Uplink power allocation for interference coordination in multi-cell OFDM systems

In multi-cell orthogonal frequency division multiplexing cellular systems, the co-channel interference (CCI) from adjacent cells becomes the dominant interference. Considering the CCI in multiple cells, the optimal solution for data rate maximization is derived from the dual decomposition method. Based on the optimal solution, a simplified uplink distributed power allocation (UDPA) algorithm is proposed. In this simplified algorithm, the Lagrangian multiplier is determined off-line and the power allocation iterative function is updated in every transmit time interval (TTI). The UDPA only needs the traffic loading information in adjacent cells and the local information of each user, and performs power allocation in a distributed way, which is easily realized and reduces overhead cost. In the simulation, the parameter and convergence of the UDPA algorithm is analyzed and the performance is compared with optimal power allocation and equal power allocation. The simulation results show that the proposed algorithm exploits the spectral diversity gain on the co-channel in adjacent cells, so the system throughput is improved.