Energy-efficient Management of Heterogeneous Wireless Sensor Networks

Overview

This project focuses on the investigation of efficient and reliable communication mechanisms that are required for the efficient operation of a wireless sensor network (WSN) management framework. An appropriate WSN management architecture needs to be identified and implemented. The main scientific contributions will be in the design and evaluation of reliable unicast, multicast, and broadcast protocol mechanisms that are essential for the efficient maintenance of WSNs to support individual node management but also for application and operating system code updates / installations in the whole WSN or in parts of it. Reliable and robust transport protocols are needed to distribute operating system / application level code and node parameters efficiently as well as to solicit specific node information.

Project Details

MARWIS Architecture

MARWIS (Management ARchitecture for heterogeneous WIreless Sensor networks ) supports common management tasks such as visualization, monitoring, (re)configuration, updating and reprogramming in a wireless sensor network (WSN). It considers specific characteristics of WSNs and restricted physical resources of the nodes such as battery, computing power, memory or network bandwidth and link quality. To handle large heterogeneous WSN we propose to subdivide the network into smaller sensor subnetworks (SSNs), which contains sensor node of one type. A wireless mesh network (WMN) operates as backbone and builds the communication gateway between these SSNs. The mesh nodes operate also as communication gateway between the WSN and the Internet and perform the management tasks. All management tasks are controlled by a management station located in the Internet.

Figure 1: MARWIS architecture

Currently available sensor nodes are mainly prototypes for research purposes. We have evaluated a number of sensor nodes and selected some of them to build a heterogeneous WSN: ESB/MSB nodes, tmoteSKY/TelosB, BTnodes, and MICAz. As mesh node Wireless Router Application Platform boards (WRAP) has been selected. It contains an AMD Geode 233 CPU, 128 MB RAM and two IEEE 802.11g interfaces. On the sensor nodes Contiki is running as operating system. On the mesh nodes a small Linux distribution (kernel 2.6.14.6) is running.

Reliable Transport Protocols

Beside the MARWIS architecture we focuss on developping reliable transport protocols. In order to realize an interconnection between the WSN and an external network, we propose to use TCP/IP as the standard protocol for all network entities. TCP/IP is the de facto standard protocol suite for wired communication. By running TCP/IP in the WSN, it is possible to directly connect the WSN to a wired network infrastructure, without proxies or middle-boxes. While UDP can be used to transmit sensor data to a sink, TCP is used for administrative tasks such as sensor node configuration and updating program code. Because of the limited resources of the sensor nodes, the high packet loss, and the inefficiency in memory and energy consumption of TCP, it is rather difficult to implement TCP/IP on sensor nodes.

Using TCP/IP requires optimization and harmonization of the different layers, such as physical, data link, network, and transport layer. Protocols at the different layers have to exchange information across the layers. We present a cross layer designed communication architecture to enanble the use of TCP/IP. The main parts of the communication architecture are a MAC protocol, which implements the MAC layer of nonbeacon-enabled PANs defined in the IEEE 802.15.4 standard for peer-to-peer topologies, the Hop-to-Hop Reliability (H2HR) protocol, and the TCP Support for Sensor Nodes (TSS) protocol. For reliable multicast transport we propose the Sensor Node Overlay Mulitcast (SNOMC) protocol and the Reliable IP-Mulicast (REMC) protocol. The protocol stack is shown in Figure 2.

Figure 2: Protocol stack

Publications

	Gerald Wagenknecht, Markus Anwander, Marc Brogle, Torsten Braun: Reliable Multicast in Wireless Sensor Networks, 7. GI/ITG KuVS Fachgespräch Drahtlose Sensornetze , Berlin, Germany, September 25 - 26, 2008, pp. 69-72, Freie Universität Berlin, Fachbereich Mathematik und Informatik, Tech. Report B 08-12
	Markus Anwander, Gerald Wagenknecht, Torsten Braun: Management of Wireless Sensor Networks using TCP/IP, International Workshop on Sensor Network Engineering (IWSNE) at the 4th IEEE/ACM International Conference on Distributed Computing in Sensor Systems , Santorini Island, Greece, June 11, 2008, pp. II.1-II.8, ISBN 978-90-9023209-6
	Gerald Wagenknecht, Markus Anwander, Torsten Braun, Thomas Staub, James Matheka, Simon Morgenthaler: MARWIS: A Management Architecture for Heterogeneous Wireless Sensor Networks, 6th International Conference on Wired/Wireless Internet Communications (WWIC'08) , Tampere, Finland, Vol. LCNS, Nr. 5031, May 28 - 30, 2008, pp. 177-188, Springer, ISBN 978-3-540-68805-1
	Markus Anwander, Gerald Wagenknecht, Thomas Staub, Torsten Braun: Management of Heterogenous Wireless Sensor Networks, 6. GI/ITG KuVS Fachgespräch Drahtlose Sensornetze , Aachen, Germany, July 16 - 17, 2007, pp. 63-66, Distributed Systems Group, RWTH Aachen University, ISSN 0935-3232