HISNs: Distributed gateways for application-level integration of heterogeneous wireless networks

Integration of different kinds of wireless networks to provide people seamless and continuous network access services is a major issue in the B3G network. In this paper, we propose and implement a novel Heterogeneous network Integration Support Node design (HISN) and a distributed HISN network architecture for the integration of heterogeneous networks, under which the Session Mobility, Personal Mobility, and Terminal Mobility for mobile users can be maintained through the Session Management mechanism. Thus, the HISN node can serve as an agent for the user to access Internet services independent of underlying communication infrastructure. Our design is transparent to the bearer networks and the deployment of the HISN network does not need to involve the operators of the heterogeneous wireless networks. This paper is an extension of the work that won the championship of the Mobile Hero contest sponsored by Industrial Development Bureau of Ministry of Economic Affairs, Taiwan, R.O.C., and was awarded USD 30,000. The work of Lin, Chang and Cheng was supported in part by the National Science Council (NSC), R.O.C, under the contract number NSC94-2213-E-002-083 and NSC94-2213-E-002-090, and NSC 94-2627-E-002-001, Ministry of Economic Affairs (MOEA), R.O.C., under contract number 93-EC-17-A-05-S1-0017, the Computer and Communications Researches Labs/Industrial Technology Research Institute (CCL/ITRL), Chunghwa Telecom Labs, Telcordia Applied Research Center, Taiwan Network Information Center (TWNIC), and Microsoft Corporation, Taiwan. The work of Fang was supported in part by the US National Science Foundation Faculty Early Career Development Award under grant ANI-0093241 and US National Science Foundation under grant DBI-0529012. Phone Lin (M’02-SM’06) received his BSCSIE degree and Ph.D. degree from National Chiao Tung University, Taiwan, R.O.C. in 1996 and 2001, respectively. From August 2001 to July 2004, he was an Assistant Professor in Department of Computer Science and Information Engineering (CSIE), National Taiwan University, R.O.C. Since August 2004, he has been an Associate Professor in Department of CSIE and Graduate Institute of Networking and Multimedia, National Taiwan University, R.O.C. His current research interests include personal communications services, wireless Internet, and performance modeling. Dr. Lin is an Associate Editor for IEEE Transactions on Vehicular Technology, a Guest Editor for IEEE Wireless Communications special issue on Mobility and Resource Management, and a Guest Editor for ACM/Springer MONET special issue on Wireless Broad Access. He is also an Associate Editorial Member for the WCMC Journal. P. Lin’s email and website addresses are plin@csie.ntu.edu.tw and http://www.csie.ntu.edu.tw/∼plin, respectively. Huan-Ming Chang received the BSCSIE degree and Master CSIE degree from National Taiwan University, R.O.C. in 2003 and 2005, respectively. His current research interest includes wireless Internet. H.-M. Chang’s email address is r91114@csie.ntu.edu.tw. 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 to Associate Professor with tenure in August 2003 and to Full Professor in August 2005. He has published over 180 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). Shin-Ming Cheng received the BSCSIE degree in 2000 from National Taiwan University, Taiwan, R.O.C., where he is currently working toward the Ph.D. degree in the Department of Computer Science and Information Engineering, National Taiwan University. His current research interests include mobile computing, personal communications services, and wireless Internet. S.-M. Cheng’s email and website addresses are shimi@pcs.csie.ntu.edu.tw and http://www.pcs.csie.ntu.edu.tw/∼shimi, respectively.     

Design and Performance Study for a Mobility Management Mechanism (WMM) Using Location Cache for Wireless Mesh Networks

Wireless mesh networks (WMNs) have emerged as one of the major technologies for 4G high-speed mobile networks. In a WMN, a mesh backhaul connects the WMN with the Internet, and mesh access points (MAPs) provide wireless network access service to mobile stations (MSs). The MAPs are stationary and connected through the wireless mesh links. Due to MS mobility in WMNs, mobility management (MM) is required to efficiently and correctly route the packets to MSs. We propose an MM mechanism named Wireless mesh Mobility Management (WMM). The WMM adopts the location cache approach, where mesh backhaul and MAPs (referred to as mesh nodes (MNs)) cache the MS's location information while routing the data for the MS. The MM is exercised when MNs route the packets. We implement the WMM and conduct an analytical model and simulation experiments to investigate the performance of WMM. We compare the signaling and routing cost between WMM and other existing MM protocols. Our study shows that WMM has light signaling overhead and low implementation cost.     

A Privacy-Preserving Attribute-Based Reputation System in Online Social Networks

Online social networks (OSNs) have revolutionarily changed the way people connect with each other. One of the main factors that help achieve this success is reputation systems that enable OSN users to ...     

