A handover management scheme for mobile IPv6 networks

Mobile IPv6 provides IP layer mobility management for IPv6 networks. Despite many advantages it offers in comparison to Mobile IPv4, handover management still remains an issue for Mobile IPv6. For real-time connections, the handover latency and signaling overhead incurred by the protocol may become significant. This paper presents a new method named crossover MAP based hierarchical mobile IPv6 (XMAP-HMIPv6), which inherits the advantage of hierarchical mobile IPv6 of reducing signaling load for inter-domain mobility and incorporates an analytical model for the performance analysis of this new scheme along with other existing handover management proposals. Finally, we present analytical results in different environments and compare our scheme with other existing proposals. The analytical model results show that, our scheme performs almost similar to [F+H] MIPv6 in terms of reducing handover latency and outperforms both HMIPv6 and MIPv6

The Minimum Shared Edges Problem on Grid-like Graphs

We study the NP-hard Minimum Shared Edges (MSE) problem on graphs: decide whether it is possible to route $p$ paths from a start vertex to a target vertex in a given graph while using at most $k$ edges more than once. We show that MSE can be decided on bounded (i.e. finite) grids in linear time when both dimensions are either small or large compared to the number $p$ of paths. On the contrary, we show that MSE remains NP-hard on subgraphs of bounded grids. Finally, we study MSE from a parametrised complexity point of view. It is known that MSE is fixed-parameter tractable with respect to the number $p$ of paths. We show that, under standard complexity-theoretical assumptions, the problem parametrised by the combined parameter $k$, $p$, maximum degree, diameter, and treewidth does not admit a polynomial-size problem kernel, even when restricted to planar graphs

Understanding internet usage and network locality in a rural community wireless mesh network

© 2015 ACM. Community networks owned and operated by local communities have recently gained popularity as a low cost solution for Internet access. In this paper, we seek to understand the characteristics of Internet usage in community networks and provide useful insights on designing and improving community networks in rural areas. We report the results of a socio-technical study carried out during a three month measurement of a community wireless mesh network (CWMN) which has been operating for two years in a rural area of northern Thailand. An on-site social interview was also conducted to supplement our analysis. The results reveal several interesting findings: rural users do use online social networks, instant messaging applications and online games similarly to urban users; they install unnecessary applications on their mobile phones and are completely obvious to their side effects - the traffic from these applications accounts for a major share of the traffic leading to numerous network anomalies. Finally our analysis uncovers the characteristic of locality in community networks where users in close geographical proximity interact with each other.TakNet was achieved thanks to sponsorship from THNIC Foundation. Part of this work was also supported by EU H2020 UMobile Project (Grant agreement no: 645124)

A hop-count based positioning algorithm for wireless ad-hoc networks

We propose a range-free localization algorithm for a wireless ad-hoc network utilizing the hop-count metric’s ability to indicate proximity to anchors (i.e., nodes with known positions). In traditional sense, hop-count generally means the number of intermediate routers a datagram has to go through between its source and the destination node. We analytically show that hop-count could be used to indicate proximity relative to an anchor node. Our proposed algorithm is computationally feasible for resource constrained wireless ad-hoc nodes, and gives reasonable accuracy. We perform both real experiments and simulations to evaluate the algorithm’s performance. Experimental results show that our algorithm outperforms similar proximity based algorithms utilizing received signal strength and expected transmission count. We also analyze the impact of various parameters like the number of anchor nodes, placements of anchor nodes and varying transmission powers of the nodes on the hop-count based localization algorithm’s performance through simulation

Ubiquitous robust communications for emergency response using multi-operator heterogeneous networks

A number of disasters in various places of the planet have caused an extensive loss of lives, severe damages to properties and the environment, as well as a tremendous shock to the survivors. For relief and mitigation operations, emergency responders are immediately dispatched to the disaster areas. Ubiquitous and robust communications during the emergency response operations are of paramount importance. Nevertheless, various reports have highlighted that after many devastating events, the current technologies used, failed to support the mission critical communications, resulting in further loss of lives. Inefficiencies of the current communications used for emergency response include lack of technology inter-operability between different jurisdictions, and high vulnerability due to their centralized infrastructure. In this article, we propose a flexible network architecture that provides a common networking platform for heterogeneous multi-operator networks, for interoperation in case of emergencies. A wireless mesh network is the main part of the proposed architecture and this provides a back-up network in case of emergencies. We first describe the shortcomings and limitations of the current technologies, and then we address issues related to the applications and functionalities a future emergency response network should support. Furthermore, we describe the necessary requirements for a flexible, secure, robust, and QoS-aware emergency response multi-operator architecture, and then we suggest several schemes that can be adopted by our proposed architecture to meet those requirements. In addition, we suggest several methods for the re-tasking of communication means owned by independent individuals to provide support during emergencies. In order to investigate the feasibility of multimedia transmission over a wireless mesh network, we measured the performance of a video streaming application in a real wireless metropolitan multi-radio mesh network, showing that the mesh network can meet the requirements for high quality video transmissions