Improved message passing algorithms for resource allocation in two-tier femtocell networks

Abstract

Deploying femtocells in macrocell network is an economical and reliable way to increase network coverage and efficiency. However, such deployment poses great challenges for the resource allocation of two tier femtocell networks due to the existence of inter-tier and intra-tier interference. We propose a uplink transmission resource allocation scheme with the goal of maximizing the total power efficiency. Nevertheless, the resource allocation optimization problem is NP-hard and non-convex, thereby, we adopt message passing (MP) method which approaches the optimality by iteratively passing the messages between each user equipments (UEs) and access points (APs). To reduce excessive number of iterations, we present two improved MP algorithms, i.e. best selection message passing (BSMP) algorithm as well as UE priority message passing (UPMP) algorithm. BSMP algorithm is optimal allocation algorithm which could avoid excessive number of iterations. Based on BSMP algorithm, UPMP algorithm take the UEs' priorities into consideration to ensure the fairness of resource allocation. Compared to existing schemes, simulation results show that improved MP algorithms have excellent convergences. Meanwhile, the vast improvements on power efficiency as well as weighted power efficiency have been demonstrated.