Aleksey G. Vostretsov

CDMA robust demodulation algorithm in the presence of multiple access interference

The multiuser asymptotically robust invariant demodulation algorithm for CDMA systems is considered. It provides multiple access interference (MAI) suppression and does not require controlling of power of mobile transmitters. In addition, the algorithm provides high quality demodulation under the conditions of non-Gaussian noise. The algorithm characteristics were obtained by computer simulation for the case of binary differential phase modulation.

Integrated measurement and recording of loads, displacements and electromagnetic emission in rocks under uniaxial compression

The authors describe an automatized three-channel system intended for joint recoding of loads, displacements and electromagnetic emission in rock samples subjected to uniaxial compression testing. This system includes an optoelectronic displacement sensor. The developed and tested controller and computer product allow synchronous three-channel recording, analysis and processing of experimental data, and displaying of the analytical results.

Research of the sign demodulation algorithm under the action of high power external interference

We consider the single user detection of signal in the spread spectrum communication system used for high mobility applications. Due to the complexity of initial phase estimation differential phase shift keying (DPSK) is employed. The performance of the linear correlation algorithm and the sign algorithm in the presence of additive Gaussian noise, multipath interference and high power external interference is investigated. Interference parameters are assumed to be unknown.

Adaptive asymptotically robust invariant detection of signals in uncertain noise environments

New adaptive asymptotically robust invariant (AARI) detection algorithm is proposed. The algorithm is used for the detection of signals with some unknown parameters observed in additive noise with unknown distribution. It is based on asymptotically robust invariant (ARI) algorithms previously developed by the authors. The extended model of approximately finite probability distributions (q-point model) is employed for detection algorithm synthesis. Adaptation is achieved by estimating and optimizing the algorithm for the actually unknown parameters of the q-point model. It is demonstrated that, for the case of heavy-tailed noise distributions in DS-CDMA systems, the AARI detector based on the extended q-point model outperforms significantly the correlating detector. The main advantage of the proposed algorithm is its feature of self-adjustment to unknown signal parameters and noise distribution.

Robust generation of invariant detectors in uncertain noise environments

New adaptive asymptotically robust invariant algorithms are proposed, and examined. These algorithms are used for the detection of signals with some unknown parameters observed in additive noise with unknown distribution. The algorithms are based on asymptotically robust invariant (ARI) algorithms previously developed by the authors. The extended model of approximately finite probability distributions (q-point model) is employed for algorithm synthesis. Adaptation is achieved by estimating and optimizing the algorithm for the unknown parameters of the q-point model. The algorithms characteristics were obtained by computer simulation for the case of BPSK modulation.

Rock failure diagnostics based on structural changes in the electromagnetic emission signals by stages of rock loading

The paper discusses results of the laboratory loading of rock samples and synchronous recording of the electromagnetic emission and load rate. It is shown that appearance of low frequency components in the structure of the electromagnetic emission signals at the first stages of loading can be the sign of a discontinuity.

Asymptotically Invariant Optimal (AIO) Algorithm for Detection of a Signal with Selective Fading

A new approach to synthesis of asymptotically invariant optimal algorithm for detection of a signal with selective fading was developed. Synthesized algorithm has such useful property as the invariance of its characteristics with respect to statistical dependence of the quadrature components of noise at coinciding time points. When using the algorithm we can put no attention to such dependence of the noise.