5G Procedure, RAN Architecture, and Protocol

In this chapter, the newly introduced procedures (IAM/Beam management/Power control/HARQ) in 5G NR are first described by taking into account the characteristics of the NR design. The concept “beam” is used in NR and the beam-based operation is applied in the procedures such as initial access and beam management for both downlink and uplink. HARQ is enabled to be much more flexible to achieve the low latency requirement. Then RAN architecture is introduced considering different 5G deployment options including NR standalone and LTE-NR dual connectivity, and RAN functionality split. Finally, the protocols related to higher layer procedures including UE state transition, paging, mobility, etc. for standalone NR are described.