Section: Contracts and Grants with Industry

OCARI

Participants : Ichrak Amdouni, Saoucène Mahfoudh, Pascale Minet, Khaldoun Al Agha, Joseph Rahmé.

The OCARI (Optimization of Ad hoc Communications in Industrial networks) project, funded by ANR, started in February 2007. It has a duration of 36 months. The industrial partners are EDF (coordinator), DCN and One-RF. The academic partners are LIMOS (Clermont Ferrand university), LATTIS (Toulouse university), LRI (Paris Sud university) and INRIA.

The OCARI project deals with wireless sensor networks in an industrial environment. It aims at responding to the following requirements which are particularly important in power generation industry and in warship construction and maintenance:

• Support of deterministic MAC layer for time-constrained communication,

• Support of optimized energy consumption routing strategy in order to maximize the network lifetime,

• Support of human walking speed mobility for some particular network nodes, (e.g. sinks),

• Support of IEC61804/EDDL and HART application layer.

The development of OCARI targets the following industrial applications:

• Real time centralized supervision of personal dose in nuclear power plants,

• Condition Based Maintenance of mechanical and electrical components in power plants as well as in warships,

• Environmental monitoring in and around power plants,

• Structure monitoring of hydroelectric dams.

To meet the requirements of supported applications (remote command of actuators, tele-diagnostic...), new solutions will be brought to manage several communication modes, ranging from deterministic data transfers to delay tolerant transfers. A key issue is how to adapt routing algorithms to the industrial environment, taking into account more particularly limited network resources (e.g.; bandwidth), node mobility and hostile environment reducing radio range.

The OCARI project aims at developing a wireless sensor communication module, based on IEEE 802.15.4 PHY layer and supporting EDDL and HART application layer. The INRIA contribution concerns more particularly energy efficient routing and node activity scheduling.

• The energy efficient extension of OLSR, called EOLSR, will be implemented on top of the MAC protocol defined by LATTIS and LIMOS. The MAC protocol is a variant of ZigBee ensuring some determinism and quality of service and allowing leave nodes (e.g. sensor, actuator) as well as router nodes to sleep. The EOLSR protocol avoids nodes with low residual energy and selects the routes minimizing the energy consumed by an end-to-end transmission. EMPRs (multipoint relays taking into account the residual energy) are used to build energy efficient routes. We have shown by simulations that EOLSR increases the network lifetime and outperforms multipath routing (both with different links and with different nodes). The specifications of the EOLSR protocol have been delivered to the industrial partners.

• SERENA, the protocol used to schedule router node activity, is based on three-hop coloring. It allows any node to sleep during the slots thaht are attributed neither to its color nor to its one-hop neighbors. SERENA contributes to a more efficient use of energy: less energy is spent in the idle and interference states. Hence, network lifetime is considerably increased. Specifications of SERENA adapted to the specific context of OCARI (i.e.; very limited bandwidth 250kbps, small size messages 127 bytes, limited memory and limited processing power) have been delivered.

Moreover, INRIA has specified the network layer implementing EOLSR and SERENA. INRIA has defined the message format as well as the network primitives offered to the application layer and management entity. Furthermore, primitives between the network and MAC layers have been specified in cooperation with LIMOS.