基于粒子滤波的协作式空时联合频谱检测方法

Particle Filtering based Joint Spatial-Temporal Spectrum Sensing Method with Cooperation

认知无线电系统中,通过频谱检测所获得的主用户位置信息和信道使用状态信息分别反映空间域和时间域的频谱使用情况,其准确性关系到次用户伺机频谱接入的效率。本文研究空间和时间联合频谱检测问题,将其建模为主用户位置参数和信道使用状态的联合估计问题,提出了一种基于粒子滤波的协作式空时联合频谱检测方法,主要思想是采用离散随机测度逼近位置参数和信道状态的联合后验概率分布函数,根据该分布估计出主用户位置和信道状态。同时,该方法结合由估计得到的空间和时间信息,自适应选择靠近主用户且对称分布的次用户参与协作检测,增加各次用户提供信息的有效性,从而提高估计的准确性;最后,通过仿真验证了方法的有效性。

In cognitive radio systems,the information of primary user location and channel usage state,which can be obtained by spectrum sensing,dipicts the spectrum usage in spatial and temporal domain,respectively.And the accuracy of the information effects the efficiency of opportunity spectrum accessing of secondary users.Joint spatial-temporal spectrum sensing problem was investigated and modeled as a combined estimation problem of primary user location and channel usage state.Then,a joint spatial-temporal cooperative spectrum sensing method based on particle filtering was proposed.The main idea of the method is to estimate primary user location and channel usage state by their joint posterior probability density function that approximated by discrete random measure.Further, considering the estimated information in spatial and temporal domain,the proposed method adaptively selects those secondary users, who are closed to the primary user and symmetrically distributed in spatial domain,for cooperative spectrum sensing.The adaptive selection of secondary user improves the availability of the information provided by secondary users,resulting in a more accuracy of the estimation.Finally,the efficiency of this method was evaluated through simulations.