Multiple-input and multiple-output (MIMO) technique can significantly improve transmission reliability and bandwidth efficiency in wireless networks. However, many upper layer aspects of MIMO links, especially in mobi...Multiple-input and multiple-output (MIMO) technique can significantly improve transmission reliability and bandwidth efficiency in wireless networks. However, many upper layer aspects of MIMO links, especially in mobile networks with heterogeneous antennas and strong interference environments, need further investigation. In this paper, we study its impact on medium access and network capacity. Since MIMO links can enhance physical layer capacity and co-channel interference suppression that affects network access scheduling directly, we develop a capacity-optimized access scheduling control (COASC) scheme for mobile ad hoc networks (MANETs) with MIMO links. We formulate the distributed scheduling taking the key of optimization into design to improve the network capacity and transmission reliability. Simulation results are presented to show the effectiveness of the proposed scheme.展开更多
According to the analysis of the very high frequency (VHF) self organized time division multiple access (S TDMA) aviation data link, a new dynamic slot assignment scheme is proposed in this paper, which adopts var...According to the analysis of the very high frequency (VHF) self organized time division multiple access (S TDMA) aviation data link, a new dynamic slot assignment scheme is proposed in this paper, which adopts variable data frame structure and can eliminate the effect of the idle slot on message delay. By using queue theory, the analysis models of the new scheme and previous scheme are presented, and the performance of message delay and that of system throughput are analyzed under two schemes. The simulation results show that the new scheme has a better performance than the previous one in the message delay and system throughput.展开更多
This paper studies the effect of phase noise and fronthaul compression on a downlink cloud radio access network(C-RAN), where several remote radio heads(RRHs) are coordinated to communicate with users by a baseband un...This paper studies the effect of phase noise and fronthaul compression on a downlink cloud radio access network(C-RAN), where several remote radio heads(RRHs) are coordinated to communicate with users by a baseband unit(BBU) on the cloud server. In the system, the baseband signals are precoded at BBU, and then compressed before being transmitted to RRHs through capacity-limited fronthaul links which results in the compressive quantization noise. We assume the regularized zero-forcing precoding is performed with an imperfect channel state information and a compression strategy is applied at BBU. The effect of phase noise arising from nonideal local oscillators both at RRHs and users is considered. We propose an approximate expression for the downlink ergodic sum-rate of considered C-RAN utilizing large dimensional random matrix theory in the large-system regime. From simulation results, the accuracy of the approximate expression is validated, and the effect of phase noise and fronthaul compression can be analyzed theoretically based on the approximate expression.展开更多
本文研究了智能反射面(IRS)辅助OFDMA(Orthogonal Frequency Division Multiple Access,正交频分多址接入)云无线接入网(C-RAN)的下行链路传输系统,其中基带处理单元(BBU)池通过多个远端射频头(RRH)与多个用户进行通信.RRH到用户的接入...本文研究了智能反射面(IRS)辅助OFDMA(Orthogonal Frequency Division Multiple Access,正交频分多址接入)云无线接入网(C-RAN)的下行链路传输系统,其中基带处理单元(BBU)池通过多个远端射频头(RRH)与多个用户进行通信.RRH到用户的接入链路采用OFDMA接入技术.对于BBU池到RRH,采用无线前传链路,并且部署多个IRS以增强链路传输能力.在BBU池和每个RRH发射功率约束下,本文提出通过联合优化前传链路和接入链路资源配置使下行用户和速率最大化.由于该资源配置问题是非凸的,首先采用连续凸逼近(SCA)对目标以及约束条件进行转换.其次,将转换后的问题拆分成三个子问题来交替性求解.最后,计算机仿真结果显示了所提出的联合资源分配方法与其他基准方案相比具有显著的传输性能增益.展开更多
当底层无线接入网(Radio Access Network,RAN)发生多链路故障时,为了提高网络切片的恢复能力并且提高网络资源利用率,提出一种基于业务类型的可生存网络切片资源部署(Survivable Network Slice Resource Deployment algorithm Based on ...当底层无线接入网(Radio Access Network,RAN)发生多链路故障时,为了提高网络切片的恢复能力并且提高网络资源利用率,提出一种基于业务类型的可生存网络切片资源部署(Survivable Network Slice Resource Deployment algorithm Based on Service Types,SNSRD-BST)算法。该算法基于节点核心度完成节点映射,区分切片所承载的业务类型。在链路映射阶段,为高可靠、低时延类型切片寻找备份路径,预留备份资源,在故障发生后,如果备份路径可用,则直接迁移至备份路径,否则,采取基于熵权法的多属性路径排序方法进行重映射;对于受故障影响的高带宽类型切片,基于路径资源关键度模型对虚拟链路进行重映射,恢复故障链路。仿真结果表明,在稳定运行后,所提算法的请求接受率为92%,故障恢复率为93%,平均网络故障恢复时延为0.09个时间单元,长期平均收益开销比为0.62,物理链路利用率为63%。与相关算法相比,所提算法的网络切片恢复能力与网络资源利用率较高。展开更多
文章提出了一种基于地理信息系统(Geographic Information System,GIS)呈现的密集城区集中无线接入网络(Centralized Radio Access Network,CRAN)区分裂评估方法。该方法利用GIS技术,通过数据收集和参数GIS呈现,综合评估CRAN区域内微网...文章提出了一种基于地理信息系统(Geographic Information System,GIS)呈现的密集城区集中无线接入网络(Centralized Radio Access Network,CRAN)区分裂评估方法。该方法利用GIS技术,通过数据收集和参数GIS呈现,综合评估CRAN区域内微网格的业务需求和设备接入能力。通过现网环路带宽分析和判断是否需要分裂,制订最优匹配调整CRAN范围和CRAN分裂回传组网的方案,满足网络的健康发展和适应未来需求。该方法为密集城区CRAN网络规划和优化提供了科学的参考和决策依据。展开更多
文摘Multiple-input and multiple-output (MIMO) technique can significantly improve transmission reliability and bandwidth efficiency in wireless networks. However, many upper layer aspects of MIMO links, especially in mobile networks with heterogeneous antennas and strong interference environments, need further investigation. In this paper, we study its impact on medium access and network capacity. Since MIMO links can enhance physical layer capacity and co-channel interference suppression that affects network access scheduling directly, we develop a capacity-optimized access scheduling control (COASC) scheme for mobile ad hoc networks (MANETs) with MIMO links. We formulate the distributed scheduling taking the key of optimization into design to improve the network capacity and transmission reliability. Simulation results are presented to show the effectiveness of the proposed scheme.
