LTE-M Protocol Stack | Protocol layers of LTE-M stack

This page describes LTE-M Protocol Stack for user plane and control plane.It mentions protocol layers viz. PHY,MAC,RLC,PDCP and RRC of LTE-M protocol stack.

LTE-M follows 3GPP specifications similar to LTE technology. LTE-M stands for Long Term Evolution for Machine-Type Communications. It is mainly developed to fulfill cellular IoT device objectives such as low device cost, deep coverage, longer battery life, higher cell capacity and so on. There are different categories of LTE-M devices viz. Cat-0, Cat-M1 and Cat-M2 as per different 3GPP releases. LTE-M Cat-0, Cat-M1 and Cat-M2 follow 3GPP TS 36 series of rel.12, rel.13 and rel.14 respectively. Let us understand functions of LTE-M Protocol Stack layers.

LTE-M Protocol Stack

LTE-M Protocol Stack

The figure depicts LTE-M Protocol Stack layers. Both user plane and control plane protocol layers are shown in the figure. Refer LTE Physical Layer >> and LTE Protocol Stack >> for functions of each of these layers.


•  CRC attachment
•  Coding block
•  scrambling/descrambling
•  modulation/de-modulation
•  measurement
•  Resource element mapping/demapping

In the uplink it does channel mapping,multiplexing, handling control elements, random access procedure, logical channel priority,HARQ and sending BSRs. In the downlink it does channel mapping, de-multiplexing,DRX,Handling control elements,HARQ.

In the uplink it provides buffer status report,segmentation and concatenation,ARQ(for AM mode). In the downlink it does re-ordering,assembly and ARQ(for AM mode).

In the uplink it performs sequence number addition, handover data handling,integrity protection, ciphering and header compression. In the downlink it does in sequence delivery,duplicate packet detection,integrity validation, deciphering,header decompression.

•  Configuration Management
•  Connection Management
•  Paging control
•  Security Management
•  Broadcast
•  Measurement configuration
•  Measurement Reporting
•  Cell selection and reselection
•  Mobility Management

NB-IoT Related Stuff


This tutorial section on LTE basics covers following sub topics:
LTE tutorial  LTE-M tutorial  LTE features  LTE terminologies  Frame  TDD FDD  Channel types  PHY  stack  throughput  CA   cell search  network entry  Timers  PSS vs SSS  Security   LTE Bands  EARFCN  Hotspot  router  What is VoLTE  VoLTE originating call flow  VoLTE UE attach and registration procedure 

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