Traffic characteristics of several typical instant messager services under certain scenarios are firstly analyzed,based on real-time data collected in the commercial mobile network.Then criteria for the evaluation of ...Traffic characteristics of several typical instant messager services under certain scenarios are firstly analyzed,based on real-time data collected in the commercial mobile network.Then criteria for the evaluation of the efficiency of the mobile network for the transmission of packet services are proposed in both transport layer and physical layer over air interface.The transmission efficiency of IM services is evaluated and compared under the proposed criteria.Furthermore,a so-called smart resource adaptation algorithm is verified in the effectiveness of improving the wireless transmission efficiency.Finally,improvements to the smart resource adaptation are proposed to further improve the wireless transmission efficiency,and its effectiveness is verified by the calculations.展开更多
Though the WiMedia supports higher data rates than other WPAN technologies,a WiMedia device cannot reach other devices that are separated from it by more than 10 m,which is the typical limited transmission range of th...Though the WiMedia supports higher data rates than other WPAN technologies,a WiMedia device cannot reach other devices that are separated from it by more than 10 m,which is the typical limited transmission range of the WiMedia protocol.In this work,we propose a multi-hop QoS routing protocol to enable WiMedia devices to transmit real-time data to devices that are located out of the transmission range.The proposed routing protocol is a hybrid algorithm,which mixes the table-driven and on-demand routing algorithms,searching one or more routes according to the number of hops to a destination device.WiMedia MAC is potentially capable of learning the existence of neighbor devices by using a beacon frame.By utilizing the neighbors' information,all devices can create routing entries for devices within 2-hops periodically.For devices beyond the 2-hop range,the newly designed on-demand routing algorithm is applied to multi-hop routing.If a routing entry for a destination device is not listed in the routing table,the source device sends a request packet to 2-hop range devices which could be found in the routing table.Since every device maintains routing entries for 2-hop range devices in the routing table,the request packet is replied in advance before its arrival at the destination device.Also,to decide the optimal route for a destination device,the number of medium access slots(MASs),received signal strength indicator(RSSI)and hop count are utilized to establish a QoS-enabled routing table.We perform ns-2 simulation to investigate the performance of the proposed routing protocol with AODV and DSDV.The simulation results show that the proposed protocol has better throughput and lower overhead than other protocols.展开更多
Introduced a Web-based real-time network monitoring and control system design methods, the 3-D VR was applied in a remote monitor system based on browser/server structure, and a VRML and Java based 3-D remote monitor ...Introduced a Web-based real-time network monitoring and control system design methods, the 3-D VR was applied in a remote monitor system based on browser/server structure, and a VRML and Java based 3-D remote monitor system was realized. Meanwhile, give possible solutions of the real-time data transmission and the stability of the system.展开更多
基金Supported by the National Natural Science Foundation of China(No.61301103)the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions(No.CIT&TCD201504039)Funding Project for Academic Human Resources Development in Beijing Union University(No.BPHR2014A03,Rkl00201510)
文摘Traffic characteristics of several typical instant messager services under certain scenarios are firstly analyzed,based on real-time data collected in the commercial mobile network.Then criteria for the evaluation of the efficiency of the mobile network for the transmission of packet services are proposed in both transport layer and physical layer over air interface.The transmission efficiency of IM services is evaluated and compared under the proposed criteria.Furthermore,a so-called smart resource adaptation algorithm is verified in the effectiveness of improving the wireless transmission efficiency.Finally,improvements to the smart resource adaptation are proposed to further improve the wireless transmission efficiency,and its effectiveness is verified by the calculations.
基金Project supported by the Second Stage of Brain Korea 21 ProjectsProject(10035236)supported by the IT_R&D Program of MKE/KEIT,Korea
文摘Though the WiMedia supports higher data rates than other WPAN technologies,a WiMedia device cannot reach other devices that are separated from it by more than 10 m,which is the typical limited transmission range of the WiMedia protocol.In this work,we propose a multi-hop QoS routing protocol to enable WiMedia devices to transmit real-time data to devices that are located out of the transmission range.The proposed routing protocol is a hybrid algorithm,which mixes the table-driven and on-demand routing algorithms,searching one or more routes according to the number of hops to a destination device.WiMedia MAC is potentially capable of learning the existence of neighbor devices by using a beacon frame.By utilizing the neighbors' information,all devices can create routing entries for devices within 2-hops periodically.For devices beyond the 2-hop range,the newly designed on-demand routing algorithm is applied to multi-hop routing.If a routing entry for a destination device is not listed in the routing table,the source device sends a request packet to 2-hop range devices which could be found in the routing table.Since every device maintains routing entries for 2-hop range devices in the routing table,the request packet is replied in advance before its arrival at the destination device.Also,to decide the optimal route for a destination device,the number of medium access slots(MASs),received signal strength indicator(RSSI)and hop count are utilized to establish a QoS-enabled routing table.We perform ns-2 simulation to investigate the performance of the proposed routing protocol with AODV and DSDV.The simulation results show that the proposed protocol has better throughput and lower overhead than other protocols.
文摘Introduced a Web-based real-time network monitoring and control system design methods, the 3-D VR was applied in a remote monitor system based on browser/server structure, and a VRML and Java based 3-D remote monitor system was realized. Meanwhile, give possible solutions of the real-time data transmission and the stability of the system.
