Airborne networks（ANs） are special types of ad hoc networks that can be used to enhance situational awareness, flight coordination and flight efficiency in civil and military aviation.Compared to ground networks, AN...Airborne networks（ANs） are special types of ad hoc networks that can be used to enhance situational awareness, flight coordination and flight efficiency in civil and military aviation.Compared to ground networks, ANs have some unique attributes including high node mobility, frequent topology changes, mechanical and aerodynamic constrains, strict safety requirements and harsh communication environment.Thus, the performance of conventional transmission control protocol（TCP） will be dramatically degraded in ANs.Aircraft commonly have two or more heterogeneous network interfaces which offer an opportunity to form multiple communication paths between any two nodes in ANs.To satisfy the communication requirements in ANs, we propose aeronautical multipath transport protocol（Aero MTP） for ANs, which effectively utilizes the available bandwidth and diversity provided by heterogeneous wireless paths.Aero MTP uses fountain codes as forward error correction（FEC） codes to recover from data loss and deploys a TCP-friendly rate-based congestion control mechanism for each path.Moreover, we design a packet allocation algorithm based on optimization to minimize the delivery time of blocks.The performance of Aero MTP is evaluated through OMNe T＋＋ simulations under a variety of test scenarios.Simulations demonstrate that Aero MTP is of great potential to be applied to ANs.展开更多
Providing efficient packet delivery in vehicular ad hoc networks （VANETs） is particularly challenging due to the vehicle move- ment and lossy wireless channels. A data packet can be lost at a forwarding node even wh...Providing efficient packet delivery in vehicular ad hoc networks （VANETs） is particularly challenging due to the vehicle move- ment and lossy wireless channels. A data packet can be lost at a forwarding node even when a proper node is selected as the for- warding node. In this paper, we propose a loss-tolerant scheme for unicast routing protocols in VANETs. The proposed scheme employs multiple forwarding nodes to improve the packet reception ratio at the forwarding nodes. The scheme uses network coding to reduce the number of required transmissions, resulting in a significant improvement in end-to-end packet delivery ratio with low message overhead. The effectiveness of the proposed scheme is evaluated by using both theoretical analysis and computer sim-展开更多
In order to solve the problem of losing voice packets in voice over internet protocol(VoIP),a kind of lost packets double recovery algorithm is proposed. The algorithm is based on erasure coding technique which comes ...In order to solve the problem of losing voice packets in voice over internet protocol(VoIP),a kind of lost packets double recovery algorithm is proposed. The algorithm is based on erasure coding technique which comes from highly available data storage systems. An efficient coding scheme with higher tolerance based on STAR and Reed-Solomon( RS) erasure code is described. An efficient method is also provided which could transform the voice data packets of one dimensional bit stream into two dimensional array according to given window size. If the lost rate has increased beyond the error correction capability,packet-loss concealment will be adopted. Under various conditions of packet-loss simulation during the experiments,the algorithm has proved its better performance on MOS rating and coding rate.展开更多
