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In this paper, we present a method to localize multiple sources using randomly distributed wireless sensor nodes. The principle of maximum power collection is used to obtain the beamforming weights which add the source signal constructively at the sensor outputs. The beamforming weights give the time difference of arrival (TDOA) for each of the sources from which the source location is subsequently...
A wide range of forwarding strategies have been developed for multi-hop wireless networks, considering the broadcast nature of the wireless medium and the presence of random fading that results in time-varying and unreliable transmission quality. Two recently proposed strategies are opportunistic forwarding, which exploits relay diversity by opportunistically selecting an overhearing relay as a forwarder,...
The support of delay-sensitive applications like VoIP, video conferencing, video streaming, etc. on scheduled mesh networks requires careful configuration of routing and scheduling. We formulate a delay-optimal joint routing and scheduling optimization problem that minimizes the maximum average delay perceived by any flow under the physical interference model. Due to the non-convex nature of this...
The Internet's tremendous success as well as our maturing realization of its architectural shortcomings have attracted significant research attention towards clean-slate re-designs in recent times. A number of these shortcomings can be traced back to naming. The current Internet uses IP addresses to conflate identity and network location, which results in poor support for mobility and multihoming;...
In this paper, we propose two adaptive algorithms to control Destination Advertisement Option (DAO) packet emissions in RPL non-storing mode: a centralized, or controlled by the DAG root, and a distributed. We propose new mechanisms to derive the most appropriate value for the DelayDAO Timer, a timer that determines how long a node should wait before transmitting its destination advertisement packet...
Network attacks and in particular denial of service (DoS) attacks have emerged as a major way to compromise the availability of servers and interrupt legitimate online services provided by servers. These attacks are among one of the hardest security problems to address because they are simple to implement but hard to prevent and difficult to trace. Tracing the attacker after an attack is crucial to...
Our paper focuses on two aspects of certifying a cloud-based network system: i) metrics to quantify the dependability of cloud-based applications; and ii) identifying techniques to measure these metrics prior to deployment of applications. We treat system dependability as an application-level QoS for management purposes, and advocate a probabilistic evaluation of dependability. Our approach is corroborated...
Delay-Tolerant Networks (DTNs) are wireless mobile networks having intermittent connectivity among the nodes. DTN nodes mostly operate on limited battery power. Hence, in such networks, there is an immediate need to have energy efficient routing protocol, allowing the network to perform better and live longer for a message with lifetime Et and delivery probability Dp. Most of the work in DTN assumes...
The key requirements for enabling real-time remote healthcare service on a mobile platform, in the present day heterogeneous wireless access network environment, are uninterrupted and continuous access to the online patient vital medical data, monitor the physical condition of the patient through video streaming, and so on. For an application, this continuity has to be sufficiently transparent both...
Power utilities worldwide face two major challenges — peak demand and power (supply-demand) imbalance. In the midst of these difficulties faced by utilities, growing fuel costs, environmental awareness and government directives have increased the push to deploy Electric Vehicles (EVs). One single EV being charged at its peak rate imposes an instantaneous load equivalent to that of 10 average households...
In this paper, we analyze the effects of using directional antennas for broadcasting in DTNs (Delay Tolerant Networks) in realistic mobility scenarios. Directional antennas (DA) can create longer range contacts than omnidirectional antennas with the same transmission power, and hence have the potential to cover a larger area faster if deployed suitably. In many DTN applications, reducing the latency...
We describe the design, implementation and evaluation of a RObust and Distributed MAC (RODMAC) protocol for cognitive radio networks which exploit spectrum white spaces for communication. RODMAC incorporates two novel features. These are a robust design resilient to node failure and a scheme for on-demand channel hopping. Other features include a fully distributed architecture and incorporation of...
Single-carrier frequency division multiple access (SC-FDMA) has become a popular alternative to orthogonal frequency division multiple access (OFDMA) in multiuser communication on the uplink. This is mainly due to the low peak-to-average power ratio (PAPR) of SC-FDMA compared to that of OFDMA. Long-term evolution (LTE) uses SC-FDMA on the uplink to exploit this PAPR advantage to reduce transmit power...
Existing network simulators do not account for the overhead of communication software execution, which can be significant when devices in the network are resource constrained, like in MANETs and sensor networks. We propose an approach to extend network simulators to model the execution of communication software and to map the resulting behaviour onto existing protocol models. The approach can be used...
This paper considers optimal resource allocation in integrated framework of cognitive radio and ad hoc network. The design problem looks for an optimal solution in power and channel allocation in multihop cognitive radio network (CRN) with linear topology. The overall goal is to minimize outage probability and enhancement in network lifetime, while meeting the limits of total transmit power and interference...
In this work, we consider a vehicular environment in which vehicles moving along roads in a city are interested in different types of information or events generated at different parts of the city. We investigate the use of the publish-subscribe framework for such environments in which vehicles subscribe to a service provider for specific types of events through roadside units; the events are also...
Quality of Service (QoS) based scheduling in Cognitive radio networks (CRN) is a pressing research problem. The objective of this work is to study the feasibility of using CRN for delay sensitive applications in the presence of primary users with random ON/OFF periods. The first contribution of this work is the modeling of a cognitive node as a Queuing system and characterization of the average delay...
We propose a multichannel MAC protocol for cognitive radio enabled Secondary Users (SUs) called Residual White Space Distribution based Cognitive MAC protocol (RWS-CMAC). Channel access in RWS-CMAC is based on residual idle time distribution of the channels. RWS-CMAC assumes a common control channel, which is used by sender and receiver SU nodes to exchange control messages for data channel negotiation...
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