  360{\deg} video is attracting an increasing amount of attention in the
context of Virtual Reality (VR). Owing to its very high-resolution
requirements, existing professional streaming services for 360{\deg} video
suffer from severe drawbacks. This paper introduces a novel end-to-end
streaming system from encoding to displaying, to transmit 8K resolution
360{\deg} video and to provide an enhanced VR experience using Head Mounted
Displays (HMDs). The main contributions of the proposed system are about
tiling, integration of the MPEG-Dynamic Adaptive Streaming over HTTP (DASH)
standard, and viewport-aware bitrate level selection. Tiling and adaptive
streaming enable the proposed system to deliver very high-resolution 360{\deg}
video at good visual quality. Further, the proposed viewport-aware bitrate
assignment selects an optimum DASH representation for each tile in a
viewport-aware manner. The quality performance of the proposed system is
verified in simulations with varying network bandwidth using realistic view
trajectories recorded from user experiments. Our results show that the proposed
streaming system compares favorably compared to existing methods in terms of
PSNR and SSIM inside the viewport.
