  By allowing a mobile device to offload computation-intensive tasks to a base
station, mobile edge computing (MEC) is a promising solution for saving the
mobile device's energy. In real applications, the offloading may span multiple
fading blocks. In this paper, we investigate energy-efficient offloading over
multiple fading blocks with random channel gains. An optimization problem is
formulated, which optimizes the amount of data for offloading to minimize the
total expected energy consumption of the mobile device. Although the formulated
optimization problem is non-convex, we prove that the objective function of the
problem is piecewise convex, and accordingly develop an optimal solution for
the problem. Numerical results verify the correctness of our findings and the
effectiveness of our proposed method.
