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Wireless Communications, IEEE

Issue 5 • Date Oct 2002

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Displaying Results 1 - 14 of 14
  • Collaborative context determination to support mobile terminal applications

    Page(s): 39 - 45
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (956 KB) |  | HTML iconHTML  

    Mobile devices, together with their users, are constantly moving from one situation to another. To adapt applications to these changing contexts, the devices must have ways to recognize the contexts. There are various sources for context information: sensors, tags, positioning systems, to name a few. The raw signals from these sources are translated into higher-level interpretations of the situation. Unfortunately, such data is often unreliable and constantly changing. We seek to improve the reliability of context recognition through an analogy to human behavior. Where multiple devices are around, they can jointly negotiate on a suitable context and behave accordingly. This approach is becoming particularly attractive with the multitude of personal devices on the market. We present a collaborative context determination scheme, suggest examples of potential applications of such collaborative behavior, and raise issues of context recognition, context communication, and network requirements. View full abstract»

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  • Deployment of IP multimedia streaming services in third-generation mobile networks

    Page(s): 84 - 92
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1068 KB) |  | HTML iconHTML  

    In this article, an end-to-end quality of service framework for streaming services in 3G mobile networks is considered. Under this scenario, the interaction between UMTS and IETF's protocols and mechanisms for a streaming session is analyzed. By signaling flowcharts, it is shown that both groups of protocols and mechanisms can co-operate to provide seamless end-to-end real-time services. Specifically, the article proposes to make the IP multimedia subsystem aware of the real time streaming protocol, in order to extend its control from SIP to RTSP-based services, such as multimedia streaming services. Supported by this proposed framework, provisioning of audio streaming services over 3G mobile networks is also outlined. View full abstract»

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  • Uncoordinated real-time video transmission in wireless multicode CDMA systems: An SMPT-based approach

    Page(s): 100 - 110
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1434 KB) |  | HTML iconHTML  

    We consider the real-time transmission of encoded video from distributed, uncoordinated wireless terminals to a central base station in a multicode CDMA system. Our approach is to employ the recently proposed simultaneous MAC packet transmission (SMPT) approach at the data link layer (in conjunction with UDP at the transport layer). We consider the real-time transmission of both video encoded in an open loop (i.e., without rate control) and video encoded in a closed loop (i.e., with rate control). We conduct extensive simulations and study quantitatively the trade-off between video quality, transmission delay (and jitter), and number of supported video streams (capacity). We find that the simple-to-deploy SMPT approach achieves significantly higher video quality and smaller delays than the conventional sequential transmission approach, while ensuring high capacity. In typical scenarios, with SMPT the probability of in-time video frame delivery is more than twice as large as with sequential transmission (for given delay bounds). Our results provide guidelines for the design and dimensioning of cellular wireless systems as well as ad hoc wireless systems. View full abstract»

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  • Context-aware pervasive computing [Guest Editorial]

    Page(s): 8 - 9
    Save to Project icon | Request Permissions | PDF file iconPDF (311 KB)  
    Freely Available from IEEE
  • HotTown, enabling context-aware and extensible mobile interactive spaces

    Page(s): 18 - 27
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (300 KB) |  | HTML iconHTML  

    This article introduces a novel, open, and scalable service architecture for context-aware personal communication. In contrast to the network-centric open service access in third-generation mobile networks, this architecture moves the point of integration for user services out to the mobile devices, where we can create support for context-aware computing and communication. Support for peer-to-peer service negotiation with minimal a priori shared knowledge, context representation, and reasoning about context enables the mobile agents (that represent users and other entities) to be aware of and react to any event and thus context. Hence, the delivery of context-aware applications to users intertwining digital and physical objects in mobile interactive spaces leverages events from sensors, mobility support, and digital entities. Finally, a presentation of our prototype and experiences from the HotTown project demonstrates the feasibility of the approach and provides some examples of the enabled user communication for large-scale mobile networks. View full abstract»

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  • Mobility management for VoIP service: Mobile IP vs. SIP

    Page(s): 66 - 75
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1125 KB) |  | HTML iconHTML  

    Wireless Internet access has gained significant attention as wireless/mobile communications and networking become widespread. The voice over IP service is likely to play a key role in the convergence of IP-based Internet and mobile cellular networks. We explore different mobility management schemes from the perspective of VoIP services, with a focus on Mobile IP and session initiation protocol. After illustrating the signaling message flows in these two protocols for diverse cases of mobility management, we propose a shadow registration concept to reduce the interdomain handoff (macro-mobility) delay in the VoIP service in mobile environments. We also analytically compute and compare the delay and disruption time for exchanging signaling messages associated with the Mobile IP and SIP-based solutions. View full abstract»

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  • Intelligent service mediation for supporting advanced location and mobility-aware service provisioning in reconfigurable mobile networks

    Page(s): 28 - 38
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1811 KB) |  | HTML iconHTML  

