  NOMA is as a strong candidate for the Future Radio Access Network (FRA) due
to its potential to support massive connectivity and high spectral efficiency.
However, the most important drawback of NOMA is the error during Successive
Interference Canceller (SIC) is implemented because of the inter-user
interferences. In this paper, we derive closed-form exact Bit-Error Rate
expressions for Downlink(DL) NOMA over Nakagami-m fading channels in the
presence of SIC errors. The derived expressions are validated by the computer
simulations. It is shown that the m parameter still represents the diversity
order like as OMA systems. Besides, the BER performances of users for NOMA have
substantially depended on the power allocation coefficient.
