Iterative rake equalization method for low-complexity OTSM in high-speed mobile environment

Abstract

Aiming at the problems of poor anti-noise performance and high computational complexity of the existing orthogonal time sequency multiplexing (OTSM) equalization methods, a low-complexity iterative rake equalizer based on maximum ratio combining (MRC) was proposed.The main idea was to use MRC to iteratively extract and coherently combine the received multipath components of the transmitted symbols in the delay-time domain to improve the signal-to-noise ratio of the combined signal.In order to speed up the convergence of the MRC iterative algorithm, a single-tap time-frequency equalizer was designed to provide an initial estimate, and then combined with an external error correction code to further improve the bit error performance.The simulation results show that the performance of the iterative rake equalizer based on MRC is significantly better than that of the LMMSE linear equalizer, and the performance and computational complexity are greatly improved compared with the currently widely used Gauss-Seidel (GS) iterative equalizer.

Keywords

• orthogonal time sequency multiplexing
• maximum ratio combining
• delay-time domain
• single tap time-frequency equalizer