A New QoS-Guarantee Strategy for NOMA Assisted Semi-Grant-Free Transmission

Semi-grant-free (SGF) transmission has recently received significant attention due to its capability accommodate massive connectivity and reduce access delay by admitting grant-free users channels which would otherwise be solely occupied grant-based users. In this paper, a new SGF scheme that exploits the flexibility in choosing decoding order non-orthogonal multiple (NOMA) is proposed. Compared existing schemes, can ensure completely transparent users, i.e., users’ quality-of-service experience guaranteed same as for orthogonal access. addition, compared proposed significantly improve robustness of transmissions effectively avoid outage probability error floors. To facilitate performance evaluation scheme, an exact expression obtained asymptotic analysis conducted show achievable multi-user diversity gain proportional number participating Computer simulation results demonstrate verify accuracy developed analytical results.