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

M. Hadef, S. Weiss

Research output: Contribution to conferencePaper

2 Citations (Scopus)

Abstract

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.

Conference

ConferenceFirst International Symposium on Control, Communications and Signal Processing
Abbreviated titleISCCSP 2004
CountryTunisia
CityHammamet
Period21/03/0424/03/04

Fingerprint

Equalizers
Code division multiple access
Multiuser detection
Mean square error

Keywords

  • 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

Cite this

Hadef, M., & Weiss, S. (2004). A blind synchronous multi-user DS-CDMA equaliser with partial loading. 803-806. Paper presented at First International Symposium on Control, Communications and Signal Processing, Hammamet, Tunisia. https://doi.org/10.1109/ISCCSP.2004.1296567
Hadef, M. ; Weiss, S. / A blind synchronous multi-user DS-CDMA equaliser with partial loading. Paper presented at First International Symposium on Control, Communications and Signal Processing, Hammamet, Tunisia.4 p.
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Hadef, M & Weiss, S 2004, 'A blind synchronous multi-user DS-CDMA equaliser with partial loading' Paper presented at First International Symposium on Control, Communications and Signal Processing, Hammamet, Tunisia, 21/03/04 - 24/03/04, pp. 803-806. https://doi.org/10.1109/ISCCSP.2004.1296567

A blind synchronous multi-user DS-CDMA equaliser with partial loading. / Hadef, M.; Weiss, S.

2004. 803-806 Paper presented at First International Symposium on Control, Communications and Signal Processing, Hammamet, Tunisia.

Research output: Contribution to conferencePaper

TY - CONF

T1 - A blind synchronous multi-user DS-CDMA equaliser with partial loading

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AU - Weiss, S.

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N2 - 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.

AB - 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.

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KW - partial loading

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KW - signals

KW - lms

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KW - spreading sequences

KW - common chip-level equaliser

KW - ber performance

KW - algorithm design and analysis

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KW - performance analysis

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KW - mean square error methods

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Hadef M, Weiss S. A blind synchronous multi-user DS-CDMA equaliser with partial loading. 2004. Paper presented at First International Symposium on Control, Communications and Signal Processing, Hammamet, Tunisia. https://doi.org/10.1109/ISCCSP.2004.1296567