基于混合overlay/underlay方式的认知无线电能效优化策略

摘要

为了提高现有频谱资源的利用率,认知无线电技术得到了广泛的关注.针对协作中继认知无线电系统中的能量效率问题,提出一种混合overlay/underlay传输方式的频谱共享策略,它兼具传统overlay与underlay方式的特性.在满足服务质量要求和功率约束的情况下,首先通过一种启发式方案对子载波进行匹配,再引入基于拉格朗日算法对功率分配问题进行优化,获得最优中继及最优功率分配,从而使整个系统的能量效率提高.仿真实验结果表明:基于混合传输方式下系统的能量效率得到显著提升,验证了所提方案的有效性.%To improve the utilization of spectrum resources ,cognitive radio technology has been widely concerned . For the problem of energy efficiency in cooperative relay cognitive radio system ,a hybrid overlay/underlay spectrum access strategy is proposed in this paper , w hich combines the characteristics of traditional overlay and underlay . In the case of satisfying the quality of service requirement and the power constraints ,firstly ,the subcarrier is matched by a heuristic scheme ,and then the power allocation problem is optimized based on the Lagrange algorithm to obtain the optimal relay and optimal power allocation ,so that the energy efficiency of the whole system is improved .The simulation results show that the energy efficiency of the system based on hybrid transmission can be significantly improved ,and the effectiveness of the proposed scheme is verified .