Scheduling Prioritized Services in Multihop OFDMA Networks

Growing popularity of high-speed wireless broadband access for real-time applications makes it increasingly relevant to study the admission control and scheduling of flows in a service differentiated manner. Next-generation wireless broadband networks employ orthogonal frequency division multiple access (OFDMA) technology that enables multiple users to communicate at the same time using a time-frequency grid. In this paper, we provide a mathematical model for prioritized admission control and scheduling in OFDMA-based multihop wireless networks. The problem is formulated as an integer linear program (ILP) that does joint admission control and scheduling of flows while satisfying its rate and latency requirements. We propose different heuristic algorithms for scheduling priority-based flows in centralized multihop OFDMA networks. We define the “Flow Admittance” (FA) metric and compare the different scheduling schemes based on this metric. Simulation results show that the Start from Frame Beginning (SFB) heuristic performs well in most of the scenarios. We also propose a combination approach that merges multiple heuristics. The FA values obtained from the combination approach are close to the ILP while incurring computation time orders of lower magnitude.