Sensor devices and the emergent networks that they enable are capable of transmitting information
between data sources and a permanent data sink. Since these devices have low-power and intermittent
connectivity, latency of the data may be tolerated in an effort to save energy for certain classes of data.
The BUBBLE routing algorithm developed by Hui et al. in 2008 provides consistent routing by employing a
model which computes individual nodes popularity from sets of nodes and then uses these popularity values
for forwarding decisions. This thesis considers enhancements to BUBBLE based on the hypothesis that nodes
do form groups and certain centrality values of nodes within these groups can be used to improve routing
decisions further.
Built on this insight, there are two algorithms proposed in this thesis. First is the Community-Based-
Forwarding (CBF), which uses pairwise group interactions and pairwise node-to-group interactions as a
measure of popularity for routing messages. By having a different measure of popularity than BUBBLE,
as an additional factor in determining message forwarding, CBF is a more conservative routing scheme
than BUBBLE. Thus, it provides consistently superior message transmission and delivery performance at an
acceptable delay cost in resource constrained environments.
To overcome this drawback, the concept of unique interaction pattern within groups of nodes is introduced
in CBF and it is further renewed into an enhanced algorithm known as Hybrid-Community-Based-
Forwarding (HCBF). Utilizing this factor will channel messages along the entire path with consideration
for higher probability of contact with the destination group and the destination node.
Overall, the major contribution of this thesis is to design and evaluate an enhanced social based routing
algorithm for resource-constrained Pocket Switched Networks (PSNs), which will optimize energy consumption
related to data transfer. It will do so by explicitly considering features of communities in order to reduce
packet loss while maintaining high delivery ratio and reduced delay
