Cell discontinuous transmission(Cell DTx)is a key technology to mitigate inter-cell interference(ICI)in ultra-dense networks(UDNs).The aim of this work is to understand the impact of Cell DTx on physical-layer sum rat...Cell discontinuous transmission(Cell DTx)is a key technology to mitigate inter-cell interference(ICI)in ultra-dense networks(UDNs).The aim of this work is to understand the impact of Cell DTx on physical-layer sum rates of SBSs and link-layer quality-of-service(QoS)performance in multiuser UDNs.In this work,we develop a cross-layer framework for capacity analysis in multiuser UDNs with Cell DTx.In particular,we first extend the traditional one-dimensional effective capacity model to a new multidimensional effective capacity model to derive the sum rate and the effective capacity.Moreover,we propose a new iterative bisection search algorithm that is capable of approximating QoS performance.The convergence of this new algorithm to a unique QoS exponent vector is later proved.Finally,we apply this framework to the round-robin and the max-C/I scheduling policies.Simulation results show that our framework is accurate in approximating 1)queue length distribution,2)delay distribution and 3)sum rates under the above two scheduling policies,and further show that with the Cell DTx,systems have approximately 30% higher sum rate and 35% smaller average delay than those in full-buffer scenarios.展开更多
A novel scheme‘user assisted cooperative relaying in beamspace massive multiple input multiple output(M-MIMO)non-orthogonal multiple access(NOMA)system’has been proposed to improve coverage area,spectrum and energy ...A novel scheme‘user assisted cooperative relaying in beamspace massive multiple input multiple output(M-MIMO)non-orthogonal multiple access(NOMA)system’has been proposed to improve coverage area,spectrum and energy efficiency for millimeter wave(mmWave)communications.A downlink system for M users,where base station(BS)is equipped with beamforming lens antenna structure having NRF radio frequency(RF)chains,has been considered.A dynamic cluster of users is formed within a beam and the intermediate users(in that cluster)between beam source and destination(user)act as relaying stations.By the use of successive interference cancellation(SIC)technique of NOMA within a cluster,the relaying stations relay the symbols with improved power to the destination.For maximizing achievable sum rate,transmit precoding and dynamic power allocation for both intra and inter beam power optimization are implemented.Simulations for performance evaluation are carried out to validate that the proposed system outperforms the conventional beamspace M-MIMO NOMA system for mmWave communications in terms of spectrum and energy efficiency.展开更多
随着第五代移动通信技术(5th Generation Mobile Communication Technology,5G)网络的大规模商业化部署,超5G(Beyond 5G,B5G)和第六代移动通信技术(6th Generation Mobile Communication Technology,6G)逐渐成为研究热点。非正交多址接...随着第五代移动通信技术(5th Generation Mobile Communication Technology,5G)网络的大规模商业化部署,超5G(Beyond 5G,B5G)和第六代移动通信技术(6th Generation Mobile Communication Technology,6G)逐渐成为研究热点。非正交多址接入(Non-Orthogonal Multiple Access,NOMA)作为一种新型接入技术,有望成为B5G和6G网络中的关键多址接入技术。与此同时,多载波通信具有抗频率选择性衰落和高频谱效率的特点,因此将多载波技术与NOMA相结合成为B5G和6G的一个重要研究方向。从能效、功耗以及速率方面概述了多载波非协作NOMA、多载波协作NOMA的资源分配问题。探讨当前研究存在的一些缺陷与不足,并展望多载波NOMA系统资源分配问题的未来研究方向。展开更多
非正交多址接入(Non-Orthogonal Multiple Access,NOMA)技术与设备到设备(Device-to-Device,D2D)通信技术相结合在实现高效频谱利用率和大规模接入上有着突出的优势。针对现有的NOMA-D2D系统存在的信道分配模式单一和D2D组内功率分配难...非正交多址接入(Non-Orthogonal Multiple Access,NOMA)技术与设备到设备(Device-to-Device,D2D)通信技术相结合在实现高效频谱利用率和大规模接入上有着突出的优势。针对现有的NOMA-D2D系统存在的信道分配模式单一和D2D组内功率分配难以获得最优解的问题,构建了以D2D组和速率为优化目标的联合资源分配算法的方案:首先,在子信道分配上,将问题转换为双边匹配问题,提出了一种基于多对一场景下的D2D组信道分配算法;然后运用基于逐次凸逼近的凸差分(Difference of two Convex functions,DC)编程方法求出接近最优的功率分配值。仿真结果表明,提出的多对一场景下信道匹配算法在和速率上明显优于一对一场景下的信道匹配算法,提出的功率分配算法相比起对偶迭代算法更接近最优功率分配。展开更多
