Currently, our research in this area focuses on interference mitigation and its effect on cross layer performance. Some of the questions we are currently investigating:
Collision mitigation: Can joint detection or other techniques be used to eliminate collisions in ranodm access networks? Can this be done in real time?
MAC Layer: What effect will collision mitigation on typical MAC layer problems such as the hidden and masked node problems? How should a rate adaptation scheme be designed with collision mitigation in mind?
Higher layers: How should TCP interpret collisions? Should they be thought of as wireless errors, or as congestion on the link? If collisions can be differentiated at the physical layer, how should this be information be utilized, if at all, by the transport layer?
To investigate these problems, we are taking several approaches. At the physical layer, we conduct extensive MATLAB simulations to evaluate potential interference mitigation schemes. Cluster based computing is utilized as needed. As reliable statistics are collected at the physical layer, such as packet reception rates, we integrate it into the network layer simulator NS-3. NS-3 allows us to then investigate the cross-layer interactions between the PHY, MAC and Transport layers.
In addition, it is important to ensure that physical layer algorithms are feasible to implement in real time. Our labratory is equipped with several software defined radios that allow us to experiment with hardware in real time. This allows verification of the physical layer algorithms.