COMB JAMMING AS A STRATEGY FOR RCIED ACTIVATION PREVENTION

The main objective of this paper is the analysis of comb jamming as a technique for RCIED activation prevention. Presentation of three strategies for comb signal generation follows after comprehensive survey of various jamming techniques in the introduction. There are two paper original contributions. The first one is quantitative comparison for three signal generation techniques of their emission power in relation to barrage jamming under the condition of equal BER value. The second contribution is determination of exact BER value as a function of emission power in the case of barrage jamming. Until now we have made different analyses and comparisons starting from estimated emission power. The analysis procedure is performed for QPSK modulated RCIED activation signal. Power saving is evident for all three methods of jamming signal generation. It is proved that additional 2.5dB of power saving is achieved by equalization of frequency components level in comb signal. The analysis in this paper shows that comb jamming allows the same effects as barrage jamming, but with lower emission power

A Decrease of Unsuccessful Pairing Probability in VAMOS Mobile Cell Using Existing Connection Rearrangement

This paper analyzes the existing connection rearrangement in mobile telephony systems with implemented VAMOS techniques. The main objective of rearrangement application is to decrease connection unpairing loss when there is exactly one idle traffic subchannel (OSC) in the system. The rearrangement technique was well-known in old multistage switching systems, where it contributed to traffic loss decrease. It is proved in this paper that connection loss probability due to pairing inability is decreased when rearrangement is implemented. Connection realization is improved in following cases: when offered traffic is greater, when allowed emission base station power difference between two paired OSCs in channels is smaller and when greater channel groups are implemented. Results are verified by computer simulation and illustrated by a numerical example

VERIFICATION OF CALCULATION METHOD FOR DRONE MICRO-DOPPLER SIGNATURE ESTIMATION

Drones micro-Doppler signatures obtained by FMCW radars are an excellent procedure for malicious drone detection, identification and classification. There are a number of contributions dealing with recorded spectrograms with these micro-Doppler signatures, but very low number of them has analyzed possibility to calculate echo caused by drone moving parts. In this paper, starting from already existing mathematical apparatus, we presented such spectrograms as a function of changing drone moving parts characteristics: rotor number, blades number, blade length and rotor moving speed. This development is the part of a wider project intended to prevent malicious drone usage

RELIABILITY ANALYSIS OF DIFFERENT RCIED ACTIVATION SIGNAL RESPONSIVE JAMMING TECHNIQUES AND THEIR COMPARISON TO ACTIVE JAMMING

In this paper we compared the time required for the successful jamming of remote controlled improvised explosive devices activation using active and responsive jamming methods. As a representative of active jamming method we analyzed jamming signal generation using frequency sweep. For the analysis of the possible activating signal presence based on responsive jamming procedures we first supposed Fast Fourier Transform (FFT) implementation and compared its analysis rate to the rate of sweep jamming. Taking into account the current technology state, it is proved that the time required to achieve the successful jamming relied on FFT analysis may be less than in the case of active sweep jamming. After that we considered pros and cons for energy detector and matched filter detector implementation in responsive jamming. For these two detector types it is shown how to determine the number of analysis blocks to achieve approximately the same number of collected samples as in the case of FFT implementation, starting from the probabilities of false detection and miss of detection

Successful Sweep Jamming Rate Determination of MPSK Modulated RCIED Activation Message Signals

This paper presents the development of the method for accurate successful jamming rate calculation when MPSK modulated RCIED activation message is jammed using sweep signal. Opposite to classical methods of error modelling where it is taken that only one bit in a symbol may be altered, it is supposed in this paper that any number of bits in a symbol is the subject of eventual modification. The derived formulas are achieved for QPSK, 8PSK and 16PSK modulated signals jamming. The results calculated by these formulas are verified and obtained by our originally developed simulation method. The results of calculation and simulation agree very well and the maximum difference between calculated and simulated successful jamming rate for any of three analyzed jamming methods and any level ratio between activation message signal and jamming signal does not overcome 1.1%. It is proved that successful jamming rate tends to maximum value 0.5 when jamming signal power increases and that only 20% lower successful jamming rate value is obtained for less than 7dB higher jamming signal level than it is the level of RCIED activation signal. These results point out that it is not necessary to apply too high emission power to achieve acceptable jamming effect. As a consequence, jammer practical implementation is easier and its dimensions are smaller

O ekvikvalitetnim značajkama kašnjenja i gubitaka paketa u paketskoj telefoniji

In this paper we present the combined influence of packet delay and packet loss on speech quality in packet telephony. We calculate equiquality lines, which demonstrate the joint influence of these factors on the packetized signal quality. The use of equiquality lines to determine the optimal size of de-jitter buffer is illustrated by couple of numerical examples.U radu se analizira združeno djelovanje kašnjenja i gubitaka paketa. Izračunate su ekvikvalitetne linije koje pokazuju utjecaj ovih čimbenika na kvalitetu paketiziranog govora. Korištenje ekvikvalitetnih linija za odre.ivanje optimalne veličine de-jitter me.uspremnika prikazano je na nekolicini primjera

Proračun funkcije raspodjele srednje izlazne snage bazne stanice u GSM-u

In this paper we calculate the distribution of output power of traffic channels of base station in GSM network depending on the traffic load. The principle of the calculation is to find the distribution of the output power of one traffic channel, and then to combine this distribution with the distribution of the number of busy traffic channels. Numerical example refers to the simplest distributions, but the principle can be implemented on the more complicate distributions.U radu se izračunava raspodjela izlazne snage bazne stanice u GSM mreži u ovisnosti o prometu. Princip računanja je nalaženje raspodjele izlazne snage jednog prometnog kanala, a zatim kombiniranje ove raspodjele s raspodjelom broja zauzetih prometnih kanala. Brojčani se primjeri odnose na najjednostavnije raspodjele, ali se princip može primijeniti i na složenije

ANALYSIS OF JAMMING SUCCESSFULNESS AGAINST RCIED ACTIVATION WITH THE EMPHASIS ON SWEEP JAMMING

In this paper we first briefly compare the performances of active jamming remote controlled improvised explosive devices activation using wide-band noise and frequency sweep signal. Frequency sweep is the most widely used technique intended for active jamming and we analyze its characteristics: 1) sweep speed, 2) conditions for certainly successful jamming, 3) successful jamming probability if jamming is not certainly successful, and 4) step of frequency change when frequency sweep is applied. The separate paper section is devoted to the successful jamming probability calculation in general. The attention is also paid to jamming probability determination when starting and ending sweep signal frequencies are varied. The initial research has been upgraded and extended. The presented results refer to jamming equipment development in IRITEL, but it is important to add that they are also applicable to the other similar jamming systems realizations

10.5937/tehnika1703383L= Development of methods for traffic simulation of telecommunication processes in IRITEL over 45 years

This paper summarizes the programs intended for simulation of traffic processes in different telecommunications systems. These programs are developed, implemented and verified by the members of the Institute IRITEL through numerous scientific papers and doctoral dissertations taken during 50 years of the Institute activities. Two main areas of traffic simulations are related (but not limited) to the analyses of switching systems and mobile telephony systems