基于混合精度ADC的大规模MIMO中继系统物理层安全性能研究

Research on Physical Layer Security Performance of Massive MIMO Relay System Based on Mixed-ADC

研究多天线窃听者场景基于混合精度模数转换器(Analog-to-Digital Converter,ADC)大规模多输入多输出(Multiple Input Multiple Output,MIMO)中继系统,中继将接收到的信号放大转发,通过在基站采用最大比合并接收信号,推导出合法用户与窃听者的频谱效率表达式,最终得出系统保密频谱效率表达式.根据能量效率定义建立功耗模型,推导保密能量效率表达式,并分析保密频谱效率和保密能量效率之间的平衡关系,进而揭示基站天线数、ADC量化位数等参数对物理层安全性能的影响.仿真结果表明,随着窃听者天线数增多,窃听能量增强,保密频谱效率会减小;ADC量化位数为4时,在保证保密频谱效率的同时也能得到较高的保密能量效率.

The multi-antenna eavesdropper scenario based on a mixed-precision analog-to-digital converter massive MIMO(Multiple Input Multiple Output)relay system is studied,where the relay amplifies and forwards the received signal.Using maximum ratio to combine the received signals at the base station,the expressions of spectral efficiency of legitimate users and eavesdroppers are derived,and the expression of secrecy spectral efficiency of the system is obtained.Based on the definition of energy efficiency,a power consumption model is established.The expression of secrecy energy efficiency is derived.And the tradeoff between the secrecy spectral efficiency and the secrecy energy efficiency is analyzed.It further reveals the influence of parameters such as the number of base station antennas and the number of ADC(Analog-to-Digital Converter)quantization bits on the physical layer security performance.The simulation results show that as the number of eavesdropper antennas increases and eavesdropping energy increases,the secrecy spectral efficiency will decrease.When the number of ADC quantization bits is 4,it can also obtain a higher secrecy energy efficiency,while ensuring the secrecy spectral efficiency.