918 research outputs found
A survey of localization in wireless sensor network
Localization is one of the key techniques in wireless sensor network. The location estimation methods can be classified into target/source localization and node self-localization. In target localization, we mainly introduce the energy-based method. Then we investigate the node self-localization methods. Since the widespread adoption of the wireless sensor network, the localization methods are different in various applications. And there are several challenges in some special scenarios. In this paper, we present a comprehensive survey of these challenges: localization in non-line-of-sight, node selection criteria for localization in energy-constrained network, scheduling the sensor node to optimize the tradeoff between localization performance and energy consumption, cooperative node localization, and localization algorithm in heterogeneous network. Finally, we introduce the evaluation criteria for localization in wireless sensor network
Distributed Recognition of Reference Nodes for Wireless Sensor Network Localization
All known localization techniques for wireless sensor and ad-hoc networks require certain set of reference nodes being used for position estimation. The anchor-free techniques in contrast to anchor-based do not require reference nodes called anchors to be placed in the network area before localization operation itself, but they can establish own reference coordinate system to be used for the relative position estimation. We observed that contemporary anchor-free localization algorithms achieve a low localization error, but dissipate significant energy reserves during the recognition of reference nodes used for the position estimation. Therefore, we have proposed the optimized anchor-free localization algorithm referred to as BRL (Boundary Recognition aided Localization), which achieves a low localization error and mainly reduces the communication cost of the reference nodes recognition phase. The proposed BRL algorithm was investigated throughout the extensive simulations on the database of networks with the different number of nodes and densities and was compared in terms of communication cost and localization error with the known related algorithms such as AFL and CRP. Through the extensive simulations we have observed network conditions where novel BRL algorithm excels in comparison with the state of art
Reference Nodes Selection for Anchor-Free Localization in Wireless Sensor Networks
DizertaÄnĂ prĂĄce se zabĂ˝vĂĄ nĂĄvrhem novĂŠho bezkotevnĂho lokalizaÄnĂho algoritmu slouĹžĂcĂho pro vĂ˝poÄet pozice uzlĹŻ v bezdrĂĄtovĂ˝ch senzorovĂ˝ch sĂtĂch. ProvedenĂŠ studie ukĂĄzaly, Ĺže dosavadnĂ bezkotevnĂ lokalizaÄnĂ algoritmy, pracujĂcĂ v paralelnĂm reĹžimu, dosahujĂ malĂ˝ch lokalizaÄnĂch chyb. Jejich nevĂ˝hodou ovĹĄem je, Ĺže pĹi sestavenĂ mnoĹžiny referenÄnĂch uzlu spotĹebovĂĄvajĂ daleko vÄtĹĄĂ mnoĹžstvĂ energie neĹž algoritmy pracujĂcĂ v inkrementĂĄlnĂm reĹžimu. ParalelnĂ lokalizaÄnĂ algoritmy vyuĹžĂvajĂ pro urÄenĂ pozice referenÄnĂ uzly nachĂĄzejĂcĂ se na protilehlĂ˝ch hranĂĄch bezdrĂĄtovĂŠ sĂtÄ. NovĂ˝ lokalizaÄnĂ algoritmus oznaÄenĂ˝ jako BRL (Boundary Recognition aided Localization) je zaloĹžen na myĹĄlence decentralizovanÄ detekovat uzly leĹžĂcĂ na hranici sĂti a pouze z tĂŠto mnoĹžiny vybrat potĹebnĂ˝ poÄet referenÄnĂch uzlu. PomocĂ navrĹženĂŠho pĹĂstupu lze znaĹžnÄ snĂĹžit mnoĹžstvĂ energie spotĹebovanĂŠ v prĹŻbÄhu procesu vĂ˝bÄru referenÄnĂch uzlĹŻ v senzorovĂŠm poli. DalĹĄĂm pĹĂnosem ke snĂĹženĂ energetickĂ˝ch nĂĄroku a zĂĄroveĹ zachovĂĄnĂ nĂzkĂŠ lokalizaÄnĂ chyby je vyuĹžitĂ procesu multilaterace se tĹemi, eventuĂĄlnÄ ÄtyĹmi referenÄnĂmi body. V rĂĄmci prĂĄce byly provedeny simulace nÄkolika dĂlÄĂch algoritmu a jejich funkÄnost byla ovÄĹena experimentĂĄlnÄ v reĂĄlnĂŠ senzorovĂŠ sĂti. NavrĹženĂ˝ algoritmus BRL byl porovnĂĄn z hlediska lokalizaÄnĂ chyby a poÄtu zpracovanĂ˝ch paketĹŻ s nÄkolika znĂĄmĂ˝mi lokalizaÄnĂmi algoritmy. VĂ˝sledky simulacĂ dokĂĄzaly, Ĺže navrĹženĂ˝ algoritmus pĹedstavuje efektivnĂ ĹeĹĄenĂ pro pĹesnou a zĂĄroveĹ nĂzkoenergetickou lokalizaci uzlĹŻ v bezdrĂĄtovĂ˝ch senzorovĂ˝ch sĂtĂch.The doctoral thesis is focused on a design of a novel anchor free localization algorithm for wireless sensor networks. As introduction, the incremental and concurrent anchor free localization algorithms are