基金Aeronautical Science F oundation of China !( N o.98E5 1116)
文摘According to the analysis of the very high frequency (VHF) self organized time division multiple access (S TDMA) aviation data link, a new dynamic slot assignment scheme is proposed in this paper, which adopts variable data frame structure and can eliminate the effect of the idle slot on message delay. By using queue theory, the analysis models of the new scheme and previous scheme are presented, and the performance of message delay and that of system throughput are analyzed under two schemes. The simulation results show that the new scheme has a better performance than the previous one in the message delay and system throughput.
基金supported in part by the Natural Science Foundation of China (NSFC) under Grant U1805262, 61871446, and 61671251supported by NSFC under Grant 61625106 and Grant 61531011
文摘This paper studies the effect of phase noise and fronthaul compression on a downlink cloud radio access network(C-RAN), where several remote radio heads(RRHs) are coordinated to communicate with users by a baseband unit(BBU) on the cloud server. In the system, the baseband signals are precoded at BBU, and then compressed before being transmitted to RRHs through capacity-limited fronthaul links which results in the compressive quantization noise. We assume the regularized zero-forcing precoding is performed with an imperfect channel state information and a compression strategy is applied at BBU. The effect of phase noise arising from nonideal local oscillators both at RRHs and users is considered. We propose an approximate expression for the downlink ergodic sum-rate of considered C-RAN utilizing large dimensional random matrix theory in the large-system regime. From simulation results, the accuracy of the approximate expression is validated, and the effect of phase noise and fronthaul compression can be analyzed theoretically based on the approximate expression.
文摘本文研究了智能反射面(IRS)辅助OFDMA(Orthogonal Frequency Division Multiple Access,正交频分多址接入)云无线接入网(C-RAN)的下行链路传输系统,其中基带处理单元(BBU)池通过多个远端射频头(RRH)与多个用户进行通信.RRH到用户的接入链路采用OFDMA接入技术.对于BBU池到RRH,采用无线前传链路,并且部署多个IRS以增强链路传输能力.在BBU池和每个RRH发射功率约束下,本文提出通过联合优化前传链路和接入链路资源配置使下行用户和速率最大化.由于该资源配置问题是非凸的,首先采用连续凸逼近(SCA)对目标以及约束条件进行转换.其次,将转换后的问题拆分成三个子问题来交替性求解.最后,计算机仿真结果显示了所提出的联合资源分配方法与其他基准方案相比具有显著的传输性能增益.
文摘当底层无线接入网(Radio Access Network,RAN)发生多链路故障时,为了提高网络切片的恢复能力并且提高网络资源利用率,提出一种基于业务类型的可生存网络切片资源部署(Survivable Network Slice Resource Deployment algorithm Based on Service Types,SNSRD-BST)算法。该算法基于节点核心度完成节点映射,区分切片所承载的业务类型。在链路映射阶段,为高可靠、低时延类型切片寻找备份路径,预留备份资源,在故障发生后,如果备份路径可用,则直接迁移至备份路径,否则,采取基于熵权法的多属性路径排序方法进行重映射;对于受故障影响的高带宽类型切片,基于路径资源关键度模型对虚拟链路进行重映射,恢复故障链路。仿真结果表明,在稳定运行后,所提算法的请求接受率为92%,故障恢复率为93%,平均网络故障恢复时延为0.09个时间单元,长期平均收益开销比为0.62,物理链路利用率为63%。与相关算法相比,所提算法的网络切片恢复能力与网络资源利用率较高。
文摘文章提出了一种基于地理信息系统(Geographic Information System,GIS)呈现的密集城区集中无线接入网络(Centralized Radio Access Network,CRAN)区分裂评估方法。该方法利用GIS技术,通过数据收集和参数GIS呈现,综合评估CRAN区域内微网格的业务需求和设备接入能力。通过现网环路带宽分析和判断是否需要分裂,制订最优匹配调整CRAN范围和CRAN分裂回传组网的方案,满足网络的健康发展和适应未来需求。该方法为密集城区CRAN网络规划和优化提供了科学的参考和决策依据。
