Rate-Splitting Assisted Massive Machine-Type Communications in Cell-Free Massive MIMO

This letter focuses on integrating rate-splitting multiple-access (RSMA) with time-division-duplex Cell-free Massive MIMO (multiple-input multiple-output) for massive machine-type communications. Due to the large number of devices, their sporadic access behaviour and limited coherence interval, we assume a random strategy all active devices utilizing same pilot uplink channel estimation. gives rise highly pilot-contaminated scenario, which inevitably deteriorates estimates. Motivated by robustness RSMA towards imperfect state information, propose novel RSMA-assisted downlink transmission framework cell-free MIMO. On basis achievable spectral efficiency common private streams, devise heuristic precoder design max-min power control method proposed scheme. Numerical results show that effectively mitigates effect contamination in achieves significant performance gain over conventional network.