This paper addresses the cell association problem in the downlink of amulti-tier heterogeneous network (HetNet), where base stations (BSs) havefinite number of resource blocks (RBs) available to distribute among theirassociated users. Two problems are defined and treated in this paper: sumutility of long term rate maximization with long term rate quality of service(QoS) constraints, and global outage probability minimization with outage QoSconstraints. The first problem is well-suited for low mobility environments,while the second problem provides a framework to deal with environments withfast fading. The defined optimization problems in this paper are solved in twophases: cell association phase followed by the optional RB distribution phase.We show that the cell association phase of both problems have the samestructure. Based on this similarity, we propose a unified distributed algorithmwith low levels of message passing to for the cell association phase. Thisdistributed algorithm is derived by relaxing the association constraints andusing Lagrange dual decomposition method. In the RB distribution phase, theremaining RBs after the cell association phase are distributed among the users.Simulation results show the superiority of our distributed cell associationscheme compared to schemes that are based on maximum signal to interferenceplus noise ratio (SINR).
展开▼
