A blind synchronous multi-user DS-CDMA equaliser with partial loading

M. Hadef, S. Weiss

Research output: Contribution to conferencePaperpeer-review

4 Citations (Scopus)
51 Downloads (Pure)


In this paper, we propose a blind multiuser detection scheme in a direct sequence CDMA downlink scenario by means of a chip-level equaliser, which can be updated even if not all possible users are active, i.e. the system is partially loaded. The active synchronous users are separated by re-establishing orthogonality of their spreading sequences in a common chip-level equaliser. The adaptation algorithm is mainly based on a constant modulus (CM) criterion applied to the active users. The inactive codes in the system must be considered, for which we proposed and compare three different methods: (i) a mean square error criterion for absent users, and a CM approach with (ii) zero modulus or (iii) the transmission of arbitrary signals with small code amplitude. For all three cases, stochastic gradient descent algorithms are derived. The proposed algorithms are analysed and compared through various simulations, which demonstrate the algorithms' convergence and BER performance.
Original languageEnglish
Number of pages4
Publication statusPublished - Mar 2004
EventFirst International Symposium on Control, Communications and Signal Processing - Hammamet, Tunisia
Duration: 21 Mar 200424 Mar 2004


ConferenceFirst International Symposium on Control, Communications and Signal Processing
Abbreviated titleISCCSP 2004


  • blind
  • synchronous
  • multi-user detection scheme
  • ds-cdma equaliser
  • partial loading
  • algorithm
  • signals
  • lms
  • chip level equaliser
  • spreading sequences
  • common chip-level equaliser
  • ber performance
  • algorithm design and analysis
  • stochastic processes
  • performance analysis
  • multiuser detection
  • multiaccess communication
  • mean square error methods
  • downlink
  • convergence
  • blind equalizers
  • analytical models


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