This paper analyses the effects of the nonlinear distortions introduced by high-power amplifiers (HPAs) on the performance of the linear decorrelating multiuser detector (MUD) in synchronous direct-sequence code-division multipleaccess (DS-CDMA) systems. By assuming and motivating the Gaussian distribution of the nonlinear distortion noise, the system bit-error rate (BER) has been derived theor...

Traffic burstiness results in the predictability of user activity at the individual source level, and the exploitation of such predictability in the receiver design for wireless packet switching random access/CDMA networks is investigated in this paper. It is shown that the conventional approach of assuming all users are active results in substantial performance loss when a linear multiuser det...

Published work on multiuser code division multiple access (CDMA) receivers often assume knowledge of most system parameters. But in a mobile system, it is unreasonable to assume perfect knowledge of the propagation delays for each mobile user at all times since these delays change when mobile units move. Therefore a method for tracking propagation delays in a practical asynchronous CDMA system ...

The decorrelating detector can afford good data estimates because it does not need to know many parameters of the received signal. However, it shows great performance deprivation when the background noise is high. On the other hand, partial parallel interference canceller(PPIC) has the potential to combat the near-far problem and have much lower computation complexity. But its performance depen...

We explore several reduced-dimension multiuser detection (RD-MUD) structures that significantly decrease the number of required correlation branches at the receiver frontend, while still achieving performance similar to that of the conventional matched-filter (MF) bank. RD-MUD exploits the fact that the number of active users is typically small relative to the total number of users in the syste...

Multiuser detection allows for the eecient use of bandwidth in Code Division Multiple Access (CDMA) channels through mitigation of near-far eeects and multiple-access noise limitations. The decorrelating detector is a linear multiuser detector that is asymptoti-cally optimal in terms of near far resistance. An adaptive decorrelator is constructed which adaptively augments an existing convention...

This paper presents the results obtained by two linear multiuser detectors, namely the decorrelating detector and the minimum mean square error (MMSE) one, when the channel is affected by the flat Rayleigh fading and gray images are transmitted through the system. All the users transmit their information with the same power, but the spreading codes are correlated one another. We will investigat...

The prohibitive—exponential in the number of users—computational complexity of the maximum-likelihood multiuser detector for direct-sequence code-division multiple-access communications has fueled an extensive research effort for the development of low-complexity multiuser detection alternatives. In this letter, we show that we can efficiently and effectively approach the error rate performance...

Efficient allocation of the communication resources such as frequency bandwidth is an important problem in multiple access technique. In this thesis, we explore the potential of code-division multiple-access (CDMA) as an efficient resource-sharing technique. We explore recently proposed receivers and develop a unified vector space interpretation. Bit error rates of each receiver in the simple t...

Code division multiple Access is a widely used channel access method by radio technologies. This method is useful as many receivers can send data simultaneously over a single communication channel. Various multi detection methods are used for the purpose. The noise is the major problem of these systems that decrease the efficiency of the system. After this Decorrelating detector were used but t...