A Hierarchical Update Buffer Management for 360Degree Video Streaming Virtual reality can provide users with immersive experience. However, because of its high requirement of bandwidth, it is still challenge to transmit 360degree video. To overcome this issue, tilebased VR transmission strategy was proposed to reduce the data by dividing the 360degree video into several tiles and streaming corresponding tiles according to userxe2x80x99s viewport. While the prediction accuracy is only guaranteed in a short time and it may cause frequent rebuffering when the network fluctuates, twotier buffer system was proposed to tackle this problem. Nevertheless the twotier method doesnxe2x80x99t consider the switching frequency of rate in userxe2x80x99s viewport. In this paper, we propose a novel hierarchical update buffer management method by jointly considering the probability of rebuffering and the switching frequency of rate in FoV to improve userxe2x80x99s QoE. The simulation results show that our proposed algorithm outperforms other methods in proving the smoothness of the viewing experience.

QoEDriven Resource Allocation Optimized for DelaySensitive VR Video Uploading over Cellular Network Uploading Virtual Reality (VR) video over cellular networks is expected to boom in near future, as general consumers could generate highquality VR videos with portable 360degree cameras and are willing to share with others. Consequently, concerns of uplink bandwidth and delay arose for current popular technology of tilebased VR video streaming, which requires high quality video to transcode into multiple representations for further adaptive streaming. Motivated by this, we proposed a novel scheme for uplink delivery of tilebased VR video over cellular network, in which encoding bit rate of each tile is determined by uplink resource allocation (RA), and quality of content (QoC) contribution of each tile and channel quality of user equipments (UEs) are jointly considered during RA. Moreover, the RA problem is formulated as a frequency and time dependent nondeterministic polynomial(NP)hard problem, which can be effectively solved by our proposed approximate convex algorithm. Simulation results show that the proposed algorithm can achieve higher utility, that is higher total quality of experience (QoE) for viewers.