CAJ | 학술논문

感知无线电是一项有希望提高频谱利用率的技术,在不干扰授权用户的前提下,通过协商或者机会地与授权用户共同占用频谱资源.实现感知无线电技术的关键就是如何可靠地检测授权用户使用的频谱情况.基于能量的频谱检测实现简单,能够快速地检测频谱的占有情况,但是也有很多缺点,比如易受噪声的影响.近几年基于能量的频谱检测得到广泛研究,但是,在噪声功率不确定情况下的频谱检测研究却不多.针对这一问题,从不同的角度分析了在噪声功率不确定情况下的基于能量的频谱检测,分析了最坏情况下的性能.最坏情况下的性能用信噪比、时间带宽积和噪声不确定峰值比的函数表示.从仿真结果中可以看出,即使不确定的噪声功率是一个很小数量.也会造成检测性能的大幅下降,而且在瑞利衰落信道下性能更差.
감지무선전시일항유희망제고빈보이용솔적기술,재불간우수권용호적전제하,통과협상혹자궤회지여수권용호공동점용빈보자원.실현감지무선전기술적관건취시여하가고지검측수권용호사용적빈보정황.기우능량적빈보검측실현간단,능구쾌속지검측빈보적점유정황,단시야유흔다결점,비여역수조성적영향.근궤년기우능량적빈보검측득도엄범연구,단시,재조성공솔불학정정황하적빈보검측연구각불다.침대저일문제,종불동적각도분석료재조성공솔불학정정황하적기우능량적빈보검측,분석료최배정황하적성능.최배정황하적성능용신조비、시간대관적화조성불학정봉치비적함수표시.종방진결과중가이간출,즉사불학정적조성공솔시일개흔소수량.야회조성검측성능적대폭하강,이차재서리쇠락신도하성능경차.
Cognitive radio (CR) is viewed as a promising technology to improve spectrum utilization via negotiated or opportunistic spectrum sharing without interference to primary or licensed users,and the key challenge of the new system implementation is the reliable detection of presence of primary users.Energy detection based spectrum sensing is quite simple and is able to locate spectrum-occupancy information quickly,but it has some limitations such as vulnerability to noise.Energy detection has been studied widely in recent years,but the effect of noise power uncertainty is seldom evaluated in relevant literatures,especially in fading channels.This paper presents another look at the problem of energy detection of unknown signals in noise of uncertain power.Worst case perform ance bounds are provided as a function of input signal-to-noise ratio(SNR),time-bandwidth product(TW) and peak-to-peak noise uncertainty(U).Even with a small fraction of noise-level uncertainty,the performance of detection degrades heavily.An even worse result than is indicated by the standard result is given in Rayleigh fadingchannels.