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.

Improved Error Performance in NOMA-based Diamond Relaying

“…We could use joint maximum likelihood (JML) detector as proposed for the second phase rather than the SIC detector. However, the JML and SIC detectors have the same error performance in the downlink NOMA[17]. Besides, the JML costs a computational complexity as discussed in Section III.…”