热点论文与带您领略5G/6G热点技术的最新进展——图书馆前沿文献专题推荐服务（30）

2020-12-04

 

        在上一期前沿文献中推荐中，介绍了5 G/6G电子器件和太赫兹方面的最新进展，选取的文献包括：宽带随机光电振荡器，基于纳米光纤网络的高精度表皮射频天线在无线可伸缩多功能电子领域的应用，InGaAs mHEMT技术中的300GHz宽带功率放大器毫米波单片集成电路，以及室内阻塞效应和可视接入并发的太赫兹网络干扰和覆盖分析。
在本期的文献推荐中，继续介绍5G/6G热点技术的最新进展，包括：高移动性5G-HetNet上下行资源动态分配的深度强化学习、通过基站充电实现无人机无线电能传输以及无人机能量消耗、毫米波系统中用于低延迟小区发现的灵活束宽波束扫描，以及毫米波OFDM分布式天线系统的混合波束赋形设计，供相关领域的科研人员参考。
 

领域一 高移动性5G-HetNet上下行资源动态分配的深度强化学习

Deep Reinforcement Learning for Dynamic Uplink/Downlink Resource Allocation in High Mobility 5G HetNet
Fengxiao Tang, etc.
IEEE Journal on Selected Areas in Communications, 2020, 38(12): 2773 - 2782

Recently, the 5G is widely deployed for supporting communications of high mobility nodes including train, vehicular and unmanned aerial vehicles (UAVs) largely emerged as the main components for constructing the wireless heterogeneous network (HetNet). To further improve the radio utilization, the Time Division Duplex (TDD) is considered to be the potential full-duplex communication technology in the high mobility 5G network. However, the high mobility of users leads to the high dynamic network traffic and unpredicted link state change. A new method to predict the dynamic traffic and channel condition and schedule the TDD configuration in real-time is essential for the high mobility environment. In this paper, we investigate the channel model in the high mobility and heterogeneous network and proposed a novel deep reinforcement learning based intelligent TDD configuration algorithm to dynamically allocate radio resources in an online manner. In the proposal, the deep neural network is employed to extract the features of the complex network information, and the dynamic Q-value iteration based reinforcement learning with experience replay memory mechanism is proposed to adaptively change TDD Up/Down-link ratio by evaluated rewards. The simulation results show that the proposal achieves significant network performance improvement in terms of both network throughput and packet loss rate, comparing with conventional TDD resource allocation algorithms.
 

领域二 通过基站充电实现无人机无线电能传输以及无人机能量消耗

UAV-Enabled Wireless Power Transfer With Base Station Charging and UAV Power Consumption
Hua Yan, etc.
IEEE Transactions on Vehicular Technology, 2020, 69(11): 12883 - 12896

Wireless power transfer (WPT) is a promising charging technology for battery-limited sensors. In this paper, we study the use of an unmanned aerial vehicle (UAV) as a charger for WPT. Unlike the previous works, our study takes into account the power consumption of the UAV (power consumption during hovering and flight), the charging process from a base station (BS) to the UAV and the conversion loss of the energy harvester. Both one-dimensional (1D) and two-dimensional (2D) WPT systems are considered. The sum-energy received by all sensors is maximized to find the optimal strategy for UAV deployment. Two different charging schemes are proposed. Numerical results show that the sum-energy received by all sensors is determined by sensors’ topology, the flight speed of the UAV and the transmit power. They also show that, when the BS charging process and the UAV power consumption are considered in the optimization, the optimal location of the UAV in the 1D and 2D WPT systems is closer to the BS than in the previous works that ignore these two practical factors.
 

领域三 毫米波系统中用于低延迟小区发现的灵活束宽波束扫描

Flexible-beamwidth beam scanning for low-latency cell discovery in mmWave systems
Jiancun Fan, etc.
Science China Information Sciences, 2020, 63

To compensate for a coverage gap in mmWave communication systems [1], a directional cell search (CS) scheme based on beam scanning was proposed [2–5]. Directional beamforming using a narrow beam (NB) can improve the coverage by considering a high beam gain; however, it will introduce a significant CS delay (CSD) if the beamwidth is too narrow as the beams have to sequentially scan the entire target area in their cell searching phase to guarantee the coverage of all possible users [6]. In [7], it has been shown that an appropriate beamwidth can balance CSD and beamforming gains, which will improve average cell/system throughput (ST). Therefore, a beam with a suitable width and gain should be designed to maximize the ST. Based on this, we propose a directional beam scanning scheme with flexible beamwidth (FB) design for maximizing the ST.
 

领域四 毫米波OFDM分布式天线系统的混合波束赋形设计

Hybrid beamforming design for mmWave OFDM distributed antenna systems
Yu Zhang, etc.
Science China Information Sciences, 2020, 63                                                                              

This paper presents a hybrid beamforming design for millimeter-wave (mmWave) orthogonal frequency division multiplexing (OFDM) distributed antenna systems (DASs). First, we derive a downlink signal transmission model that considers the delay spread differences (DSDs) caused by the distributed nature of the network. We then propose a cooperative wideband hybrid beamforming method under the transmitting power constraints of each remote access unit. In a simulation study, the proposed method performed comparably to fully-digital beamforming, even when operated with practical finite-resolution phase shifters. We further confirm that the DSDs are the dominant cause of performance degradation in mmWave OFDM DASs.
 

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