Modeling mis-routing calls due to user mobility in wireless VoIP

This letter proposes an analytic model to study the mis-routing problem caused by user mobility in a wireless VoIP system. We derive the probability that there are n mis-routed calls when a subscriber moves from IP network to the GSM network. Our study indicates that if the user residence times in GSM location areas, inter-call origination times and the inter-call delivery times are of the same order, then the mis-routing effect can not be ignored     

Component-oriented radars with probabilistic timing guarantees

In recent years, many modern phased-array radars are built with commercial off-the-shelf components, and the functions of many hardware components are also reimplemented by software modules. In such systems, radar tasks could be modeled as distributed real-time tasks which require end-to-end deadline guarantees and have precedence constraints. Different from most previous work on either algorithms with restrictions in resource utilization or heuristics without analytical ways for schedulability guarantees, the objective of this paper is to propose a joint real-time scheduling algorithm for both transmitter/receiver and signal processor workloads with an analytical framework for offline probabilistic analysis and online admission control. The strength of our approach is verified by analysis results and a series of experiments based on a real phased-array radar for air defense frigates.     

Design and implementation of a wireless internet remote access platform

Recently, mobile networks and internet technologies have been widely developed for the voice communication and information retrieval services all over the world. Compared with the wire‐line internet environment, mobile networks have lower bandwidth, longer transmission latency and unreliable connection, and the capability of mobile terminals is restricted by the limited memory size, lower CPU computation capability and inconvenient I/O interface. These limitations restrict the development of the wireless internet applications. In this paper, we design and implement a ‘wireless internet remote access platform’ (WIRAP). The WIRAP platform interconnects the wireless network and internet to provide mobile users a remote centralized storage and computation environment. A mobile user can store large volume of data and execute complex computations on WIRAP instead of on the mobile terminals. WIRAP supports different network interfaces (e.g. short message service (SMS), wireless markup language (WML) and hyper text markup language (HTML) and users may use terminals (with different network capabilities) to access WIRAP. Copyright © 2006 John Wiley & Sons, Ltd.     

A novel prebuffering scheme for IPTV service

The Internet Protocol TeleVision (IPTV) network utilizes the broadband IP network to provide users the TV service. Due to the limited bandwidth of the IP network, IPTV does not broadcast the content of all channels to its users. The channel zapping time (i.e., the delay between the time when the user switches to a new TV channel and the time when the content of the new TV channel is received by the user) and content miss (i.e., the content of the new TV channel arrives after the user switches to another TV channel so that the user did not watch the content of the new TV channel) significantly affect the QoS of IPTV service. This paper proposes Dynamic Prebuffering Scheme (DPS) that dynamically prebuffers the content of TV channels in the Home Gateways (HGs) based on the user’s behavior to reduce the channel zapping time and the content miss probability. A prebuffer timer is implemented in DPS to reduce the bandwidth consumption. Both the analytic model and simulation experiments are developed to investigate the performance of DPS. The simulation results show that the performance enhancements are bounded by the setup of the number of prebuffering channels and the prebuffer timer. Based on the performance study, the IPTV operators can properly set the number of prebuffered channels and the prebuffer timer to obtain good performance. Our study indicates that DPS can significantly reduce the channel zapping time and the content miss probability by slightly increasing bandwidth consumption.     

Performance study for HARQ–ARQ interaction of LTE

The 3GPP working group proposes the Long‐Term Evolution (LTE) system as the 4G mobile communications technology. To reduce the transmission latency in the radio access network, Evolved Universal Terrestrial Radio Access Network (E‐UTRAN), of LTE, the base station and radio network controller are merged into a single network node, namely eNB. In E‐UTRAN, the Stop‐And‐Wait Hybrid ARQ (SAW‐HARQ) protocol in the Media Access Control (MAC) layer deals with transmission errors without the need to engage the ARQ protocol in the Radio Link Control (RLC) layer. The HARQ and ARQ protocols interact only in case of dealing HARQ residual errors. In this paper, we propose an analytical model to model the behavior of the HARQ–ARQ Interaction. Our analytical model is validated against the simulation experiments that provide more performance metrics (which cannot be obtained through our analytical model). Finally, we investigate the impacts of the HARQ–ARQ Interaction on the Protocol Data Unit (PDU) transmission delay based on our simulation experiments. Copyright © 2009 John Wiley & Sons, Ltd.     

Improving GSM call completion by call reestablishment

Global system for mobile communications (GSM) call reestablishment service allows a mobile station to resume a call in which the radio link has been temporarily interrupted due to interference or bad signal (which is referred to as an interrupted call). This service increases end user satisfaction and network quality perception. We propose analytic models to study the performance for call reestablishment service. Our study indicates that call reestablishment can significantly reduces dropping for interrupted calls     

Channel Allocation for GPRS with Buffering Mechanisms

General Packet Radio Service (GPRS) provides mobile users end-to-end packet-switched services by sharing the radio channels with voice and circuit-switched services. In such a system, radio resource allocation for circuit-switched and packet-switched services is an important issue, which may affect the QoS for both services significantly. In this paper, we propose two algorithms: Dynamic Resource Allocation with Voice and Packet queues (DRAVP) and Dynamic Resource Allocation with Packet and Voice queues (DRAPV) for channel allocation of the voice calls and packets. We propose analytic and simulation models to investigate the performance of DRAVP and DRAPV in terms of voice call incompletion probability, packet dropping probability, average voice call waiting time, and average packet waiting time. Our study indicates that the buffering mechanism for GPRS packets significantly increase the acceptance rate of GPRS packets at the cost of slightly degrading the performance of voice calls.