Title :
Blind adaptive and iterative algorithms for decision feedback DS-CDMA receivers in dispersive channels
Author :
De Lamare, Rodrigo C. ; Sampaio-Neto, Raimundo
Author_Institution :
PUC-RIO, Rio de Janeiro
Abstract :
In this paper we examine blind adaptive and iterative decision feedback (DF) receivers for direct sequence code division multiple access (DS-CDMA) systems in frequency selective channels. Code-constrained minimum variance (CMV) and constant modulus (CCM) design criteria for DF receivers based on constrained optimization techniques are investigated for scenarios subject to multipath. Computationally efficient blind adaptive recursive least squares (RLS) algorithms are developed for estimating the parameters of DF detectors along with successive, parallel and iterative DF structures. A new successive parallel arbitrated DF scheme is presented and combined with iterative techniques for use with cascaded DF stages for mitigating the deleterious effects of error propagation. Simulations for an uplink scenario assess the new blind algorithms, DF structures and the effects of error propagation of the new techniques
Keywords :
automatic repeat request; code division multiple access; dispersive channels; least squares approximations; multipath channels; optimisation; spread spectrum communication; blind adaptive algorithms; code-constrained minimum variance; constant modulus design; constrained optimization techniques; decision feedback DS-CDMA receivers; direct sequence code division multiple access; dispersive channels; error propagation; frequency selective channels; iterative algorithms; recursive least squares algorithms; uplink scenario assess; Concurrent computing; Constraint optimization; Design optimization; Direct-sequence code-division multiple access; Dispersion; Feedback; Frequency conversion; Iterative algorithms; Least squares approximation; Multiaccess communication;
Conference_Titel :
Global Telecommunications Conference, 2005. GLOBECOM '05. IEEE
Conference_Location :
St. Louis, MO
Print_ISBN :
0-7803-9414-3
DOI :
10.1109/GLOCOM.2005.1578398
