Baseband Receiver Design for Wireless MIMO-OFDM Communications, 2nd Edition

Chapter 8

MIMO Detection

MIMO signal processing is the most complicated and challenging task in MIMO-OFDM baseband receivers, mainly because of the various matrix–vector operations involved. All the MIMO techniques, for example, spatial multiplexing, space block code, and precoding, require MIMO detection with quite sophisticated computation.

8.1 Introduction

As shown in Figure 8.1, a MIMO-OFDM baseband receiver performs MIMO detection with the acquired channel estimates, and the detector outputs are fed to the channel decoder. The MIMO detection block plays the same role as the equalization block in the single-input single-output (SISO) OFDM systems. For some MIMO detection algorithms, channel preprocessing is adopted to improve system efficiency.

The complexity of MIMO detection depends on many factors, such as SNR, channel response, required throughput, required latency, and the MIMO preprocessing at the transmitter side. The more processing there is at the MIMO transmitter, the less complicated the MIMO detection at the receiver becomes. The spatial multiplexing MIMO scheme that transmits independent spatial streams without any preprocessing will require the most complicated MIMO detector at the receiver. Consequently, in this chapter, detection methods that deal with spatially-multiplexed signals are first introduced. Iterative MIMO receivers are also introduced. Finally, the MIMO detection algorithms for MIMO systems with precoding and space block code are presented. ...