模糊测试是目前比较流行的网络协议漏洞挖掘技术之一,但是存在现有网络协议模糊器对字段间的关联性探索不足的问题。为此,提出了一种基于字段信息和覆盖率反馈的模糊测试方法。该方法通过两个参数定量表示协议数据模型中不同字段的关系...模糊测试是目前比较流行的网络协议漏洞挖掘技术之一,但是存在现有网络协议模糊器对字段间的关联性探索不足的问题。为此,提出了一种基于字段信息和覆盖率反馈的模糊测试方法。该方法通过两个参数定量表示协议数据模型中不同字段的关系和每一个字段本身的影响力,并利用覆盖率信息持续学习更新,从而指导模糊测试向更高效的方向变异。基于该方法实现了基于字段信息和覆盖率反馈的模糊测试模糊器FMFuzzer(Field Message based Fuzzer),并与模糊器Boofuzz和PAVFuzz进行了对比实验。实验结果显示,在3种网络协议上,FMFuzzer的代码覆盖率模糊器Boofuzz和PAVFuzz分别平均提升了10.97%和6.63%,证明了本方法的有效性。展开更多
为提升FPGA(Field Programmable Gate Array)高速Serdes通讯稳定性,实时监控其通讯状态,文中设计了一种基于K码控制字符的通讯协议。创建标志用户数据帧起始的动态SOF(Start of Frame)和标志结束的静态EOF(End of Frame)两种K码控制字符...为提升FPGA(Field Programmable Gate Array)高速Serdes通讯稳定性,实时监控其通讯状态,文中设计了一种基于K码控制字符的通讯协议。创建标志用户数据帧起始的动态SOF(Start of Frame)和标志结束的静态EOF(End of Frame)两种K码控制字符,有利于通讯的连续性检测。创建TLINK(Transmit Link)、BLINK(Back Link)的K码控制字符,其中TLINK控制字符在Serdes的发送端进行定期发送,接收端收到TLINK控制字符后,控制本方的Serdes发送端优先输出BLINK控制字符进行应答,以建立通讯双方之间的握手关系,有利于通讯的超时和状态检测。校验独立于SOF、EOF之间的用户数据,进行CRC32(Cyclic Redundancy Check32)计算,有利于通讯的误码检测。实验结果表明,该协议可实现对Serdes链路的丢帧数量、误码数量、超时数量及通讯断开时长进行准确监控,最小时间精度为10μs。展开更多
随着网际互连协议(Internet Protocol,IP)网络在广播电视信号传输中的广泛应用,网络拥塞和信号质量下降等问题日益突出。针对上述挑战,深入分析IP组播、服务质量(Quality of Service,QoS)机制及网络编码等关键技术,在此基础上提出一种...随着网际互连协议(Internet Protocol,IP)网络在广播电视信号传输中的广泛应用,网络拥塞和信号质量下降等问题日益突出。针对上述挑战,深入分析IP组播、服务质量(Quality of Service,QoS)机制及网络编码等关键技术,在此基础上提出一种改进的自适应比特率算法。该算法结合网络状态感知和内容复杂度评估,可实现传输参数的动态调整。通过在模拟网络环境中进行大规模实验,结果表明所提算法在带宽利用率、传输时延及画质方面均有显著提升。此次研究成果为IP网络下广播电视信号的高效传输提供了新的技术方案。展开更多
随着高清和超高清直播需求的增长,传统编码技术在压缩效率和传输质量方面逐渐显现出局限性。针对这一问题,提出基于高效视频编码(High Efficiency Video Coding,HEVC)技术的优化策略,以期改善直播电视信号的压缩效率、传输延迟及画质清...随着高清和超高清直播需求的增长,传统编码技术在压缩效率和传输质量方面逐渐显现出局限性。针对这一问题,提出基于高效视频编码(High Efficiency Video Coding,HEVC)技术的优化策略,以期改善直播电视信号的压缩效率、传输延迟及画质清晰度。实验结果表明,HEVC技术结合快速用户数据报协议互联网连接(Quick User Datagram Protocol Internet Connections,QUIC)协议和硬件加速技术,可显著提高高分辨率场景下的信号稳定性和实时性。展开更多
文摘Airborne networks（ANs） are special types of ad hoc networks that can be used to enhance situational awareness, flight coordination and flight efficiency in civil and military aviation.Compared to ground networks, ANs have some unique attributes including high node mobility, frequent topology changes, mechanical and aerodynamic constrains, strict safety requirements and harsh communication environment.Thus, the performance of conventional transmission control protocol（TCP） will be dramatically degraded in ANs.Aircraft commonly have two or more heterogeneous network interfaces which offer an opportunity to form multiple communication paths between any two nodes in ANs.To satisfy the communication requirements in ANs, we propose aeronautical multipath transport protocol（Aero MTP） for ANs, which effectively utilizes the available bandwidth and diversity provided by heterogeneous wireless paths.Aero MTP uses fountain codes as forward error correction（FEC） codes to recover from data loss and deploys a TCP-friendly rate-based congestion control mechanism for each path.Moreover, we design a packet allocation algorithm based on optimization to minimize the delivery time of blocks.The performance of Aero MTP is evaluated through OMNe T＋＋ simulations under a variety of test scenarios.Simulations demonstrate that Aero MTP is of great potential to be applied to ANs.
