Next Generation Internet 2011 Kaiserslautern Adaptive and - PDF document

Keynote Talk @ Conference on Next Generation Internet 2011 Kaiserslautern Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Torsten Braun, Universität Bern, Switzerland Institute of Computer Science and Applied Mathematics Research Group “Computer Networks and Distributed Systems” braun@iam.unibe.ch rvs.unibe.ch joint work with Philipp Hurni, Benjamin Nyffenegger, Sebastian Barthlomé Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Overview Introduction > Experimentation in Wireless Sensor Networks > — Wireless Sensor Network (WSN) Testbed — Software-Based Energy Measurement Research Experiments > — Maximally Traffic-Adaptive and Energy-Efficient WSN MAC Protocol — Adaptive Forward Error Correction Conclusions and Outlook > Kaiserslautern, June 27, 2011 2

Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Wireless Sensor Network Applications Monitoring of buildings > Markus Wälchli, Torsten Braun: Building Intrusion Detection with a Wireless Sensor Network, 1st International Conference on Ad Hoc Networks, Niagara Falls, 2009 Kaiserslautern, June 27, 2011 3 Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Wireless Sensor Network Applications Environmental monitoring > Thomas Staub, Benjamin Nyffenegger, Desislava Dimitrova, Torsten Braun: Operational Support of Wireless Mesh Networks Deployed for Extending Network Connectivity, 1st International Workshop on Opportunistic Sensing and Processing in Mobile Wireless Sensor and Cellular networks (MobiSense), Bilbao, May 9-11, 2011 Kaiserslautern, June 27, 2011 4

Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Application Requirements Energy-efficient operation > Low delays > Reliability > Adaptivity to varying link characteristics and traffic load > Kaiserslautern, June 27, 2011 5 Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Design, Implementation, and Evaluation of Wireless Sensor Network Protocols Simulations are only meaningful with accurate calibration of > parameters, e.g., energy consumption, transmission characteristics, traffic models. Experiments in testbeds give insights about protocol behaviour > in more realistic scenarios and system-related issues, but face several problems — Experiment control — Scalability — Reproducability — Energy measurements — Mobility Kaiserslautern, June 27, 2011 6

Wireless Sensor Network Testbed Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Wireless Sensor Network Testbed (WISEBED) Recently finished FP7 FIRE STREP > Pan-European federation of 9 > wireless sensor network testbeds approx. 1000 deployed nodes > Each partner runs own testbed Testbed > Testbed Testbed with different hardware. Requirement: > uniform testbed infrastructure, Testbed i.e., standardization of access (description of experiments Testbed and results) Testbed Kaiserslautern, June 27, 2011 8

Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks General Testbed Infrastructure Portal > WSN Testbed — Gateway between Internet and WSN part of Internet WISEBED — Used for WSN management Wireless Sensor Network > — Sensor nodes communicate with each other. Portal DB — Backbone used to communicate with th portal. WSN Backbone Testbed Internet > part of WISEBED — connects all WISEBED testbeds Wireless Sensor Network (WSN) Kaiserslautern, June 27, 2011 9 Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Testbed @ Universität Bern Mesh Node Internet USB Ethernet LAN wireless Portal (running TARWIS management system) Sensor Node 10 Kaiserslautern, June 27, 2011

Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Testbed @ Universität Bern Approx. 50 TelosB/MSB nodes connected to portal > via Ethernet with temperature, humidity, light sensors Kaiserslautern, June 27, 2011 11 Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks TARWIS System Architecture Kaiserslautern, June 27, 2011 12

Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Testbed / Sensor Node Reservation Reservation system maintains per-site reservation database. > User Interfaces > — Web-based user interface — iPhone application Kaiserslautern, June 27, 2011 13 Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks TARWIS Experiment Configuration Kaiserslautern, June 27, 2011 14

Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks TARWIS Experiment Monitoring Kaiserslautern, June 27, 2011 15 Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks TARIWS-Generated Experiment Trace Kaiserslautern, June 27, 2011 16

Software-Based Estimation of Energy Consumption Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Software-Based Estimation of Energy Consumption Problem: > Equipment of sensor nodes with measurement hardware is — very expensive. — difficult in out-door environments / real-world deployments. — not sufficient to support energy-awareness. Solution: > Software-based energy measurement (calibration using measurement hardware) Kaiserslautern, June 27, 2011 18

Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Hardware-Based Energy Measurements Measurement of current draw and voltage using > Sensor Network Management Devices (SNMD) from KIT Kaiserslautern, June 27, 2011 19 Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Simple 3-State-Model A. Dunkels, F. Osterlind, N. Tsiftes, Z. He: Software-based On-line Energy Estimation for Sensor Nodes. IEEE EmNets, 2007 Kaiserslautern, June 27, 2011 20

Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Measured vs. Estimated Energy Consumption Approach: Measurement of current draw in different states and energy estimation by Kaiserslautern, June 27, 2011 21 Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks 3-State-Model with State Transitions Revised estimation: Kaiserslautern, June 27, 2011 22

Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Estimation Accuracy OLS: Ordinary Least Squares Regression Analysis Kaiserslautern, June 27, 2011 23 MaxMAC: Maximally Traffic-Adaptive and Energy-Efficient WSN MAC Protocol

Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks Energy Consumption of Wireless Sensor Nodes Energy consumption as important issue in WSNs > Transmission of 1 bit consumes similar energy as processing > 100-1000 instructions. Transmitting and receiving consume similar power. > Startup times to be considered > Medium Access Control Protocols avoid overhearing and idle listening by switching off the transceiver > collisions and retransmissions > control packets > frequent transmissions, e.g., by aggregation > Kaiserslautern, June 27, 2011 25 Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks MAC Protocols for Wireless Sensor Networks Scheduled Protocols 1. — Multiplexing and Allocation of channels, e.g., time multiplexing, requires accurate time synchronization Contention-based Protocols 2. — Channel sharing and allocation on-demand, often: periodic wake-ups — Problems: collisions and delays — Sender must ensure that receiver is awake during transmission Transmissions of long preambles/beacons (B-MAC, X-MAC, WiseMAC) – Weakly synchronized wakeups (S-MAC, T-MAC) – Receiver signals wakeup (RI-MAC) – — Load adaptation Adaptation of wakeup time dependent on activation events or load – (T-MAC, X-MAC) Wake-up interval Kaiserslautern, June 27, 2011 26

Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks WiseMAC Very energy-efficient MAC protocol > Unsynchronized nodes wakeup for a short time > T preamble = min {4θL,T} > — θ: clock drift, L: time since last update, T: duration of a cycle — Max. clock drift: 2θL, sender must start preamble transmission 2θL prior to wakeup and transmit it until 2θL after wakeup. „Piggybacking“ of wakeup times > Enz et al.: WiseNET: An Ultralow-Power Wireless Sensor Network Solution, IEEE Computer, Vol. 37, No. 8; August 2004 Kaiserslautern, June 27, 2011 27 Torsten Braun: Adaptive and Energy-Efficient Protocols for Wireless Sensor Networks IdealMAC Idealized MAC protocol: only active, when data are > transmitted or received. Kaiserslautern, June 27, 2011 28