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Vol 60, No 10 (2017)

Article

Remote identification of liquids in a dielectric container using millimeter waves. 1. Principal possibility

Pavlyuchenko A.V., Loshitskiy P.P., Shelengovskiy A.I., Babenko V.V.

Abstract

Thepossibility of applying short-range radiolocation in millimeter wave range for problem of remote identification of flammable and hazardous liquids, enclosed in dielectric containers is demonstrated for the first time. Developed measurement setup allows indoor investigations; and the level of emitted power of utilized devices is insignificantly higher than background noise level, or, equivalently, thermal radiation. The described radiometric measurement setup enables discriminating liquids having different physical and chemical properties, in particular discriminate between water and gasoline containers. Applying additional illumination, which increases the contrast of the object under test, is one of one of the features of developed design. Various noise sources were investigated to be used as additional illumination. It was shown that in case of short-range radiolocation, energy-efficient fluorescent lamp is the most affordable choice of radiometric illumination. Such lamp not only ensures sufficient noise level in the operating frequency domain, but also has in-built modulation device that allows using modulation regime of the receiver and enables higher sensitivity.

Radioelectronics and Communications Systems. 2017;60(10):423-430
pages 423-430 views

Seamless vertical handoff using modified weed optimization algorithm for heterogeneous wireless networks

Velmurugan T., Khara S., Nandakumar S., Sumathi D.

Abstract

In the global scenario, a variety of wireless access networks are available. Different types of applications such as real time, nonreal time, and high bandwidth availability are used for heterogeneous wireless networks. Therefore, it is necessary for a service provider to make an appropriate connection support. For better performance, connections are to be exchanged among the different networks using seamless vertical handoff (VHO). The proposed algorithm shows the effect of optimization technique, which involves handoff decision process using vertical handoff triggering and selection of the network. The handoff triggering is initiated by using the received signal strength (RSS). In traditional method, handoff triggering is initiated by using RSS only. This method, modified weed optimization (M-WO) algorithm, reduces the unnecessary handoff by considering both RSS and velocity of the mobile node in handoff triggering. The parameters such as battery lifetime, handoff call dropping rate, load, dynamic weights adaptation and so on are to be considered individually or combined to make an effective network selection process. This paper highlights a novel effect ofM-WOalgorithm for decision making during the VHO. Our effort is to essentially optimize the system load, so that it reduces the handoff call dropping rate and the battery power consumption of the mobile node (MN). Weight of each QoS metrics is adjusted along with the networks changing conditions to trace the M-WO. Therefore, the novel VHO decision-making algorithm is superior to the existing SSF and OPTG methods. The simulation results show that the performance ofM-WOalgorithm is far better than SSF andOPTGmethods in terms of load, handoff call dropping rate and battery lifetime of MN.

Radioelectronics and Communications Systems. 2017;60(10):431-448
pages 431-448 views

Nonlinear iterative precoding algorithm for MIMO multiuser systems

Kreyndelin V.B., Ben Rejeb T.B.

Abstract

A modification of the known linear precoding algorithm CLTD (closed-loop transmit diversity) intended for multiuser radio communication systems and using theMIMOtechnology has been proposed. The efficiency of the original precoding algorithm CLTD possessing a number of advantages as compared to earlier precoding methods based on complete information about the communication channel state is enhanced at the expense of introducing nonlinearity. The use of nonlinear procedure of ordered successive interference cancellation (OSIC) in forming the precoding matrix makes it possible to significantly increase the noise immunity of the entire system as a whole at the expense of a slight rise of algorithm computational complexity. In addition, the results of computer simulation are presented reflecting the efficiency of the proposed modification of the algorithm for forming a precoding matrix as compared to the original CLTD algorithm.

Radioelectronics and Communications Systems. 2017;60(10):449-457
pages 449-457 views

Synthesis and analysis of algorithms for digital signal recognition in conditions of deforming distortions and additive noise

Akimov A.V., Sirota A.A.

Abstract

The problem of digital signal recognition has been considered in conditions of deforming distortions of the waveform of these signals and additive Gaussian noise. A mathematical model for introducing deformations of the known or random waveform signals is proposed for synthesizing recognition algorithms. The model is based on introducing the nonlinear deformation operator as an operator of permutations with repetitions of elements of the initial discrete signal with addition of additive noise component caused by quantization errors of continuous deformation function. Two recognition algorithms were synthesized and investigated. The first is an optimal one based on the exact calculation of likelihood functions, and the second is a quasi-optimal algorithm based on using the Gaussian approximation of likelihood functions. These algorithms were simulated for different variants of the specified values of deforming distortions in the form of determinate functions and in the form of random function realizations. The experimental error probability was compared with its theoretical estimate at different values of signal-to-noise ratio.

Radioelectronics and Communications Systems. 2017;60(10):458-468
pages 458-468 views

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