http://www.eecs.ucf.edu/~dcm/Teaching/COT4810-Spring2011/Literature/SensorNetworksSurvey.pdf

Wireless sensor networks: a survey

Wireless distributed microsensor systems will enable the reliable monitoring of a variety of environments for both civil and military applications. In this paper, we look at communication protocols, which can have significant impact on the overall energy dissipation of these networks. Based on our findings that the conventional protocols of direct transmission, minimum-transmission-energy, multi-hop routing, and static clustering may not be optimal for sensor networks, we propose LEACH (Low-Energy Adaptive Clustering Hierarchy), a clustering-based protocol that utilizes randomized rotation of local cluster based station (cluster-heads) to evenly distribute the energy load among the sensors in the network. LEACH uses localized coordination to enable scalability and robustness for dynamic networks, and incorporates data fusion into the routing protocol to reduce the amount of information that must be transmitted to the base station. Simulations show the LEACH can achieve as much as a factor of 8 reduction in energy dissipation compared with conventional outing protocols. In addition, LEACH is able to distribute energy dissipation evenly throughout the sensors, doubling the useful system lifetime for the networks we simulated.

/pdf/energy-efficient-communication-protocol-for-wireless-4vhuagusz2.pdf

Energy-efficient communication protocol for wireless microsensor networks

Wireless distributed microsensor systems will enable the reliable monitoring of a variety of environments for both civil and military applications. In this paper, we look at communication protocols, which can have signicant impact on the overall energy dissipation of these networks. Based on our ndings that the conventional protocols of direct transmission, minimum-transmission-energy, multihop routing, and static clustering may not be optimal for sensor networks, we propose LEACH (Low-Energy Adaptive Clustering Hierarchy), a clustering-based protocol that utilizes randomized rotation of local cluster base stations (cluster-heads) to evenly distribute the energy load among the sensors in the network. LEACH uses localized coordination to enable scalability and robustness for dynamic networks, and incorporates data fusion into the routing protocol to reduce the amount of information that must be transmitted to the base station. Simulations show that LEACH can achieve as much as a factor of 8 reduction in energy dissipation compared with conventional routing protocols. In addition, LEACH is able to distribute energy dissipation evenly throughout the sensors, doubling the useful system lifetime for the networks we simulated.

Energy-efficient communication protocols for wireless microsensor networks

Networking together hundreds or thousands of cheap microsensor nodes allows users to accurately monitor a remote environment by intelligently combining the data from the individual nodes. These networks require robust wireless communication protocols that are energy efficient and provide low latency. We develop and analyze low-energy adaptive clustering hierarchy (LEACH), a protocol architecture for microsensor networks that combines the ideas of energy-efficient cluster-based routing and media access together with application-specific data aggregation to achieve good performance in terms of system lifetime, latency, and application-perceived quality. LEACH includes a new, distributed cluster formation technique that enables self-organization of large numbers of nodes, algorithms for adapting clusters and rotating cluster head positions to evenly distribute the energy load among all the nodes, and techniques to enable distributed signal processing to save communication resources. Our results show that LEACH can improve system lifetime by an order of magnitude compared with general-purpose multihop approaches.

/pdf/an-application-specific-protocol-architecture-for-wireless-1s7y9fiv40.pdf

An application-specific protocol architecture for wireless microsensor networks

Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

Pattern Recognition and Machine Learning

Run-Time Adaptation with Resource Co-Allocation for Grid Environments

Bulk transfers from one to multiple datacenters can have many different completion time objectives ranging from quickly replicating some $k$ copies to minimizing the time by which the last destination receives a full replica. We design an SDN-style wide-area traffic scheduler that optimizes different completion time objectives for various requests. The scheduler builds, for each bulk transfer, one or more multicast forwarding trees which preferentially use lightly loaded network links. Multiple multicast trees are used per bulk transfer to insulate destinations that have higher available bandwidth and can hence finish quickly from congested destinations. These decisions--how many trees to construct and which receivers to serve using a given tree--result from an optimization problem that minimizes a weighted sum of transfers' completion time objectives and their bandwidth consumption. Results from simulations and emulations on Mininet show that our scheduler, Iris, can improve different completion time objectives by about $2.5\times$.

Efficient Inter-Datacenter Bulk Transfers with Mixed Completion Time Objectives

Minimal Full-Access (MFA) networks are the class of all interconnection networks for N = 2n inputs and outputs that require a minimum number of switching elements and provide full access capability. In this paper, MFA networks with 2 × 2 switching elements that use the same interconnection pattern between the stages are studied; such networks are called uniform MFA (UMFA) networks. Most of the known networks, including the Omega, the binary n-cube, and the regular (2, 2)-banyan, belong to this class. A graph-theoretic approach is used to study the class of UMFA networks, and a procedure is described to derive topologically nonequivalent networks from the Omega network. It is shown that the number of UMFA networks grow exponentially with N, and a lower bound of about 2N/32 is obtained for N ⩾ 32. We also outline an extension of our methods to derive similar bounds for networks using k × k switches, for k ⩾ 3.

Uniform Minimal Full-Access Networks.

AN Efficient Sort-Last Polygon Rendering Scheme on 2-D Mesh Parallel Computers.

This paper presents a novel method for comparing the performance of multicast protocols in mobile ad hoc networks (MANETs) with respect to delay, efficiency, and robustness. For each metric, we develop the notion of optimality that allows us to compare performance against a common set of reference points. Knowing where a protocol's performance diverges from optimal also indicates where efforts at improvement will provide the most benefit. Next we present a cross-platform physical layer model that allows researchers working with different simulation packages use a common physical model of the network. We then use simulations to illustrate the performance of a candidate protocol relative to optimal. An interesting result of the simulations is that MANET nodes with very high degrees of connectivity do not necessarily improve the performance of multicast routing protocols.

Cauligi S. Raghavendra

Papers

Run-Time Adaptation with Resource Co-Allocation for Grid Environments

Efficient Inter-Datacenter Bulk Transfers with Mixed Completion Time Objectives

Uniform Minimal Full-Access Networks.

AN Efficient Sort-Last Polygon Rendering Scheme on 2-D Mesh Parallel Computers.

Comparing multicast protocols in mobile ad hoc networks