presented and their performance is compared. It was found that contemporary anchor free localization algorithms working in the concurrent manner achieve a low localization error, but dissipate signicant energy reserves. A new Boundary Recognition Aided Localization algorithm presented in this thesis is based on an idea to recognize the nodes placed on the boundary of network and thus reduce the number of transmission realized during the reference nodes selection phase of the algorithm. For the position estimation, the algorithm employs the multilateration technique that work eectively with the low number of the reference nodes. Proposed algorithms are tested through the simulations and validated by the real experiment with the wireless sensor network. The novel Boundary Recognition Aided Localization algorithm is compared with the known algorithms in terms of localization error and the communication cost. The results show that the novel algorithm presents powerful solution for the anchor free localization.
Localisation in wireless sensor networks for disaster recovery and rescuing in built environments
A thesis submitted to the University of Bedfordshire in partial fulfilment of the requirements for the degree of Doctor of PhilosophyProgress in micro-electromechanical systems (MEMS) and radio frequency (RF) technology has fostered the development of wireless sensor networks (WSNs). Different from traditional networks, WSNs are data-centric, self-configuring and self-healing. Although WSNs have been successfully applied in built environments (e.g. security and services in smart homes), their applications and benefits have not been fully explored in areas such as disaster recovery and rescuing. There are issues related to self-localisation as well as practical constraints to be taken into account.
The current state-of-the art communication technologies used in disaster scenarios are challenged by various limitations (e.g. the uncertainty of RSS). Localisation in WSNs (location sensing) is a challenging problem, especially in disaster environments and there is a need for technological developments in order to cater to disaster conditions. This research seeks to design and develop novel localisation algorithms using WSNs to overcome the limitations in existing techniques. A novel probabilistic fuzzy logic based range-free localisation algorithm (PFRL) is devised to solve localisation problems for WSNs. Simulation results show that the proposed algorithm performs better than other range free localisation algorithms (namely DVhop localisation, Centroid localisation and Amorphous localisation) in terms of localisation accuracy by 15-30% with various numbers of anchors and degrees of radio propagation irregularity.
In disaster scenarios, for example, if WSNs are applied to sense fire hazards in building, wireless sensor nodes will be equipped on different floors. To this end, PFRL has been extended to solve sensor localisation problems in 3D space. Computational results show that the 3D localisation algorithm provides better localisation accuracy when varying the system parameters with different communication/deployment models. PFRL is further developed by applying dynamic distance measurement updates among the moving sensors in a disaster environment. Simulation results indicate that the new method scales very well
An Enhanced Table Driven Source Routing Protocol for Wireless Ad Hoc Networks
Analysis of MANETs led to the research on network layer. Different routing protocols were designed for numerous objectives and purposes. The way data packets are handled with in a multi-hop wireless network refers to Opportunistic data forwarding. During present research, we propose enhanced table-driven source routing protocol. This protocol maintains additional topology information which is different from Distance Vector (DV) routing protocol. The proposed approach will reduce overhead compared to the ancient Distance Vector based protocols. Base on the test results performed using Computer Simulator (Network Simulator 2) observed that the overhead in the proposed solution is just a fraction of the overhead of the standard proactive protocols. Performance of the current solution is better for transportation of higher information compared to existing proactive routing protocols
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