Fast 802.11 link adaptation for real-time video streaming by cross-layer signaling

A Dynamic Link Adaptation for Multimedia Quality-Based Communications in IEEE_802.11 Wireless Networks

“…In the context of the Voice-over-IP and real-time video streaming (Video conferencing) which represent the most end-user demanded multimedia streaming applications to be supported over wireless connections, the proposed technique is supposed to enhance the video quality transmission by keeping the same compression degree, and so, avoiding the cross layer design implemented by (Haratcherev et al, 2005) which involves an interaction between the application and MAC layers by assuming that the video encoder can also adapt to the link quality by changing the compression degree for example, and thus modifying the data rate. This so-called Coupled scheme is based on a cross-layer signaling by letting the rate control loops -of the MAC-layer and the Video coder -be mutually associated.…”

“…In such way, the video coder will poll frequently for the current and predicted rate. For performance evaluation purpose, the same real experiment as performed in (Haratcherev et al, 2005) was carried out by streaming a video file between two laptops, both running Linux. The 802.11a cards used are based on the Atheros AR5000 chipset, and the card driver implements the discussed rate control algorithms.…”

“…Several research works (Haratcherev et al, 2005;Shun-Te et al, 2007;Chiapin & Tsungnan, 2008) have implemented a cross-layer link adaptation (CLLA) scheme based on different factors as: the number of successful transmissions, the number of transmission failures, and the channel information from the physical layer to determine actual conditions and therefore to adjust suitably transmission parameters for subsequent medium accesses. As well in (Chen et al, 2010) a proper-designed cross application-MAC layer broadcast mechanism has been addressed, in which reliability is provided by the application layer when broadcasting error corrections and next link rate adaptations (resulting from the MAC layer).…”

Link adaptation and cross-layer signaling for wireless video-streaming in a shared medium

“…As shown below, this is very important when there are other 802.11 users in the same Basic Service Set (BSS), for example. Cases 1 and 2 were explored in earlier work [5], [4], while 3 is investigated in this paper. In Table I we present the minimal degree of control complexity, depending on the video requirements and the environment conditions.…”

“…Using this approach also introduces additional overhead. A better approach, described in [4], for the video encoder is to base the adaptation on information provided by the link adaptation entity at the radio level.…”