A Cooperative Caching and Computing-Offloading Method for 3C Trade-Off in VR Video Services

Virtual reality (VR) video services are becoming increasingly popular in Internet of Things (IoT) owing to its immersive experience. The realization of immersive experience relies on extremely large amount of data transmitted, restricting its application. To meet the transmission requirement of VR video services, this paper designs a user-centric network based on the mobile edge computing (MEC) framework, where the 2D/3D field of view (FOV) files can be cached and the projection process from 2D FOV to 3D FOV can be computed at the VR device or MEC servers collaboratively. Based on this, a cooperative caching and computing-offloading strategy is formulated as a decision matrix, and its optimal closed-form expression is obtained by minimizing the transmission requirement under the strict service time constraint to realize the trade-off between communication, caching and computing (3C trade-off). Besides, the effect of the transmission requirement on the network density is also analyzed to provide useful guidelines for network design. Simulation results demonstrate that the proposed method can achieve quasi-optimal performance compared with other contrasting schemes.