Pilot-Less High-Rate Block Transmission with Two-Dimensional Basis Expansion Model for Doubly-Selective Fading MIMO Systems

We investigate non-coherent multi-antenna signal processing which requires no channel state information (CSI) at either transmitter or receiver ends. With non-coherent constellations over Grassmannian manifold, a receiver employing generalized likelihood ratio test (GLRT) algorithm offers the maximum-likelihood performance even without CSI. The conventional GLRT relies on the assumption that the wireless channel is time-invariant during a block. We propose an improved GLRT algorithm which employs a novel two-dimensional basis expansion model (2D-BEM) to cope with doubly-selective fading channels. The proposed method uses sequential GLRT for multi-symbol detection to keep high performance yet low complexity. Furthermore, we introduce Fourier-Legendre product basis to be robust against hardware impairments including carrier frequency and timing offsets. We demonstrate that the proposed scheme significantly improves performance in rapid fading channels, and realizes highly spectrum-efficient transmission up to 6 bps/Hz without any pilots.