Distributed Space-Time Systems

Ranjan K Mallik,George K Karagiannidis,Keith Q T Zhang,Mrityunjoy Chakraborty,Arogyaswami J Paulraj

doi:10.1155/2008/891036

Abstract

1Department of Electrical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India 2Department of Electrical Engineering, Stanford University, 232 Packard, 350 Serra Mall, Stanford, CA 94305, USA 3Department of Electronics and Electrical Communication Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India 4Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong 5Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, 54 124 Thessaloniki, Greece

Highlights

Cooperative or distributed space-time techniques can be used in relay networks where multiple relay nodes can form a virtual antenna array for multiple-input multiple-output (MIMO) operation
Cooperative MIMO is already supported in WIMAX 802.16e standard and has been field tested with marked success
Distributed or cooperative space-time methods raise a number of important questions: what is the network capacity? How does this capacity scale with different numbers of nodes and antennas? What are good space-time codes for distributed antennas? What are the channel models for this problem? What are good strategies for channel estimation? How do we do precoding? Can we use cross-layer information for scheduling? Does distributed space-time coding (DSTC) work well with OFDMA as it does with standard MIMO systems? How can we develop cooperative communication schemes to suit the low power needs of sensor networks?

Summary

Introduction

Cooperative or distributed space-time techniques can be used in relay networks where multiple relay nodes (and optionally, source or sink nodes) can form a virtual antenna array for MIMO operation. Space-time or multiple-input multiple-output (MIMO) wireless communication, which exploits multiple antennas at the transmitter and the receiver nodes, has been a rich and exciting research area. For a variety of reasons including size and power limitations, wireless nodes (both user terminals and base stations) can only support a limited number of antennas. Cooperative or distributed space-time techniques seek to realize the MIMO leverage by exploiting antennas spread across nodes.

Results

Conclusion