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This paper presents a empirical model for near human body UWB propagation channel that is valid for the frequency range from 3GHz to 8GHz. It is based on measurements conducted in a anechoic chamber which can be regarded as free space. The empirical model shows the joint propagation characteristics of the on body channel and the channel between body surface and external access point. It includes the...
Localization of Wireless Capsule Endoscope (WCE) inside the small intestine is a very challenging problem, which is very important for the diagnosis of certain diseases. Previous studies have shown that Time-of-Arrival (TOA) localization can be more effective than Received Signal Strength (RSS) based localization. Performance evaluation of TOA-based localization techniques for WCE requires understanding...
We investigated the secrecy outage of unicast channels in random networks exposed to unknown numbers of randomly located eavesdroppers, obtaining original expressions which include uncertainty in terms of the location of legitimate nodes relative to eavesdroppers, the number of eavesdroppers, and fading. Under such conditions, we derive the path gain distributions of legitimate and eavesdropper nodes,...
In this paper, we analyze the performance of an energy detector operating over Gamma shadowed Rice fading channels, namely Rice fading channels with the fluctuating line-of-sight components following the Gamma distribution. This composite multi-path/shadowing model has been shown to provide remarkably accurate fading characterization while leading to closed-form expressions for important channel statistics...
The recent witnessed evolution of cellular networks from a carefully planned deployment to more irregular, heterogeneous deployments of Macro, Pico and Femto-BSs motivates new analysis and design approaches. In this paper, we analyze the coverage probability in cellular networks assuming repulsive point processes for the base station deployment. In particular, we characterize, analytically using stochastic...
Wireless sensor networks are often deployed for monitoring purposes: when nodes detect the occurrence of a significant event, they transmit an information to a control entity in a multi-hop fashion. When data rate increases, congestion becomes a fundamental issue, especially when an emergency situation generates alarm messages originating from a specific area of the network. Indeed, congestion increases...
In this paper, we analyze the performances of the Medium Access Control protocol Multi-slot-ALOHA in a wireless ad hoc network modelled by a Poisson Point Process (PPP). By giving to nodes access to the medium for several time slots, Multislot ALOHA strengthens the reliability of transmissions, which is the main weakness of MAC protocols without acknowledgements. To our knowledge, this protocol has...
With the development of multi-interface terminals, a host can connect to the Internet simultaneously by multiple access technologies. Under multi-access technology, a multi-path transmission can obtain high throughput, increased available bandwidth and enhanced reliability. However, the multi-path transmission with multi-access technology also has the problems that the packet re-ordering is unavoidable,...
Cooperative spectrum sensing is employed in Cognitive Radio (CR) networks to reliably detect Primary User (PU) transmissions by fusing the sensed data of multiple Secondary Users (SUs). The local detection reliability of an individual SU is closely related to its channel condition. In this paper, we propose a scheme that uses SNR to evaluate the reliability of each individual SU's local decision....
Urban traffic congestions have become a financial and societal burden in many cities. Efficient traffic management solutions mitigating such congestions require a reliable modeling and estimation of traffic jams. In urban traffic, the modeling challenges are related to flow collisions and gridlocks created at intersections. In this paper, we propose a traffic light extended Cell Transmission Model...
This paper presents an initial study on how to model user mobility in a wireless cellular network scenario. The model provides realistic patterns of movement between a number of locations. The aforementioned mobility model is built upon to introduce a base station (BS) energy efficient power state control algorithm (EESC) that is able to provide significant energy savings for the simulated scenario...
Maximization of network lifetime is one of the most important design goals in Wireless Sensor Networks (WSNs). In WSNs with static base stations, sensor nodes close to the base station dissipate most of their energies for relaying other sensor nodes' data. Although cooperation among the sensor nodes results in longer network lifetimes in comparison to greedy approaches, there is an inherent limit...
Growing energy demands, the increasing depletion of traditional energy resources, together with the recent surge in mobile internet traffic, all call for green solutions to address the challenge of energy-efficient wireless access networks. In this paper, we consider possible power saving by reducing the number of active BSs and adjusting the transmit power of those that remain active while maintaining...
Spectrum management task is difficult to achieve in a dynamic and distributed network where cognitive radio users may only make local decision and have to react to the environment changes. In this paper, we describe a novel spectrum management approach for a cognitive radio ad-hoc network. Our proposal is based on multi-agent auctions and provides a decentralized control. First, we implement in a...
Network reliability and survivability are important features for hosting high-demanding services in virtual network environments. Since multiple virtual networks can share the physical resources of the underlying substrate, even a single failure in the substrate can affect a large number of virtual networks and the services they offer. To overcome the physical link failure impact on virtual network...
In this paper, cooperative multicast with the help of short-range data sharing is studied in the cognitive radio networks (CRNs). The original multicast data is split into many segments, and the transmission of each segment is divided into two stages. In the first stage, cognitive base station transmits each segment to the corresponding cooperative user, and in the second stage, the cooperative user...
In the literature, Poisson or ON/OFF models have been commonly used to characterize the primary arrival process in cognitive radio networks (CRNs). In this paper, the performance analysis of CRNs with VoIP traffic considering either Poisson or ON/OFF models for the primary arrival characterization is evaluated and compared. To provide a fair basis of comparison for the ON/OFF and Poisson arrival models,...
In our previous work, we proposed to use a vehicle network for data gathering, i.e. as an urban sensor. In this paper, we aim at understanding the theoretical limits of data gathering in a time slotted wireless network in terms of maximum service rate per node and end to end packet delivery ratio. The capacity of wireless networks has been widely studied and boundaries for that capacity expressed...
With the increasing demand for traffic safety and efficiency and constant search for innovative solutions within the automotive market coupled with supporting initiatives from regulatory domains, the potential of Intelligent Transportation Systems (ITS) is immense. Basic vehicle and roadside infrastructure collaboration allows an increase in efficiency and safety and acts as the foundation for an...
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