Quality of service for multimedia traffic using cross-layer design

Quality-of-service (QoS) guarantees are critical for the transmission of multimedia traffic over mobile wireless networks. Currently, wireless networks provide QoS guarantees using the legacy layered protocol architecture where each layer provides a separate, independent solution, with its own optimised adaptation and protection mechanisms. Cross-layer design has been proposed as a methodology to extend that paradigm in wireless links where there is interdependence between the layers and hence opportunity for information sharing. Recently, cross-layer adaptation mechanisms have been proposed which attempt to solve the QoS provisioning problem. However, most of these mechanisms only use the lower (physical and data link) layers and the possibility of using higher protocol layers remains unexplored. As a result, restrictions are placed on the system which introduces functional and efficiency limitations. Here, one such limitation is highlighted, namely the inability to insert more than one class of traffic in a physical layer frame. A physical and application layer cross-layer adaptation mechanism is then proposed, which overcomes this limitation. The performance results of the scheme show that the cross-layer mechanism can be efficiently applied for the purpose of providing QoS guarantees for multimedia traffic.