Baseband design and implementation for micro/pico base stations （mBS） in 5G ultra-dense network （UDN） is studied. Low cost is an essential requirement for mBS baseband in UDN. Digital baseband cost of ASIC/ASIP （...Baseband design and implementation for micro/pico base stations （mBS） in 5G ultra-dense network （UDN） is studied. Low cost is an essential requirement for mBS baseband in UDN. Digital baseband cost of ASIC/ASIP （Application Specific Integrated Circuit / Instruction-set processor） is of the most uncertainty in roBS system. However. the actual costs and hardware feasibility of the baseband are yet unknown to network deployers and researchers. In this paper, we studied the baseband hardware system design and implementation for low-cost roBS. We analyzed popular baseband algorithms and architectures for both full-digital and hybrid beamforming （BF） for UDN. We then proposed feasible chip-level solutions for the baseband with up to 128-antenna BS system, and estimated their implementation cost. Results show that among lull-digital BF algorithms, zero-forcing is a choice of high performance and low cost; for hybrid BF, 4×32 architecture （32 RF chains） provides good reduction in baseband cost with acceptable performance loss, thus it can be a preferable solution under low cost consider- ation. The proposed system planning method can also be used for the design of other related systems.展开更多
The analysis of urban drainage networks(UDNs)is one of the most important topics in the study of water systems.The interest in strategies aimed at analyzing the impacts of sewer pipes failure on the urban drainage sys...The analysis of urban drainage networks(UDNs)is one of the most important topics in the study of water systems.The interest in strategies aimed at analyzing the impacts of sewer pipes failure on the urban drainage system operation is growing,and the need of developing methodologies aimed at vulnerability assessment and system management is increasingly important.To this purpose,the present work shows and discusses the use of complex network theory.In particular,the recently developed relevance‐based centrality metrics have been used to classify UDNs and to identify the most critical pipes.First,the relevancebased degree is applied to the direct graph of the drainage network to classify the systems.Afterward,the relevance‐based edge betweenness is used for ranking the importance,that is,the criticality with respect to fluxes,for the pipes.The relevance‐based metrics assign importance to the network elements(pipes and nodes),considering both the intrinsic relevance of nodes and the network connectivity structure.Results provide useful information to support pipe maintenance programs to be prepared for malfunctioning events by means of a criticality analysis in advance.The relevance‐based metrics are presented by using the direct graph of a simple example network,and they are then applied both to a benchmark and a real urban drainage system to show the effectiveness even for real systems.展开更多
基金supporting from National High Technical Research and Development Program of China(863 program)2014AA01A705 is sincerely acknowledged by authors
文摘Baseband design and implementation for micro/pico base stations （mBS） in 5G ultra-dense network （UDN） is studied. Low cost is an essential requirement for mBS baseband in UDN. Digital baseband cost of ASIC/ASIP （Application Specific Integrated Circuit / Instruction-set processor） is of the most uncertainty in roBS system. However. the actual costs and hardware feasibility of the baseband are yet unknown to network deployers and researchers. In this paper, we studied the baseband hardware system design and implementation for low-cost roBS. We analyzed popular baseband algorithms and architectures for both full-digital and hybrid beamforming （BF） for UDN. We then proposed feasible chip-level solutions for the baseband with up to 128-antenna BS system, and estimated their implementation cost. Results show that among lull-digital BF algorithms, zero-forcing is a choice of high performance and low cost; for hybrid BF, 4×32 architecture （32 RF chains） provides good reduction in baseband cost with acceptable performance loss, thus it can be a preferable solution under low cost consider- ation. The proposed system planning method can also be used for the design of other related systems.
文摘5G超密集网络(ultra-dense network,UDN)的引入是为了提升吞吐量,特别是针对静态和低速场景,因此,无法同时满足高吞吐量和高移动速度的需求。对于未来需要同时支持高容量和高速移动的6G新场景,提出一种同心圆模型(homocentric sphere model,HSM)的网络架构,采用控制面/用户面数据分离、多发送接收节点(transmission and reception point, TRP)协同传输的方法来处理密集部署网络中多普勒效应影响大和TRP频繁切换的问题,使得该模型成为密集部署网络下提升网络容量、应对高速移动的有效方法。数据结果证明,所提的HSM有效减小了密集组网高速移动场景下多普勒频移效应,同时能够提供更高的网络遍历频谱效率。
文摘针对超密集网络(ultra dense network,UDN)中基站密集部署导致的严重层间干扰问题,构建了考虑频谱复用和共信道干扰条件下最大化系统总吞吐量问题模型,提出了一种基于块坐标下降(block coordinate descent,BCD)法的联合频谱资源优化(joint resource optimization based on BCD,JROBB)方法。该方法将原问题分解为分簇、子信道分配和功率分配三个子问题,通过BCD法迭代优化子信道分配和功率分配,逼近原问题的最优解。仿真分析表明,在复杂度提升有限的情况下,系统总吞吐量比现有典型算法平均至少提升22%,可以有效提升频谱利用率。
文摘The analysis of urban drainage networks(UDNs)is one of the most important topics in the study of water systems.The interest in strategies aimed at analyzing the impacts of sewer pipes failure on the urban drainage system operation is growing,and the need of developing methodologies aimed at vulnerability assessment and system management is increasingly important.To this purpose,the present work shows and discusses the use of complex network theory.In particular,the recently developed relevance‐based centrality metrics have been used to classify UDNs and to identify the most critical pipes.First,the relevancebased degree is applied to the direct graph of the drainage network to classify the systems.Afterward,the relevance‐based edge betweenness is used for ranking the importance,that is,the criticality with respect to fluxes,for the pipes.The relevance‐based metrics assign importance to the network elements(pipes and nodes),considering both the intrinsic relevance of nodes and the network connectivity structure.Results provide useful information to support pipe maintenance programs to be prepared for malfunctioning events by means of a criticality analysis in advance.The relevance‐based metrics are presented by using the direct graph of a simple example network,and they are then applied both to a benchmark and a real urban drainage system to show the effectiveness even for real systems.
