Cross-Layer Design of an Energy-Efficient Cluster Formation Algorithm with Carrier-Sensing Multiple Access for Wireless Sensor Networks

A new energy-efficient scheme for data transmission in a wireless sensor network (WSN) is proposed, having in mind a typical application including a sink, which periodically triggers the WSN, and nodes uniformly distributed over a specified area. Routing, multiple access control (MAC), physical, energy, and propagation aspects are jointly taken into account through simulation; however, the protocol design is based on some analytical considerations reported in the appendix. Information routing is based on a clustered self-organized structure; a carrier-sensing multiple access (CSMA) protocol is chosen at MAC layer. Two different scenarios are examined, characterized by different channel fading rates. Four versions of our protocol are presented, suitably oriented to the two different scenarios; two of them implement a cross-layer (CL) approach, where MAC parameters influence both the network and physical layers. Performance is measured in terms of network lifetime (related to energy efficiency) and packet loss rate (related to network availability). The paper discusses the rationale behind the selection of MAC protocols for WSNs and provides a complete model characterization spanning from the network layer to the propagation channel. The advantages of the CL approach, with respect to an algorithm which belongs to the well-known class of low-energy adaptive clustering hierarchy (LEACH) protocols, are shown

A Study of Topology Characteristics on the Real Deployment of Wireless Sensor Networks

This paper investigates the effects of three parameters on the power consumption of sensor motes namely transmit power, frequency channel and sampling rate. Two wireless sensor network (WSN) test-beds have been deployed with two different types of topology; distributed and centralized. The WSN test-beds are built by using Crossbow IRIS motes where the effects of both real indoor and outdoor environment are investigated. Two different scenarios are considered which are line of sight (LOS) and non-LOS for both scenarios. In the case of centralized WSN with star topology, we discovered an interesting finding that the various transmit powers (ranging from 3.2dBm to -17dBm) do not vary the consumed power or in other word, the consumed powers across various transmit powers are almost the same for a given fixed distance value. The only parameter that affects the power consumption is the sampling rate. By increasing the rate, we can reduce the power consumption significantly. In the case of distributed WSN, we discovered that both transmit power and sampling rate affect the power consumption. The transmit power must be reduced and the sampling rate must be increased in order to save power in distributed WSN

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