Viewpoint-Switching Delay of Multi-viewpoint 360 VR in a Bandwidth-limited Environment

The transmission of multi-view or free-view 360VR contents, which selects the viewer's viewpoint and experiences 360VR contents, consumes a very large bandwidth. In a cellular environment in which multiple users exist, only a limited bandwidth can be allocated to a specific user, and thus transmission quality is inevitably deteriorated or transmission delay occurs. In the case of multi-viewpoint 360VR content, if the viewer changes the position of the viewpoint, the contents of the corresponding position are transmitted. In a bandwidth-limited communication environment, a large transmission delay occurs when the viewpoint is moved, resulting in a very poor user experience. In this paper, in order to reduce the transmission delay when attempting to change the viewpoint in a multi-view 360 video, a transmission method of appropriately pre-loading the video of the surrounding location is considered. In addition, the delay performance according to the viewpoint change was analyzed in a practical 5G network environment. In order to lower the viewpoint switching delay below a certain level, an appropriate prediction technique for the user movement pattern is required, and the decrease in the delay in accordance with the accuracy is presented through an experiment.