One of the exigent problems in wireless sensor networks is the recognition of network boundary and the detection of holes within the network. In this paper, we propose an algorithm in which every node in the network s...
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ISBN:
(纸本)9781424444885
One of the exigent problems in wireless sensor networks is the recognition of network boundary and the detection of holes within the network. In this paper, we propose an algorithm in which every node in the network self-detects whether it is a boundary node or an inner node by utilizing the available connectivity information and making no assumptions about the location awareness. the algorithm is efficient than existing schemes in terms of accuracy and energy consumption. It does not need high degree of connectivity as compare to other existing schemes. the simulation results prove the efficiency and accuracy of our algorithm.
We consider the multi-rate retry (MRR) capability provided by current 802.11 implementations and carry out simulation-based study of its impact on performance with state-of-the-art rate control mechanisms in typical i...
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ISBN:
(纸本)9781424444885
We consider the multi-rate retry (MRR) capability provided by current 802.11 implementations and carry out simulation-based study of its impact on performance with state-of-the-art rate control mechanisms in typical indoor wireless LAN scenarios. We find that MRR is more effective in non-congested environments, necessitating the need for a mechanism to differentiate between congested and non-congested situations to better exploit the MRR capability. We also observe that decoupling the long-term rate adaptation algorithm from the MRR mechanism is key to fully realizing the benefits of MRR.
Recently, ieee 802.11-based wireless networks have been widely adopted as the main access technology. this type of wireless network is know for its low cost, easy deployment and easy configuration. However, the radio ...
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ISBN:
(纸本)9781424444885
Recently, ieee 802.11-based wireless networks have been widely adopted as the main access technology. this type of wireless network is know for its low cost, easy deployment and easy configuration. However, the radio range of access points in an ieee 802.11-based wireless network is limited, thereby mobile nodes have to switch their access points frequently in order to maintain connections in a mobile environment. the question of how to minimize the handoff latency is still a research challenge in ieee 802.11 wireless networks. In this paper, a self-configured MAC layer handoff scheme is proposed to shorten the handoff latency by adjusting the MinChannelTime and MaxChannelTime dynamically. Simulation results demonstrate that this scheme can significantly reduce the handoff latency and achieve successful handoff at a reasonable probability.
In this paper, we establish a relationship between resource discovery protocol and cluster head election procedure. While doing so, we propose a multi-resource-criteria cluster head election mechanism that reduces the...
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ISBN:
(纸本)9781424444885
In this paper, we establish a relationship between resource discovery protocol and cluster head election procedure. While doing so, we propose a multi-resource-criteria cluster head election mechanism that reduces the computational and communication overhead incurred in resource discovery. the consequent resource discovery protocol thus necessitates a minimalist exchange of information that we provide through custom packet formats and message flows. the extent of improvement thus achieved in the proposed protocol over existing resource discovery mechanisms is shown by performance evaluation.
Optimized Link State Routing (OLSR) protocol is a table-driven proactive routing protocol for wireless mobile ad hoc networks. the key idea behind this protocol is to reduce the control message overheads by marking su...
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ISBN:
(纸本)9781424444885
Optimized Link State Routing (OLSR) protocol is a table-driven proactive routing protocol for wireless mobile ad hoc networks. the key idea behind this protocol is to reduce the control message overheads by marking subset of neighbors as Multi-Point Relays (MPRs). In this paper, we discuss problems of OLSR or other routing protocols that are due to mobility of nodes. We integrate our solutions to OLSR protocol and call it as Position-based OLSR (P-OLSR). Performance evaluation of OLSR and P-OLSR is done through NS simulation. Simulation results show that P-OLSR outperforms OLSR with respect to packet delivery, throughput, latency and normalized overheads.
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.
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.
Over the years, a considerable research effort has been applied to the design of ad hoc network routing protocols. However, there is still a lack of understanding of the subtle interactions between routing protocols a...
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ISBN:
(纸本)9781424444885
Over the years, a considerable research effort has been applied to the design of ad hoc network routing protocols. However, there is still a lack of understanding of the subtle interactions between routing protocols and lower layers in the protocol stack. In this paper, the instability which may arise when reactive routing protocols interact withthe ieee 802.11 MAC protocol is investigated. In particular, several erratic behaviours of the Ad hod On-demand Distance Vector (AODV) routing protocol in a congested ieee 802.11 ad hoc network are demonstrated. A cross-layer solution is proposed based on an Adaptive Bulk Trigger policy and a Dynamic Window Selection scheme. Simulation studies are presented which show that the proposed solution is effective in alleviating erratic behaviour of AODV and improving the end-to-end path stability.
In 802.16 networks, bandwidth request-grant mechanisms allow managing the uplink bandwidth needs of subscriber stations. Subscriber stations send their bandwidth requests to the base station, where most of the bandwid...
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ISBN:
(纸本)9781424444885
In 802.16 networks, bandwidth request-grant mechanisms allow managing the uplink bandwidth needs of subscriber stations. Subscriber stations send their bandwidth requests to the base station, where most of the bandwidth scheduling is centralized. After processing such requests, the base station schedules the transmission of uplink traffic. In this paper we present a preliminary investigation of some bandwidth allocation issues, related to the management of the perception of subscriber stations' bandwidth needs at the base station. We illustrate how the bandwidth perception varies depending on the policy used to manage bandwidth requests and grants. Focusing on the case of TCP Best Effort traffic, we assess by simulation the potential impact of such policies on the system's aggregate throughput.
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