12,704 research outputs found
Coverage Protocols for Wireless Sensor Networks: Review and Future Directions
The coverage problem in wireless sensor networks (WSNs) can be generally
defined as a measure of how effectively a network field is monitored by its
sensor nodes. This problem has attracted a lot of interest over the years and
as a result, many coverage protocols were proposed. In this survey, we first
propose a taxonomy for classifying coverage protocols in WSNs. Then, we
classify the coverage protocols into three categories (i.e. coverage aware
deployment protocols, sleep scheduling protocols for flat networks, and
cluster-based sleep scheduling protocols) based on the network stage where the
coverage is optimized. For each category, relevant protocols are thoroughly
reviewed and classified based on the adopted coverage techniques. Finally, we
discuss open issues (and recommend future directions to resolve them)
associated with the design of realistic coverage protocols. Issues such as
realistic sensing models, realistic energy consumption models, realistic
connectivity models and sensor localization are covered
Unified clustering and communication protocol for wireless sensor networks
In this paper we present an energy-efficient cross layer protocol for providing application specific reservations in wireless senor networks called the “Unified Clustering and Communication Protocol ” (UCCP). Our modular cross layered framework satisfies three wireless sensor network requirements, namely, the QoS requirement of heterogeneous applications, energy aware clustering and data forwarding by relay sensor nodes. Our unified design approach is motivated by providing an integrated and viable solution for self organization and end-to-end communication is wireless sensor networks. Dynamic QoS based reservation guarantees are provided using a reservation-based TDMA approach. Our novel energy-efficient clustering approach employs a multi-objective optimization technique based on OR (operations research) practices. We adopt a simple hierarchy in which relay nodes forward data messages from cluster head to the sink, thus eliminating the overheads needed to maintain a routing protocol. Simulation results demonstrate that UCCP provides an energy-efficient and scalable solution to meet the application specific QoS demands in resource constrained sensor nodes. Index Terms — wireless sensor networks, unified communication, optimization, clustering and quality of service
Overlapping Multi-hop Clustering for Wireless Sensor Networks
Clustering is a standard approach for achieving efficient and scalable
performance in wireless sensor networks. Traditionally, clustering algorithms
aim at generating a number of disjoint clusters that satisfy some criteria. In
this paper, we formulate a novel clustering problem that aims at generating
overlapping multi-hop clusters. Overlapping clusters are useful in many sensor
network applications, including inter-cluster routing, node localization, and
time synchronization protocols. We also propose a randomized, distributed
multi-hop clustering algorithm (KOCA) for solving the overlapping clustering
problem. KOCA aims at generating connected overlapping clusters that cover the
entire sensor network with a specific average overlapping degree. Through
analysis and simulation experiments we show how to select the different values
of the parameters to achieve the clustering process objectives. Moreover, the
results show that KOCA produces approximately equal-sized clusters, which
allows distributing the load evenly over different clusters. In addition, KOCA
is scalable; the clustering formation terminates in a constant time regardless
of the network size
Energy Efficiency in Two-Tiered Wireless Sensor Networks
We study a two-tiered wireless sensor network (WSN) consisting of access
points (APs) and base stations (BSs). The sensing data, which is
distributed on the sensing field according to a density function , is first
transmitted to the APs and then forwarded to the BSs. Our goal is to find an
optimal deployment of APs and BSs to minimize the average weighted total, or
Lagrangian, of sensor and AP powers. For , we show that the optimal
deployment of APs is simply a linear transformation of the optimal -level
quantizer for density , and the sole BS should be located at the geometric
centroid of the sensing field. Also, for a one-dimensional network and uniform
, we determine the optimal deployment of APs and BSs for any and .
Moreover, to numerically optimize node deployment for general scenarios, we
propose one- and two-tiered Lloyd algorithms and analyze their convergence
properties. Simulation results show that, when compared to random deployment,
our algorithms can save up to 79\% of the power on average.Comment: 11 pages, 7 figure
Performance Analysis of Hierarchical Routing Protocols in Wireless Sensor Networks
This work focusses on analyzing the optimization strategies of routing
protocols with respect to energy utilization of sensor nodes in Wireless Sensor
Network (WSNs). Different routing mechanisms have been proposed to address
energy optimization problem in sensor nodes. Clustering mechanism is one of the
popular WSNs routing mechanisms. In this paper, we first address energy
limitation constraints with respect to maximizing network life time using
linear programming formulation technique. To check the efficiency of different
clustering scheme against modeled constraints, we select four cluster based
routing protocols; Low Energy Adaptive Clustering Hierarchy (LEACH), Threshold
Sensitive Energy Efficient sensor Network (TEEN), Stable Election Protocol
(SEP), and Distributed Energy Efficient Clustering (DEEC). To validate our
mathematical framework, we perform analytical simulations in MATLAB by choosing
number of alive nodes, number of dead nodes, number of packets and number of
CHs, as performance metrics.Comment: NGWMN with 7th IEEE International Conference on Broadband and
Wireless Computing, Communication and Applications (BWCCA 2012), Victoria,
Canada, 201
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