Joint Optimization of Area Spectral Efficiency and Fairness in Ultra-Dense Networks with Application of Joint Transmission

Abstract

Ultra-dense network (UDN) is one of the most important techniques to support massive number of different types of user equipments (UEs). With the increasing density of small cell base stations (SBSs), the interferences among adjacent cells increase accordingly, and using joint transmission (JT), a specific technique of coordinated multi-point transmission, can effectively reduce or even eliminate the severe inter-cell interferences. This paper focuses on the resource allocation problem in UDNs when considering the application of JT. As area spectral efficiency (ASE) is a primary performance indicator in UDNs, we take ASE as an objective in the resource-allocation problem. If only ASE is considered as the objective, the resources tend to be allocated to UEs with better channel conditions, and thus some UEs may be allocated no resources. In order to cope with this problem, a second objective, i.e., fairness among UEs, is also considered. Thus, a multi-objective optimization problem is constructed. Then, both alternating direction method of multipliers (ADMM) and particle swarm optimization (PSO) algorithms are adopted to solve the optimization problem.