Date Added: Dec 2010
Cognitive Radio (CR) and Multiple-Input Multiple-Output (MIMO) are two independent physical layer technologies that have made significant impact on wireless networking. CR operates on the channel/band level to exploit white space across spectrum dimension while MIMO operates within the same channel to improve spectral efficiency within the same band. In this paper, the authors explore MIMO-empowered CR network, which the authors call CRNMIMO, to achieve the ultimate flexibility and efficiency in dynamic spectrum access and spectrum utilization. Given that CR and MIMO handle interference at different levels (across channels vs. within a channel), they are interested in how to jointly optimize both so as to maximize user throughput in a multi-hop network.