LTE Protocols and Procedures Additional Materials

Copyright by IS-Wireless. All rights reserved. www.is-wireless.com

LTE Channel Architecture Radio Bearer Type to Logical Channel Mapping

Radio Bearers

Logical Channels PCCH BCCH CCCH DCCH DTCH MCCH MTCH

SRB0 SRB0 SRB0

SRB1 – Prior to security

SRB2 – after secrutity SRB2 DRB DRB

PDCP

RLC

Ciphering and RoHC Ciphering and Integrity

ARQ

Common signalling Dedicated signalling Data – dedicated links

Copyright by IS-Wireless. All rights reserved. www.is-wireless.com

PRACH: RA Preamble

UE finds the opportunity for

PRACH transmission

and chooses the RA Preamble

PDCCH: DL Allocation

PDSCH: RA Response

UE decodes PDCCH to read

allocation given to RA-RNTI

eNB calculates RA-RNTI

UE reads the UL allocation in

PUSCH and allocated C-RNTI

PUSCH: RRC Connection Request

eNB authenticates user by

S-TMSI

UE decodes PHICH and

PDCCH to read allocation given

to C-RNTI PHICH: HARQ-ACK

PDCCH: DL Allocation

PDSCH: RRC Connection Setup UE authenticates itself by

reading ping-ponged S-TMSI,

enters RRC-Connected state

and configures lower layers PUCCH: HARQ-ACK

PDCCH: UL Allocation

UE selects MME and transmits

the first NAS message within

RRC message

PUSCH: RRC Connection Setup Complete

PHICH: HARQ-ACK

eNB forwards the first NAS

message towards selected MME

or chooses it randomly if not

specified by UE

UE decodes PDCCH to read

allocation given to C-RNTI

PDCCH: UL Allocation

t t

RRC IDLE

RRC Connected

LTE RRC Procedure PHY Channels Included: Connection Establishment

eNB

Copyright by IS-Wireless. All rights reserved. www.is-wireless.com

Scheduling Request Procedure UE Requesting Uplink Scheduling Grant (UL Grant Required)

Data Occured in UL Buffer

Start

PUSCH resources available? N Y

UL Data Transmission on

PUSCH

RAP Pending

Stop

PUCCH resources available? N Y

Send SR on PUCCH

UL Grant on PUSCH? N Y

Random Access Procedure

Random Access Response? N Y

SR Pending

User can be in RRC_Connected

state, thus receiving DL data, but

have no or too little UL resources

Copyright by IS-Wireless. All rights reserved. www.is-wireless.com

IP

header Payload

IP

header Payload

IP

header Payload

EPS Bearer 1 packet n EPS Bearer 1 packet n+1 EPS Bearer 2 packet n

Payload Payload Payload

PDCP SDU PDCP

header PDCP SDU

PDCP

header PDCP SDU

PDCP

header

Header

compression

Ciphering

PDCP

RLC SDU RLC SDU RLC SDU

RLC

header

RLC

header

RLC

header

Segmentation

concatenation

RLC

MAC

header MAC SDU

MAC

header

Multiplexing

MAC

Transport Block CRC

MAC SDU

CRC

PHY

Transport Block

AMC

Variable sizes (one TB per TTI)

LTE Data Flow Example

Copyright by IS-Wireless. All rights reserved. www.is-wireless.com

SCTP

IP

L2

PHY

SCTP

IP

L2

PHY

UDP

IP

L2

PHY

UDP

IP

L2

PHY

UDP

IP

L2

PHY

UDP

IP

L2

PHY

E-UTRAN and EPC Protocol Stacks End-to-End Control Plane

NAS

RRC

PDCP

RLC

MAC

PHY

PDCP

RLC

MAC

PHY

RRC S1-AP S1-AP

NAS

GTP-C

Uu MME SGW

S1-MME S11

Control Plane

eNB

GTP-C GTP-C GTP-C

PGW

S5/S8

3GPP

Protocol

IETF

Protocol

Copyright by IS-Wireless. All rights reserved. www.is-wireless.com

E-UTRAN and EPC Protocol Stacks End-to-End User Plane

User Plane

Application

IP

PDCP

RLC

MAC

PHY

PDCP

RLC

MAC

PHY

IP

L2

L1

GTP-U

UDP/IP

L2

PHY

GTP-U

UDP/IP

L2

PHY

GTP-U

UDP/IP

L2

PHY

SGW PGW

S1-U S5 Uu

eNB

3GPP

Protocol IETF

Protocol

Application

GTP-U

UDP/IP

L2

PHY

L2

L1

SGi App. Server

IP

Copyright by IS-Wireless. All rights reserved. www.is-wireless.com

HO Timers HOF and RLF Related Timers

RLF Related Timer

HOF Related

Timer

3GPP TS 36.331: RRC, Section 7.3 Timers

3GPP TS 36.423: X2-AP, Section 9.5 Timers

T304

Reception of RRCConnectionReconfiguration message including the

MobilityControl Info or reception of MobilityFromEUTRACommand message

including CellChangeOrder

TX2RELOCoverall Specifies the maximum time for the protection of the overall handover

procedure in the source eNB