Abstract:
Latest development of electronic and communication technologies enabled Wireless Sensor
Networks (WSNs) deployed for data collection from an area of interest. The sensed data is then
aggregated and transmitted to the base station (sink), where the collected data is further processed
for end-user queries. With the increase of WSNs applications, there has been a growing demand for
gathering information from environments for an expected network lifetime. Since the sensor nodes
have limited power and it is impractical to replace the energy source of the nodes, an energy
efficient data gathering technique need to be design to shrinks the use of radio waves propagation to
ensure a desired lifetime. According to the co-operative modes of the sensor nodes, the most
popular data gathering techniques in WSNs are cluster-based, chain-based and tree-based. Due to
the minimum graph structure and for easy implementation, we consider tree topology based
algorithms in our research work. However, most of the existing tree based schemes introduce lower
energy bottleneck nodes as intermediate nodes making them overburden during tree construction,
shortening the lifetime of the network. To solve the overburden nodes problem, other categories of
algorithms perform a load balancing operation to decrease the load of bottleneck nodes. In this
thesis, we propose two load balancing tree based data gathering schemes. A mathematical model for
load calculation and nodes categorized are also proposed for both the schemes. The first algorithm
“Energy aware bottleneck node avoidance data gathering tree (EBA-DG)” is proposed to construct
a load balance tree to gather data from environment. Considering the transmission cost with node
degree an energy-aware load balancing scheme named “Energy aware bottleneck nodes avoidance
shortest-path data gathering tree (EBASP-DG)” is also proposed. In EBASP-DG, a new data
structure called data gathering sequence (DGS) is also proposed for the benefits of constructing
tree. Theoretical analysis and simulation results show that both EBA-DG and EBASP-DG can
achieve better performance than the existing other schemes.
