@conference {
	title = {Performance Metric Sensitivity Computation for Optimization and Trade-off Analysis in Wireless Networks},
	author = {Baras, John S., Tabatabaee, Vahid., Papageorgiou, George., Rentz, Nicolas.},
	year = {2008},
	month = {11/2008},
	abstract = {We develop and evaluate a new method for estimating and optimizing various performance metrics for multihop wireless networks, including MANETs. We introduce an approximate (throughput) loss model that couples the physical, MAC and routing layers effects. The model provides quantitative statistical relations between the loss parameters that are used to characterize multiuser interference and physical path conditions on the one hand and the traffic rates between origin-destination pairs on the other. The model takes into account effects of the hidden nodes, scheduling algorithms, IEEE 802.11 MAC and PHY layer transmission failures and finite packet transmission retries at the MAC layer in arbitrary network topologies where multiple paths share nodes. We apply Automatic Differentiation (AD) to these implicit performance models, and develop a methodology for sensitivity analysis, parameter optimization and trade-off analysis for key wireless protocols. Finally, we provide simulation experiments to evaluate the effectiveness and performance estimation accuracy of the proposed models and methodologies.},
	address = {New Orleans, LA},
	booktitle = {IEEE Global Communications Conference (IEEE Globecom 2008)},
	pages = {pp. 1-5}
}
@conference {
	title = {Modelling and Optimization for Multi-hop Wireless Networks Using Fixed Point and Automatic Differentiation},
	author = {Baras, John S., Tabatabaee, Vahid., Papageorgiou, George., Rentz, Nicolas.},
	year = {2008},
	month = {03/2008},
	abstract = {We develop and evaluate a new method for estimating and optimizing various performance metrics of multi-hop wireless networks, including MANETs. We introduce a simple approximate (throughput) loss model that couples the physical, MAC and routing layers effects. The model provides quantitative statistical relations between the loss parameters that are used to characterize multiuser interference and physical path conditions on the one hand and the traffic rates between origin-destination pairs on the other. The model considers effects of the hidden nodes, node scheduling algorithms, MAC and PHY layer failures and unsuccessful packet transmission attempts at the MAC layer in arbitrary network topologies where multiple paths share nodes. We apply Automatic Differentiation (AD) to these implicit performance models~and develop a methodology for sensitivity analysis and parameter optimization for wireless protocols. Finally, we provide simulation experiments to evaluate the effectiveness and performance estimation accuracy of the proposed models and methodologies.},
	address = {Berlin, Germany},
	booktitle = {6th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt{\textquoteright}08)},
	pages = {pp.  295 -300}
}
@conference {
	title = {Loss Model Approximations and Sensitivity Computations for Multi-Hop Wireless Network Design},
	author = {Baras, John S., Tabatabaee, Vahid., Papageorgiou, George., Rentz, Nicolas., Shang, Yadong.},
	year = {2007},
	month = {10/2007},
	abstract = {We develop and evaluate a new method for estimating various performance metrics of multi-hop wireless networks, including MANETs. The estimates depend implicitly on network design parameters, and therefore the method can form the basis for designing such networks so as to achieve predictable performance bounds. Explicit simulation models for large wireless networks are too complex and can not be used for analysis and design of wireless networks in realistic settings. We introduce a simple approximate (throughput) loss model that couples the physical, MAC and routing layers. The model provides quantitative statistical relations between the loss parameters used to characterize multiuser interference and physical path conditions on the one hand and traffic rates between origin-destination pairs on the other. We use a fixed point approach together with recently proposed models for the MAC layer to find a consistent solution satisfying all equations in the set. The result is an implicit model of performance metrics, such as throughput, packet loss, delay, parameterized by design variables, such as path routing probabilities, power levels, noise levels. We next apply Automatic Differentiation (AD) to these implicit performance models and develop a methodology for design and parameter selection/tuning of wireless protocols.},
	address = {Orlando, FL},
	booktitle = {2007 Military Communication Conference},
	pages = {pp. 1-7}
}
@conference {
	title = {Flexible and Dynamic Communication Architecture for Lunar Exploration},
	author = {Zeng, Hui., Roy-Chowdhury, Ayan., Rentz, Nicolas., Hadjitheodosiou, Michael., Baras, John S.},
	year = {2006},
	month = {06/2006},
