Date Added: Jul 2011
Cognitive radio systems allow secondary users to operate on underutilized licensed spectrum. When considering highly congested communication channels, however, opportunities for channel access based on time or frequency division can be limited for secondary user networks. In this paper, the authors consider leveraging enhanced spatial diversity through directional steerable antennas to allow secondary user channel access in parallel with licensed spectrum users. Furthermore, they consider effects of mobility on directional secondary user networks and introduce a mechanism for maintaining point-to-point directional communication links in the presence of mobility.