Low Complexity Turbo SIC-MMSE Detection for Orthogonal Time Frequency Space Modulation

Recently, orthogonal time frequency space (OTFS) modulation has garneredconsiderable attention due to its robustness against doubly-selective wirelesschannels. In this paper, we propose a low-complexity iterative successiveinterference cancellation based minimum mean squared error (SIC-MMSE) detectionalgorithm for zero-padded OTFS (ZP-OTFS) modulation. In the proposed algorithm,signals are detected based on layers processed by multiple SIC-MMSE linearfilters for each sub-channel, with interference on the targeted signal layerbeing successively canceled either by hard or soft information. To reduce thecomplexity of computing individual layer filter coefficients, we also propose anovel filter coefficients recycling approach in place of generating the exactform of MMSE filter weights. Moreover, we design a joint detection and decodingalgorithm for ZP-OTFS to enhance error performance. Compared to theconventional SIC-MMSE detection, our proposed algorithms outperform otherlinear detectors, e.g., maximal ratio combining (MRC), for ZP-OTFS with up to 3dB gain while maintaining comparable computation complexity.