Comparison of subspace adaptive filtering techniques for DS-CDMA interference suppression

Michael L Honig*

*Corresponding author for this work

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

16 Scopus citations


We compare the performance of two subspace adaptive filtering techniques for suppressing multiple-access interference in a Direct-Sequence (DS) Code-Division Multiple-Access (CDMA) system. A military scenario is considered in which the processing gain is very large compared with the number of users. Also, communications is peer-to-peer so that power control cannot be used to solve the near-far problem. Two subspace techniques are considered. The first projects the received vectors on to an estimated signal subspace obtained by an appropriate eigen-decomposition. The second partially despreads the received signal, as proposed in [1]. The dimension of the lower-dimensional sub-space affects both the Minimum Mean Squared Error, and the response time to interference transients. There is a tradeoff between these two quantities which determines the optimum choice of dimension. This is illustrated numerically for a particular model in which the interferers turn on and off according to a two-state Markov chain. Simulation results are also presented which show that recursively updated algorithms are much more sensitive to large interference transients than block-oriented adaptive filtering algorithms.

Original languageEnglish (US)
Title of host publicationProceedings - IEEE Military Communications Conference MILCOM
Editors Anon
Number of pages5
StatePublished - Dec 1 1997
EventProceedings of the 1997 MILCOM Conference. Part 2 (of 3) - Monterey, CA, USA
Duration: Nov 3 1997Nov 5 1997


OtherProceedings of the 1997 MILCOM Conference. Part 2 (of 3)
CityMonterey, CA, USA

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Electrical and Electronic Engineering

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