Joint Resource Configuration and MCS Selection Scheme for Uplink Grant-Free URLLC

Ultra-reliable and low-latency communications (URLLC) addresses the most challenging set of services for 5G New Radio. Uplink grant-free transmissions is recognized as a promising solution to meet the ambitious URLLC target (1 ms latency at a 99.999% reliability). Achieving such a high reliability comes at the expense of poor spectral efficiency, which ultimately affects the load supported by the system. This paper proposes a joint resource allocation solution including multiple modulation and coding schemes (MCSs) and power control settings for grant-free uplink transmissions on shared resources. The scheme assigns smaller bandwidths parts and higher MCS to the UEs in good average channel conditions, reducing the probability of fully overlapping transmissions. The performance analysis shows that the scheme is capable of increasing the system outage capacity by ~90%, compared to prior art solutions using a conservative single-MCS configuration with fully overlapping transmissions.