2 LTE ERAN6.0 Connection Management Feature ISSUE 1.00

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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.

LTE eRAN3.0 Connection Management Feature

Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved. Page3

Objectives

Upon completion of this course, you will be able to:

Describe the concepts of the LTE UE connections

Outline the connection management procedures

Outline the parameters for the connection

management


Contents

1. Connection Management Overview

2. Random Access

3. Signaling Connection Management

4. Data Radio Bearer Management


UE Connections

LTE UE connection includes :

Connection between the UE and eNodeB

Connection between the UE and EPC

The connection management is performed in:

Control plane

User plane


Control Plane Connection


User Plane Connection


Classification of EPS Bearer

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UE PDN-GWDefault EPS Bearer

Dedicated EPS Bearer (Maximum of 7) TFTTFT

Each Dedicated EPS Bearers has an associated TFT (Traffic Flow Template)


UE Connection Setup Procedure


Contents


2. Random Access




Purposes Random Access

Through the RA procedure, the UE can:

Obtain the uplink synchronization signals from the

network

Request dedicated resources for data transmission


Trigger of Random Access

UE initiates RA procedure in following scenarios :

initial RRC connection establishment

RRC connection reestablishment

Handover

UE is noticed downlink data arrival

UE detects Uplink data arrival

For positioning purpose


Contention-based and Non-Contention-based Random Access the RA procedure can be categorized into the

following types :

Non-Contention-based RA

Handover

UE is noticed downlink data arrival

For positioning purpose

Contention-based RA

initial RRC connection establishment

RRC connection reestablishment

UE detects Uplink data arrival


Contention-based Random Access

Contention-based Random Access Procedure :

UE eNodeB

Random Access Preamble (RACH)

Random Access Response (DL-SCH)

Scheduled Data Transmission (UL-SCH)

Contention Resolution (DL-SCH)


Random Access preamble

SequenceCP

TCP TSEQ Guard PeriodPreamble

The structure of preamble

UE eNodeB


UE sends preamble to eNodeB.


Random Access preamble Format

Preamble Format Burst TCP TSEQ

FDD Cell Radius (R) TDD Cell Radius (R)

0 1,000 µs 103.1 µs 800 µs R ≤ 14.5km 1.4 km < R ≤ 14.5 km

1 2,000 µs 684.4 µs 800 µs 29.5 km < R ≤ 77.3 km 29 .5km < R ≤ 77.3 km

2 2,000 µs 203.1 µs 1,600 µs 14 .5km < R ≤ 29.5 km 14.5 km < R ≤ 29.5 km

3 3,000 µs 684.4 µs 1,600 µs 77 .3km < R ≤ 100 km 77 .3km < R ≤ 100 km

4 167.9 µs 14.58 µs 133.33 µs Not involved. R ≤ 1.4 km


Related Parameters Command: MOD CELL

Page17

Parameter to set the preamble format

Parameter to set the cell radius


Preamble Sequence

logical index

Preamble 1

...

Cyclic shift

Preamble 63

Zadoff-Chu sequence

Group B

Group A

...

Preamble 0For contention-based random accessGroup B is chosen if UE needs a relatively large amount of UL resource for scheduled data transmission in step 3.

For contention-free random access


Related Parameters Command: MOD CELL

Page19

Parameter to set the root sequence index


Random Access Response

UE eNodeB



Random access response includes timing alignment instruction, initial UL grant and temporary C-RNTI.

TARUL GrantTA

UL GrantUL Grant

Temporary C-RNTITemporary C-RNTI

8bits

Structure of MAC random access response


Uplink Scheduled Data Transmission

UE eNodeB




This could be L2/L3 message. (RRC CONNECTION REQUEST e.g.)


Contention Resolution

UE eNodeB




Contention Resolution (DL-SCH)

The contention resolution message is addressed to the C-RNTI or Temporary C-RNTI.For initial RRC connection, the contention solution is addressed to temporary C-RNTI. In contention resolution message the eNodeB echoes NAS UE ID which is carried in RRC CONNECTION REQUEST message for contention resolution.


RA Backoff Control

UE eNodeB




BI (backoff indicator) can be carried by random access response.

Once msg3 is transmitted, UE starts mac-ContentionResolutionTimer.

If mac-ContentionResolutionTimer expires, no contention resolution is

received, UE consider the contention resolution is not successful.

If the contention resolution is not successful, UE will retransmit random access preamble after

backoff time. Retransmission of Random Access Preamble (RACH)

Mac-ContentionResolutionTimer

Backoff time


Non-Contention-based Random Access

Non-contention-based Random Access Procedure :

UE eNodeB


Random Access Assignment (DL-SCH)


eNodeB assigns contention-free random access preamble to UE via dedicated signaling. (RRC CONNECTION RECONFIGURATION in handover procedure e.g.)


