  Virtual reality (VR) over wireless is emerging as an important use case of 5G
networks. Immersive VR experience requires the delivery of huge data at
ultra-low latency, thus demanding ultra-high transmission rate. This challenge
can be largely addressed by the recent network architecture known as mobile
edge computing (MEC), which enables caching and computing capabilities at the
edge of wireless networks. This paper presents a novel MEC-based mobile VR
delivery framework that is able to cache parts of the field of views (FOVs) in
advance and run certain post-processing procedures at the mobile VR device. To
optimize resource allocation at the mobile VR device, we formulate a joint
caching and computing decision problem to minimize the average required
transmission rate while meeting a given latency constraint. When FOVs are
homogeneous, we obtain a closed-form expression for the optimal joint policy
which reveals interesting communications-caching-computing tradeoffs. When FOVs
are heterogeneous, we obtain a local optima of the problem by transforming it
into a linearly constrained indefinite quadratic problem then applying concave
convex procedure. Numerical results demonstrate great promises of the proposed
mobile VR delivery framework in saving communication bandwidth while meeting
low latency requirement.
