Sensing time-based throughput performance in OFDM cognitive radio system

The required time for spectrum sensing is critical issue in cognitive radio (CR). Secondary User (SU) must sense license spectrum to seek opportunities as quick as possible. However, quick sensing decreases the fidelity of sensing outcome. Sensing time has a significant impact to the throughput performance. This paper studies the impact of sensing time to the throughput performance at low signal to noise ratio (SNR). The throughput is evaluated in idle and busy states with certain and uncertain noises. OFDM technique with 16 QAM is used as primary user (PU) signal. At low SNR with a certain probability of false alarm (Pf) target during 50 ms, the throughput performance is gradually increased. In case of idle state, throughput has better performance compared with busy state.