Authentication Enhancement In Heterogeneous Wireless Networks (WLAN And Cellular GPRS/UMTS Networks)

As major communication milestones, the Internet and mobile wireless techniques are rapidly converging to necessitate interworking solutions for local and wide area wireless networks in today's communication environments. The need for global roaming to improve wireless mobility promises current and future trends in interworking solutions for Heterogeneous Wireless Networks like WLAN and cellular technologies that take advantage of the varying features provided by different technologies through compensating each others weaknesses with individual strengths. These wireless technologies support multiple Internet applications like web browsing, emails, video and audio streaming with varying QoS requirements. During different scenarios, some are tolerant to packet delays and packet losses while others are not. In instances like vertical handoff, these two would have to be suitably designed in order to achieve smooth roaming. Suitable vertical handoff authentication mechanisms would go a long way in enhancing the QoS provided by the HWNs.Since the existing authentication control mechanisms can grant multiple users permission to utilize resources using QoS classification to help establish hierarchy in the users. Service providers use this strategy to help soothe traffic congestion and so that client mobile stations receive value‐for‐money which means some clients are offered superior treatment. For instance, in overcrowded networks, some roaming MSs would benefit from such classifications by experiencing minimal handoff authentication delay while others are disconnected. However, this isn't a genuine solution as most clients seek cheaper services. In cases such as that of WLAN, the authentication system is normally stable for providing authentication services to its normal clients, however, during peak periods, like multiple MSs roaming from the cellular networks combined with the new clients authenticating and other established ones re‐authenticating, this can significantly impact on the AC causing some connections to be dropped if the QoS mechanism is applied.This thesis presents a dynamic authentication enhancement mechanism that couples GPRS (2G) and UMTS (3G) cellular network with a wireless local area network (WLAN) in cases of multiple mobile nodes requiring simultaneous vertical handoff. A gauge is used to measure the number of collected handoff authentication requests which after hitting a particular number'threshold'of requests activates a Standby Authentication Mechanism (SAM) facilitating the handling of multiple handoffs in a way that minimizes handoff latency and dropped connections. The MATLAB and OPNET simulation results obtained are discussed later showing that, during peak periods, the mobile services'clients would be enabled to enjoy continuous real‐time services while switching between networks when the vertical roaming authentication process is enhanced.