Power control is essential for code-division multiple-access CDMA cellular systems to overcome the near-far problem since all users share the same bandwidth. In this paper, we solve the power control problem for the multicarrier direct sequence CDMA (MC-DS-CDMA) system. We propose two algorithms based on the measure of the signal to interference ratio (SIR) allowing for the elimination of the effect of distance and slow shadowing in the case of indoor and outdoor environments.

Many equalizers based on neural networks have been proposed across the literature. Unfortunately, the complexity and the slow convergence still have to be overcome for neural equalizers to be implemented in real time. This paper presents neural equalizers suitable for multi-level QAM constellations, and trained using complex extended Kalman and RLS algorithms, which makes them more robust against severely dispersive channels, like broadband outdoor or indoor mobile communication channels. The activation function is optimized to obtain good performance for large size signal constellations (i.e. up to 256-QAM). Extensive simulations show the benefits and limitations of these neural equalizers over traditional decision-feedback equalizers.

Systematic design of pipelined recursive filters is presented. The procedure is based on a multiplication algorithm which generates the result with most significant digit first. Since the latency of such a multiplier is low, a reduced number of pipelining delays may be introduced in the reduction loop, resulting in a high sampling rate. The implementation obtained exhibits minimum hardware and ensures minimum latency. It is shown that its flexibility allows, on one hand, the ability to choose freely the number system radix and, on the other hand, the interleaving of two multiplier arrays into one. This is illustrated by the realization of a second-order all-pole filter, operating in a radix-4 representation and using only one array to perform two multiplications. In this way, long interconnections are avoided and denser and more regular layout is achieved. It turns out that the design procedure can also be applied successfully to various types of realization where multiplications are required.>

A novel digital implementation of time-domain block LMS (least mean square) filtering is presented. The primitive operators are serial-parallel multipliers which produce the results digit by digit, most significant first. The use of a redundant notation is essential here. These operators are placed in a parallel and pipeline structure, resulting in a fast realization with O(log(L*N) mod /sub L/) time, where N and L are filter length and block length, respectively. This new realization is particularly suitable for VLSI implementation because of this modularity and the high integration capacity of the serial-parallel multipliers.>

By factorizing a finite sum of harmonics, an expression is obtained for an FM demodulator output when the modulating signal is a simple sinusoid and the RF filter is an ideal bandpass filter. Using this result, harmonic distortions and the signal-to-distortion ratio are defined and computed; several curves are drawn to show the variation of these quantities in terms of the modulation index and the normalized bandwidth.

This concise paper analyses the performance of noncoherentM-ary digital systems in presence of a generalized stationary Poisson impulsive noise process, with a receiver operating as a maximum likelihood detector in white Gaussian interference. Methods to bound the error probability for ASK, PSK, and FSK systems in the cases where the noise is impulsive and quasi-Gaussian are described and the results discussed.