Non-orthogonal multiple access (NOMA) is considered as a promising candidate for fifth generation (5G) wireless networks. Although, NOMA promises large data rates, however, it also offers significant interference especially when the number of users is large. Therefore, in this paper, we propose a low complexity orthogonal frequency division multiple access (OFDMA)-based NOMA system, which uses the concept of successive bandwidth division (SBD) that not only reduces the complexity of the receiver, but also enhances the overall signal-to-interference plus noise ratio (SINR) of the uplink NOMA by supporting 2N users with just N base station (BS) antennas. Power allocation is being performed in SBD-NOMA to maximize the sum rate using a divide-and-allocate approach such that all users are allocated with an optimal transmission power. Simulations results are provided to access and compare the performance of the proposed scheme with other contemporary approaches.