Hanh Le

A Survey on Clustering Algorithms for Wireless Sensor Networks

A wireless sensor network (WSN)consisting of a large number of tiny sensors can be an effective tool for gathering data in diverse kinds of environments. The data collected by each sensor is communicated to the base station, which forwards the data to the end user. Clustering is introduced to WSNs because it has proven to be an effective approach to provide better data aggregation and scalability for large WSNs. Clustering also conserves the limited energy resources of the sensors. This paper synthesises existing clustering algorithms newss and highlights the challenges in clustering.

A survey on clustering algorithms for wireless sensor networks

A wireless sensor network (WSN)consisting of a large number of tiny sensors can be an effective tool for gathering data in diverse kinds of environments. The data collected by each sensor is communicated to the base station, which forwards the data to the end user. Clustering is introduced to WSNs because it has proven to be an effective approach to provide better data aggregation and scalability for large WSNs. Clustering also conserves the limited energy resources of the sensors. This paper synthesises existing clustering algorithms newss and highlights the challenges in clustering.

S-Web: An Efficient and Self-organizing Wireless Sensor Network Model

One of the major weaknesses of existing centralized algorithms in Wireless Sensor Network (WSN) routing is that sensor nodes are required to report their status (e.g. remaining energy level) to the central node (i.e. the Base Station ---BS) and receive configuration information from the BS (e.g. next hop routing). As a result, the WSNs suffer from high communication and/or computation overheads at sensor nodes to accommodate topology changes in the WSN. This paper proposes a novel scheme, called a Sensor Web (or S-Web), that organizes sensors into clusters based on their geographical location without requiring the sensors to have a Global Positioning System or actively locate themselves. The S-Web enables nodes to route data packets while consuming low energy in a decentralized manner. The model is self-organizing and distributed without the need of global network knowledge.

An Efficient Hybrid Medium Access Control Technique for Digital Ecosystems

A schedule-based approach, such as time division multiple access, is more efficient than a contention-based approach in terms of energy saving by switching sensors into sleeping mode. However, it does not use the transmission media effectively as each time slot is dedicated to a sensor and therefore cannot be used by others should it be idle. Moreover, a schedule-based approach requires a central node to manage and broadcast the schedule to other members, causing high delay and unscalability. On the other hand, contention-based protocols can be used in a distributed fashion. However, contention-based protocols such as IEEE 802.11 waste a lot of energy in idle listening. In this paper, we propose a hybrid approach between contention- and schedule-based protocols. The preliminary results using simulation and a test bed show that our proposed approach uses transmission media more efficiently, leading to lower delay while preserving energy for wireless sensor networks.

Investigation into Batman-adv Protocol Performance in an Indoor Mesh Potato Testbed

In this paper, we describe the performance of the B.A.T.M.A.N advanced (Batman-adv) protocol on an indoor Mesh Potato (MP) test bed. The MPs are small devices used for voice communications over the wireless medium but also supports data. The Batman-adv protocol is designed for ad hocwireless networks. We measure delay, packet loss in order to understand the MPs network performance. The experiments used packets of varying sizes over multiple hops. We analyze the data to see if the network latency for up to four hops is within the recommended boundaries set by ITU Recommendation G. 114. We also observe the how thenetworks performance is affected by the varying packet sizes. Finally the experiments also reveal the common issues found on the wireless medium and also indoor testbeds.

An Electronic Health Care - Cardiac Monitoring System

To address the issue of increasing health care costs and overcrowded care giving institutions, there is an increasing focus on the use of mobile technology and biological sensors in developing better Tele-health systems. Remote monitoring of cardiac activity is a central endeavor of Telemedicine. This article describes the implementation and evaluation of the performance of an electronic health ECG monitoring system utilizing mobile phones and Bluetooth-enabled ECG sensors.

An efficient mechanism for mobility support using peer-to-peer overlay networks

Expanding the Internet infrastructure to span mobile devices is a challenging task. The Internets addressing and routing scheme was originally designed for fixed devices making it inoperable without redirection and tracking functions such as those proposed by mobile IP. However, mobile IP requires prior network setup, and causes a large added overhead. In this paper, we propose a new approach to support mobile IP users using a peer-to-peer overlay network. The proposed overlay exploits locality to efficiently use the network resources and manage location data in a self-organizing and distributed fashion. The simulation results are presented.

PIPPON: A Physical Infrastructure-aware Peer-to-Peer Overlay Network

The scalability and efficiency of P2P systems are determined largely by two factors: the degree of matching between the P2P overlay and its underlying physical network, and the efficiency of the P2P application routing scheme. Most current P2P systems address one or the other but not both in an integrated manner. This paper proposes PIPPON, a two-layer architecture to address these performance issues. At the overlay network layer, the paper proposes a simple but effective geo-LPM/geo-partitioning scheme for constructing overlay that mirrors the physical Internet. At the application routing layer, the paper introduces a dynamic key tree that is built on the optimized overlay to rout P2P messages efficiently. Simulation results indicate that PIPPON is scalable and efficient, and holds promise as a platform for large scale P2P applications.

Investigation into BATMANd-0.3.2 Protocol performance in an indoor mesh potato testbed

The paper describes the performance of the B.A.T.M.A.N daemon (Batmand) protocol in an indoor Mesh Potato (MP) testbed. The MPs are small devices used for voice communications over the wireless medium but can also support data. The MPs along with the Batmand protocol are used to bring cheap telephony to rural areas. However there are no performance tests that show the quality of the service provided by the MPs and the Batman protocols. The experiments performed in this paper look at jitter, delay, packet loss and throughput in order to understand the MPs network performance. This work is an extension on an earlier work. This work adds to the initial work by providing more results and more conclusive conclusions. This work is an extension on an earlier work. This work adds to the initial work by providing more results and more conclusive conclusions. The experiments used packets of different sizes over an increasing number of hops. The data collected is analyzed and the network performance given the scenarios we present is observed. Furthermore, comparisons are made between the data obtained from the experiments and the ITU-Recommendation G.114 to see if the results from the experiments fall within the recommended boundaries.

A self-organising model for topology-aware overlay formation

One of the major weaknesses of existing peer-to-peer (P2P) networks is that their overlay structures do not correlate to the physical underlying network topology. As a result, the overlays waste network resources and introduce excessive end-to-end latency for P2P applications. In this paper, we present a new model for topology-aware overlay formation. Firstly, it clusters nodes that are close to each other in terms of network latency and network membership. Secondly, it discovers the underlying topology between clusters to form an efficient overlay. The model is self-organising and distributed without the need of global knowledge.