智能反射面辅助下行NOMA系统中权衡最大化的方法

Tradeoff Maximization Scheme of the IRS-Aided Downlink NOMA Systems

智能反射面(IRS)辅助的单簇下行非正交多址接入(NOMA)系统中,无法同时实现信号传输速率与能量效率最优平衡,对此提出了一种资源分配方法。首先,建立了一个优化问题,旨在使信号传输速率和能量效率权衡最大化,其中的参数包括用户功率和IRS相移;然后,对该问题进行了简化,将参数简化为总功率和IRS相移;其次,通过最大化等效信道增益之和来确定IRS相移,并在已知IRS相移的情况下,通过函数极值法找到最大化速率和能量效率权衡的总功率;最后,根据得到的IRS相移和总功率,计算单个用户的功率。仿真实验结果表明,在相同速率需求的情况下,所提方案在速率与能量效率的权衡方面优于同一场景中已有的方案。

Aiming at the problem that the signal transmission rate and energy efficiency cannot be taken into account for single cluster downlink non-orthogonal multiple access(NOMA)systems assisted by intelligent reflecting surface(IRS),a resource allocation scheme is proposed to maximize the tradeoff between signal transmission rate and energy efficiency.First,the tradeoff problem between the rate and energy efficiency is formulated,with power of each user and IRS phase shifts as the optimization parameters.Secondly,the optimization problem is simplified,after which the optimization parameters become total power and IRS phase shifts.Then,the IRS phase shifts are solved by maximizing the sum of the equivalent channel gains,and with given IRS phase shifts,the total power that maximizes the rate and energy efficiency tradeoff is found by the function extremum method.Finally,the power of each user is calculated based on the obtained IRS phase shifts and the total power.The simulation results show that the tradeoff of the proposed scheme is higher than that of existing schemes in the same scenario and rate requirement.