基于OFDM的认知无线电系统联合资源分配

为充分利用现有无线电频谱资源, 研究了基于正交频分复用的认知无线电系统, 以填充和下垫联合方式进行分配资源的问题, 提出了新的子载波分配算法和最优功率分配算法。该算法在保证总功率和每个子载波所受干扰在一定阈值内的前提下, 采用最优功率分配算法最大化次用户传输速率。同时, 为降低算法的复杂度, 将置零子载波功率算法应用到资源分配中。最后, 基于Worst-case 方法, 对次用户和主用户间的信道不确定性进行鲁棒性分析。仿真结果表明, 在相同条件下, 该资源分配最优算法和次优算法都优于单独的填充式或下垫式资源分配算法。

Hybrid Resource Allocation for OFDM-Based Cognitive Radio Systems

To make full use of existing spectrum, we study the problem of a joint overlay and underlay resources allocation for the OFDM(Orthogonal Frequency Division Multiplexing) based cognitive radio systems. A new subcarrier and optimal power allocation scheme is proposed under the joint overlay and underlay fashion. This scheme can provide maximum transmission capacity for secondary users while keeping the total power and the interference introduced to the subcarrier below a given threshold. In consideration of the computation complexity of the scheme, the nulling scheme can be used in the proposed method to obtain sub-optimal scheme. Finally,the analysis of the robustness of this power allocation algorithm is presented when considering the uncertainty ofthe channel gain between secondary user and primary user in the sense of the Worst-Case. Simulation results show that the proposed schemes demonstrate better performance than the overlay or the underlay resource allocation schemes.