Efficiently handling transmission in Wireless networks – GETRF

The project will focus on four technical approaches which are:
- Coloring for the development of a TDMA system for energy saving and delay control,
- Cross-layer (MAC/routing) mechanism for «low-duty-cycle« mode
- Network coding,
- Opportunistic routing and mobile mobility to use relays to minimize retransmissions of packets with a target time.

The first two approaches are intended to provide energy efficient sensor networks. The second two approaches try to provide mechanisms for building ad hoc networks capable of handling high node mobility.

The project will provide four cross-layer architectures for the implementation of the following mechanisms:
- Coloring mechanism for the development of a TDMA system for energy saving and control of delivery times,
- cross layer (MAC/routing) mechanism designed for «low-duty-cycle« sensor networks,
- Mechanism of network coding,
- Opportunistic mobile routing.
The project wishes to publish the results on these four schemes presenting implementation details and performance gains compared to existing technologies.

For sensor networks, the GETRF project paves the way to very energy efficient networks while offering acceptable delivery delays. For surveillance sensor networks (carrying very little information) the project should lead to networks with very long lifetimes.
For ad hoc networks using the GETRF results, we expect networks capable of operating even with a very high mobility, whereas existing networks based on protocols such as OLSR or AODV can not operate under this condition.

[1] Performance of Opportunistic Routing in Low Duty-Cycle Wireless Sensor Networks. Wireless Days 2012. 21-23 November 2012. Dublin.
[2]. OSERENA: a Coloring Algorithm Optimized for Dense Wireless Networks. International Journal of Networked and Distributed Computing, Vol. 1, No. 1 (January 2013), 9-24
[3] VCM: The Vector-Based Coloring Method for Grid Wireless
Ad Hoc and Sensor Networks. MSWiM’12, October 21–25, 2012, Paphos, Cyprus.

The GETRF (Gestion Efficace des Transmissions dans les Réseaux sans Fil) project proposes to study new mechanisms to improve the performance of wireless multihop military networks.
This project considers wireless multihop networks as a whole of which mobile ad hoc networks (MANETs) and of sensor wireless networks (WSNs) are specific cases, with both differences and commonalities.

The goal is to address two major challenges in tactical military networks:
1. efficient management of energy, latency and network capacity.
2. efficient management of the network in mobile or degraded environment.

These objectives may for instance answer two scenario of functioning of military tactical networks: on one hand, a stabilized, static, situation in operating normally, where the goal is to optimize the network usage ; and on the other hand, the case of more critical scenarios, for instance, the case of high mobility, the case of unexpected degradation of the quality of one part of the network, and, also, the case where the broadcast information is exceeding the capacity, which are all cases where the goal is to operate despite the very high constraints.

To answer the objectives, three type of mechanisms will be studied in the project:
- network coding techniques. These recent schemes allow for more robust information broadcast in the case of changes in the network (mobility, degradation of one part of the network), to reduce the control traffic exchanges, and more generally, to increase network efficiency (less transmissions, more capacity).
- coloring techniques. They allow time-slots to be assigned to nodes or links of the wireless network. These techniques allow one to build efficient Time Division Multiple Access techniques. The medium access scheme obtained can be very energy efficient and can also offer very good end-to-end delays
- the opportunistic routing schemes. Opportunistic routing protocols, usually based on geographic routing, can improve the total throughput of ad hoc networks. They can also be combined with medium access schemes to build network nodes operating in low-duty cycle mode. These schemes
can be very energy efficient. Another application of opportunistic routing is a coupling with mobility (mobile opportunistic routing schemes). On can take advantage of nodes' mobility to optimize the delivery delay.