认知无线电周期性合作频谱感知研究

Research on periodic cooperative spectrum sensing in cognitive radio

为了降低对认知无线电授权用户的干扰和提高认知无线电的能量检测性能，提出了采用合作频谱感知和周期性检测授权用户的频谱感知算法。该算法可使认知无线电在每个感知周期内先检测后传输，如果检测到授权用户存在，认知无线电需要搜索新的空闲信道继续通信。为了对此合作频谱感知算法进行优化，给出了二重迭代优化算法，通过优化本地感知时间和合作用户数，认知无线电能够获得最大的吞吐量和最小的搜索时间。仿真表明：上述方法计算量较低，并且相比以往算法，当信噪比（SNR）为5dB时，吞吐量提高了6．3％，搜索时间降低了25％。

In order to decrease the interference to authorized users of cognitive radio networks and improve the energy detecting performance of the networks, a spectrum sensing algorithm that periodically detects authorized users by co- operative spectrum sensing is proposed in this paper. When using the algorithm, cognitive radio networks perform the sensing first and then the transmitting during each period, and after the presence of an authorized user is detec- ted, the networks have to search another idle channel. To optimize the proposed cooperative spectrum sensing algo- rithm, a duplicate iterative optimization algorithm is given. The maximal throughput and the minimal searching time can be respectively obtained through the optimization of the local sensing time and the number of cooperative users. The simulation shows that the proposed algorithm has the lower computational quantity, and the throughput can in- crease by 6.3% and the searching time can decrease by 25% compared with the former algorithms under the signal noise ratio （SNR） being 5dB.