In this paper, we propose an underlay two-way relaying scheme with the successive interference cancellation (SIC) solution in which two secondary sources transmit simultaneously their data to each other through secondary relays. The proposed scheme is operated in only two time slots and under an interference constraint of a primary receiver, denoted as the UTW-2TS scheme. In the UTW-2TS scheme, the secondary relays employ the SIC operation to decode successively the data from received broadcast signals and then encode these data by two techniques: digital network coding (DNC) enforced by XOR operations (denoted as the UTW-2TS-DNC protocol) and superposition coding (SC) enforced by power domain additions (denoted as the UTW-2TS-SC protocol). A selected secondary relay which subjects to maximize decoding capacities and to minimize collection time of channel state information in two protocols UTW-2TS-DNC and UTW-2TS-SC experiences residual interferences from imperfect SIC operations. Outage probabilities and throughputs are solved in terms of exact closed-form expressions to evaluate the system performance of the proposed protocols. Simulation and analysis results provide performance enhancement of the proposed protocols UTW-2TS-DNC and UTW-2TS-SC owing to increase the number of the cooperative secondary relays, the interference constraints, and the distances from the secondary network to the primary receiver. The best throughputs are pointed at optimal interference power allocation coefficients and optimal locations of the selected secondary relay. Considering the same power consumption, the UTW-2TS-DNC protocol outperforms the UTW-2TS-SC protocol. Finally, the simulation results are collected to confirm the exact analysis values of the outage probabilities and throughputs.

中文翻译：

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底层双向中继认知网络的SIC编码方案

在本文中，我们提出了一种具有连续干扰消除（SIC）解决方案的底层双向中继方案，其中两个辅助源通过辅助中继同时向彼此传输数据。所提出的方案仅在两个时隙中并且在被称为UTW-2TS方案的主要接收机的干扰约束下操作。在UTW-2TS方案中，辅助中继采用SIC操作对接收到的广播信号中的数据进行连续解码，然后通过两种技术对这些数据进行编码：通过XOR操作实施的数字网络编码（DNC）（表示为UTW-2TS- DNC协议）和通过电源域添加（称为UTW-2TS-SC协议）实施的叠加编码（SC）。在两个协议UTW-2TS-DNC和UTW-2TS-SC中，要使解码能力最大化并最小化信道状态信息收集时间的所选辅助继电器会遭受SIC操作不完善带来的残留干扰。中断概率和吞吐量可以通过精确的闭式表达式来解决，以评估所提出协议的系统性能。仿真和分析结果通过增加协作辅助中继的数量，干扰约束以及从辅助网络到主接收器的距离，提供了所提议协议UTW-2TS-DNC和UTW-2TS-SC的性能增强。最佳吞吐量指向最佳干扰功率分配系数和所选辅助继电器的最佳位置。考虑到相同的功耗，UTW-2TS-DNC协议的性能优于UTW-2TS-SC协议。最后，收集模拟结果以确认停机概率和吞吐量的准确分析值。