Designing large-scale ad hoc networking systems capable of supporting heterogeneous traffic types involves a large number of factors (e.g., protocols, parameters, network size, traffic characteristics) that interact in a very complex manner, making system optimization a non-trivial problem. The principle goal of this project is to develop a deeper understanding of the fundamental performance, scaling properties, and tradeoffs and includes two main research thrusts. The first is focused on constructing analytical and empirical models that accurately characterize the functional relationship between performance metrics (e.g., end-to-end delay) and significant factors. Analytical end-to-end delay and packet discard models are being developed that account for interactions among the traffic arrival process, wireless channels, error control mechanisms, and mobility-induced path failures. The empirical models are based on two modeling approaches: (1) response surface methodology and regression analysis and (2) the class of Levenberg-Marquardt multilayer perceptron neural networks. In the second research thrust, we are using the above models to explore several scaling and performance properties, including which system configuration(s) lead to optimal, robust, scalable, or satisfiable performance response(s) over specified regions of interests. Using the predictive empirical models, adaptive cross-layer feedback-based mechanisms are being designed for transport and QoS-sensitive routing strategies. The success of the proposed project will produce solid models, principles, and protocols on which to build large-scale ad hoc networks. An educational component will enhance education by integrating statistical experimental design and modeling research into wireless networking courses and will enhance national research initiatives by establishing research partnerships with non-Ph.D. granting universities.
The principle aim of this research project was to develop a deeper understanding of the fundamental performance, scaling properties, and design tradeoffs of large-scale mobile ad hoc and broadband mesh networks. The outcomes of this work falls into one two interrelated research thrusts (1) empirical and analytical modeling and performance characterization of large-scale multi-hop networks, and (2) the design and evaluation of adaptive cross-layer protocols for more efficient and reliable data delivery. Specifically, our performance modeling and experimental design work focused on i) analyzing the utilization of wireless system resources and characterizing the performance (e.g., delay, throughput, and loss rates) of multi-hop wireless networks under various deployment scenarios and environmental conditions; ii) engineering distributed protocols and algorithms capable of satisfying specific application QoS demands; and iii) designing, implementing, and deploying autonomic performance management mechanisms capable of efficiently monitoring the performance of multi-hop wireless systems and responding appropriately with little to no human intervention. The network protocol design work spans several specific topics including, mobility management in broadband mesh networks, cooperative diversity-based relay-routing, multi-channel medium access control, multi-path routing, fast handoff, localization, control-theoretic-based reliable transport, and dynamic spectrum management (i.e., probabilistic spectrum sharing, interference management, compressed sensing). In addition to basic research, we have established three distinct wireless testbeds as part of this project: (1) a campus-wide multi-hop mesh network covering 70 acres; (2) a 700 MHz-based WiFi testbed; and (3) an FPGA-based cognitive radio networking (CRN) testbed including the design and implementation of basic spectrum management mechanisms (e.g., spectrum sensing and spectrum handoff). To our knowledge, our 700MHz testbed was the first to be established at an academic institution in the US. The resulting CRN architecture and underlying spectrum management protocols provide a key building block for researchers in the areas of opportunistic spectrum access, self-management and performance optimization, and CRN protocol design. In addition to the technical and intellectual outcomes, this research project also includes several key educational and broader impacts. Most importantly, this project has supported the research work of six Ph.D. students and six MS students, helping to facilitate their development as scientist with the necessary ethical, analytical, and experimental skills required to build dynamic large-scale multi-hop wireless systems. Moreover, this research program has contributed significantly to curriculum development as well as mentoring and outreach. Specifically, we have developed two graduate level courses Wireless Computing and Networking Systems and Experimental Design, Modeling, and Analysis which incorporates various aspects of this research program, providing students with experience in cutting-edge wireless research. The PI also participated in multiple mentoring and outreach programs at Southern University of Baton Rouge, Tuskegee University, Michigan State University, and Louis Stokes Louisiana Alliance for Minority Participation (LS-LAMP) programs, all of which seek to recruit, retain, and mentor minority students in STEM areas. The results of this research project have generated seven journal and nineteen conference articles. The following list represents some of the key publications. Abdelhamid Moursy, Ahmed Aly, Bide Xu, Dmitri Perkins, and Magdy Bayoumi, "Testbed Implementation for Autonomic Performance Management of Wireless Mesh Networks", in The Proceedings of the IEEE Global Communications Conference (GLOBECOM): IEEE Workshop on Management of Emerging Networks and Services, Anaheim, CA, December 2012. Ahmed Khattab, D. Perkins, and M. A. Bayoumi, "Experimental Evaluation of Opportunistic Spectrum Access in Distributed Cognitive Radio Networks," in The Proceedings of the The 8th International Wireless Communications and Mobile Computing Conference, Cyprus, August 2012. Ahmed Khattab, Dmitri Perkins, and M. A. Bayoumi, "Opportunistic Spectrum Access: From Theory to Practice," IEEE Vehicular Technology Magazine: Applications of Cognitive Radio Networks, vol.7, no.2, pp. 62-68, June 2012. Ahmed Khattab, Dmitri Perkins, Magdy A Bayoumi, "Probabilistic Framework for Opportunistic Spectrum Management in Cognitive Ad hoc Networks," EURASIP Journal on Wireless Communications and Networking 2011, 2011:188 (28 November 2011) Van Nguyen and Dmitri Perkins, "A Cooperative Diversity-Based Opportunistic Virtual MISO (OVM) Protocol for Multi-Hop Wireless Networks," International Journal of Sensors, Wireless Communications and Control, Vol. 1 Issue 2, pp. 137-146, (2011) Yan He, Dmitri Perkins, and Sritej Velaga, "Design and Implementation of CLASS: a Cross-Layer ASSociation Scheme for Wireless Mesh Networks," Elsevier Ad Hoc Networks Journal, Vol. 9, Issue 8, (2011), pp. 1476-1488. Yan He and D. Perkins, "Achieving Seamless Handoffs via Backhaul Support in Wireless Mesh Networks," Springer Telecommunications System Journal: Special Issue on Mobile Computing and Networking Technologies, (2011), pp. 1-14. Yan He, Van Nguyen, Dmitri Perkins, and Nian-Feng Tzeng, "Exploring 700MHz WiFi-Based Wireless Mesh Networking", in the Proceedings of the 10th ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc), New Orleans, LA, Poster, pp. 349-350, May 2009. Michael Totaro and Dmitri Perkins, "Statistical Design of Experiments for Analyzing Mobile Ad Hoc Networks," in the Proceedings of the ACM/IEEE International Symposium on Modeling, Analysis and Simulation of Wireless and Mobile Systems, October 2005, pp.159-168.
