Statistical spectral analysis: a nonprobabilistic theory
Statistical spectral analysis: a nonprobabilistic theory
MMSE RAKE Reception for Asynchronous DS/CDMA Overlay Systems and Frequency-Selective Fading Channels
Wireless Personal Communications: An International Journal
Blind adaptive multiuser detection in multipath CDMA channels basedon subspace tracking
IEEE Transactions on Signal Processing
Wideband DS-CDMA for next-generation mobile communications systems
IEEE Communications Magazine
UMTS/IMT-2000 based on wideband CDMA
IEEE Communications Magazine
Multiuser detection in fast-fading multipath environments
IEEE Journal on Selected Areas in Communications
Blind Multiuser Detection in Multirate CDMA Based on Cyclic LMS Adaptation
Wireless Personal Communications: An International Journal
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In a Dual-Rate DS/CDMA system, a primary, ``high rate'' network coexists witha secondary one with a slower rate. Demultiplexinghigh-rate users typically entails, at the receiverend, a time-varying processing ifVariable Spreading Length (VSL), Variable Chip Rate (VCR), or Variable ChipRate with Frequency Shift (VCRFS) modulation formats are used, and Rake-Typedemodulation schemes if the chip rate exceeds the channel coherence bandwidth.The realization of fully adaptive receivers thus requires the joint estimationof(a) the interference to be suppressed, whether from other users ofthe high-ratenetwork or from the secondary network, and (b) the channel tap weights.The solutionthat we consider here assumes that,for each user, a pilot signal is transmitted alongwith the information-bearing signal, whether in a time-multiplexed orin a parallel-channel format. We consider both the uplink and the downlink channel and, based on a Minimum-Mean-Square-Error(MMSE) optimality criterion, we have come up with a fully adaptive system,capable on the one handof tracking, through a cyclic Recursive-Least-Squares typealgorithm, the periodically time-varying variations of theinterference subspace andon the other of updating the channel tap weights estimates.A thorough performance assessment is presented, and the convergence dynamicsof the system are derived through computer simulations in order to assessthe impact of the prior uncertainty with regard to the other-users signaturesand thechannel tap weights realizations.