Oriented Multipath Transmission The Application-Layeer Qos Evaluating Model And Policy-Decision Method

IMS is the main direction of the next generation of telecommunications technology, The IMS media transmission adopts the single-path transmission mode which entirely depends on the bearer network, but he bearer network transmission technology lags behind the development needs of business network, it’s difficult to meet the development needs of IMS services due to the disadvantages of the transmission mode, such as difficulty of guarantying end-to-end QoS, prominent effect of bandwidth bottleneck, low transmission efficiency, et al. which also has seriously hampered the IMS business development. Building the IMS media multipath transmission based on application layer relay, helps to weaken the condition which IMS services depend on the bearer network QoS guarantee conditions, even if physical paths in bearer network are not able to provide QoS guarantee, as long as the multipath transmission "coupling conditions" beyond a "threshold", it’s also probable to realize the transmission service of satisfying user QoE. Building the relational models and relative methods among user Quality of Experience(QoE)、application layer QoS conditions and QoS conditions of each section path, are the technical basis of achieving multipath transmission, and the main research and goal of the paper.The paper analyzes service QoE and relational conception model about path QoS in detail, investigate the relation between service QoE and path QoS, and combining the application need of multipath transmission service QoS, in-depth study relational application layer QoS evaluation models and policy-decision methods. The main work and achievements in the paper are as follows, firstly, the paper proposes the method of "threshold decision" which meet QoE conditions, it’s the basis of multipath transmission application layer QoS policy-decision; secondly, oriented QoE technical evaluation, through the expansion of traditional QoS four elements, combined with the path and relay two factors presents relational model between service QoE and end-to-end QoS guarantee conditions, and relational model between end-to-end QoS guarantee conditions and each section path QoS conditions; thirdly, oriented QoE non-technical evaluation, adopting the method of fuzzy decision, presents the QoE quantitative model of user expectation on the subjective factor of "service price"; finally, the paper designs the simulation method of multipath transmission application layer QoS policy-decision, and verify the effectiveness of the "threshold decision" technical program and the policy-decision model.The application layer QoS evaluation model and policy-decision method are the policy-decision basis of IMS session negotiation、the relay path selection, end-to-end path selection、and the load distribution strategy of multipath transmission control, are also the key technology of achieving multipath transmission QoS guarantee, the work in the paper are just the useful explore on the technical area.