Nonorthogonal Multiple Access With Orthogonal Time–Frequency Space Signal Transmission

Orthogonal time frequency space (OTFS) is being pursued in recent times as a suitable wireless transmission technology for use high mobility scenarios. In this work, we propose nonorthogonal multiple acess (NOMA) based OTFS which may be called NOMA-OTFS system and evaluate its performance from level link perspective. The challenge lies the fact that while known resilience to conditions, NOMA yield spectral efficiency low scenarios comparison orthogonal access (OMA). We present minimum mean square error (MMSE)- successive interference cancellation (SIC) receiver NOMA-OTFS, derive expression symbol-wise post-processing SINR order sum (SE). develop power allocation schemes maximize SE high-mobility version of NOMA. further design realizable codeword SIC (CWIC) using LDPC codes along with MMSE equalization evaluating such practical system. proposed are compared against benchmark OMA-OTFS, OMA-orthogonal division multiplexing (OMA-OFDM) NOMA-OFDM schemes. From system-level evaluation, observe interestingly provides higher than OMA-OTFS. When NOMA-OFDM, find outage improved at cost decrease SE. Whereas link-level results show developed CWIC performs significantly better terms block rate (BLER), goodput throughput.