Delay-Aware Uplink User Association and Power Control in Heterogeneous Cellular Networks

In this letter, the delay-aware uplink user association problem in conjunction with power control is considered for energy efficiency in heterogeneous cellular networks. We aim at minimizing the energy consumption of user terminals under the delay constraints. Due to the mutual interference and the coupled queue dynamics, the problem is NP-hard and thus is difficult to solve. To overcome this issue, we first analyze the optimal solution for single user case by assuming the transmit power of others are unchanged, based on which we then propose a heuristic algorithm for the formulated problem. Simulation results demonstrate the efficiency of our proposed schemes.