Ming-En Chen, Jen-Ming Wu
2021 IEEE 94th Vehicular Technology Conference
In this paper, a code-domain non-orthogonal multiple access (NOMA) scheme called “Subcarrier and Permutation Index Modulation Multiple Access” (SPIMMA) scheme is proposed over the Orthogonal Frequency Division Multiplexing-Subcarrier and Permutation Index Modulation (OFDM-SPIM) architecture. The Index Modulation Multiple Access(IMMA) which applies index modulation (IM) technique is a codebook-based NOMA scheme. It uses the active subcarriers to make index indices which can carry additional bits besides the modulation bits. The proposed scheme uses the concept of IMMA and improves it by transmitting additional bits through different modes. Index bits which deliver additional information are not only produced from the active and inactive subcarriers but also from the different modes permutation. Therefore, the performance of energy efficiency (EE) and
spectral efficiency (SE) are improved. The rotation code is proposed in the SPIMMA to solve the problem of inter-user interference (IUI) in contention based multiple access. Due to the diversity gain from the rotation code, the simulation results show that the bit error rate (BER) of SPIMMA is improved with rotation code.