Today, the IPTV technology is emerging as a new concept for delivering and accessing audiovisual services over IP networks. To allow the transmission of IPTV services on wired and wireless networks, different issues should be overcome: scalability, QoS provisioning, security guaranty, and terminals heterogeneity. In this regards, there is a relation between QoS and security as both need to be carefully and tightly managed in a complete framework and not tackled separately. In this paper, we show how QoS and security are tightly managed in a complete end-to-end architecture for providing IPTV services while addressing the majority of the above issues (scalability, QoS, security, and heterogeneity). In particular, we propose an IPTV architecture that deals with end-to-end QoS and security management at two segments: the core network and the access network. The core network is composed of independent domains where each of them is managed by a local domain manager having service level negotiation capabilities. The access network is considered as WLAN (802.11) which connects heterogeneous mobile terminals. The proposed IPTV architecture includes two main entities: the Content Server which provides the TV stream in the core network and the Adaptation Gateway that assures the TV stream adaptation in wireless network according to terminal capabilities and user profile.

Thanks to its cost-effectiveness and wide deployment, the 802.11 WLAN is considered today as the de-facto wireless access network for the last mile connection. In this regards, QoS provisioning in 802.11 WLAN for multimedia services is becoming a main objective that should be enforced to enable reliable commercial offers. To reach this goal, the different mechanisms proposed by 802.11 standards, including fragmentation, physical rate variation, retransmission, and transmission power adjustment, should be exploited intelligently by the application using a cross-layer interaction. This would allow service scalability by improving resources availability and enhancing QoS provisioning. In this paper, we propose an adaptive cross layer fragmentation technique aiming to provide a reliable and QoS-based IPTV service delivery over 802.11 WLAN. In our architecture, the link layer fragmentation is controlled automatically by the application layer in a cross-layer interaction to find a trade-off between the video quality degradation and the overhead ratio introduced by the MAC fragmentation. Performance evaluation conducted using an experimental test-bed shows the ability of our cross-layer mechanism to reduce packets video losses and to enhance the overall video objective quality given by the PSNR and the SSIM metrics.

This paper describes a new architecture and implementation of an adaptive streaming system (e.g., television over IP, video on demand) based on cross-layer interactions. At the center of the proposed architecture is the meet in the middle concept involving both bottom-up and top-down cross layer interactions. Each streaming session is entirely controlled at the RTP layer where we maintain a rich context that centralizes the collection of (i) instantaneous network conditions measured at the underlying layers (i.e.: link, network, and transport layers) and (ii) user- and terminal-triggered events that impose new real-time QoS adaptation strategies. Thus, each active multimedia session is tied to a broad range of parameters, which enable it to coordinate the QoS adaptation throughout the protocol layers and thus eliminating the overhead and preventing counter-productiveness among separate mechanisms implemented at different layers. The MPEG-21 framework is used to provide a common support for implementing and managing the end-to-end QoS of audio/video streams. Performance evaluations using peak signal to noise ratio (PSNR) and structural similarity index (SSIM) objective video quality metrics show the benefits of using the proposed Meet In the Middle cross-layer design compared to traditional media delivery approaches.

This paper describes the issues related to IP multicast support in satellites networks. The IGMP multicast membership management protocol is considered as inappropriate for multicast group management over satellite network. In fact, IGMP leads to flooding, latency and scalability issues when used over asymmetric satellite networks. Thus, we propose a new architecture for multicast services provisioning based on IP multimedia subsystem (IMS) as a service delivery platform. The interworking between IP multicast protocol (i.e., IGMP) and IMS protocol (i.e., SIP) is demonstrated to overcome these multicast scalability issues inherent to satellite networks. Implementation and deployment of the proposed platform over an advanced satellite network emulator is also described.