Post on 05-Jan-2016
description
Opportunity-based Topology Control in Wireless Sensor Networks
Date: 2009.12.30Speaker: Chang, Chien-Yang
IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS ||||
Outline Introduction Related Work System Model CONREAP Performance Evaluation Conclusion
Introduction Topology control is an effective method to improve the energy efficiency of wireless sensor networks (WSNs)
connectivity-based topology control reliable links
opportunity-based topology control lossy link reliable links
Related Work Connectivity-based topology control Cone-Based Topology Control (CBTC)
System Model Assumptions
individual link reachability is available the link reachability is fixed the link reach ability is pretty stable (not asymmetric) the node is stationary only sink-to-sensors communications
Without consideration do not consider the node failure no node sleeping is considered in this work. no congestion or packet collision is considered either.
Motivation
Problems Reachability Preserving Problem ( RPP)
data-critical applications to minimize the energy cost while guaranteeing that the network reachability is no less than a given threshold
Energy Preserving Problem long-term monitoring to maximize the network reachability while guaranteeing that the network energy cost is no greater than a given threshold
Efficiency Maximization Problem no constraint on energy or network reachability to maximize the reachability-energy ratio
Basic Idea Reachability Preserving Problem
Greedy algorithm
CONREAP Initially, v broadcasts a “Hello” message and initials its neighbor set Nbv
CONREAP Step2. from the known λTi (u), v selects a node ui that provides v the highest tree reachability λTi (v) as its parent node in the tree
0.80.4
0.2
0.9
CONREAP Step3. node v selects the tree with the highest λTi (v) to join,
denoted as
and
CONREAP Step4. Upon receiving the Nbv node reachability, v updates avg(˜λGR(v))
Until
Performance Evaluation Experiment parameters
50 Berkeley Mica2 nodes uniformly deployed transmission power: -10dbm maximal distance: 5 hops link reachability is measured using 1000 “Hello” messages receivers continuously measure the link quality and piggyback the results to senders
Performance Evaluation Experiment results
Performance Evaluation Simulation parameters
evaluate CONREAP in a large scale of 200 nodes fixed-size field of 300m × 300m 1/9 of the simulated wireless links are reliable the other 8/9 are lossy links
Performance Evaluation Simulation results
Conclusion We propose a novel opportunity-based topology control We focus on the reachability preserving problem
this problem is NP-hard we propose CONREAP algorithm by exploring reliability theory we prove that CONREAP has the guaranteed network reachability and the energy cost can be significantly reduced the worst running time is O(|E|) and the space requirement is O(d)