Rendering-Aware VR Video Caching Over Multi-Cell MEC Networks

Delivering high fidelity virtual reality (VR) video over mobile networks is very challenging since VR applications usually require very high bandwidth and ultra low latency. With the evolution of 5G mobile networks, multi-cell multi-access edge computing (MEC) networks enable low latency data communication. However, even in this setting, the requirements of VR applications are tough to meet. To optimize the end-to-end latency for VR video delivery over multi-cell MEC networks, we propose a rendering-aware tile caching scheme. As a first step we propose collaborative tile caching in 5G MEC networks by enabling multiple cell sites to share caches so that the network caching performance is improved. Hence, the amount of redundant data delivered and eventually the latency are both significantly reduced. Second, our scheme offloads viewport rendering of VR video to the MEC server and closely couples this with cache placement, allowing thus the rendering-induced latency to be reduced. Finally, a low-delay request routing algorithm is integrated with the proposed cache placement scheme to further optimize the end-to-end latency of VR video delivery. Extensive simulation results show that the proposed rendering-aware caching scheme can achieve better latency performance than the state-of-the-art decoupled caching/rendering schemes.