In this paper an improved version of the graded precision localizationalgorithm GRADELOC, called IGRADELOC is proposed. The performance of GRADELOCis dependent on the regions formed by the overlapping radio ranges of the nodesof the underlying sensor network. A different region pattern couldsignificantly alter the nature and precision of localization. In IGRADELOC, twoimprovements are suggested. Firstly, modifications are proposed in the radiorange of the fixed-grid nodes, keeping in mind the actual radio range ofcommonly available nodes, to allow for routing through them. Routing is notaddressed by GRADELOC, but is of prime importance to the deployment of anyadhoc network, especially sensor networks. A theoretical model expressing theradio range in terms of the cell dimensions of the grid infrastructure isproposed, to help in carrying out a deployment plan which achieves thedesirable precision of coarse-grained localization. Secondly, in GRADELOC it isobserved that fine-grained localization does not achieve significantperformance benefits over coarse-grained localization. In IGRADELOC, thisfactor is addressed with the introduction of a parameter that could be used toimprove and fine-tune the precision of fine-grained localization.
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