Toward Optimizing Delivery Probability in NR Sidelink by MCS Selection

To further enhance the reliability and throughput of the Vehicle-to-Everything (V2X) communications via New Radio (NR) sidelink, the flexible Modulation and Coding Scheme (MCS) was approved by 3GPP in Release 16. However, most available works neglect the variations in message data size and adopt fixed MCS, which unavoidably limits the NR sidelink spectral efficiency. Using the theory of stochastic geometry, we are able to present a mathematical framework and analytically investigate the impact of MCS selection on the achievable message delivery probability in NR sidelink, following the general message data size in 3GPP. Then, the optimal MCS is selected by enlarging the surplus between the Signal to Interference-plus-Noise Ratio (SINR) measured at the receiver and the SINR Threshold Required for Successful Delivery (TRSD). The numerical results prove that the optimal MCS is extremely beneficial for the V2X message transmission.