The aim of this work is to propose new approaches for maximizing the energy efficiency of downlink 5G mobile communication systems, in the presence of a reactive jammer. The concepts of non-orthogonal multiple access (NOMA) and distributed antenna systems (DAS) are exploited to devise joint subband, power and antenna assignment techniques, so as to guarantee a certain quality of service (QoS) to users. Also, the scheduler relies on jamming statistics, observed at the end of each timeslot, to perform resource allocation based on the prediction of the jammer behavior over the next timeslot. A particular care is given, in the proposed techniques, to maintain a moderate complexity at the receiver level, and to limit the number of active RRHs (remote radio heads) in the cell. Simulation results show that a proper combination of NOMA with DAS can allow a significant enhancement of the system robustness to jamming, with respect to centralized antenna systems and orthogonal multiple access.