Lagrange and IMPSO based power adjustment scheme for hyper-dense HetNets

This paper studies the power adjustment algorithm for the hyper-dense heterogeneous networks (HetNets), where each user selects its serving cell according to the strongest received power from the cells and the serving cell alters with the power adjustment of the cells. The objective is to improve the system throughput by cooperatively adjusting the transmit power of the small cells while the macrocells are transmitting with full power to guarantee the seamless coverage. A time-saving power adjustment algorithm based on Lagrange duality (LD) and improved modified particle swarm optimization (IMPSO), called LDEM, is proposed to tackle the NP-hard power adjustment problem caused by the alteration of the serving cells. Simulations show that compared with the existing schemes, the proposed algorithm can achieve the best performance in both system throughput and run time. Benefiting from IMPSO, LDIM can significantly improve the system throughput compared with LD, while benefiting from LD, the required run time can be greatly saved compared with IMPSO.