As today's wireless networks transition from circuit-switched voice to internet protocol (IP) based traffic, there is a critical need to accurately and rapidly model the performance of emerging end-to-end user applications. Surprisingly, today's wireless systems treat all the higher layer protocols of the network stack as invisible and irrelevant in the development of wireless standards (e.g., WCDMA, EDGE, and IEEE 802.11a). Future wireless networks must abandon this archaic viewpoint of separation, and must use cross-layer knowledge to enable the next generations of ubiquitous wireless applications. In fact, one of the major stumbling blocks to designing and deploying the new generation of wireless network services is the lack of sophisticated computational tools for end-to-end systems modeling and simulation. Next generation simulation environments must address both the fidelity of modeling needed for the channel and physical levels of the protocol hierarchy and, at the same time, interactively exploit these features in software protocols employed at the higher layers. When such an approach is used, it becomes possible to create a powerful, accurate, end-to-end modeling environment for the development of the next generation of wireless data networks. This proposal will develop the first academic end-to-end multi-layer simulator and emulator for wireless networks. Montage -an integrated protocol development environment -will support the evolutionary design, development, and test of wireless network protocols. It will enable wireless and ad-hoc mobile network researchers and system operators across the country to design, develop, and analyze wireless hardware, network protocols, middleware algorithms, and network applications in a single integrated public-domain environment. Key research issues addressed in this proposal include a unified multi-modeling methodology (simulation + emulation + direct code execution), algorithms for smart scheduling, building a dynamic compositional environment, and incorporating sophisticated performance models of various network protocol layers. Montage thus addresses both the TPES (Technology for Performance Engineered Systems) and the CADDS (Complex Application Design and Support Systems) goals of the NSF Next Generation Software (NGS) program. Development of Montage drives development of new methods and techniques for integration of complex systems. It is simply not possible to create an integrated system from several existing and semantically complex systems on an ad hoc basis. The research tasks of this project derive from interfacing and integration of systems, which have quite different semantic bases, varied execution models, and span multiple levels of abstraction. One task is to design interface specification languages that will enable representation of the translations across the multiple semantics, execution models and levels of abstraction. Applying the interface language to interface and integrate the software systems, which together implement the Montage methodology, will be a major component of this research. As application case studies, this project will address key validation and design problems for large-scale ad-hoc wireless networks, as well as large commercial cellular networks that are transitioning from 2.5G to 3G. Today, these computational capabilities do not exist. Broader Impacts: Montage will be made available as a public domain web portal with customized design scenario interfaces for network researchers, educators, and commercial carriers. Montage shall also serve as a national archive for measured network performance and as a repository of designs selected by the user community. Montage will enable researchers to setup virtual testbeds, validate their modeling, and design and test middleware algorithms for wireless networks of the future. The principal investigators have an excellent track record for creating valuable research products and learning materials for education and training purposes. Furthermore, the investigators have proven records for fostering economic growth by creating high-tech spinout companies. Montage already has the support of key industrial constituencies (see supporting letters), and will emerge as a valuable resource for researchers and educators.
