Femtocell network is an efficient configuration to improve coverage and Quality of Service (QoS) in cellular networks. However, due to dense deployment, users in a femtocell may be interfered by the base stations nearby, resulting in a deteriorated throughput of the femtocell. In this paper, the authors investigate the resource allocation problem targeting at maxmin throughput of the femtocells. Under the assumption that a number of discrete power levels are available for each device, a joint optimization problem over power control and channel allocation is formulated. They show its hardness and propose a particle swarm optimization based algorithm PCASO.