We study coherent binary direct-sequence code division multiple access (DS-CDMA) systems operating over frequency-selective Nakagami fading channels. In particular a performance comparison between maximal-ratio combining (MRC) and equal-gain combining (EGC) RAKE receivers is considered. For interference limited systems, perfect MRC RAKE receivers can accommodate about 5m=(5m ? 1) more users tha...

Power control possiblities are explored for the downlink of a Time-Division Duplex (TDD) CDMA system while employing three different kinds of multipath diversity combining schemes namely the RAKE, the pre-RAKE [2] and the transmit antenna pre-selection. In the latter two, knowledge of the channel characterstics is employed at the base-station to provide maximum decoupling between users on the d...

A bsiract— Two methods for mult ipath combining are compared for rake reception of a CDMA cellular forward-link traffic channel. Combining based on estimation of the signal-to-interference ratio of the output of each tap of the rake receiver is shown to provide significant performance improvement in comparison with the more commonly considered combiner that is based on measurement of the signal...

In order to suppress the Multiple-Access Interference (MAI) in the DS CDMA system, a new RAKE receiver based on parallel interference elimination is proposed in this paper. The multiple-access interference is evaluated by tentative decision and known user information. Then the performance over Rayleigh fading channel are analyzed and compared to MRC receiver and PIC RAKE receiver. It is shown t...

In this work, we present an application of the recently proposed unsupervised keyword extraction algorithm RAKE to a corpus of Polish legal texts from the field of public procurement. RAKE is essentially a language and domain independent method. Its only languagespecific input is a stoplist containing a set of non-content words. The performance of the method heavily depends on the choice of suc...

The main principle of RAKE receiver is that they exploit multipath propagation by receiving the multipath components of the transmitted signal separately and combining their energies. The complete design, for this purpose, can be segmented into distinct stages or blocks based on their functionality. The incoming data is fed to different fingers after different delays. In each finger the data is...

The constrained MMSE (CMMSE) receiver, which has been developed for flat fading channels [6], is applied to each finger of a RAKE receiver in multipath fading environment. The optimal filter coefficients of the CMMSE receiver in steady state are derived. The results indicate that the performance of CMMSE receivers can be degraded by interpath interference (IPI) when the channel fade rate is slo...

Conventional DS-CDMA systems employ a RAKE receiver in an attempt to make full use of the signal energy scattered in the time domain; however, the multipath effect causes a loss of orthogonality which degrades RAKE receiver performances. The literature on multi-carrier CDMA (MC-CDMA) has shown that receivers employing frequency diversity (in an effort to make full use of energy spread in the fr...

In high rate DS-UWB systems with low spreading factor, the selective multipath interference canceller with linear equalization (SMPIC-LE) is developed to alleviate severe multipath interferences induced by the poor orthogonality of spreading codes. The SMPIC iteratively mitigates the strongest inter-path interference, inter-chip interference and inter-symbol interference, while the former two a...

In this paper, a multipath mitigation tracking system is presented for static GPS applications. It is comprised of four function blocks, those being (1) adaptive path estimator (APE), (2) multipath interference reproducer (MPIR), (3) Rake-based delay locked loop (RB-DLL), and (4) Rake-based phase locked loop (RB-PLL). Only the short delay condition with delay less than 1.5 PN chip is considered...