Cooperative wireless networks

Speaker: Dr Frederique Oggier , Caltech


Recently, attention has been focused on wireless networks. Methods to exploit diversity using the antennas of different users in a cooperative way have been studied, in order to look for the diversity known to be achieved in the multiple antennas point to point case. We consider a wireless network where a transmitter and a receiver are distinguished, with enough computational capacity and power to encode/decode the data, and use several antennas to transmit/receive the signal. The other nodes are relays, small devices with few power and computational ability, with only one antenna (as for example in sensor networks). In this scenario, it is not realistic to assume nodes can decode the information. We thus propose a strategy based on the idea of Distributed Space-Time Coding, where the nodes just do a very simple operation before forwarding the information. Our scheme relies on known algebraic Space-Time Codes. It is suitable for any number of transmit/receive antennas and nodes. It is shown to perform better than random codes, with less encoding complexity. We also briefly discuss the scenario where nodes may be down in the network, and show that our strategy is resistant to node failures.

Full presentation