The performance of a COFDM’CDM4 radio communication system in the presence of partial-band jamming is presented where the eflects of multipath and additive noise are included The importance of interleaving and coding is emphasised and their impact on the bit error-rate performance is evaluated. In the first part of the paper, the effect of jamming on a COFDA4 system is obtained under worst-case...

The critical rheology of sheared frictional granular materials near jamming transition is numerically investigated. It is confirmed that there exists a true critical density which characterizes the onset of the yield stress and two fictitious critical densities which characterize the scaling laws of rheological properties. We find the existence of a hysteresis loop between two of the critical d...

In order to verify the chaff jamming performance, according to the time-frequency distribution and statistical characteristics of chaff echo, this paper presents a modeling and simulation method of chaff echo based on its mechanism of generation, Also it presents a simulation study of chaff echo signal based on LFM signals. The simulation results indicate that the generated chaff echo of this m...

We studied the percolation and jamming of elongated objects using the Random Sequential Adsorption (RSA) technique. The objects were represented by linear sequences of beads forming needles. The positions of the beads were restricted to vertices of two-dimensional square lattice. The external field that imposed ordering of the objects was introduced into the model. The percolation and the jammi...

We study broadcasting on multiple access channels with dynamic packet arrivals and jamming. The communication environments is represented by adversarial models which specify constraints on packet arrivals and jamming. We consider deterministic distributed broadcast algorithms and give upper bounds on the worst-case packet latency and the number of queued packets in relation to the parameters de...

Wireless Sensor Networks (WSNs) are one of the most widely used technologies in our daily lives. However, since wireless sensor networks are based on communication within radio channels, WSNs are susceptible to malicious attempts to block the channel. One of the most frequently used attacks is a jamming attack. This type of attack not only blocks the ongoing communication but also exhaust the e...

We report a novel experimental study on the jamming transition of dry fine powders with controlled attractive energy and particle size. Like in attractive colloids dry fine particles experience diffusion-limited clustering in the fluidlike regime. At the jamming threshold fractal clusters crowd in a metastable state at volume fractions depending on attractive energy and close to the volume frac...

We calculate the distribution of interparticle normal forces P(F) near the glass and jamming transitions in model supercooled liquids and foams, respectively. P(F) develops a peak that appears near the glass or jamming transitions, whose height increases with decreasing temperature, decreasing shear stress and increasing packing density. A similar shape of P(F) was observed in experiments on st...

Chaos-based communication systems are known to offer advantages that are shared by spread-spectrum communications. One important aspect of performance of any spreadspectrum communication system is the ability to resist jamming. This area of study, however, is not available in the literature. In this paper, the anti-jamming performance of the coherent CSK system is presented. Two common types of...

Partial-time jamming or interference can severely affect the performance of communication systems. Error-control coding can reduce the effect of the jamming, but accurate knowledge of which received symbols are jammed is essential for best performance. In this paper we model the jammer using a finite-state Markov model and apply the BCJR algorithm to estimate which symbols are jammed, as well a...