Lancaster University, U.K.
de Catalunya, Barcelona, Spain
University of Bern, Switzerland
Delft University of Technology,
of Technology, germany
University of geneva,
University of Berlin,
Institute of Patras, greece
heterogeneous Sensor nodes
The federation comprises more than 500 stationary sensor nodes (mainly iSense, 5 MicaZ, 8
and Pacemate, 24 SunSPOT, 29 and TelosB25) supporting a range of sensor modalities, including
temperature, humidity, light, acceleration, and magnetic fields, as well as approximately 60
mobile sensor nodes and 40 outdoor nodes. each site offers a “portal server” that exposes its
capabilities to the outside world through an i WSn interface. Most sites also contribute one or
more simulator engines running simulated parts of VTBs.
figure. 1. wiseBeD physical testbed environment. in this federation of physical wsn testbed sites (nine today), each differs in its choice of
hardware, software, and physical layout.
emulate node mobility (of physical,
simulated, and emulated nodes) by dynamically changing the emulated connectivity between nodes according to a
time-based script. 3
From the user’s point of view, a VTB
would appear as an instance of a Web
services interface called i WSN supporting a comprehensive set of testbed-re-lated operations, including loading experimental code and collecting results.
Users typically employ a GUI-based
front-end to mediate access to their
VTB rather than interact with their
i WSN instance directly.
The user’s view of the entire VTB-based WSN experimentation process is
captured in a series of (potentially iterated) steps (see Figure 2):
Experimental software development.
Users employ our software development kit (SDK, http://www.wisebed.eu)
to develop and synthesize software that
can be deployed in a VTB;
VTB specification. They specify a
custom VTB that meets the requirements of their experiment in terms of
its physical, simulated, and emulated
VTB reservation. They contact our
reservation system to request their
custom-specified VTB be instantiated
at a particular time for a particular
duration. The reservation system re-
serves a set of underlying resources
able to support the VTB and returns a
“reservation key” that uniquely iden-
tifies the reservation and serves as a
promise that a VTB (as specified) will
be made available at the requested
figure 2. user view of VtB-based wsn system development.
User’s desired dates/times
to run experiment User’s code linked
with SDK runtime
3. V TB
User’s V TB
V TB specification
jAnUARY2012 | VOL. 55 | nO. 1 | CoMMuniCations of the aCM 85