基于SWIPT的双向中继CR-NOMA系统研究

Research on two-way relay CR-NOMA system based on SWIPT

针对现有研究中CR-NOMA(认知无线电非正交多址接入)系统均配置单向中继,频谱利用率和能源利用率低的缺点,提出在CR-NOMA系统中通过双向中继辅助用户传输,并且中继采用无线信息和能量同时传输的方式.推导出在用户服务质量和最小能量捕获等约束条件下的次用户传输能效,将目标函数转化为单目标问题分别求解;利用交替迭代算法,对中继发射功率和功率分配因子等单目标最优解进行联合优化,以最大化次用户系统传输能效.仿真结果表明:与传统单向中继系统相比,所提方案在提高频谱利用率的同时,次用户传输能效也提高了45%.

As the CR-NOMA(cognitive radio-non-orthogonal multiple access)system is equipped with one-way relay,which has the disadvantages of low spectrum utilization and low energy utilization in the present work,thus,the two-way relay was introduced in the CR-NOMA system to assist user transmission and the relay adopted simultaneous wireless information and power transmission.The secondary user transmission energy efficiency was derived with the constraints of quality of service of user and the minimum energy harvested.The objective function was transformed into single-objective problems,which could be solved separately.Alternative iterative algorithm was proposed to jointly optimize the single-objective optimal solutions such as the relay transmit power and power splitting to maximize the energy efficiency of cognitive users.Simulation results show that compared with the traditional one-way relay system,the proposed solution not only improves the spectrum utilization,but also improves the energy efficiency of the secondary user transmission by 45%.