Book contents
- Frontmatter
- Contents
- Preface
- List of Abbreviations
- List of Notation
- 1 Overview of Wireless Communications
- 2 Path Loss and Shadowing
- 3 Statistical Multipath Channel Models
- 4 Capacity of Wireless Channels
- 5 Digital Modulation and Detection
- 6 Performance of Digital Modulation over Wireless Channels
- 7 Diversity
- 8 Coding for Wireless Channels
- 9 Adaptive Modulation and Coding
- 10 Multiple Antennas and Space-Time Communications
- 11 Equalization
- 12 Multicarrier Modulation
- 13 Spread Spectrum
- 14 Multiuser Systems
- 15 Cellular Systems and Infrastructure-Based Wireless Networks
- 16 Ad Hoc Wireless Networks
- Appendix A Representation of Bandpass Signals and Channels
- Appendix B Probability Theory, Random Variables, and Random Processes
- Appendix C Matrix Definitions, Operations, and Properties
- Appendix D Summary of Wireless Standards
- Bibliography
- Index
10 - Multiple Antennas and Space-Time Communications
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface
- List of Abbreviations
- List of Notation
- 1 Overview of Wireless Communications
- 2 Path Loss and Shadowing
- 3 Statistical Multipath Channel Models
- 4 Capacity of Wireless Channels
- 5 Digital Modulation and Detection
- 6 Performance of Digital Modulation over Wireless Channels
- 7 Diversity
- 8 Coding for Wireless Channels
- 9 Adaptive Modulation and Coding
- 10 Multiple Antennas and Space-Time Communications
- 11 Equalization
- 12 Multicarrier Modulation
- 13 Spread Spectrum
- 14 Multiuser Systems
- 15 Cellular Systems and Infrastructure-Based Wireless Networks
- 16 Ad Hoc Wireless Networks
- Appendix A Representation of Bandpass Signals and Channels
- Appendix B Probability Theory, Random Variables, and Random Processes
- Appendix C Matrix Definitions, Operations, and Properties
- Appendix D Summary of Wireless Standards
- Bibliography
- Index
Summary
In this chapter we consider systems with multiple antennas at the transmitter and receiver, which are commonly referred to as multiple-input multiple-output (MIMO) systems. The multiple antennas can be used to increase data rates through multiplexing or to improve performance through diversity. We have already seen diversity in Chapter 7. In MIMO systems, the transmit and receive antennas can both be used for diversity gain. Multiplexing exploits the structure of the channel gain matrix to obtain independent signaling paths that can be used to send independent data. Indeed, the initial excitement about MIMO was sparked by the pioneering work of Winters, Foschini, Foschini and Gans, and Telatar predicting remarkable spectral efficiencies for wireless systems with multiple transmit and receive antennas. These spectral efficiency gains often require accurate knowledge of the channel at the receiver – and sometimes at the transmitter as well. In addition to spectral efficiency gains, ISI and interference from other users can be reduced using smart antenna techniques. The cost of the performance enhancements obtained through MIMO techniques is the added cost of deploying multiple antennas, the space and circuit power requirements of these extra antennas (especially on small handheld units), and the added complexity required for multidimensional signal processing. In this chapter we examine the different uses for multiple antennas and find their performance advantages. This chapter uses several key results from matrix theory: Appendix C provides a brief overview of these results.
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- Wireless Communications , pp. 321 - 350Publisher: Cambridge University PressPrint publication year: 2005
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