In recent days, vehicles have been equipped with smart devices that offer various multimedia-related applications and services, such as smart driving assistance, traffic congestions, weather forecasting, road safety alarms, and many... more
In recent days, vehicles have been equipped with smart devices that offer various multimedia-related applications and services, such as smart driving assistance, traffic congestions, weather forecasting, road safety alarms, and many entertainment and comfort applications. Thus, these smart vehicles produce a large amount of multimedia-related data that require fast and real-time processing. However, due to constrained computing and storage capacities, such huge amounts of multimedia-related data cannot be processed in on-board standalone devices. Thus, multimedia cloud computing (MCC) has emerged as an economical and scalable computing technology that can process multimedia-related data efficiently while providing improved Quality of Service (QoS) to vehicular users from anywhere, at any time and on any device, at reduced costs. However, there are certain challenges, such as fast service response time and resource cost optimization, that can severely affect the performance of the MC...
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Vehicular Ad Hoc Networks (VANETs) are getting more popularity due to the potential Intelligent Transport Systems (ITS) technology. It provides many efficient network services such as safety warnings (collision warning), entertainment... more
Vehicular Ad Hoc Networks (VANETs) are getting more popularity due to the potential Intelligent Transport Systems (ITS) technology. It provides many efficient network services such as safety warnings (collision warning), entertainment (video and voice), maps based guidance, and emergency information. VANETs most commonly use Road Side Units (RSUs) and Vehicle-to-Vehicle (V2V) referred to as Vehicle-to-Infrastructure (V2I) mode for data accessing. IEEE 802.11p standard which was originally designed for Wireless Local Area Networks (WLANs) is modified to address such type of communication. However, IEEE 802.11p uses Distributed Coordination Function (DCF) for communication between wireless nodes. Therefore, it does not perform well for high mobility networks such as VANETs. Moreover, in RSU mode timely provision of data/services under high density of vehicles is challenging. In this paper, we propose a RSU-based efficient channel access scheme for VANETs under high traffic and mobilit...
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Detecting user's quality of experience is a method which deals with estimating how a user perceives the... more
Detecting user's quality of experience is a method which deals with estimating how a user perceives the network performance. Although user's behavior is very complex, only analyzing a large amount of operational network data enables us to effectively detect the users satisfaction from the network. One important parameter to detect user's behavior is user's interruption of the TCP connections in
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ABSTRACT Open medium access is an inherent feature of wireless networks that makes them vulnerable to security threats and unauthorized access by foreign entities and malicious users. In cognitive radio networks, effect of these malicious... more
ABSTRACT Open medium access is an inherent feature of wireless networks that makes them vulnerable to security threats and unauthorized access by foreign entities and malicious users. In cognitive radio networks, effect of these malicious users on network performance becomes more threatening, where they impersonate primary users by emitting similar signals, causing secondary users to vacate the occupied channel needlessly. As a result, network resources are unfairly monopolized by malicious users denying other secondary users their fair share. In this paper, we introduce a cross-layered approach to provide secondary users the ability to differentiate between a primary user and a malicious user, using Hidden Markov Model at MAC layer. Hence, our proposed framework allows the transport layer protocol to respond appropriately in a way that the effect of the presence of malicious user on the network is mitigated. The effectiveness of our proposed approach is shown by calculating the throughput of the network and number of channel switches with respect to varying number of secondary and malicious nodes and by comparing it to an earlier proposed TCP protocol.
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Delay Tolerant Networks (DTN) are a class of networks that lack continuous connectivity between nodes due to limited wireless radio coverage, widely scattered mobile nodes, constrained energy resources, high levels of interference or due... more
Delay Tolerant Networks (DTN) are a class of networks that lack continuous connectivity between nodes due to limited wireless radio coverage, widely scattered mobile nodes, constrained energy resources, high levels of interference or due to some other similar channel impairment. Examples of such networks are those operating in mobile networks or extreme terrestrial environments, or simply as planned networks in
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Cognitive radio networks provide a reasonable solution to the problem of spectrum scarcity by allowing secondary users opportunistic access to licensed spectrum bands which were till now reserved for exclusive usage of primary incumbent... more
Cognitive radio networks provide a reasonable solution to the problem of spectrum scarcity by allowing secondary users opportunistic access to licensed spectrum bands which were till now reserved for exclusive usage of primary incumbent users. The problem of coexistence arises when multiple colocated networks are in close vicinity and have to share the same part of the wireless spectrum. In this paper, the problem of channel assignment which ensures coexistence among co-located, non-cooperative, independent cognitive radio networks has been addressed using a game-theoretic model. We assume that each base station, representing a Wireless Regional Area Network (WRAN), senses its environment (which includes interference experienced due to other communicating WRANs in its vicinity) in a distributed manner to take appropriate decision about its operating channel. This problem is modeled as a non-cooperative repeated potential game in which the players are the coexisting WRANs with customer premises equipment only used to gather information regarding the changing conditions of the channel. The existence of Pareto optimal solution is discussed and an algorithm which converges to such a solution is proposed. Our study shows that the proposed approach provides significant performance gain as compared to existing approaches.
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In this paper, we present a game theoretic framework for spectrum allocation in distributed cognitive radio networks containing both unicast and broadcast traffic. Our proposed scheme aims to minimize broadcast latency for broadcast... more
In this paper, we present a game theoretic framework for spectrum allocation in distributed cognitive radio networks containing both unicast and broadcast traffic. Our proposed scheme aims to minimize broadcast latency for broadcast traffic and minimize interference and access contention for both types of traffic. We develop a utility function that ensures that both objectives are met yielding a higher network throughput. Our proposed spectrum allocation game is also formulated as a potential game and is guaranteed to converge to a Nash equilibrium if the sequential best response dynamics is followed. A proof of concept of the proposed algorithm has been implemented on the Orbit radio testbed and the results verify the convergence of the potential game. Our simulation and experimental results also reveal that the choice of utility function improves the average network throughput for a mixed traffic profile.
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Failure of backbone nodes/links can have catastrophic consequences unless they are addressed in a timely manner. Multi-Protocol Label Switching (MPLS), is an increasingly popular technology that employs various recovery mechanisms from... more
Failure of backbone nodes/links can have catastrophic consequences unless they are addressed in a timely manner. Multi-Protocol Label Switching (MPLS), is an increasingly popular technology that employs various recovery mechanisms from such failures. In addition to failure recovery these mechanisms minimize downtime, data loss and convergence time while also avoiding inefficient bandwidth utilization. The aim of this survey paper is
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... of Sciences and Technology (NUST) H12 Sector Islamabad 44000, Pakistan {najmul.hassan, adeel.baig, junaid.qadir, madeeha.owais}@seecs.edu.pk ... F. Aslam, S. Raza, and ZA Uzmi, Band sharing with primary paths for restoration routing... more
... of Sciences and Technology (NUST) H12 Sector Islamabad 44000, Pakistan {najmul.hassan, adeel.baig, junaid.qadir, madeeha.owais}@seecs.edu.pk ... F. Aslam, S. Raza, and ZA Uzmi, Band sharing with primary paths for restoration routing in MPLS network, in INFOCOM 2006 ...