  On-demand video accounts for the majority of wireless data traffic. Video
distribution schemes based on caching combined with device-to-device (D2D)
communications promise order-of-magnitude greater spectral efficiency for video
delivery, but hinge on the principle of `concentrated demand distributions.'
This paper presents, for the first time, the analysis and evaluations of the
throughput--outage tradeoff of such schemes based on measured cellular demand
distributions. In particular, we use a dataset with more than 100 million
requests from the BBC iPlayer, a popular video streaming service in the U.K.,
as the foundation of the analysis and evaluations. We present an achievable
scaling law based on the practical popularity distribution, and show that such
scaling law is identical to those reported in the literature. We find that also
for the numerical evaluations based on a realistic setup, order-of-magnitude
improvements can be achieved. Our results indicate that the benefits promised
by the caching-based D2D in the literature could be retained for cellular
networks in practice.
