A review on new technologies in 3GPP standards for 5G access and beyond

The world is witnessing the rapid development of commercial fifth-generation (5G) networks that enable diverse applications and services with enhanced mobile broadband, ultra-reliability, low latency, and massive connectivity performance. Technical specifications and requirements for 5G networks have been officially standardized by the Third Generation Partnership Project (3GPP) organization since Release (Rel) 15. Subsequently, several advanced technologies have been involved in the standards through recent updates. This paper investigated the evolution of 5G access networks derived from stable 3GPP standards to obtain a systematic view of the technology. In particular, Rel 15 initiated the first complete 5G network along with the standalone New Radio (NR) architecture. While Rel 16 focused on improving system performance, expanding user cases, and exploiting new spectrum resources, Rel 17 targeted the cellular Internet of Things, multimedia services, and intelligent computing capabilities. In addition, expected features in Rel 18 and Rel 19 are studied and considered for future research for 5G and beyond. This paper aims to provide interested readers with a reference framework on the standard 5G access technology development and trends.