OCARI

Ocari Logo

OCARI (acronym of Optimization of Communication for Ad hoc Reliable Industrial network) is a communication protocol for Industrial Wireless Sensor Network. It is developed by the following consortium during the OCARI project that is funded by the French National Research Agency (ANR):

Électricité de France, project leader
DCNS
One-RF Technologies now Telit RF
LATTIS
LIMOS
INRIA
LRI

Since the end of the ANR project, DCNS, EDF and INRIA continued to work together (with the participation of Adwave and BeamLogic) to industrialize OCARI and form an industrial alliance (see OCARI website) to develop a sustainable ecosystem of OCARI. The industrial implementation of OCARI is currently based on Dresden-Elektronik deRFsam3-23T09-3 and Adwave ADWRF24-LRS hardware platforms that use the Cortex M3 MCU and the Atmel AT86RF233 transceiver.

OCARI Features

OCARI distinguishes from protocols such as ZigBee, WirelessHART and Isa100.11a by the following characteristics:

A medium access method that combines CSMA/CA and an optimized TDMA based on 3-hops coloring.
A proactive energy efficient routing strategy supporting nomadism, called EOLSR (Energy efficient OLSR).
An activity scheduling mechanism that is based on a three-hop coloring algorithm helps to reduce interference and thus optimizes node's energy consumption, called OSERENA.

The operating cycle of OCARI is divided into four periods:

[T0-T1]: Multihop deterministic synchronization of nodes using beacons.
[T1-T2]: Transmission of messages and signaling by competition.
[T2-T3]: Transmission of data messages with requirements (collection and dissemination) by colored slots
[T3-T0]: Sleep

The topology of an OCARI network is organized as follows:

Coordinator (equivalent of "IEEE 802.15.4 PAN coordinator"): global coordinator of a sensor cluster. Its role is to initiate the network and manage it: allocation of network addresses, network access management and access point to the whole sensor network.
Router participates in the hierarchical tree relay (with TTL) when the colors are not yet assigned and the ad hoc routing.

OCARI Stack

OCARI Applications

OCARI was developed to satisfy the user needs in constraint environments that are founded in Power Plants and in Warships. Typical applications of OCARI are:

Real time monitoring of dosimetry.
Real time radiation protection monitoring using mobile radiameters.
Fire detection.
Machine and equipment surveillance for predictive maintenance.
Mobile instrumentation for test and measurement during outage periods.
Open-loop control.

References

(English) Khaldoun Al Agha, Marc-Henri Bertin, Tuan Dang, Alexandre Guitton, Pascale Minet, Thierry Val and Jean-Baptiste Viollet, “Which wireless technology for industrial wireless sensor networks? The development of OCARI technology”, IEEE Transactions on Industrial Electronics, Vol. 56, No. 10, October 2009.

External links

(English) the OCARI Alliance