operating the linear estimation and non-linear estimator iteratively, the OAMP based detector can overcome the ICI. Simulation results demonstrate that, with much-reduced complexity, the proposed detector can approach the error rate performance of the conventional message passing (MP) algorithm. The impact of diversity gain and incomplete channel estimation is also analyzed.