Enhancing the Physical Layer Security of Non-Orthogonal Multiple Access in Large-Scale Networks
Enhancing the Physical Layer Security of Non-Orthogonal Multiple Access in Large-Scale Networks
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DOI：
10.1109/twc.2017.2650987
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发表时间：
2017-03-01
影响因子：
10.4
通讯作者：
Hanzo, Lajos
中科院分区：
文献类型：
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作者：
Liu, Yuanwei;Qin, Zhijin;Hanzo, Lajos
运用随机几何理论研究了大规模网络中非正交多址接入（NOMA）的物理层安全问题。单天线和多天线辅助传输的情况下，被认为是基站（BS）与随机分布的NOMA用户进行通信。在单天线的情况下，我们采用了一个保护区周围的BS建立窃听者排除区的帮助下仔细的NOMA用户的信道排序。在多天线场景中，在BS处生成人工噪声以进一步提高波束成形辅助系统的安全性。为了表征的保密性能，我们推导出新的精确表达式的安全中断概率为单天线和多天线辅助的情况下。对于单天线的情况下，我们进行保密分集阶数分析选定的用户对。分析结果表明，保密分集阶数由所选用户对中信道条件最差的用户决定。对于多天线的情况下，我们推导出渐近保密中断概率，当发射天线的数量趋于无穷大。蒙特卡洛模拟验证了分析结果，并表明：1）通过在基站处引入保护区和产生人工噪声，可以提高NOMA网络的安全性能; 2）渐近秘密中断概率与精确秘密中断概率接近。
This paper investigates the physical layer security of non-orthogonal multiple access (NOMA) in large-scale networks with invoking stochastic geometry. Both single-antenna and multiple-antenna aided transmission scenarios are considered, where the base station (BS) communicates with randomly distributed NOMA users. In the single-antenna scenario, we adopt a protected zone around the BS to establish an eavesdropper-exclusion area with the aid of careful channel ordering of the NOMA users. In the multiple-antenna scenario, artificial noise is generated at the BS for further improving the security of a beamforming-aided system. In order to characterize the secrecy performance, we derive new exact expressions of the security outage probability for both single-antenna and multiple-antenna aided scenarios. For the single-antenna scenario, we perform secrecy diversity order analysis of the selected user pair. The analytical results derived demonstrate that the secrecy diversity order is determined by the specific user having the worse channel condition among the selected user pair. For the multiple-antenna scenario, we derive the asymptotic secrecy outage probability, when the number of transmit antennas tends to infinity. Monte Carlo simulations are provided for verifying the analytical results derived and to show that: 1) the security performance of the NOMA networks can be improved by invoking the protected zone and by generating artificial noise at the BS and 2) the asymptotic secrecy outage probability is close to the exact secrecy outage probability.