	abstract = {We present work related to designing a communication network for lunar exploration. We discuss the important requirements for future space missions that influence the design of this network. We list some characteristics of the network, and highlight important issues and constraint related to performance, cost, and future network evolution. We address issues related to efficiency, fairness, end-to-end delay minimization and Quality-of-Service (QoS) framework in order to enable a flexible access and dynamic mission operation. To provide optimal or near-optimal efficient utilization and fair allocation of bandwidth of the downlink channel while guaranteeing specific QoS requirements for different service classes, we propose two-level (long-term static and short-term dynamic) sharing of a slotted high data rate satellite communication link. The long-term optimal bandwidth allocation is implemented to provide per-stream/per-user QoS guarantee and give the inputs to the next level, short-term dynamic bandwidth allocation. In our time-varying short-term bandwidth allocation with threshold regulation, a small portion of bandwidth is still assigned to all active spacecrafts in advance, but most bandwidth is dynamically allocated by the requests from them, per frame, by solving an optimal timeslot scheduling problem.},
	address = {San Diego, CA},
	booktitle = {24th American Institute of Aeronautics and Astronautics},
	pages = {pp. 1-9}
}
@conference {
	title = {Hybrid Networks with a Space Segment - Topology Design and Security Issues},
	author = {Roy-Chowdhury, Ayan., Baras, John S., Hadjitheodosiou, Michael., Rentz, Nicolas.},
	year = {2005},
	month = {10/2005},
	abstract = {In this paper we investigate a hybrid network topology that is suitable for supporting interplanetary communications. We define an architecture comprised of a network of sensor nodes on a remote planetary surface, connected to a hybrid terrestrial network of wired and wireless LANs through a series of satellite relays. All the nodes in the network are IP-addressable and support public and symmetric key cryptography. The resulting network forms a hierarchical hybrid mesh that connects users on Earth to networks on or around a remote planetary surface. We describe the design of the network and present preliminary simulation results illustrating the network performance for various parameters. We also discuss how algorithms for user authentication, message integrity and data confidentiality can be incorporated in the network infrastructure for secure end-to-end communication.},
	address = {Atlantic City, NJ},
	booktitle = {2005 Military Communications Conference (MILCOM 2005),},
	pages = {pp.1414 - 1420}
}
@conference {
	title = {Modeling and Design of a Communication Architecture Supporting Lunar Exploration},
	author = {Roy-Chowdhury, Ayan., Hadjitheodosiou, Michael., Baras, John S., Rentz, Nicolas.},
	year = {2005},
	month = {09/2005},
	abstract = {We discuss some basic requirements and trade-offs for designing a communication network supporting the needs of lunar exploration missions. We describe the unique characteristics of this network and outline a prototype network architecture. The proposed network consists of three distinct segments - a terrestrial network on Earth, a network on the lunar surface, and a space segment comprising a satellite constellation that connect the two surface networks.~We develop a simulation platform that includes the network topology, node orbits and mobility, and test the network performance with different applications and traffic loads. We present simulation results obtained with our models that illustrate the network connectivity and delay for varying satellite orbital patterns and traffic characteristics. We also discuss the requirements and constraints for providing a secure infrastructure for end-to-end communication in space exploration networks~and suggest algorithms and protocols for implementing end-to-end encryption, authentication and secure group communication.},
	address = {Rome, Italy},
	booktitle = {23rd AIAA International Communications Satellite Systems Conference and Exhibit (ICSSC)},
	pages = {pp. 1-10}
}
@techreport {
	title = {Hybrid Networks with a Space Segment - Topology Design and Security issues},
	author = {Roy-Chowdhury, Ayan., Hadjitheodosiou, Michael., Rentz, Nicolas.},
	year = {2005},
	month = {01/2005},
	abstract = {In this paper we investigate a hybrid network topology that is suitable for supporting interplanetary communications. We define an architecture comprised of a network of sensor nodes on a remote planetary surface, connected to a hybrid terrestrial network of wired and wireless LANs through a series of satellite relays. All the nodes in the network are IPaddressable and support public and symmetric key cryptography. The resulting network forms a hierarchical hybrid mesh that connects users on Earth to networks on or around a remote planetary surface. We describe the design of the network and present preliminary simulation results illustrating the network performance for various parameters. We also discuss how algorithms for user authentication, message integrity and data confidentiality can be incorporated in the network infrastructure for secure end-to-end communication.},
	number = {Number: CSHCN TR 2005-6}
}
