Date Added: Jun 2012
Cooperation among several secondary users for successful spectrum sensing defines an upper bound on the number of channels that can be sensed. Consequently, the maximum utilization is bounded by the number of sensing nodes rather than the availability of the channels. Hence, a subset of the channels should be selected based on the traffic requirements, and the secondary users should be assigned to those channels for the sensing task. In addition, secondary users experience different channel conditions due to interference, noise, and geographical location. Therefore, a secondary user should be assigned to a channel for which its sensing metrics are satisfactory.