Articles

There exist two approaches for designing communication equipment. The classical approach means that the entire radio link, including filtering, demodulation and generation of signal, is engineered using analogue components or specialized microchips. Only the control and interface parts are based on programmed microcontrollers. However, advancement of technologies (in particular, rise of ADC and DAC rates) made it possible to transfer the major part of functions to software. This approach is called Software Defined Radio (SDR) and is optimum in terms of functionality and cost effectiveness nowadays.

Approach to achieving coherence of distributed data in multiagent systems

Increasingly rising requirements to computational capability of modern computer systems along with necessity of minimizing their cost lead to change of the paradigm, from buildup of complexity of individual devices to creation of distributed systems consisting of many relatively inexpensive nodes. This trend is very topical for communications systems where the above requirements are complemented with heightened reliability and scalability requirements. However, the existing distributed systems often have some central manager which does not allow using all advantages of such systems. This study focuses on elaboration of a multiagent interaction mechanism, which fully distributed highly reliable and easily scalable solutions can be based on.

Practical approaches to development of mesh network technology

Nowadays the so-called mesh networks are increasingly widespread; they feature decentralized, flexible and dynamic structure where network nodes are not bound to the central station and any node can act as coordinator or repeater functions [1, 2, 5]. Thanks to this structure the mesh networks have a number of doubtless advantages:

  • High reliability as any node can substitute a lost coordinator or repeater,
  • Capability to "detour" physical or artificial "obstacles" in the radio channel thanks to a large number of possible combinations of routes,
  • A mesh network can transmit information using low-power radio signals which are more difficult to triangulate or intercept.

There is a collision between requirements to maintain radar's coherence and provide radar's jamming immunity. To resolve this collision, radar shall be made operating coherently and at the same time in the frequency agile mode. This paper offers a method to enable radar's coherent and frequency-agile operation.

The Use of Kullback–Leibler Divergence in Processing Pulse Signals Received from a Sea-Based RadarGerman Babin

This paper deals with the problem of processing radar signals in the presence of space-distributed interference including sea cutter. An algorithm was developed to discriminate distinctive signal amplitudes attributable to targets. The method is based on the use of the Kullback–Leibler information distance. The algorithm was validated both with real signal records from a sea-based pulse radar and with data obtained by simulation.

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