In this paper, a novel design of an incremental cooperative communication with downlink non-orthogonal multiple access is studied and analyzed for a buffer-aided cooperative relay network. The phenomenon of packet diversity is taken into consideration instead of link diversity to overcome the lousy channels. A source multi-casts data packets in the direction of two users, if the direct transmission fails, only then the source requires assistance from the strong user for successful transmission. Additionally, the quality of the relaying channel is validated at every instance for the selection of the best packet. Furthermore, direct and relayed signals are combined at the destination using the maximal ratio combining (MRC) technique. Also, a closed-form expression is derived for the computation of the outage probability at user B along with the delay, throughput and diversity gain. The model illustrates the significance of the proposed scheme in terms of the outage probability, packet diversity and throughput against buffer-less schemes.