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Presenter: Xuan Wang
Supervisor: Dr. Lin Cai

Date: Thu, September 25, 2014
Time: 14:00:00 - 00:00:00
Place: EOW 430

ABSTRACT

Abstract:

Due to the shortage of wireless spectrum, how to schedule the user based on the available resource in an efficient way in multi-user wireless systems is an important issue. This talk discusses this issue from two starting points. one is from utility-based scheduling in saturated network. Another is from throughput-optimal scheduling in network with stochastic traffic.

We show that by using superposition coding (SPC) and successive interference cancellation, the system performance can be greatly improved with utility-based scheduling. However, the stability region of the utility-based scheduling in a multi-user system with stochastic traffic is generally less than the capacity region. Depends on how to interpret an intermediate control variable, the resultant stability region may be even non-convex and exhibits undesirable properties. The throughput-optimal scheduling algorithms can achieve the capacity region, but the queue length is unstable if the system is overloaded. However, the scheduling function of the queue length is stable, and the average throughput of the system converges. In the last we study how to schedule users in a multi-user wireless system with information-theoretic security support. We show that there is a tradeoff between the arrival rate of the traffic and the secrecy outage probability. The relative channel condition of the eavesdropper also plays an important role to the secrecy outage probability.