Dear community friends, today I would like to share some information about non-access stratum signaling.
What is non-access stratum signaling?
Non-Access stratum Signaling (NAS) refers to the upper layer of the AS (Access Stratum). NAS signaling refers to information transmitted between the UE and the MME.
NAS signaling can be classified into two types:
EMM (EPS Mobility Management)
ESM (EPSSession Management)
EMM Signaling Process
ESM Signaling Process
What Is the NAS Signaling Processing Flow?
NAS>RRC>PDCP>RLC>MAC>PHY
RRC layer
The RRC processes all signaling between the UE and the E-UTRAN.
PDCP layer
On the control plane, the PDCP performs encryption, decryption, and integrity check on RRC and NAS signaling messages. On the user plane, PDCP performs only encryption/decryption but does not perform
integrity check.
RLC layer
Radio Link Control (RLC), which provides the radio link control function. The RLC Supports three transmission modes: TM, UM, and AM. It provides error correction, segmentation, concatenation, and reassembly.
MAC layer
MAC (Media Access Control) provides the following functions: mapping, multiplexing, HARQ, and radio resource allocation.
PHY layer
The LTE PHY (physical layer) provides a new range of flexible channels while taking full advantage of the features and mechanisms of the previous system (UMTS).
Dear friends in the community, that's all I'm going to share today, and you're welcome to read and comment.
