A cross-layer interworking of DVB-T and WLAN for mobile IPTV service delivery

The convergence between existing and emerging technologies such as broadband, mobile, and broadcast networks is considered as a promising opportunity for existing network operators to increase theirs services' audiences. An important research effort is undertaken by main industry actors to face the multidimensional (transport technology, session signaling, and QoS provisioning) heterogeneity in the Next Generation Network (NGN). The per-session service adaptation is crucial to accommodate terminal and network heterogeneity experienced by different mobile users. In this paper, we investigate an intermediate architecture based on interconnection of DVB-T and 802.11 WLAN networks. The 802.11 WLAN is considered today as the "de-facto" wireless access network for the last miles connection. Both its per-service cost-effectiveness and wide acceptation by users make it an ideal candidate to bridge existing broadcast TV services toward the end-users. We propose a seamless cross-layer inter-working between broadcasting network (i.e. DVB-T) and 802.11 WLAN network for adaptive and interactive mobile TV service delivery. We use a specific Adaptation Gateway (AG) at each Access Network to perform media adaptations. AG features a joint channel and video bit-rate awareness to tackle link degradations (signal strength quality, packet loss, etc.). Performance evaluations using an experimental test-bed are conducted and they show that our proposed, cross-layer adaptation gateway reduces considerably packet losses and enhances the perceived quality of the TV service. By independently adapting each individual service, it is possible to address network and terminal heterogeneity and to offer interactive and personalized service to the end users.