  Communication technology is a major contributor to our lifestyles. Improving
the performance of communication system brings with various benefits to human
beings. This report covers two typical such systems: wireless sensor networks
and cellular networks. We study the influence of mobility in these networks. In
wireless sensor networks, we consider the usage of mobile sinks to collect
sensory data from static nodes. For the latter case, we design data collection
protocols for a single mobile sink which aim at balancing the energy
consumption among sensor nodes to improve the network lifetime. We also design
an algorithm for multiple mobile sinks to collect urgent sensory information
within the allowed latency. Regarding the mobility in cellular networks, we
mean the service providers are mobile. Conventional approaches usually consider
how to optimally deploy static base stations according to a certain metric,
such as throughput. Base station densification is a solution, but it is not
cost efficient. Introducing mobility is to let the base stations fly in the
sky, resulting in less investment. We consider one of the key issues of using
drones to serve cellular users: drone deployment. We have implemented all the
proposed algorithms by either simulations or experiments, and the results have
confirmed the effectiveness of these approaches.
