Methods for optimized multimedia mobility management

Given the growing range of wireless access technologies with different characteristics along with users’ desire for mobility future access network environments are likely to be heterogeneous. However, handling the mobility and ensuring the proper quality of service in a heterogeneous network is not a trivial task. In this thesis the relationship between the network layer performance and the user perceived Quality of Service is investigated in order to determine a good metric for choosing between heterogeneous network connections. Real- time traffic like VoIP is typically sensitive to delay and jitter while ftp traffic benefits from the highest available bandwidth therefore different metrics should be used depending on traffic type. A relation between the delay, jitter and the maximum available bandwidth is presented. Furthermore an evaluation of an existing formula to calculate the Mean Opinion Score (MOS) value for a VoIP transmission from delay and jitter is evaluated. To evaluate these metrics a measurement tool was implemented and used. Results show that the maximum bandwidth metric gives good estimation of available bandwidth in an 802.11 wireless network. The MOS estimation formula produces results that are very close to results measured with a specialized VoIP diagnostic tool. Along with the ability to measure unidirectional delay these metrics can be used to provide an optimized network selection for a given application or user requirement.Validerat; 20101217 (root