Toronto Networking Seminar

We investigate an optimal scheduling problem in a discrete-time system of L parallel queues that are served by K identical, randomly connected servers. Each queue may be connected to a subset of the K servers during any given time slot. This model has been widely used in studies of emerging 3G/4G wireless systems. We introduce the class of Most Balancing (MB) policies and provide their mathematical characterization. We prove that MB policies are optimal; we define optimality as minimization, in stochastic ordering sense, of a range of cost functions of the queue lengths, including the process of total number of packets in the system. We use stochastic coupling arguments for our proof. We introduce the Least Connected Server First/Longest Connected Queue (LCSF/LCQ) policy as an easy-to-implement approximation of MB policies. We present simulation results that compare the performance of several policies to the optimal one.

Hussein Al-Zubaidy received his B.Sc. (with honors) and his M.Sc. in Communication Engineering from the University of Technology, Baghdad. He was a faculty member in Al-Mansour College University from 1995 to 1997. From 1997 to 2001, he was a faculty member at the Faculty of Engineering at Hoon - Tahaddi University. He received an M.A.Sc. degree (2005) and a Ph.D. degree (2010) in Systems and Computer Engineering from from Carleton University. He is currently a post-doctoral fellow at Carleton University conducting research in the area of stochastic modeling and optimization in wireless networks.