Two Dimensional Adaptive Multichannel Decision Feedback Equalization for OTFS System

Orthogonal time-frequency-space (OTFS) modulation has shown significant error performance advantages over orthogonal frequency division multiplexing (OFDM) in time-varying channels. However, the symbols in OTFS frames still suffer from inter-Doppler interference (IDI) and inter-symbol interference (ISI). In this letter, we propose a two dimensional (2D) adaptive multichannel decision feedback equalizer (DFE) to combat the interference. The proposed receiver constructs the input signal and feedback signal of the DFE based on the characteristic of OTFS modulation. Meanwhile, by exploiting the sparsity feature of the channels in delay-Doppler domain, the iterative improved proportionate normalized least mean squares (IPNLMS) algorithm is employed to achieve fast convergence and fast tracking. The simulation results show that the proposed equalizer could achieve satisfied BER performance with lower complexity.

Automated summary

The study proposes a solution to the interference issues in OTFS modulation, combating interference with a 2D adaptive multichannel DFE. The proposed equalizer constructs input and feedback signals based on the characteristics of OTFS modulation, and utilizes the sparse features of channels in the delay-Doppler domain, employing the IPNLMS algorithm for fast convergence and tracking.