Research Of Spectrum Sensing Based On Energy Detection In Keyhole Channel In Cognitive Radio

Nowadays,cognitive radio is a wireless technology which can improve the utilization of spectrum, it known as the next most popular wireless technology,which has a pivotal position in the communicationBecause wireless spectrum is a valuable non-renewable resources in mobile communications, radio and television, public safety, and WLAN (Wirele Local Area Network), WPAN (Wireless Personal Area Network), WMAN (Wireless Metropolitan Area Network),3G (Generation), WiMAX (Worldwide Interoperability for Microwave Access), LTE (Long Term Evolution), UWB (Ultra-wide Bandwidth) and other wireless technology continues to be widely used, making the demand for spectrum resources substantial growth to smart opportunistic characterized by the use of spectrum resources, cognitive radio came into being, the subject of attention. On the other hand, a large number of foreign scholars research shows that traditional use of the spectrum allocation of resources is based on "fragmentation" of the fixed spectrum allocation scheme, so that the average utilization rate of the global spectrum use is extremely low and unbalance.Cognitive radio technology is an important prerequisite for the realization of spectral detection capability, many academic studies have shown that in multipath fading or shadow of the energy spectrum sensing cognitive radio detection is the most easy to implement and the ability to calculate simple detection methods, therefor the communication operational efficiency as the main indicators of the premise,we have to say that energy detection algorithm is a priority, and many scholars studied the various fading channels including Rayleigh fading, Rice fading, etc. The energy detection performance, but the actual communication environment, because the formation of narrow high-rise corridor, often through the tunnel and the mountain’s forests are vast as the signal through the "keyhole" channel communication, the deterioration of transmission conditions such as the "keyhole" phenomenon caused by detection performance of the energy still in its infancy, little studied. In this paper, keyhole channel environment of the energy detection algorithm, shows performance relative to other fading channels is more unsatisfactory through the MATLAB simulation, the simulation graph shows that we can multi-user cooperative testing to on the deterioration of the channel performance under the increase the probability of detection, cost and other practical constraints in the network under the premise of this paper the optimization of cognitive performance of the user analysis.The main research as following:(1) we explain the background knowledge of cognitive radio, cognitive radio communication nowadays understanding of the development of great benefit.(2) the keyhole channel based on the elaboration of its objective existence, their research has a high value, complex keyhole channel, we chose detection algorithm does not require prior knowledge and calculation of the energy efficient detection algorithm, Keyhole channel thus energy detection under study, the channel model is established to calculate keyhole channel capacity under the detection process, but also compared the performance of a variety of classical channel simulation.(3) Based on Keyhole channel energy detection performance, it detects the characteristics of own poor performance, it shows that cooperation can effectively improve the detection performance, collaboration, the more users the better detection performance by testing a large number of literature, this same time, with the increase in the number of collaborative users are also much higher cost of hardware, so select the appropriate number of users collaborate more reason, then the number of cognitive optimization algorithm for this user.(4) we analysis and make detection performance of the overall cooperative users more optimization.