    Service differentiation, customization, and personalization in the market of 3G mobile services and applications has caused many standards groups, telecommunication companies, and institutions to introduce advanced frameworks and architectures for the support of flexible service provisioning. An important feature in such architectures is location information management, which is a key aspect in future mobile systems and networks, enabling new approaches to service provisioning, customization, and personalization. We present our proposal for a generic open flexible service provisioning architecture that supports location-aware service provisioning and management. View full abstract»

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  • Context-aware communication

    Page(s): 46 - 54
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1164 KB) |  | HTML iconHTML  

    This article describes how the changing information about an individual's location, environment, and social situation can be used to initiate and facilitate people's interactions with one another, individually and in groups. Context-aware communication is contrasted with other forms of context-aware computing, and we characterize applications in terms of design decisions along two dimensions: the extent of autonomy in context sensing and the extent of autonomy in communication action. A number of context-aware communication applications from the research literature are presented in five application categories. Finally, a number of issues related to the design of context-aware communication applications are presented. View full abstract»

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  • An overview of scheduling algorithms in wireless multimedia networks

    Page(s): 76 - 83
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (976 KB) |  | HTML iconHTML  

    Scheduling algorithms are important components in the provision of guaranteed quality of service parameters such as delay, delay jitter, packet loss rate, or throughput. The design of scheduling algorithms for mobile communication networks is especially challenging given the highly variable link error rates and capacities, and the. changing mobile station connectivity typically encountered in such networks. This article provides a survey of scheduling techniques for several types of wireless networks. Some of the challenges in designing such schedulers are first discussed. Desirable features and classifications of schedulers are then reviewed. This is followed by a discussion of several, scheduling algorithms which have been proposed for TDMA, CDMA, and multihop packet networks. View full abstract»

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  • Reliable RSVP path reservation for multimedia communications under an IP micromobility scenario

    Page(s): 93 - 99
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (887 KB) |  | HTML iconHTML  

    We focus on how quality of service (QoS) guarantees can be provided for RSVP flows during handoff events in an IP micromobility network. For this purpose, RSVP message delays and signaling overheads should be minimized, and handoff service disruption should also be minimized. By rerouting the RSVP branch path at a crossover router at every handoff event, and establishing the new RSVP path between the CR and new BS in advance while the existing reservation path is maintained, ongoing RSVP flows can be kept with the guaranteed QoS. We propose the seamless switching of an RSVP branch path for soft handoff, and also show that this scheme could provide QoS guarantee with simulation and examples. View full abstract»

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  • Location sensing and privacy in a context-aware computing environment

    Page(s): 10 - 17
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1060 KB) |  | HTML iconHTML  

    This article presents and evaluates the performance of a location sensing algorithm developed and demonstrated at Carnegie Mellon University. We compare our model with various others based on different architectures and software paradigms. We show comparative results in accuracy, the complexity of training, total power consumption, and suitability to users. Our method reduces training complexity by a factor of eight over previous algorithms, and yields noticeably better accuracy. The algorithm uses less power than previous models, and offers a more secure privacy model. View full abstract»

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  • WLAN-GPRS integration for next-generation mobile data networks

    Page(s): 112 - 124
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1905 KB) |  | HTML iconHTML  

    The ongoing wireless LAN standardization and R&D activities worldwide, which target bit rates higher than 100 Mb/s, combined with the successful deployment of WLANs in numerous hotspots justify the fact that WLAN technology will play a key role in wireless data transmission. Cellular network operators have recognized this fact, and strive to exploit WLAN technology and integrate this technology into their cellular data networks. For this reason, there is currently a strong need for interworking mechanisms between WLANs and cellular data networks. We focus on these interworking mechanisms, which effectively combine WLANs and cellular data networks into integrated wireless data environments capable of ubiquitous data services and very high data rates in hotspot locations. We discuss the general aspects of integrated WLANs and cellular data networks, and we examine the generic interworking architectures that have been proposed in the technical literature. In addition, we review the current standardization activities in the area of WLAN-cellular data network integration. Moreover, we propose and explain two different interworking architectures, which feature different coupling mechanisms. Finally, we compare the proposed interworking architectures, and discuss their advantages and drawbacks. View full abstract»

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  • Multicast for mobile hosts in IP networks: progress and challenges

    Page(s): 58 - 64
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1300 KB) |  | HTML iconHTML  

    In the past few years, multimedia applications have become very popular on the Internet, and a growing number of users have shown interest in this type of communications. IP multicasting has logically been considered to support such transmissions, mainly because its inherent nature is to efficiently minimize the bandwidth required to deliver multimedia data to a large set of targeted receivers. In the meantime, there has been a steady increase in the number of mobile wireless devices connected to the Internet. It has also clearly appeared that mobile Internet users will expect to have access to the services and applications available in traditional wired networks, and these services will surely include multimedia applications. Consequently, many efforts are being made to provide efficient mobility and multicasting support, and to bring the two together in the next generation of IP networks. View full abstract»

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Aims & Scope

IEEE Wireless Communications Magazine deals with all technical and policy issues related to personalization, location-independent communications in all media.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Hsiao-Hwa Chen
Cheng Kung University, Taiwan