The LMMSE (Linear Minimum Mean Square Error) algorithm is one of the best linear receivers for DSCDMA (Direct Sequence-Code Division Multiple Access). However, for the case of MIMO/BLAST (Multiple Input, Multiple Output / Bell Laboratories Layered Space Time), the perceived complexity of the LMMSE receiver is taken as too big, and thus other types of receivers are employed, yielding worse resul...

In this contribution we propose and study a multicarrier direct-sequence code-division multiple-access (MC DSCDMA) scheme, which employs both time (T)-domain and frequency (F)-domain spreading. We investigate the achievable detection performance in the context of synchronous TF-domain spread MC DS-CDMA, when communicating over an additive white Gaussian noise (AWGN) channel. The performance of ...

In this paper, a method of Transmission Power Control (TPC) for Orthogonal Frequency Division Multiplexing Direct Sequence Code Division Multiple Access (OFDM-DSCDMA), in order to compensate for power attenuation at each subcarrier, is proposed. Instead of assigning same power levels for all-subcarriers, different trasmission power levels are assigned to different subcarriers, according to the ...

In this paper, we have investigated the performance of a multicell S-ALOHA DSCDMA system with fast power control error on a Nakagami frequency selective environment. We analyzed how the throughput of the optimally stabilized system is affected by the channel conditions and some key system characteristics such as the processing gain or the number of fingers in the RAKE receiver. By using an idea...

The performance of the blind multiuser detector for a DSCDMA system with linearly constrained constant modulus (LCCM) criterion is known to highly depend on the exact knowledge of the desired user amplitude; it is usually not available at receiver end. In this paper, we propose a novel LC adaptive CM RLS (LC-ACM-RLS) algorithm to adaptively implement the optimal solution of the LCCM receiver, a...

As multimedia applications proliferate, there is a desire to provide wireless transport to information streams with inherently different data rates. Direct-sequence code division multiple access (DS-CDMA) is a natural multiple-access strategy for multiple data-rate systems. Recent work on multirate DSCDMA receivers has focused on signal-processing techniques, which detect all users of all rates...

In direct sequence code division multiple access (DSCDMA), variable rate transmission can be realized by simply changing the spreading factor SF for the given chip rate. In a frequency-selective fading channel, the transmission performance can be improved by using rake combining. However, when a very low SF is used for achieving a high transmission rate, error floor is produced due to insuffici...

The linear minimum mean-squared error (MMSE) detector for direct-sequence code-division multiple-access (DSCDMA) systems relies on the inverse of the covariance matrix of the received signal. In multiuser environments, when few samples are available for the covariance estimation, the matrix illconditioning may produce large performance degradation. In order to cope with this effect, we propose ...

A subspace-based linear minimum mean-squared error (MMSE) multiuser detection scheme is proposed for a multicarrier direct-sequence code-division multiple-access (MC-DSCDMA) system. Typically, a MC-DS-CDMA system employs a band-limited chip waveform. The band-limited nature of the chip waveform causes problem in applying standard subspace techniques because no nonnull noise subspace can be form...

Direct-sequence code-division multiple-access (DSCDMA) cellular systems, such as Wideband CDMA (WCDMA), are limited in performance by interference. Several types of Rake Receivers like A-Rake, S-Rake, P-Rake, Adaptive frequency Rake, Time frequency Rake, Conventional MMSE Rake and Adaptive MMSE rake are used for WCDMA. A Beam formerRake receiver can be an effective solution to provide the recei...