Supporting Mobile VR in LTE Networks: How Close Are We?

Mobile virtual reality (VR) headsets (e.g., Google Cardboard and Samsung Gear VR) seek to offer "anytime, anywhere" panorama, immerse 3D experiences for users. In this work, we study the viability of supporting mobile VR over operational 4G LTE networks, where the device provides pose information to the edge servers to offload graphical processing. We find that, contrary to common perceptions, wireless bandwidth is not the latency bottleneck for medium-quality VR. Instead, the signaling operations, which facilitate wireless data delivery, constitute a bulk portion of the latency. We report findings that challenge five common beliefs on VR network latency in LTE under both static and mobile scenarios, and quantify their impact. We design LTE-VR, a client-side solution to medium-quality VR over LTE. LTE-VR leverages cross-layer design and rich side channel information to reduce various latency sources in the signaling operations. Our prototype evaluation has confirmed its viability in 4G LTE. We discuss its applicability to the upcoming 5G.