NOMA in Cooperative Communication Systems With Energy-Harvesting Nodes and Wireless Secure Transmission
NOMA in Cooperative Communication Systems With Energy-Harvesting Nodes and Wireless Secure Transmission
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DOI：
10.1109/twc.2020.3030133
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发表时间：
2021-02
影响因子：
10.4
通讯作者：
Abdelhamid Salem;Leila Musavian
中科院分区：
文献类型：
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作者：
Abdelhamid Salem;Leila Musavian
研究了协作中继系统中的非正交多址接入（NOMA）问题，其中源节点通过一个多天线中继节点与一对能量收集（EH）用户设备进行通信。中继站采用混合协议，如果中继站能够成功解码信号，则采用解码转发（DF）协议将信号转发给用户。否则，将执行放大转发（AF）方案。假设用户采用最大比合并（MRC）方式对两个协作阶段的接收信号进行联合收割机合并，推导了中继工作在AF模式和DF模式下，在两个协作阶段中一个用户较强以及每个协作阶段中另一个用户较强的两种情况下的平均和速率的解析表达式。然后，调查的情况下，中继是一个不可信的节点，并提出了合作干扰技术，以降低中继解码信号的能力，并强制中继始终工作在AF模式。对于不可信中继情形，推导了新的平均保密率解析表达式。蒙特卡罗模拟提供验证的分析。仿真结果表明，中继的位置是实现最佳性能的关键参数。
In this paper, non-orthogonal multiple access (NOMA) in cooperative relay system is considered, where a source node communicates with a pair of energy harvesting (EH) user equipments through a multiple antennas relay node. A hybrid protocol is adopted at the relay, in which if the relay can successfully decode the signals, decode-and-forward (DF) protocol will be adopted to forward the signals to the users. Otherwise, amplify-and-forward (AF) protocol will be implemented. Assuming that the users adopt maximal ratio combining (MRC) to combine the received signals in the two cooperative phases, new explicit analytical expressions for the average sum-rate are derived when the relay works in, 1) AF mode, and 2) DF mode, in two scenarios when one user is the stronger in both cooperation phases, and when an alternative user is stronger in each phase. Then, the investigation is extended to the case where the relay is an untrusted node, and cooperative jamming technique is proposed to degrade the ability of the relay to decode the signals and enforce the relay to operate always in AF mode. For the untrusted relay scenario, new analytical expression for the average secrecy rate is derived. Monte Carlo simulations are provided to validate the analysis. The simulation results reveal that the location of the relay is the key parameter to achieve the best performance.