【作者】 唐红；

【导师】 谢显中；

【作者基本信息】 重庆邮电大学 ， 信息与通信工程， 2022， 硕士

【摘要】 随着无线通信技术的飞速发展,通信数据量的急剧增长、无线连接的海量涌现及网络基础设施的大规模建设,使得能源短缺以及频谱资源匮乏的问题日益突出。为了提高能量效率(Energy Efficiency,EE)和频谱效率(Spectrum Efficiency,SE),以及解决传统中继模型中全双工(Full Duplex,FD)模式下存在自干扰(Self-interference,SI)的问题,本文开展弹性双工(X-Duplex)和智能反射面(Intelligent Reflecting Surface,IRS)辅助的中继网络携能传输方案的研究。本文的主要工作与创新如下:1.针对认知无线电(Cognitive Radio,CR)网络中需要进行空闲频谱检测带来的能量供给和频谱利用率问题,本文以最大化系统和速率为目标,提出了一种基于射频(Radio Frequency,RF)能量收集(Energy Harvesting,EH)和弹性双工的双向放大转发(Amplify-and-Forward,AF)中继方案。区别于传统双向中继中采用半双工(Half Duplex,HD)的通信模式,本文提出的弹性双工中继模型可以在不干扰主用户的情况下,动态地切换到全双工模式。该方案从射频信号中获取能量,对于全双工模式下产生的自干扰信号,将干扰信号转化为能量收集起来,为能量受限的节点设备提供能量,并实现无线信息与能量同传(Simultaneously Wireless Information and Power Transfer,SWIPT)。进一步,采用功率分割(Power Splitting,PS)协议,弹性双工中继将接收到的RF信号按照一定的功率分割比划分成两部分,一部分用于能量收集,一部分用于信息处理,并提出了一种使系统和速率最大化的最优功率分配算法。最后,通过仿真对比分析,验证了本文设计的算法在提高系统的和速率以及能量效率(Energy Efficiency,EE)性能上存在优势。2.智能反射面因能智能地控制无线电传输环境被认为是6G移动通信中一种新的无线使能技术(Enabling Technologies),本文考虑IRS中继辅助无线信息与能量同传。不同于已有的做法是将IRS与简单的采用半双工模式的放大转发/解码转发(Decoding-and-Forwarding,DF)中继进行类比,本文将其与弹性双工中继进行结合,提出了一种基于弹性双工的IRS传输方案。当无线接入点(Access Point,AP)发射的RF信号存在有障碍的非视线传输时,通过弹性双工和IRS辅助的中继网络来进行无线信息与能量同传。针对三种不同路径的传输,本文建立了基于真实场景的传输功耗模型,对应设计了三种能量效率最大化算法来优化不同传输路径的能量效率,并探究了三种路径下的能量效率以及加权和速率(Weighted Sum Rate,WSR)性能。仿真结果显示,虽然IRS在发射功率较为充足的情况下能量效率更有优势,但它并不能完全取代传统的中继技术;将弹性双工中继和IRS进行联合部署,应对不同的传输要求,可以选择最佳的传输方式,最终使网络具有更好的可靠性、大容量、全覆盖、低能耗等性能。更多还原

【Abstract】 With the rapid development of wireless communication technology,the rapid growth of communication data,the massive emergence of wireless connections and the large-scale construction of network infrastructure,the problems of energy shortage and lack of spectrum resources have become increasingly prominent.In order to improve energy efficiency and spectrum efficiency,and to solve the problem of self-interference in the full duplex mode in the traditional relay model,this paper studies the adaptive transmission scheme of relay network assisted by X-Duplex and intelligent reflecting surface.The main work and innovation of this paper are as follows:1.Aiming at the problem of energy supply and spectrum utilization caused by idle spectrum detection in cognitive radio network,this paper proposes a two-way amplify-and-forward relay scheme based on radio frequency energy harvesting and X-Duplex with the goal of maximizing the system sum rate.Different from the communication mode of half duplex used in traditional two-way relay,the X-Duplex relay model proposed in this paper can dynamically switch to full duplex mode without disturbing the primary users.This scheme can obtain energy from the radio frequency signal.For the self-interference signal generated in full duplex mode,this paper converts the interference signal into energy and collects it to provide energy for the node equipment with limited energy,and realizes the simultaneously wireless information and power transfer.Further,using the power splitting protocol,the X-Duplex relay divides the received radio frequency signal into two parts according to a power split ratio,one part is used for energy harvesting,and the other part is used for information processing,and an optimal power allocation algorithm is proposed to maximize the system sum rate.Finally,through the comparative analysis of simulation,it is verified that the algorithm designed in this paper has advantages in improving the sum rate and energy efficiency performance of the system.2.Intelligent reflecting surface is considered as a new wireless enabling technologies in 6G mobile communications because it can intelligently control the radio transmission environment.This paper considers intelligent reflecting surface-assisted relay simultaneously wireless information and power transfer.Different from the existing work,which compares the intelligent reflecting surface with the simple amplify-and-forward/decode-and-forward relay in half duplex mode,this paper combines it with the X-Duplex relay,and proposes an intelligent reflecting surface transmission scheme based on X-Duplex.When the radio frequency signal transmitted by the wireless access point has an obstacle of non-line of sight transmission,the wireless information and energy can be simultaneously transmitted through the X-Dduplex and intelligent reflecting surface-assisted relay network.For the transmission of three different paths,this paper establishes a transmission power consumption model based on real scenarios,and correspondingly designs three energy efficiency maximization algorithms to optimize the energy efficiency performance of different paths,and explores the energy efficiency and weighted sum rate performance of the three paths.The simulation results show that although intelligent reflecting surface has more advantages in energy efficiency when the transmission power is sufficient,it cannot completely replace the traditional relay technology.The joint deployment of X-Duplex relay and IRS can meet different transmission requirements.Therefore,choosing the best transmission mode can finally make the network have better performance such as more reliability,large capacity,greater fraction of coverage and low energy consumption.更多还原