Joint optimization algorithm of user association and power control based on spatial yraffic distribution

5G networks must reduce network overhead while meeting user needs. Based on the flow model, this paper jointly optimizes the user association and power control in cellular networks, aiming at achieving a reasonable compromise between user delay and network energy consumption. Unlike previous snapshot models, flow models focus on the spatial distribution of traffic demand instead of the specific location of users. We consider a nonuniformity of spatial traffic distribution and load coupling among base stations (BSs). Firstly, an iterative algorithm is proposed to solve the optimal user association strategy under certain power of BSs. Then, a greedy power adjustment and user association algorithm (GPA-UA) is proposed to further optimize the objective function. The simulation results show that the proposed algorithm can reduce both user delay and network energy consumption in most cases, and the performance of the proposed algorithm is approximate to the Optimal scheme while GPA-UA has lower complexity.