The essential degrees of freedom in space-time fading channels

Akbar M. Sayeed, Venu Veeravalli

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The key to reliable communication is a fundamental understanding of the interaction between the signal space and the channel. In time- and frequency-selective multi-antenna (space-time) fading channels this interaction happens in time, frequency and space. In this paper we propose a four-dimensional Karhunen-Loeve-like Fourier series representation for space-time channels that captures the essence of such interaction and exposes the intrinsic degrees of freedom in the channel. The four dimensions are: time, frequency and the two spatial dimensions at the transmitter and receiver. The key signal space parameters are the signaling duration, bandwidth and the two array apertures. The corresponding channel parameters are the delay, Doppler and the two angular spreads associated with the scattering environment. The representation induces a virtual partitioning of propagation paths in time, frequency and space that reveals their contribution to channel capacity and diversity. It also exposes fundamental dependencies between time, frequency and space thereby revealing the essential independent degrees of freedom in the channel.

Original languageEnglish (US)
Title of host publication13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2002
Pages1512-1516
Number of pages5
DOIs
StatePublished - Dec 1 2002
Event13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2002 - Lisboa, Portugal
Duration: Sep 15 2002Sep 18 2002

Publication series

NameIEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC
Volume4

Other

Other13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2002
Country/TerritoryPortugal
CityLisboa
Period9/15/029/18/02

Keywords

  • Beamforming
  • Capacity
  • Diversity
  • Doppler
  • MIMO systems
  • Multipath

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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