Exact Bit Error-Rate Analysis of Two-User NOMA Using QAM with Arbitrary
Modulation Orders
Abstract
This work considers the exact bit error rate (BER) analysis of a
two-user non-orthogonal multiple access (NOMA) system using quadrature
amplitude modulation (QAM). Unlike existing work, no constraints on the
modulation order of the QAM symbols for any user. Closed-form
expressions are derived for the BER of joint multiuser detector (JMuD),
which is demonstrated that it is equivalent to the successive
interference cancellation (SIC) receiver. Moreover, a general expression
is derived for the relation between the power allocation factors for the
two users, which depends on the modulation order for each user.