Efficient Sequence Detection of Multi-Carrier Transmissions Over Doubly Dispersive Channels

Multicarrier modulation (MCM) over a doubly dispersive (DD) channel yields complicated inter-carrier interference (ICI) and intersymbol interference (ISI) responses. With appropriately designed MCM pulse shapes, however, ISI can be mostly suppressed, as can ICI outside a small subcarrier radius. In this case, the channel can be well described by a quasi-banded subcarrier coupling matrix. Several sequence detectors (SDs) have been proposed to leverage this quasi-banded structure, including linear, decision feedback (DF), and maximum likelihood (ML) schemes. Relative to linear and DF schemes, the ML schemes offer superior performance, but are significantly more complex, even when efficient Viterbi or sphere-detection algorithms are used. In this paper, we propose a new SD algorithm for the quasi-banded application with a frame error rate (FER) that is nearly indistinguishable from ML and an average complexity that is on par with DF SD