Power Control and Resource Allocation for Outage Balancing in Femtocell Networks

Given channel statistics information, we develop a joint power control (PC) and resource-allocation (RA) scheme for outage balancing in a multicarrier femto/macro system to minimize the maximum femtocell user equipments´ outage probability constrained on macrocell user equipments´ outage requirements. The formulated problem falls into the category of nonconvex mixed-integer optimization, which is in general very hard to solve. In this paper, we propose an alternating optimization scheme to find at least a local optimal point in the sense that no single femto base station can increase the system performance by changing its RA and PC strategy. Starting from a special initial RA scheme to handle cross-tier interference, PC and RA are then updated alternately. In particular, we find the optimal power for fixed RA scheme distributedly during the PC subroutine and greedily move to the most beneficial neighboring RA scheme in the RA subroutine. The proposed algorithm converges by producing monotonic improvement of system performance. Furthermore, to reduce the implementation complexity and feedback overhead, we propose a variant local search algorithm, which greatly reduces the computational burden without causing a significant loss of performance in the simulations.