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