Robust resource allocatoin for uplink sum rate maximization in multi-cell heterogeneous networks

In this paper, we investigate the robust power allocation problem in a two-tier orthogonal frequency division multiplexing (OFDM) access based heterogeneous networks, where the minimal rate requirement of each femtocell user and interference power constraint of macrocell user are properly controlled under channel uncertainties. We formulate an optimization problem to maximize the sum data rate of the femtocell users under the consideration of channel uncertainties of both cross-tier and intra-tier links while guaranteeing the rate requirement of femtocell users and controlling the interference to the macrocell users in terms of probability. According to the distribution models of estimation errors, we transform the original problem into a deterministic one and solve it by the subgradient method and Karush-Kuhn-Tuchker conditions. Simulation results show that our approach can fast converge to the optimal value and well protect the performance of macrocell users under channel uncertainties.