Title :
Reduced-rank adaptive chip-level MMSE equalization for the forward link of long-code DS-CDMA systems
Author :
Mouhouche, Belkacem ; Meraim, Karim Abed ; Ibrahim, Nicolas ; Loubaton, Philippe
Author_Institution :
Dept. TSI, Telecom Paris, France
Abstract :
In this paper, we discuss the recently proposed downlink mobile receiver structure for long code DS-CDMA consisting of a chip level MMSE channel equalizer followed by descrambling and despreading. We show that the known pilot sequence can be exploited to estimate the chip-observation cross-correlation vector (needed to train the equalizer), and propose to use two low complexity reduced rank adaptive filtering algorithms for equalization: the stochastic gradient multistage Wiener filter (SG-MSWF), and the adaptive conjugate gradient reduced rank filter (ACGRRF). Simulations show that both algorithms attain close to optimal performance with reasonable complexity.
Keywords :
Wiener filters; adaptive equalisers; adaptive filters; code division multiple access; filtering theory; least mean squares methods; mobile radio; radio receivers; spread spectrum communication; adaptive conjugate gradient reduced rank filter; chip-level MMSE equalization; chip-observation cross-correlation vector; code division multiple access; downlink mobile receiver structure; long-code DS-CDMA system; minimum mean squared error; pilot sequence; reduced-rank adaptive MMSE equalization; stochastic gradient multistage Wiener filter; Adaptive equalizers; Adaptive filters; Downlink; Fading; Filtering algorithms; Multiaccess communication; Multipath channels; Partial transmit sequences; Signal processing; Wiener filter;
Conference_Titel :
Signal Processing and Its Applications, 2003. Proceedings. Seventh International Symposium on
Print_ISBN :
0-7803-7946-2
DOI :
10.1109/ISSPA.2003.1224748