Sensing the existence or absence of primary user is the major chore of
cognitive radio networks. Nevertheless, Spectrum sensing is the core process
of cognitive radio and with target to find idle channels.Various detection
techniques exist, however, energy detection is considered as the most used
detector because of its lower computational cost. In this paper, we proposed a
study of throughput for a cognitive radio system. We had two scenarios, in
the first scenario; a study of throughput against probability of false alarm was
done; where, only one channel is sensed, to maximize the individual channel
throughput. In the second scenario, multi-channel is sensed to maximize the
overall system capacity. In addition, different number of channels is
considered with different sensing times and at different throughput costs.The
performance of the network has been investigated in terms of maximum
throughput for optimal number of cognitive radio channels.