A Transport Layer Mobility Support Mechanism

Abstract. Recently, mobile SCTP (mSCTP) has been proposed as a transport layer approach for supporting mobility. mSCTP is based on the ’multi-homing ’ feature of Stream Control Transmission Proto-col (SCTP), and utilize the functions to dynamically add or delete IP addresses of end points to or from the existing connection in order to support mobility. In this paper, we propose a mechanism to determine when to add or delete an IP address, utilizing the link layer radio signal strength information in order to enhance the performance of mSCTP. We also propose a mechanism for a mobile node to initiate the change of data delivery path based on link layer radio signal strength information. The simulation results show that the performance of proposed transport layer mobility support mechanism is competitive compared to the tradi-tional network layer mobility supporting approach. Especially, when the moving speed of mobile node is fast, it shows better performance than the traditional network layer approach.

A Road Layout Based Broadcast Mechanism for Urban Vehicular Ad Hoc Networks

Safety services of Vehicular Ad Hoc Network (VANET) require reliable broadcasts. We propose a reliable broadcast mechanism for urban roads called VANET Broadcasting for Urban areas based on Road Layout (VBURL), which tries to minimize the dependency on information that may become inaccurate to maximize the efficiency of broadcast. Specifically, the proposed mechanism takes into account the road layout information accessible from the digital map and only the real-time information obtained from the broadcast messages or beacons. VBURL basically makes the vehicle that is farthest from the current forwarding vehicle take the role of next forwarding vehicle and, if possible, makes an additional broadcast happen at the intersections where the effect of signal attenuation caused by the road side obstacles is low in order to have prompt and reliable dissemination of safety messages towards all roads connected to the intersections. The simulation results verified that VBURL achieves the same high performance as that of the compared legacy schemes in terms of reliability with much higher efficiency. Even though the message reception delay of VBURL is slightly longer than those of compared schemes, it is far less significant to impair the original purpose of safety message

A Multi-Hop Clustering Mechanism for Scalable IoT Networks

It is expected that up to 26 billion Internet of Things (IoT) equipped with sensors and wireless communication capabilities will be connected to the Internet by 2020 for various purposes. With a large scale IoT network, having each node connected to the Internet with an individual connection may face serious scalability issues. The scalability problem of the IoT network may be alleviated by grouping the nodes of the IoT network into clusters and having a representative node in each cluster connect to the Internet on behalf of the other nodes in the cluster instead of having a per-node Internet connection and communication. In this paper, we propose a multi-hop clustering mechanism for IoT networks to minimize the number of required Internet connections. Specifically, the objective of proposed mechanism is to select the minimum number of coordinators, which take the role of a representative node for the cluster, i.e., having the Internet connection on behalf of the rest of the nodes in the cluster and to map a partition of the IoT nodes onto the selected set of coordinators to minimize the total distance between the nodes and their respective coordinator under a certain constraint in terms of maximum hop count between the IoT nodes and their respective coordinator. Since this problem can be mapped into a set cover problem which is known as NP-hard, we pursue a heuristic approach to solve the problem and analyze the complexity of the proposed solution. Through a set of experiments with varying parameters, the proposed scheme shows 63–87.3% reduction of the Internet connections depending on the number of the IoT nodes while that of the optimal solution is 65.6–89.9% in a small scale network. Moreover, it is shown that the performance characteristics of the proposed mechanism coincide with expected performance characteristics of the optimal solution in a large-scale network

A Scalable VRU Protection System Based on Edge Servers

Various vulnerable road user (VRU) protection systems have been proposed based on the edge server paradigm to take advantage of the reduced latency as well as computational offloading to servers. In most existing studies, the authors presume that each edge server receives data from its associated users and takes care of the collision risks among them. Because of this presumption, the collision risks between users associated with different edge servers can be overlooked until one of the users at risk crosses the boundary of the server. Therefore, users located at or near the boundary of the edge server domain can receive late alerts or, more seriously, miss the alert entirely until a collision occurs. To address this hazardous scenario, we propose a scalable VRU protection system (SVPS) with an edge server cooperation mechanism. SVPS minimizes additional communication and computational overhead while maintaining satisfactory service accuracy even if users are moving. The numeric results demonstrate that SVPS effectively predicts users’ risks associated with different edge servers. Furthermore, SVPS is demonstrated to be scalable: The larger the edge server coverage area, the lower the overhead. Therefore, the coverage area should be set as large as possible while still satisfying latency requirements