Fair scheduling and hybrid resource allocation in OFDMA cellular system

Abstract

In this paper, a new joint scheduling and hybrid resource allocation method is derived and investigated for a multi-user downlink Orthogonal Frequency Division Multiple Access (OFDMA) system that provides Time Delay-Sensitive services (TDS) and Time Delay-Insensitive services (TDI). A three sectored multi-cellular heterogeneous traffic environment is considered where users are randomly distributed and categorised under different priority levels. The method is proposed to address the balance between throughput, outage probability, and user priorities under varying channel conditions. The proposed method is based on the Lagrangian duality framework, and have been formulated as a Mixed Integer Non Linear Problem (MINLP) constrained by the total power of the Base Station BS and users' data rate while maintaining the Quality of Service (QoS) for each user. The hybrid resource allocation includes dynamic and fixed allocations in the main problem formulation. Simulation results show that the outage probability gaps between the priority levels are reasonably balanced. This is due to the optimality conditions which restrict the resource allocation domain for each priority level to avoid sever penalisation of one priority level over the others.