Fifth-Generation Control Channel Design: Achieving Ultrareliable Low-Latency Communications

The fifth generation (5G) of wireless systems holds the promise of supporting a wide range of services with different communication requirements. Ultrareliable low-latency communication (URLLC) is a generic service that enables mission-critical applications, such as industrial automation, augmented reality, and vehicular communications [1]. URLLC has stringent requirements for the reliability and latency of delivering both data and control information. To meet these requirements, the Third Generation Partnership Project (3GPP) has been introducing new features in the upcoming releases of the cellular system standards, i.e., Releases 15 and beyond. This article reviews some of these features and introduces new enhancements for designing the control channels to efficiently support URLLC. In particular, a flexible slot structure is presented as a solution to detect a failure in delivering the control information at an early stage, thereby allowing timely retransmissions of the control information. Finally, some remaining challenges and envisioned research directions are discussed for shaping the 5G new radio (NR) as a unified wireless access technology for supporting different services.