Several downlink power control (PC) algorithms are investigated in this paper for the fifth generation MDMA based cellular system. Among them, the closed-loop PC schemes are studied, which are useful to reduce the co-channel interference and increase the system capacity. Two kinds of iterative methods are commonly discussed. One is the SIR based approach, and the other is the eigenvalue based approach. Some representative PC algorithms are evaluated in terms of different performance metrics. In addition, an enhanced PC method is proposed which combines the advantages of the previous methods. It is shown by computer simulations that the proposed method achieves both desirable capacity performance and convergence rate in a 5G multipath division multiple access cellular system. Thus, the proposed method is a feasible downlink power control solution for 5G cellular systems.