Advancements in cross-layer wireless multimedia communications
Summary form only given. Despite their low-complexity and (perceived) efficiency, many traditional wireless communication and networking approaches for handling errors and losses are far from being optimum. For example, popular wireless LANpsilas, such as 802.11 systems, heavily rely on retransmission based schemes for handling corrupted packets. These schemes waste precious wireless bandwidth when discarding packets that contain mostly good data. In this tutorial, new advancements in the development of cross-layer wireless communications that are particularly tailored for multimedia applications will be covered. New cross-layer frameworks for handling errors and losses over wireless channels will be described. In particular, a framework that is based on a cross-layer design with side information (CLDS) will be described. The benefits and limitations of cross-layer side information for combating errors in a wireless environment will be discussed. Capacity improvements (in information-theoretic sense) due to CLDS protocols will be highlighted and compared with the capacity of current popular schemes (802.11 based MAC protocols). Unlike traditional wireless link-layer methods that shift reliability and stability functions to other layers, new approaches for reliable and stable link-layer wireless channels are being developed. The impact of these approaches on both realtime video applications and non-realtime TCP-based services will be highlighted.