在云接入网络(cloud radio access network,C-RAN)中,设备至设备(device-to-device,D2D)通信共享蜂窝用户的资源,提高了频谱利用率。但是资源共享也引入干扰问题,降低了网络的和速率。提出基于教学优化法的资源分配算法(teacher learner...在云接入网络(cloud radio access network,C-RAN)中,设备至设备(device-to-device,D2D)通信共享蜂窝用户的资源,提高了频谱利用率。但是资源共享也引入干扰问题,降低了网络的和速率。提出基于教学优化法的资源分配算法(teacher learner based optimization-resource allocation,TLRA)。TLRA算法在分配资源时,考虑了干扰问题,并以蜂窝用户端的干扰不高于预定阈值为约束条件,建立目标问题。利用教学优化法求解目标问题,获取最优的资源分配策略。性能分析表明,提出的TLRA算法提高了系统和速率,Jain公平指数接近0.8。展开更多
文摘Cell discontinuous transmission(Cell DTx)is a key technology to mitigate inter-cell interference(ICI)in ultra-dense networks(UDNs).The aim of this work is to understand the impact of Cell DTx on physical-layer sum rates of SBSs and link-layer quality-of-service(QoS)performance in multiuser UDNs.In this work,we develop a cross-layer framework for capacity analysis in multiuser UDNs with Cell DTx.In particular,we first extend the traditional one-dimensional effective capacity model to a new multidimensional effective capacity model to derive the sum rate and the effective capacity.Moreover,we propose a new iterative bisection search algorithm that is capable of approximating QoS performance.The convergence of this new algorithm to a unique QoS exponent vector is later proved.Finally,we apply this framework to the round-robin and the max-C/I scheduling policies.Simulation results show that our framework is accurate in approximating 1)queue length distribution,2)delay distribution and 3)sum rates under the above two scheduling policies,and further show that with the Cell DTx,systems have approximately 30% higher sum rate and 35% smaller average delay than those in full-buffer scenarios.
文摘A novel scheme‘user assisted cooperative relaying in beamspace massive multiple input multiple output(M-MIMO)non-orthogonal multiple access(NOMA)system’has been proposed to improve coverage area,spectrum and energy efficiency for millimeter wave(mmWave)communications.A downlink system for M users,where base station(BS)is equipped with beamforming lens antenna structure having NRF radio frequency(RF)chains,has been considered.A dynamic cluster of users is formed within a beam and the intermediate users(in that cluster)between beam source and destination(user)act as relaying stations.By the use of successive interference cancellation(SIC)technique of NOMA within a cluster,the relaying stations relay the symbols with improved power to the destination.For maximizing achievable sum rate,transmit precoding and dynamic power allocation for both intra and inter beam power optimization are implemented.Simulations for performance evaluation are carried out to validate that the proposed system outperforms the conventional beamspace M-MIMO NOMA system for mmWave communications in terms of spectrum and energy efficiency.
文摘随着第五代移动通信技术(5th Generation Mobile Communication Technology,5G)网络的大规模商业化部署,超5G(Beyond 5G,B5G)和第六代移动通信技术(6th Generation Mobile Communication Technology,6G)逐渐成为研究热点。非正交多址接入(Non-Orthogonal Multiple Access,NOMA)作为一种新型接入技术,有望成为B5G和6G网络中的关键多址接入技术。与此同时,多载波通信具有抗频率选择性衰落和高频谱效率的特点,因此将多载波技术与NOMA相结合成为B5G和6G的一个重要研究方向。从能效、功耗以及速率方面概述了多载波非协作NOMA、多载波协作NOMA的资源分配问题。探讨当前研究存在的一些缺陷与不足,并展望多载波NOMA系统资源分配问题的未来研究方向。
文摘非正交多址接入(Non-Orthogonal Multiple Access,NOMA)技术与设备到设备(Device-to-Device,D2D)通信技术相结合在实现高效频谱利用率和大规模接入上有着突出的优势。针对现有的NOMA-D2D系统存在的信道分配模式单一和D2D组内功率分配难以获得最优解的问题,构建了以D2D组和速率为优化目标的联合资源分配算法的方案:首先,在子信道分配上,将问题转换为双边匹配问题,提出了一种基于多对一场景下的D2D组信道分配算法;然后运用基于逐次凸逼近的凸差分(Difference of two Convex functions,DC)编程方法求出接近最优的功率分配值。仿真结果表明,提出的多对一场景下信道匹配算法在和速率上明显优于一对一场景下的信道匹配算法,提出的功率分配算法相比起对偶迭代算法更接近最优功率分配。
文摘在云接入网络(cloud radio access network,C-RAN)中,设备至设备(device-to-device,D2D)通信共享蜂窝用户的资源,提高了频谱利用率。但是资源共享也引入干扰问题,降低了网络的和速率。提出基于教学优化法的资源分配算法(teacher learner based optimization-resource allocation,TLRA)。TLRA算法在分配资源时,考虑了干扰问题,并以蜂窝用户端的干扰不高于预定阈值为约束条件,建立目标问题。利用教学优化法求解目标问题,获取最优的资源分配策略。性能分析表明,提出的TLRA算法提高了系统和速率,Jain公平指数接近0.8。
