UMTS系统(Universal Mobile Telecommunication System,通用移动通信系统)采用了双向鉴权、信令完整性保护和数据加密等多种机制来保证用户通信的安全性。研究从挖掘协议安全缺陷出发,指出现有的UMTS系统通信协议中安全机制仍存在安全缺...UMTS系统(Universal Mobile Telecommunication System,通用移动通信系统)采用了双向鉴权、信令完整性保护和数据加密等多种机制来保证用户通信的安全性。研究从挖掘协议安全缺陷出发,指出现有的UMTS系统通信协议中安全机制仍存在安全缺陷,以此为基础描述了一种能够有效通过系统的身份认证并阻止加密算法启动的中间人攻击方法,验证隐患的存在性。详细分析了导致现有安全缺陷的原因,给出了协议修改建议。展开更多
针对UMTS(Universal Mobile Telecommunications System)无线接入网带宽受限、延时大、抖动大的特点,研究了视频业务的QoS(Quality of Service)保障机制问题。提出的内容感知选择性ARQ(Automatic Retransmission re Quest)方法改进了原...针对UMTS(Universal Mobile Telecommunications System)无线接入网带宽受限、延时大、抖动大的特点,研究了视频业务的QoS(Quality of Service)保障机制问题。提出的内容感知选择性ARQ(Automatic Retransmission re Quest)方法改进了原有传输模式下RNC(Radio Network Controller)和UE(User Equipment)间的ARQ机制,RNC根据视频业务数据的内容类型和时延要求,自适应地为不同类型的视频数据设置不同的最大重传次数,实现差异化服务。仿真结果表明,提出的方法能够提高视频传输质量,同时满足实时性要求。展开更多
Handover in Digital Video Broadcasting for Handhelds(DVB-H) aims to provide continuous mobile broadcasting services when a user is traveling through cell boundaries.A good handover control can improve the power effici...Handover in Digital Video Broadcasting for Handhelds(DVB-H) aims to provide continuous mobile broadcasting services when a user is traveling through cell boundaries.A good handover control can improve the power efficiency and gain much better reception quality.This letter provides a novel approach for DVB-H handover based on DVB-H/Universal Mobile Telecommunications System(UMTS) hybrid network,which moves the main handover function from the terminals to the networks,so that it reduces the operation complexity of the terminals and increases the power saving.When the terminal can not receive the DVB-H signal in the transmission shadow areas or because of some other reasons,the UMTS networks may offer the same service to users to make the service continuous.As the UMTS networks have the topology of the DVB-H networks,by communicating with the terminals,the UMTS networks can help the terminals to predict the handover,and avoid unnecessary handover.展开更多
文摘UMTS系统(Universal Mobile Telecommunication System,通用移动通信系统)采用了双向鉴权、信令完整性保护和数据加密等多种机制来保证用户通信的安全性。研究从挖掘协议安全缺陷出发,指出现有的UMTS系统通信协议中安全机制仍存在安全缺陷,以此为基础描述了一种能够有效通过系统的身份认证并阻止加密算法启动的中间人攻击方法,验证隐患的存在性。详细分析了导致现有安全缺陷的原因,给出了协议修改建议。
文摘针对UMTS(Universal Mobile Telecommunications System)无线接入网带宽受限、延时大、抖动大的特点,研究了视频业务的QoS(Quality of Service)保障机制问题。提出的内容感知选择性ARQ(Automatic Retransmission re Quest)方法改进了原有传输模式下RNC(Radio Network Controller)和UE(User Equipment)间的ARQ机制,RNC根据视频业务数据的内容类型和时延要求,自适应地为不同类型的视频数据设置不同的最大重传次数,实现差异化服务。仿真结果表明,提出的方法能够提高视频传输质量,同时满足实时性要求。
基金the National Science Fund for Distinguished Young Scholars (No.60525110)the National 973 Program (No.2007CB307100, No.2007CB307103)+1 种基金the Program for New Century Excellent Talents in University (No. NCET-04-0111)the Development Fund Project for Electronic and Information Industry (Mobile Service and Application System Based on 3G)
文摘Handover in Digital Video Broadcasting for Handhelds(DVB-H) aims to provide continuous mobile broadcasting services when a user is traveling through cell boundaries.A good handover control can improve the power efficiency and gain much better reception quality.This letter provides a novel approach for DVB-H handover based on DVB-H/Universal Mobile Telecommunications System(UMTS) hybrid network,which moves the main handover function from the terminals to the networks,so that it reduces the operation complexity of the terminals and increases the power saving.When the terminal can not receive the DVB-H signal in the transmission shadow areas or because of some other reasons,the UMTS networks may offer the same service to users to make the service continuous.As the UMTS networks have the topology of the DVB-H networks,by communicating with the terminals,the UMTS networks can help the terminals to predict the handover,and avoid unnecessary handover.
