  The ultra-dense small cell networks (SCNs) have been regarded as a promising
technology to solve the data traffic explosion in future. However, the
complicated relationships among large scale users and cells practically demand
a cooperative grouping mechanism to account for the shortage of resources in
SCNs. Then, a group buying market mechanism provides a win-win situation and an
effective resource allocation in the view of economics. With additional
decision information being provided, the context awareness enhances and
improves the group buying mechanism. In this article, we propose a
Context-Aware Group Buying (CAGB) mechanism to allocate the resources in
ultra-dense SCNs. The feasibility, necessity, and effectiveness of CAGB are
analyzed first. Then, we introduce the group buying mechanism and some common
context awareness. The relationship between context awareness and group buying
is also analyzed. Some important technologies in SCNs are discussed in the view
of CAGB, such as load balancing, spectrum management, and cooperative caching.
Then, the graphical coalition formation games (CFGs) of CAGB are also presented
to match the complicated network topologies in SCNs. Two CAGB-based use cases
about spectrum market and cooperative caching are presented. Finally, future
research issues about context awareness, grouping mechanism, and buying
mechanism are discussed.
