Channel parameters estimation using cross-correlation matrix of a wireless SIMO system

Author(s):  
Nessrine Ben Rejeb ◽  
Ines Bousnina ◽  
M. Bassem Ben Salah ◽  
Abdelaziz Samet
Connectivity ◽  
2020 ◽  
Vol 146 (4) ◽  
Author(s):  
O. G. Plyushch ◽  
◽  
V. V. Vyshnivskyi ◽  
S. V. Tolyupa ◽  
S. V. Prokopov ◽  
...  

Adjustment speed is one of the main operation features of adaptive antenna arrays with the steepest descent gradient algorithm in telecommunication networks of information systems. Traditionally, estimation of the transient processes involves a computer simulation of the adaptive antenna array according to the selected noise environment. Substantial time required to create a respective model, big computational load that leads to quite a long period of time for performing required mathematical operations, as well as limited possibilities of simulation results interpretations are among the main drawbacks of the traditional approach. The paper proposes an integral indicator of adjustment parameters estimation of adaptive antenna arrays optimized according to the root-mean-square criterion and that does not require performing of the time consuming computer simulation of the transient processes. Integral indicator assumes values from 1, which corresponds to the quickest adaptation process, to 0, which indicates an absence of adaptation, and is built with account of the eigenvalues distribution of the array correlation matrix, squares of direction cosines of the optimal weight vector on the eigenvalues of the antenna array correlation matrix and the trace of this matrix. Computer simulation helped to establish that the designed indicator permits to correctly predict the speed of the transient processes in adaptive antenna arrays and perform their comparative analysis for different noise environments. Additionally, computation data, which are used for obtaining this indicator, allow us to clearly explain the character of the transient processes in the adaptive antenna arrays.


Author(s):  
V.N. Antipov ◽  
S.L. Ivanov ◽  
E.Е. Koltyshev ◽  
V.V. Mukhin ◽  
A.Yu. Frolov ◽  
...  

Modern radars, along with the detection and measurement of target coordinates against the background of interference, must solve the problem of detecting radio emission sources and measuring their coordinates. Detection of interference, as well as targets, in the radar is provided in the main (total) channel based on the analysis of the rangefinder-Doppler portrait of the received signal. The main disadvantage of such a detector is that the interference coming along the side lobes of the sum antenna and falling into the dip of the antenna radiation pattern may not be detected. Therefore, the problem arises of developing and analyzing algorithms for detecting interference in a radar with several receiving channels. The article discusses the logical, energy, correlation and eigenvalues of the cross-correlation matrix of the received signals interference detectors for two receiving channels. Their characteristics are given. It is shown that two-channel interference detectors based on the analysis of the eigenvalues of the cross-correlation matrix have the highest efficiency. Energy and logical algorithms are quite a bit inferior to them. The developed algorithms make it possible to effectively detect radio emission sources even when they are in the dip of one of the antenna patterns.


2006 ◽  
Vol 96 (2) ◽  
pp. 746-764 ◽  
Author(s):  
Jos J. Eggermont

Spiking activity was recorded from cat auditory cortex using multi-electrode arrays. Cross-correlograms were calculated for spikes recorded on separate microelectrodes. The pair-wise cross-correlation matrix was constructed for the peak values of the correlograms. Hierarchical clustering was performed on the cross-correlation matrix for six stimulus conditions. These were silence, three multi-tone stimulus ensembles with different spectral densities, low-pass amplitude-modulated noise, and Poisson-distributed click trains that each lasted 15 min. The resulting neuron clusters reflect patches in cortex of up to several mm2 in size that expand and contract in response to different stimuli. Cluster positions and size were very similar for spontaneous activity and multi-tone stimulus-evoked activity but differed between those conditions and the noise and click stimuli. Cluster size was significantly larger in posterior auditory field (PAF) compared with primary auditory cortex (AI), whereas the fraction of common spikes (within a 10-ms window) across all electrode activity participating in a cluster was significantly higher in AI compared with PAF. Clusters crossed area boundaries in <5% of the cases were simultaneous recording were made in AI and PAF. Clusters are therefore similar to but not synonymous with the traditional view of neural assemblies. Common-spike spectrotemporal receptive fields (STRFs) were obtained for common-spike activity and all-spike activity within a cluster. Common-spike STRFs had higher signal-to-noise ratio than all-spike STRFs and showed generally spectral and temporal sharpening. The coincident and noncoincident output of the clusters could potentially act in parallel and may serve different modes of stimulus coding.


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