this paper presents a study on power management optimisation over a sensor network. We have proposed a set of management rules which are executed by each sensor of the network. these rules adapt themselves to sensors ...
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ISBN:
(纸本)9781424444885
this paper presents a study on power management optimisation over a sensor network. We have proposed a set of management rules which are executed by each sensor of the network. these rules adapt themselves to sensors depending on their energy status and on the network energy. Periodically, each sensor computes its rules and decides how to behave (sleeping during a long period or not). An experimentation of these rules has been implemented, we used a distributed sort algorithm on the whole network. We have observed the network behaviour and noticed that the use of these rules allows to increase the average energy life up to 20 %.
Existing soil handoff techniques lead to plenty of out-of-sequence packets during downward vertical handoffs (DVHOs). In this paper, we present two new network-layer soft vertical handoff schemes, called SHORDER and E...
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ISBN:
(纸本)9781424444885
Existing soil handoff techniques lead to plenty of out-of-sequence packets during downward vertical handoffs (DVHOs). In this paper, we present two new network-layer soft vertical handoff schemes, called SHORDER and E-SHORDER. the former can prevent mobile nodes from receiving reordered packets during DVHOs with a low overhead. the latter further hinders their correspondent nodes from receiving out-of-order packets caused by mobile nodes' DVHOs. then, we analyze the performance of our proposed approaches. By experiments, we show that they have a good effect in practice.
Mobility in a wireless heterogeneous scenario in which the mobile devices are able to connect to more than one access technology requires a new architectural development for the network connectivity management. the pr...
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ISBN:
(纸本)9781424444885
Mobility in a wireless heterogeneous scenario in which the mobile devices are able to connect to more than one access technology requires a new architectural development for the network connectivity management. the present paper describes and evaluates a set of architectural options for integrating the novel network discovery and selection functionality in the 3GPP Evolved Packet Core which enables an operator to manage the connections of the mobile devices. As the design options here presented consider different levels of network control on the mobility at the cost of new interfaces and new procedures, an evaluation based on these two criteria is given.
the ieee 802.16 standard specifies a MeSH mode of operation which permits the setup of Wireless Mesh networks (WMN) with per-link QoS support. the standard specifies both distributed as well as centralized reservation...
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ISBN:
(纸本)9781424444885
the ieee 802.16 standard specifies a MeSH mode of operation which permits the setup of Wireless Mesh networks (WMN) with per-link QoS support. the standard specifies both distributed as well as centralized reservation schemes. Distributed scheduling is highly flexible, and enables operation of the WMN even in the absence of a central controlling instance or base station. A systematic study of strategies for distributed scheduling in the ieee 802.16 MeSH mode is, however, missing. In this paper we model the individual links in the 802.16 WMN and design and derive efficient strategies for distributed scheduling to reserve bandwidth required for transmission on the modelled link. Additionally, we evaluate our proposed reservation model using simulations, study the impact of key parameters and identify issues for further research in WiMAX based WMNs.
Wireless mesh networks consist of stationary nodes that communicate over wireless connections. Since WLAN security standards are only applicable in the standard scenario where the access points are connected by a cabl...
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ISBN:
(纸本)9781424444885
Wireless mesh networks consist of stationary nodes that communicate over wireless connections. Since WLAN security standards are only applicable in the standard scenario where the access points are connected by a cable-bound backbone, nearly all mesh networks broacast messages in the clear. To secure these networks, and to reduce the amount of reencryption of messages, we propose to use group key agreement (GKA) protocols to agree on a common key for all nodes. In a mesh network, a message sent by a certain node can only be received directly by nodes within the broadcast range of the first node. thus we have neither direct point-to-point connections between nodes, nor do we have a perfect broadcast channel. We therefore compare the suitability of different GKA protocols proposed in the literature for mesh networks.
Many sensor networks are deployed to detect and track intruders. If the existence and location of sensor nodes is disclosed to the opponent, the nodes can be easily disabled or compromised. Wireless transmissions in t...
