2 results
6 - Distributed space-time block codes
- from Part III - Relay-based cooperative cellular wireless networks
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- By Matthew C. Valenti, West Virginia University, USA, Daryl Reynolds, West Virginia University, USA
- Edited by Ekram Hossain, University of Manitoba, Canada, Dong In Kim, Vijay K. Bhargava, University of British Columbia, Vancouver
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- Book:
- Cooperative Cellular Wireless Networks
- Published online:
- 03 May 2011
- Print publication:
- 10 March 2011, pp 153-175
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Summary
Introduction
In this chapter, we consider space-time coding strategies for multiple-relay cooperative systems that effectively harness available spatial diversity. More specifically, the goal is to examine ways to forward signals efficiently from multiple relays to the destination while addressing the important practical issue of synchronization among the relays. We assume a general two-phase transmission protocol as illustrated in Figure 6.1. In the first phase of the protocol, the source broadcasts a message which is received by the relays and (possibly) the destination. During the second transmission phase, a subset of the relays, possibly in conjunction with the source, transmits additional information to the destination. This protocol is useful in practical scenarios where signals received at the destination due to transmissions directly from the source (Phase 1) will not carry enough useful information because of noise, fading, and/or interference.
It is expected that Phase 2 will dramatically increase the reliability of the system, but if the symbols cannot be decoded correctly after the second phase, the protocol can restart by returning to Phase 1 or Phase 2.
The primary problem associated with forwarding information from multiple relays to the destination is determining how the information should be spread out among the relays over space and time. This is analogous to the classic spacetime coding problem in point-to-point multiple-transmit-antenna systems, and so it is often called the distributed space-time coding problem.
20 - Multiuser MIMO systems
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- By H. Vincent Poor, Princeton University, Daryl Reynolds, West Virginia University, Xiaodong Wang, Columbia University
- Edited by H. Bölcskei, ETH Zürich, Switzerland, D. Gesbert, Eurecom Institute, C. B. Papadias, Bell Labs, Lucent Technologies, A.-J. van der Veen, Technische Universiteit Delft, The Netherlands
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- Book:
- Space-Time Wireless Systems
- Published online:
- 25 February 2010
- Print publication:
- 15 June 2006, pp 406-425
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Summary
Receiver design for multiuser MIMO systems
Introduction
The seemingly insatiable demand for performance and capacity in cellular wireless systems has prompted the development of myriad receiver-based signal processing techniques for using system resources more efficiently. One of the most powerful coding and signal processing paradigms for this purpose is space-time processing with multiple transmit and/or receive antennas. As discussed in previous chapters, information theoretic-results show that multiple antennas can increase rate (multiplexing gain), reliability (diversity gain), or both. In this section, we propose specific coding and signal processing schemes for blind adaptive space-time processing of MIMO multiuser systems. We make use of the Alamouti space-time block code (STBC) (Alamouti, 1998; Tarokh et al., 1999) for uplink transmission, which has been adopted in a number of 3G WCDMA standards (Lucent Technologies, 1999), and blind adaptive MMSE joint multiuser detection (Reynolds and Wang, 2001; Wang and Poor, 2004; Verdú, 1998; Honig et al., 1995), and space-time decoding for base station reception. Related work includes the results by Hochwald et al. (2001), Papadias and Huang (2001).
Some of the results in this section have been published previously in Reynolds et al. (2002b).
Blind space-time multiuser MIMO reception
We consider a K-user code division multiple access (CDMA) wireless cellular system with processing gain N operating in flat block fading with MB base station antennas and MU antennas at each mobile unit. For simplicity of exposition, we will consider only MU = MB = 2 and BPSK modulation in this section.
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