nextgeneration wireless communication systems target to provide guaranteed Quality of Service (QoS) for multimedia applications. In this paper, a multiple-threshold bandwidth reservation scheme combined with a call a...
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ISBN:
(纸本)9781424412501
nextgeneration wireless communication systems target to provide guaranteed Quality of Service (QoS) for multimedia applications. In this paper, a multiple-threshold bandwidth reservation scheme combined with a call admission control algorithm is proposed and analyzed. The objective of our work is to be able to achieve better QoS provisioning for mobile users while achieving efficient utilization of the available limited bandwidth. The proposed scheme is modelled as M/M/C/C queueing system and the performance measures, call blocking probability and call dropping probability are computed. The performance of our scheme is compared to the Complete Sharing (CS) policy. Simulation results show that our scheme surpasses the CS policy in terms of call blocking probability, call dropping probability and bandwidth utilization.
The nextgeneration wireless networks will consist of several overlapping tiers. Provision of undisrupted communication to mobile users is a challenging task. In this paper, we propose handoff management schemes for h...
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ISBN:
(纸本)9781424412716
The nextgeneration wireless networks will consist of several overlapping tiers. Provision of undisrupted communication to mobile users is a challenging task. In this paper, we propose handoff management schemes for hybrid IEEE 802.11g and IEEE 802.16e networks. We assume that mobile nodes can roam in the area under hybrid WiMAX (TM)(IEEE 802.16e) and Wi-Fi (TM) (IEEE 802.11g) two-tier networks architecture. Some network information such as bandwidth, blocking probability, dropping probability, and different type of traffics are considered as performance metrics. Using the above metrics, we propose two proper handoff management schemes. Therefore, different kinds of users can gain the suitable service. We also consider the cost of service and quality of service (QoS) to obtain user's best benefit. The results show that the system performance is really improved over the original scheme.
This article studies disruption tolerant networks (DTNs) where each node knows the probabilistic distribution of contacts with other nodes. It proposes a framework that allows one to formalize the behaviour of such a ...
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ISBN:
(纸本)97830540726050
This article studies disruption tolerant networks (DTNs) where each node knows the probabilistic distribution of contacts with other nodes. It proposes a framework that allows one to formalize the behaviour of such a network. It generalizes extreme cases that have been studied before where either (a) nodes only know their contact frequency with each other or (b) they have a perfect knowledge of who meets who and when. This paper then gives an example of how this framework can be used;it shows how one can find a packet forwarding algorithm optimized to meet the delay/bandwidth consumption trade-off: packets are duplicated so as to (statistically) guarantee a given delay or delivery probability, but not too much so as to reduce the bandwidth, energy, and memory consumption.
In 2006 Deutsche Telekom initiated a full scale roll-out of VDSL-based broadband access technology providing the coverage of about 8 Mio. Customers with very high speed internet accesses by end of the year. Motivation...
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ISBN:
(纸本)9783800730421
In 2006 Deutsche Telekom initiated a full scale roll-out of VDSL-based broadband access technology providing the coverage of about 8 Mio. Customers with very high speed internet accesses by end of the year. Motivation, realization and practical experiences will be discussed.
Wireless sensornetworks represent a new generation of real time traffic communications and high data rate sensor applications such as structural health monitoring and control. In this work we study some problems of d...
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The paper investigates the antenna design to be applied in the ESPACENET sensor node. The project involves a network of autonomous pico satellites working at a large number of communication standards and as passive ra...
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ISBN:
(纸本)9780769528663
The paper investigates the antenna design to be applied in the ESPACENET sensor node. The project involves a network of autonomous pico satellites working at a large number of communication standards and as passive radar sensors for earth observation. They would form the nextgeneration of "eyes in the skies";looking out for natural disasters, helping in the survey and effective utilization of natural resources and also form a seamless network of global communication which will have the potential to evolve itsetf with the growing demands of tomorrow's world. We discuss the need for a multiple frequency broadband antenna which would help cover a larger range of microwave frequencies enabling the antenna to work as both a communications antenna and a sensor device.
Providing efficient and reliable communication in wireless sensornetworks is a challenging problem. To recover from corrupted packets, previous approaches have tried to use retransmissions and FEC mechanisms. The ene...
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ISBN:
(纸本)9781424410460
Providing efficient and reliable communication in wireless sensornetworks is a challenging problem. To recover from corrupted packets, previous approaches have tried to use retransmissions and FEC mechanisms. The energy efficiency of these mechanisms, however, is very sensitive to unreliable links. In this paper, we present cluster-based forwarding, where each node forms a cluster such that any node in the next-hop's cluster can take forwarding responsibility. This architecture, designed specifically for wireless sensornetworks, achieves better energy-efficiency by reducing retransmissions. Cluster-based forwarding is not a routing protocol. Rather, it is designed as an extension layer that can augment existing routing protocols. Using simulations, we demonstrate that duster-based forwarding is effective in improving both end-to-end energy efficiency and latency of current routing protocols.
For an ad hoc IEEE 802.11 WLAN we investigate how the stations' incentives to launch a backoff attack i.e., to configure small minimum and maximum CSMA/CA contention windows in pursuit of a larger-than-fair bandwi...
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ISBN:
(纸本)97830540726050
For an ad hoc IEEE 802.11 WLAN we investigate how the stations' incentives to launch a backoff attack i.e., to configure small minimum and maximum CSMA/CA contention windows in pursuit of a larger-than-fair bandwidth share, affect a proposed capacity-fairness index (CFI). We link CFI to the network size, "power awareness," a station's perception of the other stations' susceptibility to incentives, and the way of learning how the other stations perceive the other stations' susceptibility to incentives.
In this paper, we present the experiments with robots in a wireless sensor network environment to support intelligent generation of group behaviors. We propose real-time software architecture in a wireless sensor netw...
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ISBN:
(纸本)9780769529752
In this paper, we present the experiments with robots in a wireless sensor network environment to support intelligent generation of group behaviors. We propose real-time software architecture in a wireless sensor network (WSN) environment for practical applications. The architecture is a layered architecture including decision making, knowledge processing, execution, and communication and sensor/actuator layers. The proposed architecture is tested for the multi-robot environment, where the robots are expected to exhibit group behaviors. The rules are written in CLIPS expert system tool to perform intelligent behavior generation and dynamic reasoning so as to make the behaviors more realistic.
nextgeneration mobile networks frequently offer services and applications that require the stations position. It is well known that adding nodes to an existing wireless network enhances the localization accuracy of t...
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ISBN:
(纸本)9781424409761
nextgeneration mobile networks frequently offer services and applications that require the stations position. It is well known that adding nodes to an existing wireless network enhances the localization accuracy of the network nodes. We exploit a recent compact expression of the Cramer-Rao bound to identify the nodes whose localization is improved. Further, we define the exact conditions for error reduction. In particular, in a planar network, an additional node must have at least three connections, not all of them to anchors, to affect the accuracy. We also show that the accuracy improvement is limited by a bound, which is independent of the number of additional nodes. Finally, we provide numerical examples that shed some light on the accuracy improvement.
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