  Mobile virtual reality (VR) delivery is gaining increasing attention from
both industry and academia due to its ability to provide an immersive
experience. However, achieving mobile VR delivery requires ultra-high
transmission rate, deemed as a first killer application for 5G wireless
networks. In this paper, in order to alleviate the traffic burden over wireless
networks, we develop an implementation framework for mobile VR delivery by
utilizing caching and computing capabilities of mobile VR device. We then
jointly optimize the caching and computation offloading policy for minimizing
the required average transmission rate under the latency and local average
energy consumption constraints. In a symmetric scenario, we obtain the optimal
joint policy and the closed-form expression of the minimum average transmission
rate. Accordingly, we analyze the tradeoff among communication, computing and
caching, and then reveal analytically the fact that the communication overhead
can be traded by the computing and caching capabilities of mobile VR device,
and also what conditions must be met for it to happen. Finally, we discuss the
optimization problem in a heterogeneous scenario, and propose an efficient
suboptimal algorithm with low computation complexity, which is shown to achieve
good performance in the numerical results.
