Device cooperation-assisted scalable video multicast with heterogeneous QoE guarantees

This paper proposes a device cooperation-assisted solution for efficient quality-of-experience (QoE)-differentiated scalable video multicast. The proposed solution targets a group of co-located user equipments (UEs) with heterogeneous QoE requirements that are able to cooperate with each other through direct device-to-device (D2D) short-range communication to receive the same scalable multicast video stream. Content delivery to the group of UEs under consideration occurs in two phases, namely, a multicast phase where multiple video source layers are fountain encoded and mapped to hierarchical quadrature amplitude modulation (H-QAM) symbols of varying robustness levels, followed by a cooperation phase where UEs within the multicast group use their D2D connections to help their neighbors achieve their respective QoE targets. Three main features characterize the proposed UE cooperation-assisted scalable video multicast solution: (i) hierarchical modulation is used at the physical layer to provide unequal error protection for the different layers of the scalable video stream while guaranteeing some basic quality of service for most UEs in the multicast group, (ii) UE cooperation through D2D communications is used to meet heterogeneous QoE requirements, and (iii) different video source layers are fountain encoded during both multicast and cooperation phases in order to minimize the cooperation overhead required to ensure heterogeneous QoE guarantees.