Effective spectrum sensing with antenna diversity for cognitive radio systems

Cognitive radio (CR), which is proposed as a technology that utilizes the frequency resources effectively, has studied to relive scarcity of the frequency resources. CR provides opportunistically under-utilize licensed frequency to the secondary user. Spectrum sensing is the most important technology to detect primary user. However, in the wireless channels, according to the effect of fading and shadowing environments spectrum sensing performance is compromised. Therefore, in this paper, we apply diversity scheme that is a useful technique for combating multipath fading in wireless communications. There are several classes of diversity scheme, which are time diversity, antenna diversity, multipath diversity, frequency diversity, and so on. In this paper, we adopt antenna diversity that is a kind of space diversity. By using the proposed method, we can improve spectrum sensing performance. Also the simulation results show that the performance of spectrum sensing using antenna diversity improves compared with cooperative spectrum sensing.