Equalization and Decoding for Multiple-Input Multiple-Output Wireless Channels

Abstract

We consider multiple-input, multiple-output (MIMO) wireless communication systems that employ multiple transmit and receive antennas to increase the data rate and achieve diversity in fading multipath channels. We begin by focusing on an uncoded system and define optimal and suboptimal receiver structures for this system in Rayleigh fading with and without intersymbol interference. Next, we consider coded MIMO systems. We view the coded system as a serially concatenated convolutional code (SCCC) in which the code and the multipath channel take on the roles of constituent codes. This enables us to analyze the performance using the same performance analysis tools as developed previously for SCCCs. Finally, we present an iterative ("turbo") MAP-based equalization and decoding scheme and evaluate its performance when applied to a system with transmit antennas and receive antennas. We show that by performing recursive precoding prior to transmission, significant interleaving gains can be realized compared to systems without precoding.

Keywords

• MIMO systems
• multiple antennas
• fading channels
• MLSE
• linear equalization
• DFE
• MRC
• union bound
• turbo equalization