2 research outputs found
Minimum Power Range Assignment for Symmetric Connectivity in Sensor Networks with two Power Levels
This paper examines the problem of assigning a transmission power to every
node of a wireless sensor network. The goal is to minimize the total power
consumption while ensuring that the resulting communication graph is connected.
We focus on a restricted version of this Range Assignment (RA) problem in which
there are two different power levels. We only consider symmetrical transmission
links to allow easy integration with low level wireless protocols that
typically require bidirectional communication between two neighboring nodes. We
introduce a parameterized polynomial time approximation algorithm with a
performance ratio arbitrarily close to . Additionally, we give an
almost linear time approximation algorithm with a tight quality bound of
Parameterized Algorithms for Power-Efficiently Connecting Wireless Sensor Networks: Theory and Experiments
We study an NP-hard problem motivated by energy-efficiently maintaining the
connectivity of a symmetric wireless communication network: Given an
edge-weighted -vertex graph, find a connected spanning subgraph of minimum
cost, where the cost is determined by letting each vertex pay the most
expensive edge incident to it in the subgraph. On the negative side, we show
that -approximating the difference between the optimal solution
cost and a natural lower bound is NP-hard and that, under the Exponential Time
Hypothesis, there are no exact algorithms running in time or in
time for any computable function . Moreover, we show
that the special case of connecting network components with minimum
additional cost generally cannot be polynomial-time reduced to instances of
size unless the polynomial-time hierarchy collapses. On the positive
side, we provide an algorithm that reconnects connected components
with minimum additional cost in polynomial time. These algorithms are motivated
by application scenarios of monitoring areas or where an existing sensor
network may fall apart into several connected components due to sensor faults.
In experiments, the algorithm outperforms CPLEX with known ILP formulations
when is sufficiently large compared to .Comment: Additional experiments, lower bounds strengthened to metric case,
added kernelization lower bound