  UAV networks often partition into separated clusters due to the high node and
link dynamic. As a result, network connectivity recovery is an important issue
in this area. Existing solutions always need excessive movement of nodes and
thus lead to low recovery efficiency in terms of the time and energy
consumption. In this paper, we for the first time study the issue of how to
utilize cooperative communication technology to improve the connectivity
recovery efficiency in UAV networks. We propose a Cooperative Communication
based Connectivity Recovery algorithm for UAV Networks, named C3RUN. The key
novelty is C3RUN not only uses cooperative communication to enlarge node's
communication range and thus achieve quick repair of network connectivity, but
also enables nodes to proactively move to better places for ensuring the
establishment of cooperative communication links. We conduct extensive
simulations to evaluate the performance of C3RUN. The simulation results reveal
that C3RUN can not only achieve connectivity recovery with less nodes and
shorter distance to move, but also always finish recovery with less time, when
comparing with existing work. Furthermore, C3RUN can achieve 100% success ratio
for connectivity recovery.
