Architecture
The architecture targeted in the project includes:
- TILAS multimedia end device (source device): Sensors equipped with cameras. These nodes will monitor the environment and periodic multimedia traffic (jpeg photo) and route them to the gateway.
- TILAS Gateway end device: initializes the network and collects multimedia traffic generated by the multimedia device.
- TILAS end device: sensors with routing capabilities. These nodes will route the multimedia traffic to the gateway.
Overview about Odysse
Odysse has as a primary objective the optimization of the energy resource of sensor nodes. In addition, other keys design are taken into consideration:
- Limited storage capacity of wireless sensors
- Engineering difficulty to validate with real platform and not only with simulations
The main idea of Odysse consists in applying a duty cycle mechanism where nodes turn off their radio to save energy (sleep state). This is because it has been proved that the radio communication is the most energy consuming task for the sensor.
In Odysse, nodes enter the sleep state asynchronously and randomly, (i.e., without synchronization between them). However, the duty cycle mechanism results in a new challenge. Indeed, as nodes are inactive for some time, radio links and hence the network topology are dynamic and unpredictable. In this case, classical reactive and proactive routing protocols cannot be exploited since the topology is not stable.
To overcome this challenge, Odysse protocol adopts an opportunistic routing approach. Unlike classical routing schemes, the opportunistic routing does not build a routing table beforehand. The data relay is selected among awake neighbors according to some routing metrics. Consequently, the energy consumption is balanced in the network and the reliability is increased. In Odysse protocol, the relay is the neighbor offering a best compromise between its i) residual energy, and ii) its distance relative to the gateway and iii): its quality of wireless link.