EcoNet

A brief overview of the technologies involved in the EcoNet Project:

EcoNet is a spontaneously formed and self-maintained ad-hoc sensor network built of two types of nodes: collectors and aggregators. A collector node is equipped with sensors. It is capable of connecting data even if not connected with other nodes. Its memory resources allow it to store about half a year of data on its own. This data can then be retrieved by an aggregator once connectivity is established.

Aggregators are responsible for forwarding sensor data to processing stations, which can be computers or gateways to wide area networks. They implement automatic multi-hop operation, as needed for reliable data delivery. They are also capable of storing data locally to compensate for possible lapses in connectivity. All nodes operate in a highly power-efficient fashion by the virtue of implicitly orchestrated duty cycling. A node can run for a year or more on a single battery. The exact life span of a node depends on the type of sensors attached to it and the target frequency of data transmission.

Both types of nodes are built around inexpensive microcontrollers and RF modules. Typically, the cost of a node is dominated by the sensors it carries.

TARP Technology

TARP (the Tiny Ad-hoc Routing Protocol) is our proprietary routing solution. The platform has been designed with the premise of self-scalable, ad-hoc oriented collaboration of small and generally unreliable nodes. By assuming that the nodes are unreliable our solution is more resilient than typical wireless sensor network protocols. TARP is based on an ad-hoc mesh network that:

• Requires no central authority (no access points)
• Self-organizing into local micro-networks based on population of users rather than pre-deployed infrastructure
• Good for network applications driven by personal proximity rules

Before we describe TARP in depth, take a look at a traditional ad-hoc routing scheme (e.g., AODV in ZigBee®), which operates like this:

• Nodes advertise themselves by broadcasting HELLO messages. This way a node is able to learn the identity of neighbors, i.e., other nodes within its communication range.
• When node S wants to establish a data path to node D, it initiates a route discovery procedure, whereby the prospective intermediate nodes exchange special messages to figure out the best path among them.
• Once the best path has been established, every node on it knows the identity of the next hop neighbor on the path. On every leg of its trip, the packet is forwarded to a single specific neighbor.
• If the path breaks (because of mobility or node failure), the first node discovering the breakage starts a route recovery procedure, which essentially works in the same way as the original route discovery.

Click Here for an Indepth Description of TARP