Due to the rapid development of broadband access technologies, the broadband access networks have wider and wider application. However, with the development, the security issue became a public concern. Under the envir...Due to the rapid development of broadband access technologies, the broadband access networks have wider and wider application. However, with the development, the security issue became a public concern. Under the environment of access network, customers, access equipment and networks all face various threats, especially those from the user side. Such technologies and solutions as port positioning, fraud prevention on Medium Access Control (MAC) addresses and monitoring of illegal services might be the solution to the security problem existing in the current networks.展开更多
This paper presents the design and implementation of access controller used for Ethernet passive optical network （ EPON）. As a first step to develop an ASIC product, the entire system is designed on a field programm...This paper presents the design and implementation of access controller used for Ethernet passive optical network （ EPON）. As a first step to develop an ASIC product, the entire system is designed on a field programmable gate array （FPGA） with an embedded CPU. To reduce working frequency of the FPGA, the byte-to-word conversion is proposed. Propagation delays are equalized by ranging procedure so as to avoid data collision. Implementations of synchronization, classification, as well as Linux porting are illustrated in detail. The interface between the FPGA and CPU are also presented. Experimental results show that the proposed system can properly function in a relatively low cost FPGA.展开更多
The planning of wireless communication networks in underdeveloped countries is studied for landline telephone, fixed broadband wireless access and PLMN systems via investigation and discussion of the LDC networks＇ ch...The planning of wireless communication networks in underdeveloped countries is studied for landline telephone, fixed broadband wireless access and PLMN systems via investigation and discussion of the LDC networks＇ characteristic, technology selection, deployment consideration, network configuring, civil work evaluation and investment estimation. An example is embedded all through providing a general展开更多
宽带接入网络中光纤到户(Fiber To The Home,FTTH)光分配网络结构面临用户密度差异与管线资源限制双重挑战,需围绕分光模式构型与节点层级关系展开结构优化。结合一级与二级分光模式构成特征,提出分光器布局位置调整、主干段光缆容量压...宽带接入网络中光纤到户(Fiber To The Home,FTTH)光分配网络结构面临用户密度差异与管线资源限制双重挑战,需围绕分光模式构型与节点层级关系展开结构优化。结合一级与二级分光模式构成特征,提出分光器布局位置调整、主干段光缆容量压降、分纤节点接入范围限定、接入链路末端跳接下移、成端资源占比配置修正等优化措施,构建多场景适配的光分配网络组织体系,提升网络部署弹性与资源调度精度。展开更多
McWiLL(multi-carrier wireless information local loop,多载波无线信息本地环路)是集智能天线、CS-OFDMA、增强零陷、信道跟踪和预测、动态信道分配、频空联合检测等核心技术为一体的宽带无线通信系统。为此,介绍了McWiLL系统在配电...McWiLL(multi-carrier wireless information local loop,多载波无线信息本地环路)是集智能天线、CS-OFDMA、增强零陷、信道跟踪和预测、动态信道分配、频空联合检测等核心技术为一体的宽带无线通信系统。为此,介绍了McWiLL系统在配电网通信中应用的测试情况,重点在于McWiLL系统的覆盖面、业务容量和业务承载能力。基于中低压配电网的特点及其对通信的需求,提出了在中低压配电网中McWiLL的应用模型。展开更多
文摘Due to the rapid development of broadband access technologies, the broadband access networks have wider and wider application. However, with the development, the security issue became a public concern. Under the environment of access network, customers, access equipment and networks all face various threats, especially those from the user side. Such technologies and solutions as port positioning, fraud prevention on Medium Access Control (MAC) addresses and monitoring of illegal services might be the solution to the security problem existing in the current networks.
基金Project supported by Science Foundation of Shanghai Municipal Commission of Science and Technology (Grant No .04dz12045)
文摘This paper presents the design and implementation of access controller used for Ethernet passive optical network （ EPON）. As a first step to develop an ASIC product, the entire system is designed on a field programmable gate array （FPGA） with an embedded CPU. To reduce working frequency of the FPGA, the byte-to-word conversion is proposed. Propagation delays are equalized by ranging procedure so as to avoid data collision. Implementations of synchronization, classification, as well as Linux porting are illustrated in detail. The interface between the FPGA and CPU are also presented. Experimental results show that the proposed system can properly function in a relatively low cost FPGA.
文摘The planning of wireless communication networks in underdeveloped countries is studied for landline telephone, fixed broadband wireless access and PLMN systems via investigation and discussion of the LDC networks＇ characteristic, technology selection, deployment consideration, network configuring, civil work evaluation and investment estimation. An example is embedded all through providing a general
文摘宽带接入网络中光纤到户(Fiber To The Home,FTTH)光分配网络结构面临用户密度差异与管线资源限制双重挑战,需围绕分光模式构型与节点层级关系展开结构优化。结合一级与二级分光模式构成特征,提出分光器布局位置调整、主干段光缆容量压降、分纤节点接入范围限定、接入链路末端跳接下移、成端资源占比配置修正等优化措施,构建多场景适配的光分配网络组织体系,提升网络部署弹性与资源调度精度。
文摘McWiLL(multi-carrier wireless information local loop,多载波无线信息本地环路)是集智能天线、CS-OFDMA、增强零陷、信道跟踪和预测、动态信道分配、频空联合检测等核心技术为一体的宽带无线通信系统。为此,介绍了McWiLL系统在配电网通信中应用的测试情况,重点在于McWiLL系统的覆盖面、业务容量和业务承载能力。基于中低压配电网的特点及其对通信的需求,提出了在中低压配电网中McWiLL的应用模型。
文摘为了实现同一地域范围内的众多用户在有限带宽条件下提出的高QoS要求,本文对基于IEEE 802.16标准的宽带无线接入网中数据包级QoS(Quality of Service)性能进行了研究.具体做法是,首先采用批马尔可夫到达过程(BMAP,Batch Markov Arrival Process)和连续时间马尔科夫链(CTMC,Continuous Time Markov Chain)对到达过程和流量源进行建模,得到更符合实际和更准确的排队模型;然后基于状态空间,对一个无线接入网络系统进行建模,通过对得到的系统模型并结合前面得到的排队模型的深入分析,从而获得该模型下的各项QoS性能指标,如平均队列长度、丢包率、队列吞吐量和平均包时延.仿真实验结果表明,本文提出的算法模型相比于其他典型的算法模型,能够使得各项QoS性能指标有较大的改善和提高.
