Joint base station association and power control for uplink cognitive small cell network

In this paper, we propose a framework to jointly optimize user association and power control for the uplink cognitive small cell network (CSN). In the considered CSN, small cell base stations (SBSs) are deployed to serve a set of small cell user equipments (SUEs) by sharing the same licensed spectrum with a macrocell base station. The problem of joint user association and power allocation is formulated as an optimization problem, in which the goal is to maximize the overall uplink throughput while guaranteeing the SINR requirements of the served SUEs and MBS protection. To solve this problem, a distributed framework based on dual decomposition is proposed to find sub-optimal solution of the user association and transmit power in distributed manner. Moreover, distributed frameworks to achieve suboptimal solutions with low-computation complexity are also proposed. Simulation results show that the proposed approaches obtain suboptimal solutions with a small number of iterations.