THE INFLUENCE OF MAC BUFFER ON THE CONTENTION-BASED ACCESS SCHEME WITH BURSTING OPTION FOR IEEE 802.11E WIRELESS NETWORKS

Wireless LANs are increasingly being used for inelastic applications. Currently, there is little support for quality of service in the IEEE 802.11 MAC protocol, and IEEE task group E has defined the 802.11e MAC extension. Enhanced distributed channel access (EDCA) is a contention-based scheme of the 802.11e standard. To allow a station to transmit more than one frame from a single contention, an optional feature known as controlled frame-bursting (CFB) is introduced in the standard. In this paper, we initially performed an average analysis to determine a suitable burst duration limit. Then, a detailed evaluation and comparison of the EDCA protocol with the CFB option is carried out through simulation to quantify its performance gain. The impact of the MAC transmit buffer size is also incorporated. Accordingly, we have proposed a suitable approach to guide the configuration of the burst duration limit. It is demonstrated that an optimized CFB configuration allows the MAC protocol to achieve 30% more capacity than the basic EDCA scheme

Incomplete LU preconditioner for FMM implementation

An incomplete LU (ILU) preconditioner using the near-field matrix of the fast multipole method (FMM) is investigated to increase the efficiency of the iterative conjugate gradient squared (CGS) solver. Unlike the conventional LU, ILU requires no fill ins, and hence no extra memory and CPU time in computing the LU decomposed preconditioner. It is shown that, due to the nature of the near-field matrix, ILU preconditioning decreases the number of iterations dramatically. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 26: 265–267, 2000.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35044/1/18_ftp.pd

The time controlled clustering algorithm for optimised data dissemination in Wireless Sensor Networks

As the communication task is a significant power consumer, there are many attempts to improve energy efficiency. Node clustering, to reduce direct transmission to the base station, is one such attempt to control data dissemination. Here, we derived the optimal number of clusters for TCCA clustering algorithm based on a realistic energy model using results in stochastic geometry

A configurable time-controlled clustering algorithm for wireless sensor networks

Future large-scale sensor networks may comprise thousands of wirelessly connected sensor nodes that could provide an unimaginable opportunity to interact with physical phenomena in real time. These nodes are typically highly resource-constrained. Since the communication task is a significant power consumer, there are various attempts to introduce energy-awareness at different levels within the communication stack. Clustering is one such attempt to control energy dissipation for sensor data routing. Here, we propose the time-controlled clustering algorithm to realise a network-wide energy reduction by the rotation of clusterhead role, and the consideration of residual energy in its election. A realistic energy model is derived to accurately quantify the network\u27s energy consumption using the proposed clustering algorithm

An Adaptive Data Dissemination Strategy for Wireless Sensor Networks

Future large-scale sensor networks may comprise thousands of wirelessly connected sensor nodes that could provide an unimaginable opportunity to interact with physical phenomena in real time. However, the nodes are typically highly resource-constrained. Since the communication task is a significant power consumer, there are various attempts to introduce energy-awareness at different levels within the communication stack. Clustering is one such attempt to control energy dissipation for sensor data dissemination in a multihop fashion. The Time-Controlled Clustering Algorithm (TCCA) was proposed to realize a network-wide energy reduction. A realistic energy dissipation model is derived probabilistically to quantify the sensor network’s energy consumption using the proposed clustering algorithm. A discrete-event simulator is developed to verify the mathematical model and to further investigate TCCA in other scenarios. The simulator is also extended to include the rest of the communication stack to allow a comprehensive evaluation of the proposed algorithm

An Energy Efficient Event Processing Algorithm for Wireless Sensor Networks

Abstract. Wireless sensor networks are being deployed in many monitoring scenarios as fundamental data collection protocols are becoming efficient in handling simple sense-and-send function. As the computation capacity of sensor nodes grows, these nodes are capable of performing more complicated functions. Moreover, the need to realize the complete loop of sense-controlactuate as the wired sensing facility demands for more in-network processing to be able to generate meaningful in-network actuation. One such useful primitive function for many applications is edge or boundary detection of a phenomenon. In this work, we propose a localized edge detection algorithm using basic geometry rules that just uses one-hop neighbourhood information. This algorithm is accordingly benchmarked against one of the best localised edge detection scheme available in the public domain. It is found that the proposed algorithm readily outperforms its counterpart. Moreover, its energy efficient operation is attractive as a primitive implementation for other more complex primitives or applications themselves. Keywords: In-network processing, edge detection, localized algorithm, data processing, pattern recognition.

An Adaptive Data Dissemination Strategy for Wireless Sensor Networks

Future large-scale sensor networks may comprise thousands of wirelessly connected sensor nodes that could provide an unimaginable opportunity to interact with physical phenomena in real time. However, the nodes are typically highly resource-constrained. Since the communication task is a significant power consumer, various attempts have been made to introduce energy-awareness at different levels within the communication stack. Clustering is one such attempt to control energy dissipation for sensor data dissemination in a multihop fashion. The Time-Controlled Clustering Algorithm (TCCA) is proposed to realize a network-wide energy reduction. A realistic energy dissipation model is derived probabilistically to quantify the sensor network's energy consumption using the proposed clustering algorithm. A discrete-event simulator is developed to verify the mathematical model and to further investigate TCCA in other scenarios. The simulator is also extended to include the rest of the communication stack to allow a comprehensive evaluation of the proposed algorithm