  In this paper, we compare the individual rate of MIMO-NOMA and MIMO-OMA when
users are paired into clusters. A power allocation (PA) strategy is proposed,
which ensures that MIMO-NOMA achieves a higher individual rate for each user
than MIMO-OMA with arbitrary PA and optimal degrees of freedom split. In
addition, a special case with equal degrees of freedom and arbitrary PA for OMA
is considered, for which the individual rate superiority of NOMA still holds.
Moreover, it is shown that NOMA can attain better fairness through appropriate
PA. Finally, simulations are carried out, which validate the developed
analytical results.
