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Architecture Overview
Developing a wireless sensor network that can immediately
be used for a commercial application is a daunting task. Even
with radio reference designs, radio chips, and software stacks,
significant experience with radio engineering, advanced embedded
development skills, and most importantly, a history of installing
real sensor network applications is necessary to deploy a
wireless sensor network that functions properly and reliably
in various environments.
OEMs and integrators can take advantage of our experience
in developing and deploying wireless sensor networks for real
commercial applications and can now wirelessly connect sensors,
actuators or controllers into a mesh network with little or
no effort. The H900 Nodes have long battery lives, extremely
long range for penetration of indoor walls, sleek form factors,
support for a variety of sensor and actuator types, and best
of all, an extremely low cost.
Bi-Directional Routing for Command and Control.
Not only is every message that is sent from a node acknowledged
by the system (and will resend if not acknowledged), but the
two-way communication nature of the network allows network
designers to send calibration commands to sensors, wirelessly
trigger relays, or send messages out into the network for
display or control of remote devices.
Self-Forming for Quick, Simple Deployment.
The H900 allows for the quickest and easiest installation
possible. Just look at the LEDs and when they turn green,
you know you are in range of one or two other nodes in the
system
Self-Healing for Total Reliability.
Redundancy is built-in ensuring that if a node happens to
be removed from the network, messages will automatically route
to an alternate node ensuring reliability and robustness.
The H900's built in redundancy allows for the most reliable
wireless system that can be purchased today.
SensiNet Networking Protocol
The SensiNet Networking Protocol is the most robust mesh
networking solution available. Based on practical field testing,
SensiNet provides an RF mesh networking solution that leverages
frequency diversity to ensure reliable point-to-point connections.
SensiNet offers all of the benefits that you would expect
from a wireless mesh sensor network - self-configuring, self-healing,
bi-directionality and multi-hop capabilities. It is SensiNet's
implementation of these four features that persuaded GE
Corporate Research to select Sensicast as the provider
of mesh networking software for a Department of Energy contract
upon which they are working.
At 900MHz, SensiNet uses a slow Frequency-Hopping Spread
Spectrum (FHSS) modulation technique to transmit and receive
messages on only the clearest channels in the band.
At 2.4GHz, SensiNet supports IEEE 802.15.4 radios with Distributed
Frequency Spread Spectrum (DFSS) modulation techniques. This
technology ensures that clear 802.15.4 channels in the band
will be used for as long as they remain clear. It also creates
less interference and permits higher effective throughput
from the entire mesh network, as each Routing node can operate
on unique bands simultaneously.
SensiMesh Software and Gateways
The SensiMesh software and associated gateways are one of
the most important aspects to any wireless mesh sensor networking
system. Serving as the integration point between wireless
mesh sensor networks and existing, enterprise automation applications,
SensiMesh provides core services needed for all applications.
Network Proxy - The ad hoc nature of mesh sensor
networks makes commissioning these systems very easy. Simply
power on a node and it joins the network and begins operating.
However, this same phenomenon makes it very difficult to understand
what the network looks like at any given point in time - wreaking
havoc on application developers (e.g., Is the node that was
just sent the command to turn on a fan still part of the network?).
SensiMesh provides a mesh sensor network proxy to help the
user (and to help applications) maintain a clear understanding
of not only what nodes are connected to the network, but also
what are the most recent attributes of those nodes.
Protocol Conversions - Integrating new or existing
systems (software or hardware) with wireless mesh sensor networks
is vital to extracting the most value from them. SensiMesh
is designed to support various control system protocols (e.g.,
Modbus, BACnet, OPC, LonWorks) allowing the endpoints of the
network to seem as if they are traditional control system
endpoints.
Application Programming Interface (API) - Complementing
the Protocol Conversion service, is a system-level API that
allows developers access to real-time and historical sensor
and actuator information - as well as network formation and
health information. These APIs allow developers to not only
rapidly integrate a mesh sensor network into their system,
but they can also monitor and maintain the system from their
current applications.
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Ethernet
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