基于非理想感知的认知无线电系统感知时间与频谱分配联合优化算法

摘要

针对非理想感知情况下感知时间与频谱分配联合优化问题,同时考虑漏检与主用户重新占用频谱两种场景所造成的主次用户碰撞,并通过量化主用户对认知用户的干扰,给出有无主用户存在时认知系统可获得的吞吐量.在总传输功率约束以及对主用户的最大干扰功率约束两个限制条件下,以最大化系统平均吞吐量为优化目标,给出感知时间与频谱分配联合优化算法.算法首先通过折半法搜索最优感知时间,在既定的感知时间下,将子信道分配给能获得最大平均吞吐量的认知用户,在此基础上,利用凸优化相关理论求得最优功率分配.仿真结果表明,本文所提算法相比于传统频谱分配算法系统平均吞吐量性能提升了10％左右.%Considering the optimization problem of sensing time and spectrum allocation on imperfect sensing condition,the collision between primary user(PU) and secondary user(SU) caused by misdetection and PU's return is taken into account in this paper,and instantaneous throughput of the cognitive radio(CR) system without PU by measuring the SU's interference from PU is given.In the constraint of the total transmission power and maximum interference power to PU,the algorithm of joint optimization of sensing time and spectrum allocation is demonstrated aiming at maximizing average throughout of the system.The algorithm firstly bisearch for optimal sensing time,then allocate the subchannel to user who has the maximum average throughout under certain sensing time,based on that,obtain the optimal solution via convex optimization.Simulation result shows that the proposed algorithm gains better average capacity performance by 10％ compared with the traditional spectrum allocation algorithm.