Power Assignment Problems in Wireless Communication: Covering Points by Disks, Reaching few Receivers Quickly, and Energy-Efficient Travelling Salesman Tours

  • Authors:
  • Stefan Funke;Sören Laue;Rouven Naujoks;Zvi Lotker

  • Affiliations:
  • Max-Planck-Institut für Informatik, Saarbrücken, Germany;Max-Planck-Institut für Informatik, Saarbrücken, Germany;Max-Planck-Institut für Informatik, Saarbrücken, Germany;Ben Gurion University, Beer Sheva, Israel

  • Venue:
  • DCOSS '08 Proceedings of the 4th IEEE international conference on Distributed Computing in Sensor Systems
  • Year:
  • 2008

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Abstract

A fundamental class of problems in wireless communication is concerned with the assignment of suitable transmission powers to wireless devices/stations such that the resulting communication graph satisfies certain desired properties and the overall energy consumed is minimized. Many concrete communication tasks in a wireless network like broadcast, multicast, point-to-point routing, creation of a communication backbone, etc. can be regarded as such a power assignment problem.This paper considers several problems of that kind; the first problem was studied before in [1,6] and aims to select and assign powers to kout of a total of nwireless network stations such that all stations are within reach of at least one of the selected stations. We show that the problem can be (1 + 茂戮驴) approximated by only looking at a small subset of the input, which is of size , i.e. independent of nand polynomial in kand 1/茂戮驴. Here ddenotes the dimension of the space where the wireless devices are distributed, so typically d≤ 3 and describes the relation between the Euclidean distance between two stations and the power consumption for establishing a wireless connection between them. Using this coresetwe are able to improve considerably on the running time of $n^{((\alpha/\epsilon)^{O(d)})}$ for the algorithm by Bilo et al. at ESA'05 ([6]) actually obtaining a running time that is linearin n. Furthermore we sketch how outliers can be handled in our coreset construction.The second problem deals with the energy-efficient, bounded-hop multicast operation: Given a subset Cout of a set of nstations and a designated source node swe want to assign powers to the stations such that every node in Cis reached by a transmission from swithin khops. Again we show that a coreset of size independent of nand polynomial in k, |C|, 1/茂戮驴exists, and use this to provide an algorithm which runs in time linear in n.The last problem deals with a variant of non-metric TSP problem where the edge costs are the squared Euclidean distances; this problem is motivated by data aggregation schemes in wireless sensor networks. We show that a good TSP tour under Euclidean edge costs can be very bad in the squared distance measure and provide a simple constant approximation algorithm, partly improving upon previous results in [5], [4].