A Robust Authentication Protocol with Non-Repudiation Service for Integrating WLAN and 3G Network

The third-generation cellular systems provide great coverage, complete subscriber management and nearly universal roaming. Nevertheless, 3G systems suffer the high installation cost and low bandwidth. Though WLAN provides hot spot coverage with high data rates, it lacks roaming and mobility support. From users' points of views, the integration of WLAN and 3G systems is an attractive way that will provide them a convenient access to network. When integrating WLAN and 3G, there are still some problems should be concerned in terms of authentication and security, such as authentication efficiency and repudiation problem. In this paper, we review the authentication scheme for WLAN and 3G/UMTS interworking which is specified by 3GPP and propose a robust localized fast authentication protocol with non-repudiation service for integrating WLAN and 3G network. The localized re-authentication protocol can shorten the authentication time delay. On the other hand, with the non-repudiation service, the assumption, that subscriber has to fully trust 3G home operator, can be deleted and the trust management between the independent WLAN operator, 3G visited operator and 3G home operator can be eliminated. In other words, our proposed protocol provides legal evidences to prevent the 3G home operator from overcharge toward the subscriber and also prevent the WLAN operator and 3G visited operator from overcharge toward the 3G home operator. The authentication protocol employs HMAC, hash-chaining techniques, and public-key digital signature to achieve localized fast re-authentication and non-repudiation service.     

OSA--软件和通信两大信息产业之间的桥梁

OSA(开放业务体系结构)定义了一种3G领域的体系结构,这种体系结构将电信网络的能力开放出来,使得营运商和第三方业务开发方能够通过一个标准的OSAAPI(应用编程接口),使用电信网络的能力,灵活快捷的开发出新的电信增值业务。以前,由于软件开发人员对电信领域知识的匮乏,很难涉足电信业务的开发。OSA的出现,屏蔽了网络的复杂性,使得软件业进军电信领域成为可能。     

A client‐side design and implementation for push to talk over cellular service

This paper proposes a client architecture for the push to talk over cellular (PoC) service based on the open mobile alliance (OMA) PoC specifications v1.0 release. We show that most standard VoIP modules can be reused for the PoC client, and the VoIP software can be easily extended to support PoC service. Then we present the detailed message flows between the PoC client and other network entities in the PoC system. A PoC client prototype has been implemented in the Industrial Technology Research Institute (ITRI) and National Chiao‐Tung University (NCTU) Joint Research Center. Copyright © 2006 John Wiley & Sons, Ltd.     

A delay based backoff scheme for WLAN with QoS guarantee and its performance

Based on the Distributed Coordination Function (DCF) and the Enhanced DCF (EDCF) mechanisms in IEEE 802.11 and 802.11e, a novel backoff scheme for Wireless Local Area Network (WLAN) is proposed. The scheme is to solve the problem of the packet loss and the decrease of performance due to the increasing Contention Window (CW) when there are continuous collisions. In the proposed scheme, the CW of the packet will change dynamically with different delay for the different traffics. Mathematic formulas are presented to indicate the relationship between the CW and the delay character. The performance of the new scheme is also discussed with simulation results. The results show that it helps WLAN system handle multimedia simultaneously.     

一种改进的WLAN-3G融合网络认证协议

本文在分析了现有3GPP WLAN-3G融合网络接入认证协议EAP-AKA的优势和不足的基础上,引入WAPI证书鉴别机制,提出WAPI-3G互联结构模型,并针对该互联模型设计了一种接入认证协议EAP-WAPI.本文提议的WLAN-3G互联结构模型及接入认证机制解决了融合组网环境下WLAN终端统一接入认证的问题.分析和仿真结果表明,相比于原有的WAPI认证协议WAPI-XG1,本文所提议的协议具有较高的安全性和执行效率.     

未来低轨信息网络发展与架构展望

近年来,伴随着运载、卫星、通信、网络、智能等技术的发展,天基网络形态正在发生质的变化。低轨(LEO)星座网络已经成为众多应用场景、业务承载需求的新选项,有向着全球覆盖、天地一体、多业务承载、持续演进、安全可控的天基通用信息网络基础设施发展的趋势,而这样的愿景对未来低轨星座网络架构提出了更高的要求。该文首先从空间网络、先进卫星以及天地网络融合3方面技术领域对近年来低轨星座网络相关技术的发展现状进行了概述,并对低轨星座网络发展的愿景与趋势进行了分析研判。在此基础上,该文提出基于软件定义(SDN)和网络功能虚拟化(NFV)的全云化卫星-5G融合网络架构,使网络具备架构可编程、网络功能抽象解耦以及去中心化的核心优势,辅以意图驱动网络等智能网络运行管理方法,实现网络的多业务承载、持续演进、自动化管理等能力。最后,该文对需重点关注的技术方向进行了展望。     