基金supported in part by JSPS KAKENHI under Grant Number25730053
文摘Providing efficient packet delivery in vehicular ad hoc networks （VANETs） is particularly challenging due to the vehicle move- ment and lossy wireless channels. A data packet can be lost at a forwarding node even when a proper node is selected as the for- warding node. In this paper, we propose a loss-tolerant scheme for unicast routing protocols in VANETs. The proposed scheme employs multiple forwarding nodes to improve the packet reception ratio at the forwarding nodes. The scheme uses network coding to reduce the number of required transmissions, resulting in a significant improvement in end-to-end packet delivery ratio with low message overhead. The effectiveness of the proposed scheme is evaluated by using both theoretical analysis and computer sim-
基金Supported by the National Science and Technology Planning Project(No.2012BAH38F00)
文摘In order to solve the problem of losing voice packets in voice over internet protocol(VoIP),a kind of lost packets double recovery algorithm is proposed. The algorithm is based on erasure coding technique which comes from highly available data storage systems. An efficient coding scheme with higher tolerance based on STAR and Reed-Solomon( RS) erasure code is described. An efficient method is also provided which could transform the voice data packets of one dimensional bit stream into two dimensional array according to given window size. If the lost rate has increased beyond the error correction capability,packet-loss concealment will be adopted. Under various conditions of packet-loss simulation during the experiments,the algorithm has proved its better performance on MOS rating and coding rate.
文摘模糊测试是目前比较流行的网络协议漏洞挖掘技术之一,但是存在现有网络协议模糊器对字段间的关联性探索不足的问题。为此,提出了一种基于字段信息和覆盖率反馈的模糊测试方法。该方法通过两个参数定量表示协议数据模型中不同字段的关系和每一个字段本身的影响力,并利用覆盖率信息持续学习更新,从而指导模糊测试向更高效的方向变异。基于该方法实现了基于字段信息和覆盖率反馈的模糊测试模糊器FMFuzzer(Field Message based Fuzzer),并与模糊器Boofuzz和PAVFuzz进行了对比实验。实验结果显示,在3种网络协议上,FMFuzzer的代码覆盖率模糊器Boofuzz和PAVFuzz分别平均提升了10.97%和6.63%,证明了本方法的有效性。
文摘随着网际互连协议(Internet Protocol,IP)网络在广播电视信号传输中的广泛应用,网络拥塞和信号质量下降等问题日益突出。针对上述挑战,深入分析IP组播、服务质量(Quality of Service,QoS)机制及网络编码等关键技术,在此基础上提出一种改进的自适应比特率算法。该算法结合网络状态感知和内容复杂度评估,可实现传输参数的动态调整。通过在模拟网络环境中进行大规模实验,结果表明所提算法在带宽利用率、传输时延及画质方面均有显著提升。此次研究成果为IP网络下广播电视信号的高效传输提供了新的技术方案。
文摘随着高清和超高清直播需求的增长,传统编码技术在压缩效率和传输质量方面逐渐显现出局限性。针对这一问题,提出基于高效视频编码(High Efficiency Video Coding,HEVC)技术的优化策略,以期改善直播电视信号的压缩效率、传输延迟及画质清晰度。实验结果表明,HEVC技术结合快速用户数据报协议互联网连接(Quick User Datagram Protocol Internet Connections,QUIC)协议和硬件加速技术,可显著提高高分辨率场景下的信号稳定性和实时性。
