通过对无线分配系统WDS(Wireless Distribution System)的研究分析,提出一种基于无线分配系统自动协商构建无线网络的设计方案。该方案包括设计一种私有网络连接协议——无线网桥自动组网协议,以及协议栈在无线网桥中的实现。无线网桥...通过对无线分配系统WDS(Wireless Distribution System)的研究分析,提出一种基于无线分配系统自动协商构建无线网络的设计方案。该方案包括设计一种私有网络连接协议——无线网桥自动组网协议,以及协议栈在无线网桥中的实现。无线网桥自动组网协议的设计采取了逐步完善的策略,协议的实现采用了Linux线程机制,应用原始套接字直接对数据链路层操作,将无线网桥自动组网协议帧封装在DIX Ethernet V2帧中来完成协议通信。针对无线网络可能出现分裂的情况,采取了无线网络工作组重组的方法,确保无线分配网络整体性。展开更多
针对当前卫星应急通信网在管控时存在卫星通信系统通道切换时间长、切换过程中存在通信数据丢失严重影响管控效果等问题,引入传输控制协议/网际协议(Transmission Control Protocol/Internet Protocol,TCP/IP)组网技术开展管控系统设计...针对当前卫星应急通信网在管控时存在卫星通信系统通道切换时间长、切换过程中存在通信数据丢失严重影响管控效果等问题,引入传输控制协议/网际协议(Transmission Control Protocol/Internet Protocol,TCP/IP)组网技术开展管控系统设计研究。在明确TCP/IP组网技术及具体应用的基础上,对管控系统整体结构进行设计,并针对其具体硬件进行选型研究。通过对比实验,该管控系统的切换时间均为12~30 ms,而对照组切换时间均超过了150 ms。新的管控系统在应用中能够有效缩短卫星通信到地面通信传输的时间,并确保在传输过程中不会出现通信数据丢失,提高卫星应急通信网的通信质量。展开更多
Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective ...Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective and reliable to guarantee successful packet delivery.Based on the data delivery structure,most of the existing multicast routing protocols can be classified into two folders:tree-based and mesh-based.We observe that tree-based ones have high forwarding efficiency and low consumptions of bandwidth,and they may have poor robustness because only one link exists between two nodes.As a treebased multicast routing protocol,MAODV(Multicast Ad hoc On-demand Vector) shows an excellent performance in lightweight ad hoc networks.As the load of network increases,QoS(Quality of Service) is degraded obviously.In this paper,we analyze the impact of network load on MAODV protocol,and propose an optimized protocol MAODV-BB(Multicast Ad hoc On-demand Vector with Backup Branches),which improves robustness of the MAODV protocol by combining advantages of the tree structure and the mesh structure.It not only can update shorter tree branches but also construct a multicast tree with backup branches.Mathematical analysis and simulation results both demonstrate that the MAODV-BB protocol improves the network performance over conventional MAODV in heavy load ad hoc networks.展开更多
文摘通过对无线分配系统WDS(Wireless Distribution System)的研究分析,提出一种基于无线分配系统自动协商构建无线网络的设计方案。该方案包括设计一种私有网络连接协议——无线网桥自动组网协议,以及协议栈在无线网桥中的实现。无线网桥自动组网协议的设计采取了逐步完善的策略,协议的实现采用了Linux线程机制,应用原始套接字直接对数据链路层操作,将无线网桥自动组网协议帧封装在DIX Ethernet V2帧中来完成协议通信。针对无线网络可能出现分裂的情况,采取了无线网络工作组重组的方法,确保无线分配网络整体性。
基金This work is supported by the NSFC （National Natural Science Foundation of China） No. 61371068 and No. 61172130, the National 863 program No.2011AA11A102-04-02 and Shenzhen Technology Research and Development Program No. CXZZ20120830100839333.
文摘Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective and reliable to guarantee successful packet delivery.Based on the data delivery structure,most of the existing multicast routing protocols can be classified into two folders:tree-based and mesh-based.We observe that tree-based ones have high forwarding efficiency and low consumptions of bandwidth,and they may have poor robustness because only one link exists between two nodes.As a treebased multicast routing protocol,MAODV(Multicast Ad hoc On-demand Vector) shows an excellent performance in lightweight ad hoc networks.As the load of network increases,QoS(Quality of Service) is degraded obviously.In this paper,we analyze the impact of network load on MAODV protocol,and propose an optimized protocol MAODV-BB(Multicast Ad hoc On-demand Vector with Backup Branches),which improves robustness of the MAODV protocol by combining advantages of the tree structure and the mesh structure.It not only can update shorter tree branches but also construct a multicast tree with backup branches.Mathematical analysis and simulation results both demonstrate that the MAODV-BB protocol improves the network performance over conventional MAODV in heavy load ad hoc networks.
