Improving the performance of rate adaptation schemes in heterogeneous wireless networks

The emerging heterogeneous networking environment will comprise diverse link layer technologies like 3G, WLANs and WPANs. In this context, multimedia applications should be able to cope with packet losses and delays due to congestion, wireless transmission errors and vertical handovers. This paper addresses the functional requirements from an advanced adaptation architecture, which incorporates enhanced end-to-end adaptation schemes that exploit information delivered by the next-generation terminal. The terminal’s management entity should provide information at least for the local access network condition, e.g. estimates of the available bandwidth and wireless link losses, and handover notifications. The adaptation architecture does not count on the existence of QoS infrastructure; however, exploitation of such infrastructure is possible through the collaboration between the terminal and a network management entity. We have extended the LDA and TFRC rate adaptations algorithms to make use of the enhanced functionality. Through simulations we validate the robustness of these extended schemes against vertical handovers.