@conference {
	title = {Rate-Control System with Heterogeneous Time-varying Delays in Broadband Satellite Networks},
	author = {Zeng, Hui., Hadjitheodosiou, Michael., Baras, John S.},
	year = {2009},
	month = {09/2009},
	abstract = {In a broadband satellite communications network, the propagation delays are not only significant, but also variable among users due to their different geographical locations and the problem becomes more severe with increasing data rates. We consider rate control algorithms with user feedback in the form of single bits and formulate analytic fluid flow models composed of first-order delay differential equations. Both single-flow and multi-flow system models are analyzed, with special attention paid to the Mitra-Seery algorithm. The stationary solutions are investigated first. For the fluctuating solutions, their dynamic behavior is analyzed, in terms of amplitude, transient behavior, fairness, and adaptability, etc., analytically and numerically. Especially the effects of heterogeneous time-varying delays are investigated. It is shown that with proper parameter design the system can achieve stabling behavior with close to pointwise proportional fairness among flows.},
	address = {Sardinia, Italy},
	booktitle = {The Ka and Broadband Communications Conference Navigation and Earth Observation Conference 2009 (KaConf2009)},
	pages = {pp. 1-8},
	organization = {Cagliari}
}
@conference {
	title = {Two-Level Dynamic Bandwidth Allocation for A Space-To-Ground Relay Network},
	author = {Zeng, Hui., Hadjitheodosiou, Michael., Baras, John S.},
	year = {2006},
	month = {11/2006},
	abstract = {We address issues related to efficiency, fairness, end to- end delay minimization and Quality-of-Service in order to enable a flexible access and dynamic mission operation capability in the next generation NASA space-to-ground communication infrastructure. To provide efficient and fair utilization while guaranteeing specific service requirements for different traffic classes, we propose a two-level (long-term and short-term) sharing of a slotted high data rate satellite communication link. The implemented long-term optimal bandwidth allocation provides per-user/per-flow service guarantee and gives the inputs to the next level. In our short-term bandwidth allocation with threshold regulation, a small portion of bandwidth is still assigned to all active spacecraft in advance, but most bandwidth is dynamically allocated per frame by solving an optimal timeslot scheduling problem. We finally discuss simulation results and our design optimization approach.},
	address = {San Francisco, CA},
	booktitle = {2006 IEEE Globecom Technical Conference},
	pages = {pp. 1-6}
}
@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 = {Dynamic Bandwidth Allocation for a Space Relay Communications Network},
	author = {Zeng, Hui., Hadjitheodosiou, Michael., Baras, John S.},
	year = {2006},
	month = {04/2006},
	abstract = {We address issues related to efficiency, fairness, end-to-end delay minimization and Quality-of-Service framework in order to enable a flexible access and dynamic mission operation capability in the next generation NASA space-to-ground communication infrastructure. To provide optimal or near-optimal efficient utilization and fair allocation of bandwidth of the downlink channel while guaranteeing specific service 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 service 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 spacecraft in advance but most bandwidth is dynamically allocated by the requests from them per frame by solving an optimal time slot scheduling problem.},
	address = {Charlottesville, Virginia},
	booktitle = {2006 IEEE Systems and Information Engineering Design Symposium (SIEDS06)},
	pages = {pp.75-80}
}
@conference {
	title = {Dynamic Resource Allocation for an IP-based Communications Network Supporting Space Exploration},
	author = {Zeng, Hui., Hadjitheodosiou, Michael., Baras, John S.},
	year = {2005},
	month = {09/2005},
	abstract = {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 capability in the next generation NASA space-to-ground IP-based communication infrastructure. In our scenario, the downlink channel of the NASA Tracking and Data Relay Satellite System is shared by a number of spacecraft, which we model as streams with different priority levels going through a common queue and a router. Both the current and future potential architectures for this relay system are addressed. We formulate an optimization problem for long-term static bandwidth allocation and present its solution to serve as initial bandwidth allocation algorithm and periodical regulation approach. Along with it, a hybrid Time Division Multiple Access (TDMA)-based protocol is proposed and then an assignment problem for the short-term dynamic optimal timeslot scheduling is studied. By using simulation, the performance of a suitable Medium Access Control (MAC) protocol with timeslot scheduling is analyzed and compared with that of the existing static fixed-assignment scheme.},
	address = {Rome, Italy},
	booktitle = {23rd AIAA International Communications Satellite Systems Conference and Exhibit (ICSSC)},
	pages = {pp. 1-12}
}
