Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgements
- List of notation
- 1 Introduction
- 2 The wireless channel
- 3 Point-to-point communication: detection, diversity and channel uncertainity
- 4 Cellular systems: multiple access and interference management
- 5 Capacity of wireless channels
- 6 Multiuser capacity and opportunistic communication
- 7 MIMO I: spatial multiplexing and channel modeling
- 8 MIMO II: capacity and multiplexing architectures
- 9 MIMO III: diversity–multiplexing tradeoff and universal space-time codes
- 10 MIMO IV: multiuser communication
- Appendix A Detection and estimation in additive Gaussian noise
- Appendix B Information theory from first principles
- References
- Index
7 - MIMO I: spatial multiplexing and channel modeling
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface
- Acknowledgements
- List of notation
- 1 Introduction
- 2 The wireless channel
- 3 Point-to-point communication: detection, diversity and channel uncertainity
- 4 Cellular systems: multiple access and interference management
- 5 Capacity of wireless channels
- 6 Multiuser capacity and opportunistic communication
- 7 MIMO I: spatial multiplexing and channel modeling
- 8 MIMO II: capacity and multiplexing architectures
- 9 MIMO III: diversity–multiplexing tradeoff and universal space-time codes
- 10 MIMO IV: multiuser communication
- Appendix A Detection and estimation in additive Gaussian noise
- Appendix B Information theory from first principles
- References
- Index
Summary
In this book, we have seen several different uses of multiple antennas in wireless communication. In Chapter 3, multiple antennas were used to provide diversity gain and increase the reliability of wireless links. Both receive and transmit diversity were considered. Moreover, receive antennas can also provide a power gain. In Chapter 5, we saw that with channel knowledge at the transmitter, multiple transmit antennas can also provide a power gain via transmit beamforming. In Chapter 6, multiple transmit antennas were used to induce channel variations, which can then be exploited by opportunistic communication techniques. The scheme can be interpreted as opportunistic beamforming and provides a power gain as well.
In this and the next few chapters, we will study a new way to use multiple antennas. We will see that under suitable channel fading conditions, having both multiple transmit and multiple receive antennas (i.e., a MIMO channel) provides an additional spatial dimension for communication and yields a degree-of-freedom gain. These additional degrees of freedom can be exploited by spatially multiplexing several data streams onto the MIMO channel, and lead to an increase in the capacity: the capacity of such a MIMO channel with n transmit and receive antennas is proportional to n.
Historically, it has been known for a while that a multiple access system with multiple antennas at the base-station allows several users to simultaneously communicate with the base-station.
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- Information
- Fundamentals of Wireless Communication , pp. 290 - 331Publisher: Cambridge University PressPrint publication year: 2005
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