  Edge caching and computing have been regarded as an efficient approach to
tackle the wireless spectrum crunch problem. In this paper, we design a general
coded caching with device computing strategy for content computation, e.g.,
virtual reality (VR) rendering, to minimize the average transmission bandwidth
with the caching capacity and the energy constraints of each mobile device, and
the maximum tolerable delay constraint of each task. The key enabler is that
because both coded data and stored data can be the data before or after
computing, the proposed scheme has numerous edge computing and caching paths
corresponding to different bandwidth requirement. We thus formulate a joint
coded caching and computing optimization problem to decide whether the mobile
devices cache the input data or the output data, which tasks to be coded cached
and which tasks to compute locally. The optimization problem is shown to be 0-1
nonconvex nonsmooth programming and can be decomposed into the computation
programming and the coded caching programming. We prove the convergence of the
computation programming problem by utilizing the alternating direction method
of multipliers (ADMM), and a stationary point can be obtained. For the coded
cache programming, we design a low complexity algorithm to obtain an acceptable
solution. Numerical results demonstrate that the proposed scheme provides a
significant bandwidth saving by taking full advantage of the caching and
computing capability of mobile devices.
