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.
Introduction:
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

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.
PHY:
• CRC attachment
• Coding block
• scrambling/descrambling
• modulation/de-modulation
• measurement
• Resource element mapping/demapping
• HARQ
• MIMO
MAC:
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.
RLC:
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).
PDCP:
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.
RRC:
• Configuration Management
• Connection Management
• Paging control
• Security Management
• Broadcast
• Measurement configuration
• Measurement Reporting
• Cell selection and reselection
• Mobility Management
NB-IoT Related Stuff
LTE and LTE-M RELATED LINKS
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
Difference between LTE Advanced vs LTE Advanced Pro vs 5G Links
Article on LTE Advanced>> LTE-a vs LTE-a Pro>> 5G vs LTE Advanced Pro>>
What is Difference between
difference between FDM and OFDM
Difference between SC-FDMA and OFDM
Difference between SISO and MIMO
Difference between TDD and FDD
Difference between 802.11 standards viz.11-a,11-b,11-g and 11-n
OFDM vs OFDMA
CDMA vs GSM