Project
Proposal for Tiffany
Background:
The
PicoRadio project is a research effort exploring dense networks of very small
low-power System-On-Chip (SOC) devices. These devices communicate with each
other via radio links. The application
space for PicoRadio includes numerous types of sensor networks and anything
else that requires large numbers of inexpensive devices producing relatively
low-bandwidth data in a decentralized way.
In
order to build a system of this nature, we have to define very clearly how the
network will work i.e. what the pieces are, and how they fit together. A common way to do this is to construct a
high-level model of the system.
High-level means that it describes network function completely but in a
very general way - no unneeded details such as what kind of radios to use or
the specific way data is transmitted between nodes. A model is a formal description of a system that contains enough
information to completely describe how the system works. In our case we are viewing the system at a
high level, so the model tends to be symbolic, that is, a device (or node) may
be represented by a rectangle in a diagram and its behaviour may be described
using 'C' code or a finite state machine.
Communication between nodes may
be represented by lines between rectangles and communication behaviour
may also be described by finite state machines or some other of "model of
computation".
We use a software program called VCC (Virtual Component Compiler) to create our models. VCC allows you to draw the symbolic pictures an the relationships between nodes. It also allows you to "execute" the model i.e. provide a stimulus (sometimes called an event) at some input and see how the system described by the model would behave under the same circumstances.
We
already have a pretty good idea of how a PicoRadio system would look (its
"architecture"). We're
currently in the process of building an executable VCC model of a likely sensor
network. This network has three primary
node types, each with its own role.
These are: the sensor, the controller, and the actuator. Simply put, the controller asks for data
from a sensor (maybe a temperature sensor, or humidity, or whatever). The sensor responds with a sample. The controller has to know which sensor to
ask, where that sensor is, and how to ask it in order to get the right
data. The action of requesting a sample
may seem simple on the outside, but there are complexities in this dialog that
the model helps us to understand.
Actuators
are similar to sensors except that instead of sampling a physical attribute
(read-only), actuators "act" on the physical world (write-only). For instance, an actuator may be a
mechanical solenoid that moves a robot arm, a remote light switch, or an air
conditioner control.
Currently,
we have a team of two undergraduate researchers under the guidance of graduate
students working on the model. They are
focusing on the controller and sensor nodes and the communication between them. The actuator node also needs to be modeled.
Project
Outline:
This project will be the VCC modeling and simjlation of a
PicoRadio actuator node.
It
will follow these steps, more-or-less:
We’ll work together to refine these steps along the
way.
What
you will learn: