Cooperative Communications

Wireless links are more error prone than wired links. Moreover, wireless links usually present a high quality variation. For instance, in Indoor and urban scenarios, even static nodes may be exposed to harsh fading. The use of spatial diversity has already proved to be efficient in combat fading and increasing the wireless channel capacity. Nevertheless, using this technology on single-antenna nodes is not a simple task. Cooperative communication is an evolving technique, which allows single-antenna nodes to benefit from spatial diversity. In order to make cooperation work on ad hoc networks, nodes must coordinate to share theirs antennas and relay other nodes communications. Many different approaches have been proposed at the Physical layer and dedicated MAC protocols are being developed. Our group focuses on the Network layer perspective and we are currently developing a cooperation-aware routing metric. The proposed metric takes into account the available relays and the statistics of the wireless links to choose routes where the benefits of the cooperation are maximized. It is expected that the proposed metric will enhance the network efficiency.

Selected Publications

• Cunha, D. O., Duarte, O. C. M. B., and Pujolle, G. - "An Enhanced Routing Metric for Fading Wireless Channels", to appear in IEEE Wireless Communications and Networking Conference - IEEE WCNC 2008, pp. 2723-2728, Las Vegas, USA, March/April 2008 (GTA-07-21).

• Cunha, D. O., Duarte, O. C. M. B., and Pujolle, G. - "A Cooperation-Aware Routing Scheme for Fast Varying Fading Wireless Channels", to appear in IEEE Communications Letters, ISSN 1089-7798 (GTA-08-29).