THE COHERENT RADAR SIGNALS PROCESSING: HISTORY, PRESENT STATE AND PROSPECTS
V. G. Bartenev, VNIIRT, professor; firstname.lastname@example.org
In this article presented the survey of the coherent systems development in radars almost over 70 years. The main attention was concentrated on the history of the first coherent systems in our country and abroad both with analog and digital realization. It was underlined that the future of coherent radar systems in realization using FPGA and DSP.
Key words: The analog and digital coherent systems, moving-target indicator (MTI) radars, clutter, software adaptive moving-target detector using DSP and FPGA.
ANALYSIS OF OVERLAYS IN ISP`S NETWORKS
А. А. Dort-Golts, The Bonch-Bruevich Saint Petersburg State University of Telecommunications, post-graduate; email@example.com
Today the problem of interaction between the physical and various virtual overlaying networks is the one of the most critical tasks for ISPs. Article contains traffic growth trends analysis and survey of the state-of-the-art overlays. The processes of traffic generation by overlays are illustrated with typical anonymous and file-sharing P2P-networks. Also there are ways out of this difficult situation for the ISPs and overlay`s developers proposed.
Keywords: overlays, P2P-networks.
MODELING OF OPERATOR’S REVENUE INDICATOR FOR AN ASSESSMENT OF RFS CONVERSION’S ECONOMIC EFFICIENCY
The article presents methodological approach and the simulation results of operator’s revenue per 1 MHz spectrum unit in the mobile sector based on annual statistical data of radio spectrum used by mobile operators and their revenue, depending on mobile services and technologies. Specific indicator of profitability of the spectrum is a market indicator of the current demand for radio spectrum for operators due to the use of which can be solved optimization problem by linear programming expenditures of the state budget for the conversion of frequency bands for different mobile radio technologies.
Key words: radio spectrum, spectrum conversion, optimal distribution of spectrum resources, mobile operator’s revenue per spectrum unit.
ADJUSTMENT OF A SIGNAL POWER ON M-QAM-OFDM MODULATOR’S CHANNELS
I. R. Mamedov, Azerbaijan Technical University, professor, firstname.lastname@example.org
A. M. Sharifov, Azerbaijan Technical University, graduated student, aflatun. email@example.com
In this paper increasing of noise-immunity in the M-QAM-OFDM system by adjustment of signal power on modulator channels are considered. Reduction of the signal/noise ratio in channels without hindrances is calculated at adjustment of a signal power in channels with hindrances. Depth of adjustment of the signal/noise ratio defined.
Key words: M-QAM modulator, OFDM modulation, adaptive power control, frequency-selective channel, noise immunity of system, signal/noise ratio.
ANTENNA DEVELOPMENT FOR PORTABLE GSM DEVICES BY MEANS OF MODERN CAD SYSTEMS
R. V. Sverdlov, Arzamas Polytechnical Institute (branch) Nizhny Novgorod State Technical University, docent, Ph.D.; firstname.lastname@example.org
The article presents antenna structure for portable GSM devices improving communication quality in conditions of intermittent reception. Their characteristics are determined; the results of computer modeling and optimization, use recommendations of developed antennas are given.
Key words: GSM, log-periodic antenna, optimization, directional diagram, integrated vibrator, monopillar helix antenna.
EFFICIENCY OF TELECOMMUNICATION SYSTEMS WITH THE USE OF MODIFIED GOLD PSEUDORANDOM SEQUENCE
A. I. Semenko, State Telecommunication University (SUT), Kiev, Ukraine, Telecommunications Department, Professor, Dr. habil. Sci. Ing. (Dr. II of Sci.), email@example.com
N. I. Bokla, Odessa National Academy of Telecommunication (ONAT) after A. Popov, Ukraine, Cand. Dr. Sci. Ing, firstname.lastname@example.org
Modified Gold pseudorandom sequences are proposed for the use in telecommunication systems with channel code division, which make possible to use M-position signals. In MATLAB system graphical user interface is being designed to investigate the correlation characteristics of the signals with pseudorandom sequences. The research of the systems with FM-4 correlation characteristics through the use of the graphic user interface was made. It is shown that the application of modified Gold pseudorandom sequences makes possible to reduce the required bandwidth of the radio channel for a given amount of coded channels or increase the number of coded channels in a given bandwidth radio.
Key words: Gold pseudorandom sequence, autocorrelation and cross-correlation functions, — phase-shift keyed signal, user graphic interface, Mathlab system.
RESEARCH OF CONDITIONS OF GSM AND LTE NETWORKS' COMBINATION IN THE RANGE FREQUENCIES OF 1800 MHz
V. G. Skrynnikov, «Mobile TeleSystems» OJSC, expert, Ph.D.; email@example.com
The method of combination of two networks of GSM and LTE is offered at realization of a technological neutrality in the range of frequencies of 1800 MHz. The extensive analysis for justification of the most rational distribution of the radio-frequency range which is available for communications operator, between these networks is carried out. It is shown that such distribution of spectrum will demand application in the GSM network of the standardized procedure of frequency hopping. Via methods of calculation in a combination with statistical modeling on the program SEAMCAT we evaluate quantitative parameters of possible deterioration of communication in studied networks. On the basis of the received parameters are offered practical recommendations about rational combination of networks GSM and LTE in the range of frequencies of 1800 MHz in Russia.
Keywords: LTE (Long Term Evolution), spectrum, combination of networks GSM and LTE, frequency hopping (FH), probability of coincidence of frequencies at FH, probability of degradation of communication.