Vertical Fast Handoff Technique For Mobile IPv6 in Heterogeneous 4G Networks

Over the recent years, mobility in wireless communications has become a big interest of communication and network researches due to the rising demand on and expectations of wireless Internet access. However, since none of the existing wireless technologies can individually fulfill all the tasks arising from the Internet users’ demands, the integration or coexistence of different communication systems having different network characteristics is inevitable. This integration on the other hand, requires seamless inter-system mobility solutions. Every inter-system roaming which leads to vertical handoff requires proper interaction of both link and IP layers, since network point of attachment as well as the device interface are involved in handoff. Many investigations in standardization are being made to finally design and implement each of these communication layers. This thesis details out the whole research, which is done in two main components. As for the first component, a link layer mechanism with the notion of a selection algorithm based on weighted mean is primarily introduced for collecting link layer information and discovering the candidate access router. This mechanism is then used as handoff decision phase with an improved mobile-assisted handoff method as an extension of Fast Mobile IPv6 Handoff (FMIPv6) in vertical mode. The performance of the proposed methods is discussed using analysis and comparison of simulation results with wellknown methods in the field. The method has been shown to achieve performance improvements in terms of higher preference level of selection for various cases, and in terms of latency and packet loss, by 45% and 83% respectively, while maintaining comparatively lower buffer sizes. As the second component, a framework is proposed to incorporate an integration mode of cellular and wireless networks called semi tightly-coupled. This framework is further used to design and implement an end-to-end roaming solution as Vertical Fast Handoff (VFHO) for the integrated network. The performance of the proposed framework has been analyzed mathematically and through simulations which show the robustness of VFHO in terms of signaling cost, endto- end packet delivery cost, overall handoff latency, and packet loss based on various system variables. Under several simulations, the number of lost packets encountered by VFHO stayed as low as 20 packets when the arrival rate was a maximum of 50 packets per second, and did not exceed 10 packets in the case when packet sizes was at a maximum of 256 Bytes or when buffer size was set to 50 KB. Besides, the delay varied between 200 and 600 ms in cases when the Duplicate Address Detection (DAD) and wireless link delays reached up to 600 ms and 70 ms, respectively. In conclusion, the selection-based decision mechanism in vertical handoff such as VFHO, can be good for congestion control, and achieve long-term objectives such as load sharing

Friend recommendation based on the Luscher color theory: Twitter use case

At the area of information technology, social networks are becoming an unavoidable part of the Internet usage, due to their facilities for users as well as the benefits to the providers. However, the popularity and thereby, the success of social networks depends highly on number of the network members. This in turn, depends on considerations for several criteria such as networking and number of networks. On the other hand, it is believed that suggestion of appropriate friends to members performed by an effective recommender system can lead to suitable content ranking and consequently, impact the growth of the network in significant sense. The current paper introduces a novel method of recommending celebrities in a social network based on genetic algorithm and the concept of color psychology. The proposed method is applied to Twitter social network as case study, through which the cost function of the user is first optimized to achieve the ideal weights, and the celebrities are then ranked based on the specified parameters as follower and following counts, background color and description. The system is tested using real data of celebrities and number of 100 users with identical parameters. The results evidence the closest recommendation in terms of affordable recommendation error rates as low as 7.6% based on the psychological data validation

Tracking moving targets in wireless sensor networks using extended diffusion strategies of distributed Kalman filter

Using wireless sensor networks to track the position of a moving object in a 3-D spatial model requires precise information of location and speed of the object, which in turn demands for accuracy in state estimation of distributed Kalman filter. In view of reducing the impacts of noise in the dynamic linear system and achieve optimized state estimate, the current study proposes extended strategies of Kalman filter diffusion based on distributed Kalman filter. Through the proposed strategies, each node communicates merely with its neighbor nodes. The data aggregation is done in a set of neighborhood using instructions of recursive Kalman filter iterations with specific weights. The proposed algorithms provide precise state estimates in a moment as global state estimates using various updates at each step. As a simulation study, we applied the algorithms in a network to track the position and speed of a projectile and compared the results with real world circumstances, using the concept of transient mean square deviations of network as a cost function. The results report improvements over the conventional methods in terms of mean square errors

Layer-2 protocol adaptation method to improve fast handoff for mobile IPv6 vertical handoffs

Inter-technology roaming is known as one of the interesting challenges toward fourth generation of mobile and wireless communication. While FMIPv6 standardizes the fast handoff solutions in IP layer, the issues of media independency are being investigated through IEEE802.21 project. The integration of these two standards is believed to result in solutions for vertical handoffs between different network technologies. This paper presents an improved link layer mechanism to assist FMIPv6 for seamless vertical handoffs. We introduce a new access router discovery method and propose a vertical handoff algorithm accordingly. Further, we report the implementation details performed through simulations. The simulations evidence performance improvements in terms of latency and packet loss. It is also analytically shown that by enabling access router discovery method and improving link layer event services, an MN can be well prepared for handoff and perform faster movements

Layer-2 Protocol Adaptation Method to Improve Fast Handoff for Mobile IPv6 Vertical Handoffs

Abstract — Inter-technology roaming is known as one of the interesting challenges toward fourth generation of mobile and wireless communication. While FMIPv6 standardizes the fast handoff solutions in IP layer, the issues of media independency are being investigated through IEEE802.21 project. The integration of these two standards is believed to result in solutions for vertical handoffs between different network technologies. This paper presents an improved link layer mechanism to assist FMIPv6 for seamless vertical handoffs. We introduce a new access router discovery method and propose a vertical handoff algorithm accordingly. Further, we report the implementation details performed through simulations. The simulations evidence performance improvements in terms of latency and packet loss. It is also analytically shown that by enabling access router discovery method and improving link layer event services, an MN can be well prepared for handoff and perform faster movements. Index Terms—Vertical handoff, Heterogeneous networks, FMIPv6, MIH, Access Router discovery