Adaptive Free Space Optical and Radio Frequency Network Centric Cooperative Communications

The proposed research aims towards adaptively using a wide variety of distributed cooperation techniques in wireless multi-hop networks. These techniques are intended to improve overall system throughput, reduce the cost of node elements, and extend the units’ service lives. We will employ tools from the areas of Free Space Optics, signal processing, transmit and receiver diversity, error correction and detection (FEC), cluster-based forwarding and routing. This work proposes to extract diversity gain out of the redundancy inherently present in all broadcast network transmission, such as wireless sensor networks, and direct those gains for chosen receiver nodes. The redundancy in such systems is present since the signal carried over such a channel is received (if not necessarily detected) by all nodes within transmission radius. Thus, in this distributed cooperative paradigm, packets are not relayed from one network node to the next, but from one cluster of nodes to the next cluster of nodes, until it reaches its destination. Cooperative transmission provides a new opportunity for system designer to use a wide range of technologies such as free space optics and short range radio transmission (such as blue tooth) to enhance the network performance that otherwise would be useless for long radio range transmission.