A call admission and rate control scheme for multimedia support over IEEE 802.11 wireless LANs

Quality of service (QoS) support for multimedia services in the IEEE 802.11 wireless LAN is an important issue for such WLANs to become a viable wireless access to the Internet. In this paper, we endeavor to propose a practical scheme to achieve this goal without changing the channel access mechanism. To this end, a novel call admission and rate control (CARC) scheme is proposed. The key idea of this scheme is to regulate the arriving traffic of the WLAN such that the network can work at an optimal point. We first show that the channel busyness ratio is a good indicator of the network status in the sense that it is easy to obtain and can accurately and timely represent channel utilization. Then we propose two algorithms based on the channel busyness ratio. The call admission control algorithm is used to regulate the admission of real-time or streaming traffic and the rate control algorithm to control the transmission rate of best effort traffic. As a result, the real-time or streaming traffic is supported with statistical QoS guarantees and the best effort traffic can fully utilize the residual channel capacity left by the real-time and streaming traffic. In addition, the rate control algorithm itself provides a solution that could be used above the media access mechanism to approach the maximal theoretical channel utilization. A comprehensive simulation study in ns-2 has verified the performance of our proposed CARC scheme, showing that the original 802.11 DCF protocol can statically support strict QoS requirements, such as those required by voice over IP or streaming video, and at the same time, achieve a high channel utilization. Hongqiang Zhai received the B.E. and M.E. degrees in electrical engineering from Tsinghua University, Beijing, China, in July 1999 and January 2002 respectively. He worked as a research intern in Bell Labs Research China from June 2001 to December 2001, and in Microsoft Research Asia from January 2002 to July 2002. Currently he is pursuing the PhD degree in the Department of Electrical and Computer Engineering, University of Florida. He is a student member of IEEE. Xiang Chen received the B.E. and M.E. degrees in electrical engineering from Shanghai Jiao Tong University, Shanghai, China, in 1997 and 2000, respectively, and the Ph.D. degree in electrical and computer engineering from the University of Florida, Gainesville, in 2005. He is currently a Senior Research Engineer at Motorola Labs, Arlington Heights, IL. His research interests include resource management, medium access control, and quality of service (QoS) in wireless networks. He is a Member of Tau Beta Pi and a student member of IEEE. Yuguang Fang received a Ph.D degree in Systems and Control Engineering from Case Western Reserve University in January 1994, and a Ph.D degree in Electrical Engineering from Boston University in May 1997. From June 1997 to July 1998, he was a Visiting Assistant Professor in Department of Electrical Engineering at the University of Texas at Dallas. From July 1998 to May 2000, he was an Assistant Professor in the Department of Electrical and Computer Engineering at New Jersey Institute of Technology. In May 2000, he joined the Department of Electrical and Computer Engineering at University of Florida where he got the early promotion with tenure in August 2003 and has been an Associate Professor since then. He has published over one hundred (100) papers in refereed professional journals and conferences. He received the National Science Foundation Faculty Early Career Award in 2001 and the Office of Naval Research Young Investigator Award in 2002. He is currently serving as an Editor for many journals including IEEE Transactions on Communications, IEEE Transactions on Wireless Communications, IEEE Transactions on Mobile Computing, and ACM Wireless Networks. He is also actively participating in conference organization such as the Program Vice-Chair for IEEE INFOCOM’2005, Program Co-Chair for the Global Internet and Next Generation Networks Symposium in IEEE Globecom’2004 and the Program Vice Chair for 2000 IEEE Wireless Communications and Networking Conference (WCNC’2000).     

Implementation solutions for the interworking between MMS and streaming

Multimedia messaging service (MMS) and streaming are forerunner multimedia applications in mobile communication. Use of streaming in the retrieval of continuous multimedia content of MMS is the identified optimum scope (extent) of interworking between MMS and streaming. The optimum interworking can remove a limitation visible in MMS—retrieving content requiring more storage space than available in a mobile terminal. This paper presents two different solutions for implementing the interworking. The implementation solutions are consistent with the existing mobile frameworks and the working principles and procedures of both MMS and streaming. Consistency is very important here not only to avoid creating isolated solution, but also to preserve user experience. This paper describes in detail how each of the solutions operates, including the process of using streaming in the MMS retrieval. Pros and cons of both the solutions are also analysed to compare those. Other important factors tackled in the analysis are implementation flexibility, complexity, terminal capability indication, and content adaptation. Copyright © 2003 John Wiley & Sons, Ltd.