EmTOS: A Development Tool for Heterogeneous Sensor Networks

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EmTOS A Development Tool forHeterogeneous
Sensor Networks
Center for Embedded Networked Sensing
L. Girod, T. Stathopoulos, N. Ramanathan, E.
Osterweil, T. Schoellhammer, R. Kapur and D.
Estrin Laboratory of Embedded Collaborative
Systems, UCLA http//lecs.cs.ucla.edu
Introduction How to Simulate and Deploy in a
Heterogeneous Environment?
Need For Heterogeneity
Previous Simulation Models

• Real Systems are Heterogeneous
• Use large numbers of small nodes (motes) for
  dense sensor coverage and smaller numbers of
  large nodes (microservers) for higher end
  computation, sensing, communication, storage
• Multihop Over Air Programming
• Wireless code distribution utility which
  reliably publishes code updates from a
  centralized microserver to each mote in the
  network
• Extensible Sensing System
• Sensor application which allows data collected
  on the motes to flow out of the network through
  microservers

• Simulating Motes TOSSIM
• Mote simulator which implements the lowest layer
  of components in the TinyOS API.
• Simulates only TinyOS mote applications.
• Requires identical code base run on every node.
• Limited support to simulate interaction with
  external stimuli.
• Simulating Microservers EmSim
• EmStar simulator composed of multiple service
  processes all run on Linux microservers
• Simulates only EmStar code with no support for
  TinyOS mote applications

Goals Provide a Full Range of Development
Environments for Testing
From Simulation to Deployment

• Support a Heterogeneous Environment
• Provide an integrated model which simulates
  complex interactions between all components of
  the system such as motes, microservers, NIMS,
  etc
• Range from Simulation to Pure In-Situ Operation
• Scale the number of nodes in the sensor
  network, and their geographic extent
• Reality the similarity of the platform, and the
  nature of its inputs, to a deployment in the
  applications intended target environment
• Readily Move Between Simulation and Deployment
• Run real code to eliminate configuration
  changes when moving from one environment to
  another

EmTOS Bringing EmStar and TinyOS together
 
The EmTOS Platform

• What is the EmTOS Platform?
• EmTOS is an extension of EmStar that enables an
  entire TinyOS application to run as a single
  EmStar module
• A Bridge Between TinyOS and EmStar
• EmTOS provides a virtual machine for TinyOS mote
  applications
• Unmodified real code is encapsulated within an
  EmTOS wrapper library
• EmTOS wrapper library simulates mote hardware by
  interfacing with underlying EmStar services

• EmTOS capabilities
• Supports simulations with different TinyOS
  builds on different nodes.
• Supports tiered architectures consisting of
  motes and microservers applications
• Supports TinyOS applications running on the PC
  using the real Mica2 RF channel
• EmTOS applications running on microservers can
  share access to the radio with other EmStar
  devices and applications
• Provides TinyOS access to EmStar visualization
  and analysis tools for debugging purposes

• Deploying Heterogeneous Applications on EmTOS
• EmTOS provides modules to gather application
  data from TinyOS using code interfaces and serial
  connections to motes
• Full Range of Simulation options
• Pure Simulation Mode All microserver and motes
  run within the EmStar environment using the
  simulation radio and sensor channel
• Emulation mode Microserver and mote code is
  simulated within the EmStar environment but
  communication between nodes is done natively on
  the motes using a real RF channel
• Real Mode All mote code is run natively over a
  real RF channel while a serial backchannel is
  used for debugging
• Hybrid Mode A mixture of Real and Emulated
  mode where selected nodes run natively

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