5G NR

5G NR Protocol stack is divided into 2 planes: User Plane and Control Plane. User Plane is used to transfer user data and control plane is…

ARQ: Automatic Repeat Request In this procedure, RLC re-transmits RLC PDU or RLC PDU segment according to RLC status report. RLC sending…

UM stands for “Unacknowledged Mode”. In UM mode, RLC adds protocol header to RLC SDU and if required SDU can be segmented. The…

In TM mode, RLC does not perform any operations on the SDU and it is transmitted transparently. It will only buffer data on Tx side. No RLC…

In this chapter we shall see how an RLC entity is established, re-established and released. RLC entity establishment procedure When any upper…

Images are taken from TS 38.322 RLC layer is located between PDCP (or RRC layer) and MAC Layer. It communicates with the PDCP layer (or RRC…

Below shows a schematic diagram of PDCP duplication: If PDCP duplication is not enabled, a PDCP packet will be transmitted to an RLC entity…

SDU discard For DRB, When the discardTimer expires for a PDCP SDU, or the successful delivery of a PDCP SDU is confirmed by PDCP status…

In this section, we shall learn about Transmit and Receive operation along with related state variables. Constants and timers: Window_Size:…

5G NR PDCP entity establishment When upper layers request a PDCP entity establishment for a radio bearer, the UE shall: – establish a PDCP…