Data Aggregation with Fast Convergecasting in Wireless Sensor Networks

Abstract

Wireless Sensor Networks (WSN) is collection of small sized nodes. These networks have gained popularity lately because of their self organizing nature and ease of deployment. Data collection from multiple nodes known as convergecast is one of the main functions of Wireless Sensor Networks. Aggregation is performed to conserve energy, which is very dear since the size of nodes is very small and so is their battery capacity. Lots of applications demand fast data delivery, which can be obtained by parallelizing communication among nodes. But, there are factors like interfering links, half duplex transceivers, topology of the network that play as spoil sport. It is shown that with the use of multiple frequencies the parallelism in communication can be e ectively employed. That does not give the freedom to use unlimited frequencies. The numbers of frequencies which can be used in WSN are limited because of limitations of communication hardware so the nodes which use the same frequency are further assigned time slots to e ciently use the channel assigned to them. We have used di erent frequency allocation schemes to show their in uence on latency. When multiple frequencies and Time Division Multiple Access (TDMA) techniques are used the latency becomes a function of topology. For di erent topology with same number of nodes the time required for the convergecast process also varies. Schedule length is obtained by applying di erent frequency allocation schemes on di erent tree topologies. Later, the obtained schedule length is compared.