Mobile phone users are typically expected to be part of several social gatherings
during the day at different places i.e. home, workplace, and even while commuting
[110]. It is likely that a person will encounter (meet) mostly the same people
at these frequently visited places across different days. With the proliferation of
localization technologies, these encounters can be detected automatically and can be
used for opportunistic content sharing using mobile phones. For instance, Figure 4.1
shows encounter pattern among a pair of users, inferred using our self-collected WiFi
data. It can be clearly seen that the two users spent a lot of time together across
different days of the week, e.g. 12 : 00 to 19 : 00 across Day 3, 4 and 5, which can
be utilized for content sharing.
In this chapter, we describe two different systems which uses location information
to enable opportunistic communication among mobile phone users. First of these
systems, MobiShare facilitates searching and local sharing of content using mobile
phones. It is based on a hybrid architecture that uses a central entity i.e. the Cloud