Articles

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.

Model-Based Design for Software Defined Radio on an FPGA
This paper presents an approach of model-based design for implementing a digital communication system on an FPGA for software defined radio (SDR). SDR is a popular prototyping platform for wireless communication systems due to its flexibility and utility. A traditional SDR system performs nearly all computations and signal processing tasks on the host computer, and then sends the waveform to the RF front-end. For complex algorithms or high data rate, the host computer becomes the processing bottleneck and FPGA is often employed as a hardware accelerator. This paper demonstrates the procedure of using model-based design for SDR targeted on FPGA hardware. A complete digital communication system, including a transmitter with convolutional encoder and a receiver with Viterbi decoder, are implemented on an FPGA-based SDR platform and validated by over-the-air demonstration. Synchronization algorithms such as carrier frequency offset, phase offset and time recovery are also optimized for hardware efficiency.

Convergence of Software Defined Radio: WiFi, iBeacon and ePaper

With the emergence of Internet of Things (IoT), the requirements for scalability and flexibility are continuously increasing, thus easy reconfigurable systems such as Software Defined Radio (SDR) are gaining more popularity. The paper provides an overview of the related work in the field of SDR technologies and solutions for convergence of SDR applications. Furthermore, we analyze how the convergence of three selected SDR applications such as WiFi, iBeacon and ePaper can address different user needs. Finally, the paper presents the configuration of a SDR testbed and preliminary measurement results.

One of the labs at QuTech, a Dutch research institute, is responsible for some of the world’s most advanced work on quantum computing, but it looks like an HVAC testing facility. Tucked away in a quiet corner of the applied sciences building at Delft University of Technology, the space is devoid of people. Buzzing with resonant waves as if occupied by a swarm of electric katydids, it is cluttered by tangles of insulated tubes, wires, and control hardware erupting from big blue cylinders on three and four legs.

Detection and Tracking Approach Using an Automotive Radar to Increase Active Pedestrian Safety

Abstract—Vulnerable road users, e.g. pedestrians, have a high impact on fatal accident numbers. To reduce these statistics, car manufactures are intensively developing suitable safety systems. Hereby, fast and reliable environment recognition is a major challenge. In this paper we describe a tracking approach that is only based on a 24 GHz radar sensor. While common radar signal processing loses much information, we make use of a trackbefore-detect filter to incorporate raw measurements. It is explained how the Range-Doppler spectrum of pedestrian can help to initiate and stabilize tracking even in occultation scenarios compared to sensors in series.

The paper gives a brief overview of automotive radar. The status of the frequency regulation for short and long range radar is summarized because of its importance for car manufacturers and their sensor suppliers. Front end concepts and antenna techniques of 24 GHz and 77 GHz sensors are briefly described. Their impact on the sensor’s field of view and on the angular measurement capability is discussed. Esp. digital beamforming concepts are considered and promising results are presented.

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