Frequency-Domain Equalization for MIMO-OFDM Over Doubly Selective Channels
Orthogonal Frequency Division Multiplexing (OFDM) systems may confront significant Inter-Carrier Interference (ICI) when applied in doubly selective channels. Furthermore, the insufficient Cyclic Prefix (CP) leads to Inter-Block Interference (IBI) which again results in ICI. These interferences cause an early error floor in conventional receivers. In this paper, the authors characterize the doubly selective channel using a Basis Expansion Model (BEM) and propose a frequency-domain equalization approach to jointly combat the ICI and IBI. They also derive a low-complexity scheme for the proposed approach. Simulation results show the superior performance of the proposed equalizer.