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ISBN:
(纸本)9781424444885
Many sensor networks are deployed to detect and track intruders. If the existence and location of sensor nodes is disclosed to the opponent, the nodes can be easily disabled or compromised. Wireless transmissions in the presence of the opponent are an important source of disclosure. In this paper, we first describe a way to quantify the stealthiness of the sensor node, with a numerical stealthiness metric. then, we introduce a local model based dissemination protocol, Try and Bounce (TAB) which takes into account stealth considerations while reporting and forwarding observation reports. In an experimental study comparing TAB to the widely used directed diffusion dissemination protocol, we find that TAB achieves significantly higher stealth for equivalent tracking accuracy, or, alternatively, lower tracking error for equivalent stealth expenditure.
A common radio technology used in wireless sensor networks is the ieee 802.15.4 standard. Wireless sensor networks have so far used custom, light-weight, and application specific network protocols on top of ieee 802.1...
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ISBN:
(纸本)9781424444885
A common radio technology used in wireless sensor networks is the ieee 802.15.4 standard. Wireless sensor networks have so far used custom, light-weight, and application specific network protocols on top of ieee 802.15.4, often optimized for resource constrained low power hardware. In order to achieve interoperability at the network layer, the Internet Engineering Task Force published a standard for the transmission of IPv6 packets over ieee 802.15.4 low-power wireless personal area networks, which provides an additional layer adapting the IPv6 network layer to the low power and resource constrained ieee 802.15.4 link layer. this paper provides an evaluation of several independent implementations of the IPv6 over ieee 802.15.4 standard. We describe the characteristics of the implementations and the protocol features supported. Our interoperability tests, carried out using two different hardware platforms, show that at least three implementations are to a large extend compatible with each other. At the end of the paper, we summarize recent work in the IETF to improve the IPv6 over ieee 802.15.4 technology.
Using push-to-talk applications in ad hoc networks is not straightforward. there are no inherent mechanisms to support priority of the voice traffic, to avoid great jitter and packet loss in face of large background t...
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ISBN:
(纸本)9781424444885
Using push-to-talk applications in ad hoc networks is not straightforward. there are no inherent mechanisms to support priority of the voice traffic, to avoid great jitter and packet loss in face of large background traffic loads. this paper presents three preemption mechanisms that can be applied to support push-to-talk traffic in multi-hop ad hoc networks. the mechanisms differ in the way the background traffic is treated: discard, buffering and inter-scheduling. It is shown that there is a trade-off between the impact on the background traffic and the service for the push-to-talk traffic. Discarding or buffering the background traffic leaves the push-to-talk traffic with very little impact by the background traffic, while inserting the low priority packets in the interval between the high priority packets incurs some cost to the push-to-talk traffic.
the routing and wavelength assignment (RWA) problem for multipoint-to-point communications in all-optical wavelength division multiplexing (WDM) networks is investigated in this paper. Two efficient algorithms, namely...
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ISBN:
(纸本)9781424444885
the routing and wavelength assignment (RWA) problem for multipoint-to-point communications in all-optical wavelength division multiplexing (WDM) networks is investigated in this paper. Two efficient algorithms, namely Reverse Shortest Path Tree routing (RSPT) and k-Bounded Edge Disjoint Path routing (EDPR), are proposed. the problem of minimizing the total cost while establishing a multipoint-to-point session can be solved by RSPT algorithm in polynomial time. Nevertheless, EDPR algorithm produces a significant reduction in the maximum number of wavelengths required per link (i.e., the link stress) by a multipoint-to-point session. Simulations demonstrate the efficiencies of these two algorithms in supporting multipoint-to-point communications in WDM networks.
the high-speed WLAN is standardized by the ieee 802.11 task group n. For wireless access in vehicular environments, it is standardized as ieee 802.11p which is based on 802.11n. Devices for wireless communication base...
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ISBN:
(纸本)9781424444885
the high-speed WLAN is standardized by the ieee 802.11 task group n. For wireless access in vehicular environments, it is standardized as ieee 802.11p which is based on 802.11n. Devices for wireless communication based on 802.11n draft are widely spreading in the world market now, but there is no report available which discusses the performance of such 802.11n devices. In this poster, we introduce a basic performance evaluation of ieee 802.11 devices. We show experimental results using 802.11n draft 2.0 devices which are available on the market. In particular, we tested the throughput performance and the coverage range of ieee 802.11n devices in outdoor environments during a car to car communication scenario. the experimental results show the limits of using ieee 802.11n devices in vehicular networks.
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