Performance of 60 GHz Virtual Cellular Networks Using Multiple Receiving Antennas

During the past years, research covering propagation, channelcharacterization and wireless systems performance have yield asubstantial knowledge of the 60 GHz channel. The unlicensed 60 GHzfrequency band presents many attractive properties for wirelesscommunications. The environments in which the 60 GHzinfrastructure are to be designed are typically propagation- andcoverage-limited. This paper describes the important factors thatmust be taken into account when designing a wireless local areanetwork (WLAN) architecture operating in this frequency band.Therefore, we motivate the reasons of using distributedtransmitting antennas and multiple receiving antennas (MRA) inorder to mitigate the poor Direction of Arrival (DoA) diversityand to exploit the spatial diversity at the receiver. Such asystem can be considered as a multiple input multiple output(MIMO) system. We investigate the advantages of combining aVirtual Cellular Network (VCN) (using single frequency network anddistributed antennas) and MRA for the downlink. Several ways tocombine the signals with different levels of complexity arepresented. In the most complex case using Singular ValueDecomposition (SVD), it is possible to add coherently thecontribution of each antenna in a virtual cell while retaining thepath diversity inherent to the VCN infrastructure. The schemesyield several advantages: symbol diversity is improved, pathdiversity is still present, antenna gain using multiplebeamformers is increased and the multipath can be reduced. Theconcept is applicable to most types of single frequency networksbut it is especially well appropriate for the 60 GHz VCN/WLANusing orthogonal frequency division multiplexing (OFDM).Simulations give a realistic performance for QPSK, 8-PSK, and16-QAM baseband modulations with a 256-subcarrier OFDM using arate 1/2–convolutional code for a 2 ×2 VCN system.Results show a E_b/N₀ improvement of up to 6.2 dB usingthesingular value decomposition method with 16-QAM compared to thesingle input single output (SISO) coded reference.     

基于NGB接入网的组播复制点研究

通过探讨分析下一代广播电视网(NGB)接入网的主要模式,揭示组播复制点在组播传输中的重要地位。重点分析了组播复制点和组播控制点的原理、规划,实际应用中的网络设计,面临的问题和解决方案。     

Evaluation of post-fault restoration strategies in multi-domain networks

Although multi-domain survivability is a major concern for operators, few studies have considered the design of post-fault restoration schemes. This paper proposes two such strategies, based upon hierarchical routing and signaling crankback, to handle single and multi-link failure events in multi-domain IP/MPLS networks (also extendible to optical DWDM networks). Specifically, the hierarchical routing strategy relies upon abstracted domain information to compute inter-domain loose routes, whereas the crankback scheme applies signaling re-tries to restore paths in a domain-by-domain manner. The performance of these proposed solutions is then analyzed and compared via simulation.     

C-RAN机房散热问题研究

在5G机房的建设和改造当中,由于CRAN机房的特性,散热问题成为CRAN机房建设中需要考虑的主要问题之一。本文从CRAN机房的整体制冷量出发,并落脚于CRAN机房高密度网络柜散热的若干问题,针对BBU集中网络柜内部气流组织的合理性、设备安装工艺等问题展开分析,并提出了相关解决方案。     

关于赛博作战装备与技术体系建设的几点思考

概述了世界赛博作战装备与技术的发展现状并引出了构建赛博作战装备与技术体系的重要性;在此基础上,介绍了建立赛博作战装备与技术体系所需前提;最后,从赛博作战装备与技术顶层体系、作战体系、技术体系角度阐述了体系建设的思考.     

物理层网络编码机会中继及中断性能分析

该文研究了频率非选择性瑞利衰落信道中的物理层网络编码系统容量问题。基于放大转发机制提出了一种基于最大最小互信息准则的机会中继策略。在瑞利衰落信道环境下,从双向通信的角度,通过理论分析得出其中断概率解析式,同时推导了理想物理层网络编码和传统直接传输系统的中断概率解析式。通过理论分析,发现在某些节点发射功率条件下,系统中断概率将完全取决于单向链路。在此基础上完成了数值仿真实验,结果表明所提策略的中断性能与理想物理层网络编码和传统直接传输相比有了显著的提高。     

城域网中的多业务环技术

城域网数据业务不断增加,如何提高各类业务的服务质量成为人们面临的问题,ITU-T制订的多业务环技术提供了一种新的解决方法。本文主要讨论多业务环的拓扑结构、协议栈和帧结构等,根据MSR的节点流程图重点研究基于支路的各个功能模块及其各种业务的服务质量保证。最后,还讨论了MSR协议中提供的业务种类及其组网。     

论完善房屋拆迁制度促进我国数字城市建设

近年来,大多数城市政府规划部门通过网站实施政务公开和公众参与,新思路、新技术层出不穷,信息技术已成为带动体制和机制创新,转变行政管理模式、提高行政效率和服务水平的重要手段,为实现规划管理的办公自动化、决策智能化、政务公开化和服务社会化发挥着重要的基础作用。     

电信运营商云计算网络建设思路探讨

结合云计算业务的特点和电信运营商建设云计算数据中心的优势,从集中建设大型数据中心、注重可靠性设计、数据中心的通信组织、数据中心网络技术的选择等方面阐述了云计算数据中心的建设思路。     

基于CDMA智能网平台的增值业务--"位置服务"

本主要介绍基于CDMA智能网平台的一种增值业务——“位置服务”，阐述这个业务的网络结构、涉及到的技术问题和解决方案，并将这个整体思路投入到开发业务中去。