1 research outputs found
Analysis and Optimization of Service Delay for Multi-quality Videos in Multi-tier Heterogeneous Network with Random Caching
Aiming to minimize service delay, we propose a new random caching scheme in
device-to-device (D2D)-assisted heterogeneous network. To support diversified
viewing qualities of multimedia video services, each video file is encoded into
a base layer (BL) and multiple enhancement layers (ELs) by scalable video
coding (SVC). A super layer, including the BL and several ELs, is transmitted
to every user. We define and quantify the service delay of multi-quality videos
by deriving successful transmission probabilities when a user is served by a
D2D helper, a small-cell base station (SBS) and a macro-cell base station
(MBS). We formulate a delay minimization problem subject to the limited cache
sizes of D2D helpers and SBSs. The structure of the optimal solutions to the
problem is revealed, and then an improved standard gradient projection method
is designed to effectively obtain the solutions. Both theoretical analysis and
Monte-Carlo simulations validate the successful transmission probabilities.
Compared with three benchmark caching policies, the proposed SVC-based random
caching scheme is superior in terms of reducing the service delay.Comment: 13 pages, 8 figures, IEEE Systems Journal, Accepte