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UWB Multipath Simulator based on TEM Horn Antenna
No full textMost of the existing UWB models are extensions of narrowband models. These models suffer from limitations because UWB multipath propagation is frequency and antenna dependent. In this paper, a directional simulator based on TEM horn antenna is developed. This simulator illustrates the spatial impact on the received multipath profiles. Several deterministic scenarios are simulated to examine the antenna impact on receiver design and positioning accuracy
Parallel Algorithms for Look-Up Table (LUT) Inverse Haldtoning
Get PDFThe Look-Up Table (LUT) method for inverse halftoning is fast and computation-free technique employed to obtain good quality images. In this work we propose six algorithms to parallelize the LUT method so that more pixels can be concurrently inverse halftone using minimum additional hardware. The proposed algorithms partition the single LUT of serial LUT method into N smaller Look-Up Tables (s − LUTs) such that the total number of contents in all s−LUTs remain equal to the number of contents in the single LUT of serial LUT method. The proposed parallel algorithms have image quality equal to the serial LUT method when gain in clock cycles over the serial method is less and have lesser image quality comparetively to serial LUT method when gain in clock cycles over the serial method is very high. The parallel algorithms can be implemented on FPGA (Field Programmable Gate Arrays) devices with external CAM (Content Addressable Memories) and ROM (Read Only Memories)
Efficient Test Compaction for Combinational Circuits Based on Fault Detection Count-Directed Clustering
Get PDFTest compaction is an effective technique for reducing test data volume and test application time. In this paper, we present a new static test compaction technique based on test vector decomposition and clustering. Test vectors are decomposed and clustered for faults in an increasing order of faults detection count. This clustering order gives more degree of freedom and results in better compaction. Experimental results demonstrate the effectiveness of the proposed approach in achieving higher compaction in a much more efficient CPU time than previous clustering-based test compaction approaches
A Stochastic Approach To Solving The Weight Setting Problem in OSPF Networks
Get PDFIn the world of Internetworks, to maintain a good connectivity of household, business and commercial computing, an exraordinary talent is important. Unpredictable dysfunction in its proper administration adds to the problems of this sophisticated network. One of the contributions in attempting to maintain the proper functioning of internetworking is made by the Open Shortest Path First (OSPF) protocol. It is a link state protocol designed to overcome the gap created by the Routing Information Protocol (RIP) in the internetworking domain. OSPF calculates the shortest paths from each source to all destinations using the Dijkstra’s algorithm based on the weights assigned to the links. In the past, various attempts have been made to resolve the congestion issues of Traffic Engineering. With such complex issues in the frameset, assigning weights to these large networks, resulting in the best cost is an NP-hard problem. In this thesis, a prudent approach of mitigating the mentioned problem by using a Stochastic Evolution (StocE) heuristic is used which provides a close to optimal solution to these kinds of problems. Through this work, an attempt has been made to optimize the weights on the network so as to minimize congestion. This approach is well supported by the results embedded towards the end of the work. Another core issue addressed in this work is the improvement of the network by considering single link failure scenarios. Two innovative strategies have been developed, where the same set of optimized weights for both topologies, i.e., with-link and without-link-failure, have been considered
Effective Parallelization of Stochastic Evolution
No full textThe paper discusses the parallelization of Stochastic Evolution metaheuristic, identifying effective parallel strategies for a distributed parallel environment. Multiobjective VLSI cell placement is used as the optimization problem. A comprehensive set of parallelization approaches are tested and an effective strategy is identified in terms of two underlying principles: effective workload division and the effect of parallelization on metaheuristic’s search intelligence. The strategies are compared with another similar evolutionary metaheuristic called Simulated Evolution and the interrelation between effective parallelization and algorithm’s intelligence is highlighted using effective parallelization of stochastic evolution, the parallelized version of which has not been presented before
FRESH-DFE: A New Structure for Interference Cancellation
Get PDFThis paper proposes a new structure of decision feedback equalizer that exploits the cyclostationary properties of digitally modulated signals to mitigate interference. In the proposed structure, the forward filter of the conventional DFE is replaced by a cyclic filter. It is assumed that the desired and the interference signals use some mutually different signaling attributes, for example symbol rates, centre frequency etc. The resulting structure is evaluated in the presence of up to six strong interfering signals, a scenario that is typically found in wireless cellular systems. The proposed structure provides performance gains for some modulation formats but it reduces to the conventional DFE for other signal formats
Power Line Communications: An Overview - Part I
Get PDFWe give an overview of the power line communications (PLC) technology, its importance, its standards and an overview of the HomePlug standards associated with it. This is done is two parts due to publication constraints. In this part, we will concentrate on the PLC applications and the technical issues regarding it. We will also see the layers and methods that are needed to make it work