Connectivity Analysis of Large-Scale Wireless Ad Hoc Networks with Heterogeneous Nodes

ABSTRACT: Research in large-scale ad hoc and wireless sensor networks (WSNs) has developed rapidly due to the large number of applications in environmental monitoring, structure health monitoring, contaminant detection, industrial process control, and military target tracking. The nodes in WSNs communicate in a multi-hop fashion to deliver the sensed data to a unit called the sink. Communication requires network connectivity that might not be possible all of the time due to sensor deployment strategy or node failure. Hence, connectivity can be considered as an essential requirement in WSNs, because without having a connected network, not all of the nodes will be reachable to transmit information. This thesis has studied the problem of evaluating the connectivity in WSNs for a given number and given transmission ranges of nodes. Comparisons are carried out to evaluate the connectivity by using two different deployment strategies: deployment of homogeneous sensor nodes (in terms of transmission range) and heterogeneous sensor nodes. In particular, the connectivity of a WSN network with two types of nodes is analyzed. A distinct feature of the study presented is the modeling of the network as a directed graph. Phase transition behavior of connectivity that is observed in homogeneous deployments is also apparent in networks with heterogeneous deployments where the networks are modeled as directed graphs. It is established through a large set of simulations that networks with homogeneous node deployments provide higher connectivity for a given power budget. These results are consistent with previous related findings that use undirected graphs for modeling networks. Keywords: Ad Hoc Networks, Wireless Sensor Networks, Network Connectivity, Phase Transitions. ……………………………………………………………………………………………………………………………………………………………………………………………………………………