In recent times, the growth of mobile devices (especially smartphones) is phenomenal.
These devices support Bluetooth and Wifi connectivity. Further, they are equipped
with good computing power and memory. Because of this, an entirely new network
paradigm has emerged in which encounters between these mobile devices can be exploited
for opportunistic data transfer without using any fixed network infrastructure[5]. This
opportunistic network paradigm is called Pocket Switched Network (PSN) as we carry
smartphones in our pockets. Message broadcast, news spread, traffic updates, microblogging
and peer-to-peer file sharing are some of the applications which can run on such
type of network. Further, it can significantly offload infrastructure based networks such
as cellular network and infrastructure based Wifi network and reduce data cost for users
considerably[6].
As these devices are carried by humans, their encounter patterns depend on human
mobility patterns. Thus, knowledge of human movement behaviour and social structure
can be exploited for efficient peer-to-peer communication[7, 8]. As a result, this network
paradigm is also called Mobile Social Network (MSN).
