Cross-Slot User Scheduling Strategy for Fast Uplink Grant over Cell-Free Networks

Fast uplink grant effectively copes with massive ultra-reliable and low-latency communication (mURLLC) by virtue of collision avoidance and overhead savings. However, its access performance is limited by active prediction and user scheduling, resulting in serious resource wastage and accumulation of failed users. To solve this problem, we propose a cross-slot user scheduling strategy based on cell-free architecture. The strategy designs the post-compensation stage and pre-experience stage in the fast uplink grant mechanism, in which the prediction error is compensated by reserving resources to provide random access to active users, while the generated access information obtained is combined with the prediction information of the new active users as the priori information to improve one-time access success probability in continous access slots. Simulation results show that the cross-slot user scheduling strategy can effectively compensate the prediction error, greatly avoid the backlog of failed users, and reduce the access delay.