| The IP technology is expected to become the core or backbone network of the fourth or next generation wireless networks (4G/NGWN). Users should benefit of seamless roaming and services continuity when they roam across different access networks, known as handoff. The latter may be due to link layer switching or a change of the IP address. The focus of this thesis is on vertical handoff, which will be more frequent in 4G/NGWN due to the heterogeneity of access networks.; This thesis is based on four peer-reviewed journal papers. The first paper carries out performance analysis of several IP-based mobility management protocols. A novel analytical framework is proposed for performances evaluation of these protocols. The proposed framework takes into account the effect of several factors such as subnet residence time, packet arrival rate and wireless link delay for an effective modeling. The analysis performed shows that none of those protocols is better for all scenarios according to the QoS metrics considered. According to deployment goals and QoS level an operator wishes to provide to its subscribers, there is a certain level of trade-off required.; In the second paper, a novel integrated hybrid architecture called, Integrated InterSystem Architecture (IISA), and a new IP-based mobility management protocol called, Handoff Protocol for Integrated Networks (HPIN), are proposed for NGWN/4G. The proposed IISA architecture introduces a novel entity called, Interworking Decision Engine (IDE), which acts as a third-party between various access networks and technologies, and allows their integration and interworking. Each network operator or services provider which wants to allow global roaming to its subscribers establishes only one service level agreement (SLA) with the IDE manager rather than with all potential other operators. This allows significant cost and complexity reduction. The proposed HPIN scheme introduces IP-layer handoff anticipation by using link layer information in order to reduce services disruption. Moreover, HPIN performs also access networks discovery, local mobility management and context transfer. Performance evaluation shows that IISA and HPIN give better results compared to works available in the open literature.; The third paper proposes a new handoff decision function which takes into account several parameters or factors such as monetary cost or price, bandwidth, signal strength, system performance, user preferences or profile, and handoff latency. Such handoff decision scheme is more appropriate in NGWN/4G due to the heterogeneity of access networks. On the other hand, the proposed handoff protocol defines new messages which enable design of a one-suite protocol that performs network selection, fast handoff, localized mobility management, context transfer and access networks discovery. The presentation of our solution is followed by performance evaluation which shows better results compared to others protocols. The handoff decision function allows a better load balancing amongst various access networks, thus, allows provisioning of higher data rate or throughput to users and lower packet loss rate.; Finally, the fourth paper is an improvement of the protocol presented in the second paper and is called, enhanced Handoff Protocol for Integrated Networks (eHPIN) that enables seamless services continuity and QoS guarantees for real-time applications in heterogeneous wireless environments. In eHPIN, the handshake procedure of all time consuming operations such as access router discovery, handoff anticipation, cache association update, and bi-directional tunnels setup are performed before or during the link layer switching (L2 handoff). Performance evaluation results shows that eHPIN allows better performance and significant reduction of handoff latency, signaling overhead cost, and packet loss compared to existing IPv6-based mobility management schemes. Thus, a seamless mobility and services continuity may be... |
