Design And Implementation For Network Convergence Of WLAN And 3G Mobile Communications Network

With the explosive growth of the data business, the band current cell network supplying can hardly satisfy the requirement of wireless broad band access. But surfing online by cell phone is not only expensive but also with low velocity. Wireless Local Area Network (WLAN) has been used more and more widely at the unique advantages of its wide band, low cost and much higher access speed than that of cell network. The complementation existing between WLAN and cell network makes it possible to act WLAN as an access to the combination with cell network. With the rapid expansion, WLAN has been deployed in most of the hotspots, such as hotel, cafe, airport, gym,etc. Users may get resources they want from Internet by their smart phones. The appearance of dual-mode cellphones makes it urgent to combine WLAN with 3G mobile communication network.In this thesis the network architectures and their respective characteristics for gateway convergence, loose-coupled convergence and tight-coupled convergence are analysed, with reference to interworking scenarios put forward by 3GPP. And the advantages and disadvantages of them are compared. On the basis of that, a constructure that can,access 3G core network through WLAN to obtain PS domain services is designed. After that, with the characteristics of the operator network, the logical structure of the WLAN services is proposed and it provides realization of access and authentication in the convergence with the practical theoretical foundation. Meanwhile, with multimedia messaging service as application background, the convergence scheme makes an improvement on service flow.The thesis also describes the design and implementation of the PCAP sub-module in user equipment module, and the SIM sub-module of the server module in the process of the network convergence. The PCAP sub-module locates at the bottom of the whole framework of client software, acting as the driver. It fulfills the needs by mutual operation between operations of user and program processing. The SIM sub-module is mainly designed to complete the authentication by AAA server. In more specific terms, it is to manage the users'identifiers, information about contract, vectors for authentication and encrypted keys. Meanwhile this part has realized the full authentication and version negotiation.