The spreading sequences have short lengths which are more efficient in conjunction with successive interference cancellation (SIC) used at the receiver to separate superimposed symbols and low cross-correlation properties and they can be nonbinary [7; 33; 34; 35]. Paper [36] presents the performance of MUSA by comparison with two other NOMA schemes, namely SCMA and PDMA, in terms of BER versus SNR. The data were quadrature phase-shift keying (QPSK)-modulated and transmitted over a channel affected by Rayleigh fading and SIC detector at the receiver. The authors concluded that SCMA obtained better performance due to the optimal design of codebooks while MUSA and PDMA had similar performance in the given simulation scenario. The authors in [37] evaluated the performance of MUSA spreading codes by comparison with pseudo-random noise (PN) with different user overloading but when turbo coding of rate % and QPSK modulation were used in an additive white Gaussian noise (AWGN) channel with MMSE-SIC detector at the receiver. The scenario with one antenna at the transmitter and one or two antennas at the receiver has been considered. The authors demonstrated that the block error rate (BLER) of MUSA compared to Long Term Evolution (LTE) standard does not have an important degradation even if the overload is high; also, grant-free MUSA can support higher traffic than grant-free OFDMA. Paper [38] presents a grant-free MUSA transmission that can achieve high overloading, with 4 to 20 users, where the data are turbo-coded at rate 1/2 and binary phase shift keying (BPSK)-modulation. The scenario with one antenna at the transmitter and two antennas at the receiver was analyzed, and the reception used a blind minimum mean square error - successive interference cancellation (MMSE-SIC) detector. Similarly, [39] proposes a high-overloaded autonomous grant-free MUSA transmission with 4 to 16 users, where the data is turbo-coded at rate 1/2 and BPSK-modulated and introduced in an OFDM block, then sent over a channel affected by flat fading. The system with one antenna at the transmitter and one antenna at the receiver was taken into consideration, and a blind multiuser detection (MUD) without reference signal was used at the receiver. Authors in [40] propose another high-overloaded autonomous grant-free MUSA transmission with 8 to 20 users, where the data is turbo-coded of rate 1/2 and BPSK-modulated and sent over a channel affected by flat fading. The scenario with one antenna at the transmitter and two antennas at the receiver was considered and a MUD detector with spatial combining was used at the receiver. In [41], the performance of a system which employs MUSA with two other NOMA techniques, namely SCMA and IDMA, was evaluated. A turbo channel coding was performed, then data from 12, 16, and 24 users were QPSK-modulated and entered in an OFDM block after which they were transmitted over a channel affected by Rayleigh fading. At the reception, a MMSE detector was used. The scenario with one antenna at the transmitter and one antenna at the receiver was considered. In [42] the authors present the bit error rate performance of an uplink MUSA transmission with binary, 3-ary, and 5-ary codes where data from six users were QPSK-modulated and then sent over a channel affected by Rayleigh fading. At the reception, an MMSE-ordered SIC detector was used. In [43], the authors compared, theoretically and numerically, the performance of a 12-user grant-free MUSA transmission with low detection complexity by employing SIC with OFDMA, SDMA-based OFDMA, LDS, and SCMA on the uplink. A low-density parity-check (LDPC) encoder block was used, followed by QPSK modulation and OFDM blocks, the information being transmitted over a channel with AWGN. It was observed that MUSA offers better results for high SNR values and high number of overlapping users.