Miriam Tauil

IEEE 802.21: Media independent handover: Features, applicability, and realization

Providing users of multi-interface devices the ability to roam between different access networks is becoming a key requirement for service providers. The availability of multiple mobile broadband access technologies, together with the increasing use of real-time multimedia applications, is creating strong demand for handover solutions that can seamlessly and securely transition user sessions across different access technologies. A key challenge to meeting this growing demand is to ensure handover performance, measured in terms of latency and loss. In addition, handover solutions must allow service providers, application providers, and other entities to implement handover policies based on a variety of operational and business requirements. Therefore, standards are required that can facilitate seamless handover between such heterogeneous access networks and that can work with multiple mobility management mechanisms. The IEEE 802.21 standard addresses this problem space by providing a media-independent framework and associated services to enable seamless handover between heterogeneous access technologies. In this article, we discuss how the IEEE 802.21 standard framework and services are addressing the challenges of seamless mobility for multi-interface devices. In addition, we describe and discuss design considerations for a proof-of-concept IEEE 802.21 implementation and share practical insights into how this standard can optimize handover performance.

Implementing a testbed for mobile multimedia

In an effort to realize wireless Internet telephony and multimedia streaming in a highly mobile environment a testbed emulating a wireless Internet has been built. This allows the setting up of multimedia calls between IP mobiles and integration between IP and PSTN end-points in a wireless environment. Different functionalities and components involved with the wireless Internet streaming multimedia have been prototyped and experimented in the testbed. These include signaling, registration, dynamic binding, location management as well as supporting the QoS features for the mobile users. This paper describes some of the components of the testbed and highlights the experiences while building this testbed which could be beneficial to some who plan to build a similar testbed to realize several features and capabilities of Mobile Wireless Internet, before actually bringing to the market.

Realizing mobile wireless Internet telephony and streaming multimedia testbed

Streaming real-time multimedia content over the Internet is gaining momentum in the communications, entertainment, music and interactive game industries as well as in the military. In general, streaming applications include IP telephony, multimedia broadcasts and various interactive applications such as multi-party conferences, collaborations and multiplayer games. Successfully realizing such applications in a highly mobile environment, however, presents many research challenges. In order to investigate such challenges and demonstrate viable solutions, we have developed an experimental indoor and outdoor testbed laboratory. By implementing standard IETF protocols into this testbed, we have demonstrated the basic functionalities required of the mobile wireless Internet to successfully support mobile multimedia access. These requirements include signaling, registration, dynamic configuration, mobility binding, location management, Authentication Authorization and Accounting (AAA), and quality of service over a variety of radio access network (RAN) technologies (e.g. 802.11b, CDMA/GPRS). In this paper, we describe this testbed and discuss important design issues and tradeoffs. We detail the incorporation and inter-relation of a wide catalog of IETF protocols-such as SIP, SAP, SDP, RTP/RTCP/RTSP, MGCP, variants of Mobile-IP, DRCP, HMMP, PANA, and DSNP-to achieve our goals. We believe that the results and experiences obtained from this experimental testbed will advance the understanding of the pertinent deployment issues for a Mobile Wireless Internet.

C-NEDAT: A cognitive network engineering design analytic toolset for MANETs

Future force networks of the types envisioned for the network centric warfare (NCW) paradigm will be highly diverse, with the diversity spanning a wide range of (a) requirements (e.g., need for capacity, connectivity, survivability), (b) resources (e.g., radios with widely different capabilities and ‘smart’ (e.g., Software Defined Radios (SDRs)), and (c) environments (e.g., urban, rural). The need to facilitate robust and adaptable communications in such networks has in turn triggered research in the area of cognitive networks that have the ability to ‘learn’ and generate real-time control actions to adapt to the wide diversity of requirements, resources and environments. However, the combination of diversity and “smart” networking exacerbates the problem of generating reliable and robust network designs. We present in this paper, our work on the use of cognitive mechanisms to assist with the design and analysis of robust NCW-like networks. Based on formal network-science based approaches, our Cognitive Network Engineering Design Analytic Toolset (C-NEDAT) provides for a systematic way to design, analyze and maintain robustness of future force MANETs. We provide in this paper an overview of the key functional modules and design capabilities of C-NEDAT and present example results.

