Joint analysis of outage probability and energy efficiency in underlay cognitive radio-inspired NOMA systems using the AF relay in a downlink transmission

IF 4.3 3区计算机科学 Q1 COMPUTER SCIENCE, INFORMATION SYSTEMS

Computer Communications Pub Date : 2025-06-06 DOI:10.1016/j.comcom.2025.108233

Nourollah Davoudian, Hamidreza Bakhshi

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引用次数: 0

Abstract

In this paper, we investigate the performance of the underlay Cognitive Radio-Inspired Non-Orthogonal Multiple Access (NOMA) system in a downlink transmission. In our proposed model, a primary transmitter (PT) operating over a weak channel shares its frequency band with a secondary transmitter (ST) to enhance overall spectrum utilization. This work employs a coordinated direct and relay transmission (CDRT) strategy, where the relay operates in amplify-and-forward (AF) mode. We considered co-channel interference affecting both primary and secondary users. We present a novel decoding technique for the symbols of the primary and secondary users based on a combined signal-to-interference plus noise ratio (SINR) framework. This technique significantly improves the outage probability for both user types, resulting in enhanced system performance overall. The main advantage of this method lies in utilizing the combined SINR from both transmission phases, which enables a more robust decoding process. In this study, we derived a closed-form analytical expression for the outage probability of both PU and secondary users (SU). Additionally, we provided an asymptotic approximation of the outage probability at high signal-to-noise ratio (SNR) regimes. Our analytical results show that, at a high SNR, the system's performance based on the asymptotic approximation matches the simulation results, which validates the accuracy of our model. An essential aspect of this study is analyzing power allocation coefficients, as they directly affect system efficiency and energy utilization. In this regard, we derived the power allocation coefficients for the primary and secondary users and presented the corresponding analyses. Based on these coefficients, we calculated the SU's throughput, and system's overall energy efficiency. Our findings indicate that the proposed model reduces outage probability and increases throughput while also enhancing energy efficiency, which is crucial for sustainability and optimal resource utilization. Ultimately, this work can significantly enhance the performance of NOMA and cognitive radio (CR) systems, making it more applicable to the next generation of communication networks.

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在下行传输中使用AF中继的底层认知无线电启发的NOMA系统的中断概率和能源效率的联合分析

在本文中，我们研究了底层认知无线电启发非正交多址（NOMA）系统在下行传输中的性能。在我们提出的模型中，在弱信道上工作的主发射机（PT）与辅助发射机（ST）共享其频带，以提高整体频谱利用率。这项工作采用协调的直接和中继传输（CDRT）策略，其中中继以放大和转发（AF）模式工作。我们考虑了影响主用户和辅助用户的同信道干扰。提出了一种基于信干扰加噪声比（SINR）框架的主、次用户符号解码技术。这种技术显著提高了两种用户类型的停机概率，从而提高了系统的总体性能。该方法的主要优点在于利用了两个传输阶段的综合信噪比，从而实现了更稳健的解码过程。在本研究中，我们导出了PU和辅助用户（SU）的停机概率的封闭形式解析表达式。此外，我们还提供了高信噪比（SNR）状态下中断概率的渐近近似。分析结果表明，在高信噪比下，基于渐近逼近的系统性能与仿真结果吻合，验证了模型的准确性。本研究的一个重要方面是分析功率分配系数，因为它们直接影响系统效率和能源利用率。为此，推导了主、次用户的功率分配系数，并进行了相应的分析。基于这些系数，我们计算了SU的吞吐量和系统的整体能源效率。我们的研究结果表明，该模型降低了停电概率，提高了吞吐量，同时提高了能源效率，这对可持续发展和优化资源利用至关重要。最终，这项工作可以显著提高NOMA和认知无线电（CR）系统的性能，使其更适用于下一代通信网络。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Computer Communications 工程技术-电信学

CiteScore

14.10

自引率

5.00%

发文量

397

审稿时长

66 days

期刊介绍： Computer and Communications networks are key infrastructures of the information society with high socio-economic value as they contribute to the correct operations of many critical services (from healthcare to finance and transportation). Internet is the core of today''s computer-communication infrastructures. This has transformed the Internet, from a robust network for data transfer between computers, to a global, content-rich, communication and information system where contents are increasingly generated by the users, and distributed according to human social relations. Next-generation network technologies, architectures and protocols are therefore required to overcome the limitations of the legacy Internet and add new capabilities and services. The future Internet should be ubiquitous, secure, resilient, and closer to human communication paradigms. Computer Communications is a peer-reviewed international journal that publishes high-quality scientific articles (both theory and practice) and survey papers covering all aspects of future computer communication networks (on all layers, except the physical layer), with a special attention to the evolution of the Internet architecture, protocols, services, and applications.