TempLab : A Testbed to Study the Impact of Temperature on Wireless Sensor Networks C.A. Boanoy, M.A. Zúñiga, J. Brownz, U. Roedigz, C. Keppitiyagama§, and K. Römer International Conference on Information Processing in Sensor Networks IEEE IPSN Presented by Ahmed Mohammed Mikaeil

TempLab : A testbed that allow to study and control the effects of temperature variations on wireless sensor network (WSN). The method used for designing and implementation of TempLab How TempLab can accurately reproduce a traces record of real world temperature profile for outdoor environments. A use case of TempLab to examine the impacts of temperature variations on WSN networking protocols. Overview

Introduction Background and motivation TempLab : Architecture and implementation TempLab in reproducing temperature profile TempLab use cases Outline Summery

Introduction Background and motivation TempLab : Architecture and implementation TempLab in reproducing temperature profile TempLab use cases Outline Summery

 Temperature has a strong impact on the performance of electronic and networks  Wireless sensor nodes  Such variations on RSSI lead to degradation of the link quality of the network Introduction

 Temperature can also introduces dynamic heterogeneity across the network nodes  Two nodes close to each others and with the same parameters, but with different on-board temperatures, will perform differently [Wennerstr¨om et al]  But how temperature affect the network operation ?

Introduction Background and motivation TempLab : Architecture and implementation TempLab in reproducing temperature profile TempLab use cases Outline Summery

 A few studies have started to evaluate the effect of temperature on network operations Wennerstr¨om et al- model as given Background Bannister et al.Impact of temperature on link quality Wennerstr¨om et al.Impact of meteorological conditions on the quality of links

 Besides these two initial studies, temperature at the network level has not received attention as at it received at device or node level !  To date, a low-cost flexible testbed to study the impacts of temperature variations on wireless sensor network operation still does not exist !  This paper is trying to close this gap by proposing a low cost testbed capable for reproducing real-world temperature profiles that can be used for studying the impact of temperature on WSN at network level Motivation

Introduction Background and motivation TempLab : Architecture and implementation TempLab in reproducing temperature profile TempLab use cases Outline Summery

TempLab architecture

 Testbed diagram  Temperature profiles model  Trace-based profiles: temperature traces collected using on site measurements from one or more nodes.  Model-based: estimation of the temperature at a certain location (available from satellites and meteorological stations )  TempLab- based: using Templab to vary the temperature of sensor nodes: if user needs to test the effect of specific temperature pattern on their WSN solutions. A model for reproducing temperature profiles Controller: Minimize error Temp profile / on-board temp Actuators: Heat-up / cool- down, sensor on- board temperature

 Controller: (closed-loop proportional-integral -PI,C++)  Minimize the difference between the desired temperature profile and the onboard temperature of the sensor node of interest Controller receive the temperatures reading of the node, it can be :  In-band: Sensor node itself has temperature sensor  Out-of-band: additional temperature sensor ( Thermometer )  Actuators: (C++ program,Open Z-Wave stack)  In-band: Sensor node control its on-board temperature  Out-of-band: Sensor node is not involved in controlling its temperature

Introduction Background and motivation TempLab : Architecture and implementation TempLab in reproducing temperature profile TempLab use cases Outline Summery

To evaluate TempLab’s ability of reproducing a given temperature profile  the authors used two temperature traces collected in outdoor deployment in Sweden  Winter trace: TempLab in reproducing temperature profile

 Summer trace:

Introduction Background and motivation TempLab : Architecture and implementation TempLab in reproducing temperature profile TempLab use cases Outline Summery

 To study the impact of temperature variation on routing protocols,the authors took IPv6 Routing Protocol for Low-Power and Lossy Network (RPL) - as an example  They program fifteen sensor node (sensornet-sensor ) - with a basic Contiki networking APP [ microcontroller OS-2kb ram, 40Kb rom ]  Each node sends a message to the root node (id 204) every minute and logs :  The t ransmitted and received packet  The on-board temperature  And the Expected Transmission Count (ETX) of the active links Impact of temperature on routing protocols

 The following figure show the impact of temperature variation on the RPL topology

 The temperature rising lead to a sudden rise of expected transmission count ETX and lead to the network partitioning [node 200 &210]

 To study the impact of temperatures on carrier-sense multiple access CSMA- MAC protocols  An experiments consisting of several transmitter- receiver pairs of Maxfor MTM-CM5000MSP nodes running Contiki-APP that use Contiki MAC protocol Maxfor MTM-CM5000MSP Impact of Temperature on MAC Protocols

 Impact on clear channel assessment CCA efficiency  The amount of clear channel assessment CCA failures decreases at high temperatures, leading to packets loss due to wrong clear channel assessments. [ ]

 The following figure show the impact on MAC efficiency  Energy expenditure and the amount of link-layer transmissions increases at high temperatures, due to the reduction on clear channel assessment efficiency

Introduction Background and motivation TempLa : Architecture and implementation TempLab in reproducing temperature profile TempLab use cases Outline Summery

Conclusion