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arXiv 2202.01586eess.SP
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信道估计误差下的后向散射辅助NOMA V2X通信

Backscatter-Aided NOMA V2X Communication under Channel Estimation Errors

Wali Ullah Khan, Muhammad Ali Jamshed, Asad Mahmood, Eva Lagunas, Symeon Chatzinotas, Bjorn Ottersten

摘要:

反向散射通信(BC)已经成为用于在nextG(即,超越5G)无线网络。BC的基本思想是通过使用现有的环境射频信号在无线设备之间进行通信的可能性。非正交多址接入(NOMA)由于其高频谱效率和大规模连接性而近来引起了极大的关注。本文提出了一种新的优化框架,以最大限度地减少总发射功率的BC-NOMA合作车辆到一切网络(V2XneT),同时确保服务质量。更具体地,基站(BS)在第一时隙中向其关联的路边单元(RSU)发送叠加信号。然后RSU利用解码和转发协议在第二时隙中将叠加的信号发送到它们的服务车辆。RSU覆盖区域内的反向散射装置(BD)也接收叠加信号,并通过调制自身信息将其反射到车辆。因此,目标是在完美和不完美的信道状态信息下同时优化BS和RSU的发射功率以及BD的反射系数。能源效率问题是一个多变量耦合的非凸优化问题,求解起来非常复杂。因此,我们首先将原问题转化为两个子问题,然后采用迭代次梯度法来获得一个有效的解决方案。仿真结果表明,所提出的BC-NOMA V2XneT提供了比没有BC的传统NOMA V2XneT更高的能量效率。

英文摘要:

Backscatter communications (BC) has emerged as a promising technology for providing low-powered transmissions in nextG (i.e., beyond 5G) wireless networks. The fundamental idea of BC is the possibility of communications among wireless devices by using the existing ambient radio frequency signals. Non-orthogonal multiple access (NOMA) has recently attracted significant attention due to its high spectral efficiency and massive connectivity. This paper proposes a new optimization framework to minimize total transmit power of BC-NOMA cooperative vehicle-to-everything networks (V2XneT) while ensuring the quality of services. More specifically, the base station (BS) transmits a superimposed signal to its associated roadside units (RSUs) in the first time slot. Then the RSUs transmit the superimposed signal to their serving vehicles in the second time slot exploiting decode and forward protocol. A backscatter device (BD) in the coverage area of RSU also receives the superimposed signal and reflect it towards vehicles by modulating own information. Thus, the objective is to simultaneously optimize the transmit power of BS and RSUs along with reflection coefficient of BDs under perfect and imperfect channel state information. The problem of energy efficiency is formulated as non-convex and coupled on multiple optimization variables which makes it very complex and hard to solve. Therefore, we first transform and decouple the original problem into two sub-problems and then employ iterative sub-gradient method to obtain an efficient solution. Simulation results demonstrate that the proposed BC-NOMA V2XneT provides high energy efficiency than the conventional NOMA V2XneT without BC.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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