Realization of IEEE 802.21 services and preauthentication framework

Providing users of multi-interface devices the ability to roam between different access networks is becoming a key requirement for service providers. The availability of multiple mobile broadband access technologies together with increasing use of real time multimedia applications is creating strong demand for handover solutions that can seamlessly and securely transfer user sessions across different access technologies. In this paper, we discuss how the IEEE 802.21 standard and its services address the challenges of seamless mobility for multi-interface devices. We focus on a proof-of-concept implementation that integrates IEEE 802.21 services and a pre-authentication framework, realizing different possible usage scenarios to optimize handover performance. We describe the implementation of two handover scenarios using the 802.21 Services: the first one is initiated by the mobile node and the second one is initiated by the operator network. We compare the two scenarios and discuss their respective benefits. Finally, we describe the implementation challenges and lessons learned through this exercise.

Collaborative sensing using uncontrolled mobile devices

This paper considers how uncontrolled mobiles can be used to collaboratively accomplish sensing tasks. Uncontrolled mobiles are mobile devices whose movements cannot be easily controlled for the purpose of achieving a task. Examples include sensors mounted on mobile vehicles of people to monitor air quality and to detect potential airborne nuclear, biological, or chemical agents. We describe an approach for using uncontrolled mobile devices for collaborative sensing. Considering the potentially large number of mobile sensors that may be required to monitor a large geographical area such as a city, a key issue is how to achieve a proper balance between performance and costs. We present analytical results on the rate of information reporting by uncontrolled mobile sensors needed to cover a given geographical area. We also present results from testbed implementations to demonstrate the feasibility of using existing low-cost software technologies and platforms with existing standard protocols for information reporting and retrieval to support a large system of uncontrolled mobile sensors

Automated design algorithms for tactical wireless networks

To guide users who attempt to deploy wireless networks in military applications, there is an evolving need for developing systematic methodologies to analyze/predict the performance of mobile ad hoc networks (MANETs). In addition, the advance in cognitive networking research provides opportunities for exploiting unused spectrum to optimize throughput of MANETs. However, with the increasing number of parameters/constraints, there is even a more demanding need to develop automated methodologies to design/tune such networks. In this work, we study the concepts and challenges for automatic design/re-configuration of cognitive MANETs, in addition to proposing design automation algorithms. The paper is divided into two parts. In the first part, we describe the design objectives, imposed constraints, and involved parameters in MANET design. We discuss how cognitive techniques can be employed to exploit the unused spectrum in military architectures. We then discuss the challenges that face the design/re-configuration of a cognitive network and their implications at different network layers. We also describe possible implementation options for designing MANETs that employ cognitive features at all layers. In the second part of this work, we propose design automation algorithms for optimally setting parameters to achieve a desired objective and satisfy certain constraints. Despite providing the optimal configuration, the simple approach of testing all possible combinations of parameter settings has significant time complexity (the COMB approach). Thus, we propose a novel heuristic (Sequential Parameter Optimization or SEPO) for searching through the possible parameter settings and selecting the best design options. SEPO is efficient in terms of both convergence speed and parameter tuning. We also discuss the foundation for using supervised learning to speed up the design (search) process. By evaluating realistic design of military-like scenarios that require optimizing a diverse set of metrics, we show that SEPO generates comparable results to the optimal, straightforward (slow-converging) COMB approach that is based on exhaustive search.

Spectrum allocation in C-NEDAT: A tool to automate MANET design and opportunistically adapt network spectrum use

The advancements in cognitive radios coupled with the ever increasing demand for spectrum have propelled research into dynamic and adaptive spectrum management techniques. More specifically, the need to support a wide variety of network centric warfare(NCW) applications combined with the dearth in ‘available’ spectrum underscores the need for opportunistic spectrum use, whereby idle spectrum can be ‘borrowed’ used opportunistically by applications that need it. To this end, Telcordia and CERDEC have developed a cognitive network design tool called C-NEDAT to provide for a systematic method to design NCW-like networks. An important aspect that we address with C-NEDAT is spectrum assignment in multiple time scales.

Integration of IEEE 802.21 services and pre-authentication framework

Providing multi-interface device users the ability to roam between different access networks is becoming a key requirement for service providers. The availability of multiple mobile broadband access technologies together with increasing use of real time multimedia applications is creating strong demand for handover solutions that can seamlessly and securely transfer user sessions across different access technologies. In this paper, we discuss how the IEEE 802.21 standard and its services address the challenges of seamless mobility for multi-interface devices. We focus on a proof-of-concept implementation that integrates IEEE 802.21 services and a pre-authentication framework, to optimise handover performance in two different scenarios. The first scenario is initiated by the mobile node and the second one is initiated by the network. We present the measurement results for realising these scenarios. Finally, we describe the implementation challenges and lessons learned through this exercise.