DCI-Free Based Downlink Prescheduling Scheme for Ultra-Reliable and Low Latency Communications

The fifth generation (5G) cellular network are divided into three key usage scenarios as enhanced mobile broadband, massive machine-type communications and ultra-reliable and low-latency communications (URLLC). To insure the low end-to-end delay and high reliability for users in URLLC, the overhead of physical downlink control channel (PDCCH) resource needs to be greatly increased during the scheduling process. In this paper, a downlink prescheduling scheme is proposed, where we don't need to transmit downlink control information (DCI). With this DCI-Free scheme, we can not only save PDCCH resource to support more users, but also simplify the signaling interaction to reduce the time delay. Simulation results show that the proposed scheme is able to support more users and decrease transmission delay without downlink control information in URLLC.