Energy-saving user association for uplink heterogeneous cellular networks

In this paper, we present a scheme that jointly designs user association and power control in uplink heterogeneous cellular networks. Specifically, we formulate a general problem which performs user association and meanwhile minimizes the uplink sum-power under signal-to-interference-plus-noise ratio (SINR) constraints. This is a nonlinear mixed-integer optimization problem, and its optimum solutions are very difficult to be obtained when the problem is large-scale. To solve this problem, we decompose it into a user association problem and a power control problem, and then iteratively solve these two subproblems by designing a two-sided scalable (2.s.s.) algorithm. The proposed algorithm can be well implied in a distributed manner due to its simplification and efficiency. Numerical results show that, compared with the scheme proposed by Roy, the proposed scheme can significantly reduce energy consumption and increase the system throughput.