Anwar Asim, Seet Boon-Chong, Ding Zhiguo
Department of Electrical and Electronic Engineering, Auckland University of Technology, Auckland 1010, New Zealand.
School of Computing and Communications, Lancaster University, Lancaster LA1 4YW, UK.
Sensors (Basel). 2018 Feb 8;18(2):516. doi: 10.3390/s18020516.
Ubiquitous wireless sensor networks (UWSNs) have become a critical technology for enabling smart cities and other ubiquitous monitoring applications. Their deployment, however, can be seriously hampered by the spectrum available to the sheer number of sensors for communication. To support the communication needs of UWSNs without requiring more spectrum resources, the power-domain non-orthogonal multiple access (NOMA) technique originally proposed for 5th Generation (5G) cellular networks is investigated for UWSNs for the first time in this paper. However, unlike 5G networks that operate in the licensed spectrum, UWSNs mostly operate in unlicensed spectrum where sensors also experience cross-technology interferences from other devices sharing the same spectrum. In this paper, we model the interferences from various sources at the sensors using stochastic geometry framework. To evaluate the performance, we derive a theorem and present new closed form expression for the outage probability of the sensors in a downlink scenario under interference limited environment. In addition, diversity analysis for the ordered NOMA users is performed. Based on the derived outage probability, we evaluate the average link throughput and energy consumption efficiency of NOMA against conventional orthogonal multiple access (OMA) technique in UWSNs. Further, the required computational complexity for the NOMA users is presented.
无处不在的无线传感器网络（UWSNs）已成为实现智慧城市和其他无处不在的监测应用的关键技术。然而，其部署可能会受到大量传感器用于通信的可用频谱的严重阻碍。为了在不要求更多频谱资源的情况下支持UWSNs的通信需求，本文首次针对UWSNs研究了最初为第五代（5G）蜂窝网络提出的功率域非正交多址接入（NOMA）技术。然而，与在授权频谱中运行的5G网络不同，UWSNs大多在未授权频谱中运行，在该频谱中传感器还会受到来自共享同一频谱的其他设备的跨技术干扰。在本文中，我们使用随机几何框架对传感器处来自各种源的干扰进行建模。为了评估性能，我们推导了一个定理，并给出了在干扰受限环境下下行链路场景中传感器中断概率的新闭式表达式。此外，还对有序NOMA用户进行了分集分析。基于推导的中断概率，我们评估了NOMA相对于传统正交多址接入（OMA）技术在UWSNs中的平均链路吞吐量和能量消耗效率。此外，还给出了NOMA用户所需的计算复杂度。
