The Study On Joint Call Admission And Handover Control In Heterogeneous Networks

With the emergence of multiple wireless communication access technologies and the enlargement of the scale of multi-device users, heterogeneous network convergence has been the development trend of communication technologies. And the vertical handover between multiple terminals and Joint Call Admission Control (JCAC) under heterogeneous network environment has become a research hotspot within communication sector.Based on the author's research experience in an NSFC project, the thesis investigates the existing international research results on the vertical handover and JCAC algorithms of heterogeneous networks. A new JCAC algorithm is proposed to suit the application scenarios of heterogeneous wireless networks.First of all, the research background and contents are briefly stated. Then, a systematic introduction is given to the-state-of-the-art of research on heterogeneous wireless network convergence technologies, including heterogeneous network convergence architecture, vertical handover technologies, access network discovery mechanism and typical JCAC algorithms. Following the above discussion, the thesis proposes a general vertical handover scheme among user's multiple devices in the heterogeneous networks applicable to the Always Best Connected (ABC) scenario. A vertical handover supported converged network architecture is proposed with a newly defined network element designed and vertical handover flowchart provided. Furthermore, a JCAC algorithm based on user satisfaction and load balance is proposed. Taking into account the threshold control of load balance, the algorithm evaluates the impacts of different parameters on the user satisfaction by use of the non-additive principle and makes decision on admission control and network selection. Finally, the proposed JCAC algorithm is verified on an author developed system level simulation platform. The simulation results have shown that the algorithm can not only achieve satisfactory user satisfaction, but also balance the load between heterogeneous networks and maximize the number of admitted users.