  Mobile micro-cloud is an emerging technology in distributed computing, which
is aimed at providing seamless computing/data access to the edge of the network
when a centralized service may suffer from poor connectivity and long latency.
Different from the traditional cloud, a mobile micro-cloud is smaller and
deployed closer to users, typically attached to a cellular basestation or
wireless network access point. Due to the relatively small coverage area of
each basestation or access point, when a user moves across areas covered by
different basestations or access points which are attached to different
micro-clouds, issues of service performance and service migration become
important. In this paper, we consider such migration issues. We model the
general problem as a Markov decision process (MDP), and show that, in the
special case where the mobile user follows a one-dimensional asymmetric random
walk mobility model, the optimal policy for service migration is a threshold
policy. We obtain the analytical solution for the cost resulting from arbitrary
thresholds, and then propose an algorithm for finding the optimal thresholds.
The proposed algorithm is more efficient than standard mechanisms for solving
MDPs.
