Title :
Data aggregation at the gateways through sensors´ tasks scheduling in wireless sensor networks
Author :
Habib, Sami J. ; Marimuthu, Paulvanna N.
Author_Institution :
Comput. Eng. Dept., Kuwait Univ., Safat, Kuwait
fDate :
9/1/2011 12:00:00 AM
Abstract :
The authors present a novel graph-based model for aggregating sensors´ data at the gateways within wireless sensor networks (WSNs), where the proposed graph can act as a mean of guiding and assessing the needed resources for data aggregation. In this study, the authors have modelled all sensors´ tasks in a graph so that their collected data are to be smoothly aggregated (scheduled) at the gateway without losing or overlapping the collected data at the gateways. A typical WSN comprises of hundreds of sensors and few gateways; moreover, each sensor executes periodically and sequentially three tasks, which are sensing, processing and transmitting. The three tasks are modelled as a directed acyclic graph (DAG) per sensor, and then all DAGs are grouped into a super task-flow-graph (STFG). The data aggregation problem is solved by scheduling the tasks within STFG, where the authors have utilised three scheduling algorithms: as soon as possible, as late as possible and branch-and-bound. The simulation results for 50 sensors covering an area of 10´000´m2 utilising deterministic and stochastic execution models show a requirement of eight and six gateways, respectively, with minimal waiting time for aggregating the collected data from sensors to the gateways.
Keywords :
graph theory; scheduling; wireless sensor networks; DAG; STFG; WSN; data aggregation problem; directed acyclic graph; gateway; graph-based model; sensor task scheduling algorithm; stochastic execution model; super task-flow-graph; wireless sensor network;
Journal_Title :
Wireless Sensor Systems, IET
DOI :
10.1049/iet-wss.2011.0057