Random Walk Based Routing Protocol for Wireless Sensor Networks

International audienceIn recent years, design of wireless sensor networks using methodologies and mechanisms from other disciplines has gained popularity for addressing many networking aspects and providing more flexible and robust algorithms. We address in this paper the problem of random walk to model routing for data gathering in wireless sensor networks. While at first glance, this approach may seem to be overly simplistic and highly inefficient, many encouraging results that prove its comparability with other approaches have been obtained over the years. In this approach, a packet generated from a given sensor node performs a random motion until reaching a sink node where it is collected. The objective of this paper is to give an analytical model to evaluate the performance of the envisioned routing scheme with special attention to two metrics: the mean system data gathering delay and the induced spatial distribution of energy consumption. The main result shows that this approach achieves acceptable performance for applications without too stringent QoS requirements provided that the ratio of sink nodes over the total number of sensor nodes is carefully tuned

Data-collection capacity of IEEE 802.11-like sensor networks.

Chan Chi Pan.Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.Includes bibliographical references (leaves xiv-xv).Abstracts in English and Chinese.Chapter Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Overview --- p.1Chapter 1.2 --- Related Works --- p.1Chapter 1.3 --- Our Contributions --- p.2Chapter 1.4 --- Organization of the Thesis --- p.3Chapter Chapter 2 --- Definitions and Assumptions --- p.5Chapter 2.1 --- Data-collection Networks --- p.5Chapter 2.2 --- Assumptions --- p.9Chapter Chapter 3 --- Canonical Networks --- p.13Chapter 3.1 --- Theoretical Analysis --- p.13Chapter 3.1.1 --- Fixed Link Distance --- p.13Chapter 3.1.2 --- Variable Link Distance --- p.17Chapter 3.2 --- Simulation --- p.20Chapter Chapter 4 --- Beyond the Assumptions --- p.24Chapter 4.1 --- Multiple Interference --- p.24Chapter 4.2 --- HFD versus non-HFD performance --- p.27Chapter Chapter 5 --- Perfect Scheduling and IEEE 802.11 Scheduling --- p.30Chapter 5.1 --- Relationship between Perfect Scheduling and IEEE 802.11 Scheduling --- p.30Chapter 5.2 --- Throughput Analysis under IEEE 802.11 scheduling --- p.33Chapter Chapter 6 --- General Networks --- p.37Chapter 6.1 --- Discussion of HFP --- p.37Chapter 6.2 --- HFP Formulation --- p.39Chapter 6.3 --- Optimization in Finding Best HFP --- p.43Chapter 6.4 --- Experiment --- p.44Chapter 6.5 --- NS-2 Simulation --- p.47Chapter Chapter 7 --- Applying Canonical Network to General Networks --- p.49Chapter 7.1 --- Direct Application --- p.49Chapter 7.2 --- Manifold Canonical Network with Shorter Link Distance --- p.51Chapter 7.3 --- Robustness on Node Positions in Manifold Canonical Network --- p.54Chapter Chapter 8 --- Conclusion --- p.56Appendix A RTS/CTS and Power Control --- p.xReferences --- p.xi

ABSTRACT Multi-Hop Communication is Order-Optimal for Homogeneous Sensor Networks

The main goal of this paper is to show that multi-hop singleuser communication achieves the per node transport capac-ln N ity of Θ ( ) in homogeneous sensor networks, making it N order-optimal. Our contributions in this paper are threefold. First, we construct a route-discovery and scheduling scheme based on spatial TDMA for sensor networks. Second, we show that our schedule achieves a per node trans-ln N port capacity of Θ (), the same as that achievable by N beamforming. Third, we compare multi-hop communication and beamforming based methods in terms of the network power consumption required to attain a fixed throughput. Based on our power calculations, we conclude that if the channel attenuation is above a certain threshold (which we calculate), then multi-hop communication performs better, whereas below the threshold, beamforming is preferable

Distributed spatial analysis in wireless sensor networks

Wireless sensor networks (WSNs) allow us to instrument the physical world in novel ways, providing detailed insight that has not been possible hitherto. Since WSNs provide an interface to the physical world, each sensor node has a location in physical space, thereby enabling us to associate spatial properties with data. Since WSNs can perform periodic sensing tasks, we can also associate temporal markers with data. In the environmental sciences, in particular, WSNs are on the way to becoming an important tool for the modelling of spatially and temporally extended physical phenomena. However, support for high-level and expressive spatial-analytic tasks that can be executed inside WSNs is still incipient. By spatial analysis we mean the ability to explore relationships between spatially-referenced entities (e.g., a vineyard, or a weather front) and to derive representations grounded on such relationships (e.g., the geometrical extent of that part of a vineyard that is covered by mist as the intersection of the geometries that characterize the vineyard and the weather front, respectively). The motivation for this endeavour stems primarily from applications where important decisions hinge on the detection of an event of interest (e.g., the presence, and spatio-temporal progression, of mist over a cultivated field may trigger a particular action) that can be characterized by an event-defining predicate (e.g., humidity greater than 98 and temperature less than 10). At present, in-network spatial analysis in WSN is not catered for by a comprehensive, expressive, well-founded framework. While there has been work on WSN event boundary detection and, in particular, on detecting topological change of WSN-represented spatial entities, this work has tended to be comparatively narrow in scope and aims. The contributions made in this research are constrained to WSNs where every node is tethered to one location in physical space. The research contributions reported here include (a) the definition of a framework for representing geometries; (b) the detailed characterization of an algebra of spatial operators closely inspired, in its scope and structure, by the Schneider-Guting ROSE algebra (i.e., one that is based on a discrete underlying geometry) over the geometries representable by the framework above; (c) distributed in-network algorithms for the operations in the spatial algebra over the representable geometries, thereby enabling (i) new geometries to be derived from induced and asserted ones, and (ii)topological relationships between geometries to be identified; (d) an algorithmic strategy for the evaluation of complex algebraic expressions that is divided into logically-cohesive components; (e) the development of a task processing system that each node is equipped with, thereby with allowing users to evaluate tasks on nodes; and (f) an empirical performance study of the resulting system.EThOS - Electronic Theses Online ServiceGBUnited Kingdo