PFQ-OS: A packet fair queueing based opportunistic scheduler in wireless networks

In this paper, we investigate the issues of extending the Packet fair queueing (PFQ) algorithms into continuous channel model. We present a PFQ-based Opportunistic scheduler (PFQ-OS), which can improve user throughput while satisfying strict short-term fairness. We decouple the conflicting design objectives of fairness and user throughput improvement by introducing a Search radius (SR) into the framework of PFQ. We develop an analytical model and derive the fairness properties of PFQ-OS, which are related to the SR. Thereby system operators can focus on opportunistic scheduling for the users within the SR without violating the fairness guarantee. We further investigate the designing of scheduling policy under the strict fairness constraints, and propose that in order to utilize the opportunistic scheduling all the time, the selection rule should provide all the users with equal chance in being scheduled at each selection. Accordingly, we present Maximum relative SNR (Max-rSNR) selection rule for PFQ-OS. We derive the bounds in terms of user throughput under Rayleigh fading channel. An extensive set of simulations testifies our derived theoretical properties that PFQ-OS can significantly improve user throughput while providing excellent short-term fairness guarantee.