基于OFDM的认知无线电系统中最优功率分配

Optimal power allocation in OFDM-based cognitive radio systems

在基于正交频分复用(OFDM)的认知无线电系统中,主用户会受到次用户带内子载波以及邻带子载波的带外泄漏功率的干扰。为了在保护主用户通信性能的前提下高效利用机会频谱,该文提出了求解次用户子载波间的最优功率分配方案的方法,通过求解一个凸优化问题获得最优功率分配方案。较之迭代分块注水算法,该方法特别考虑了邻带子载波功率泄漏的影响。仿真结果表明:采用这种方法所获得的功率分配方案在满足各主用户干扰功率上限的条件下使得次用户信道容量最大化。

The primary user （PU） suffers interference from both in-band subcarriers and out-band subcarriers＇ sidelobes of secondary users （SU） in OFDM-based cognitive radio systems. An optimal power allocation scheme was developed to protect the PUs＇ performance while efficiently exploiting the spectrum opportunities. The scheme was obtained by solving a convex optimization problem. The effects of the subcarrier side lobe are included unlike in the iterative partitioned water-filling algorithm. Simulations show that the optimal power allocation scheme maximizes the channel capacity while satisfying the PUs＇ interference power constraints.