Downlink radio resource allocation in OFDMA-based small cells networks

Interference management and supporting quality of service (QoS) requirements are the principal challenges for the spectral resource allocation in orthogonal frequency division multiple access small cells networks. In this paper, we propose an algorithm for assigning physical resource block (PRB) with QoS constraints to omit interference among femtocells. We present our resource management method as an optimization problem where interference among femtocells is entirely avoided and multiple QoS are supported. The optimization problem imposes the fairness among different femtocells and maximizes the PRB efficiency. However, this problem is NP-complete, and thus, we propose a greedy algorithm for solving the problem. Simulation results show that the throughput of the greedy algorithm is close to the optimal solution of the optimization problem. Besides, the proposed algorithm improves the network throughput by over 30%–50% in various simulation scenarios with different femtocells densities in comparison to previous methods. Moreover, simulations illustrate the rejection ratio for all classes of services is lower than 3%.