Related Parameters

Command: MOD CELLALGOSWITCH

Page25

Some parameters for random access


Contents


2. Random Access




Architecture of the Protocol Stack for Signaling Connection


RRC States

LTE Detached

LTE ActiveRRC Connected

LTE IdleRRC Idle

PLMN SelectionBroadcast of System Information

Cell Selection

RRC Connection (SRB)RRC Context in eNBUE Known in a Cell

Send and/or Receive Data to/from UENetwork Controlled Mobility

Measurement ControlUE Monitors Scheduling Control Channel

UE Reports Channel QualityUE can send Feedback Information

DRX can be Configured

DRX configured by NASBroadcast of System Information

PagingCell Reselection Mobility

GUTI AllocatedLocated in Tracking Area(s)

No RRC Context Stored in the eNB


RRC Connection Establishment

RRC Connection RequesteNBUE

RRC Connection Setup

RRC Connection Setup Complete

RRC Connection RequestUE IdentityCause

RRC Connection SetupRadio Resource Config Dedicated- srb-ToAddModList- drb-ToAddModList- drb-ToReleaseList- MAC Main Config- SPS Config- Physical Config Dedicated

RRC Connection Setup CompleteSelected PLMN-IdentityRegistered MMEDedicated Info NAS


Related Parameters

Command: MOD RRCCONNSTATETIMER

Page31

Parameter to set timer 302


Dedicated S1 Connection SetupUE

RRC Connection Setup Complete

Initial UE Message

Security Mode Command

Security Parameter configuration

Admission and Resource Allocation

RRC Connection Reconfiguration

Security Mode Command Complete

Initial Context Setup Request

Initial Context Setup Response

MMEeNodeB

RRC Connection ReconfigurationComplete


RRC Connection Reestablishment

RRC Connection Reestablishment is applied in

following cases: Handover failure

RRC reconfiguration failure

Radio link failure

Integrity check failure

If security in the AS is not activated, a UE cannot

initiate RRC connection reestablishment.


RRC Connection Reestablishment Procedure


S1 Initial UE Message

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Initial UE MessageeNB

Initial UE MessageeNB UE S1AP ID NAS-PDUTAIE-UTRAN CGIS-TMSI (O)CSG Identity (O)RRC Establishment causeGUMMEI (O)

MME


Downlink NAS TransporteNB MME

Uplink NAS Transport

Downlink and Uplink NAS Transport

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Downlink NAS TransportMME UE S1AP ID eNB UE S1AP ID NAS-PDUHandover Restriction List (O)

Uplink NAS TransportMME UE S1AP ID eNB UE S1AP ID NAS-PDUE-UTRAN CGITAI


S1 Initial Context Setup Request

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eNB

Initial Context Setup RequestMME UE S1AP ID eNB UE S1AP ID UE Aggregate Maximum Bit RateE-RAB to Be Setup List - E-RAB ID- E-RAB Level QoS Parameters- Transport Layer Address- GTP-TEID- NAS-PDU (O)UE Security CapabilitiesSecurity KeyTrace Activation (O)Handover Restriction List (O)UE Radio Capability (O)Subscriber Profile ID for RAT/Frequency Priority (O)CS Fallback Indicator (O)SRVCC Operation Possible (O)

MME



S1 Initial Context Setup Response

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eNB MME


Initial Context Setup ResponseMME UE S1AP ID eNB UE S1AP ID E-RAB Setup List - E-RAB ID- Transport Layer Address- GTP-TEIDE-RAB Failed to Setup List (O)Criticality Diagnostics (O)


Signaling Link Release

The signaling link release is initiated in the

following two scenarios: The MME initiates a UE Context Release Command

message

After detecting an exception, the eNodeB sends the

MME a UE Context Release Request message

Signaling Link Release include:

Release of the dedicated S1 connection

Release of the RRC connection


Signaling Link Release Procedure


Related Parameters

Command: MOD RRCCONNSTATETIMER

Page42

Parameter to set UE inactive timer


Contents


2. Random Access




Dedicated Radio Bearer Establishment


S1 E-RAB Setup Request

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E-RAB Setup RequestMME UE S1AP ID eNB UE S1AP ID UE Aggregate Maximum Bit Rate (O)E-RAB to Be Setup List - E-RAB ID- E-RAB Level QoS Parameters- Transport Layer Address- GTP-TEID- NAS-PDU

E-RAB Setup RequesteNB MME

E-RAB Setup Response


S1 E-RAB Setup Response

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E-RAB Setup RequesteNB MME

E-RAB Setup Response

E-RAB Setup ResponseMME UE S1AP ID eNB UE S1AP ID E-RAB Setup List - E-RAB ID- Transport Layer Address- GTP-TEIDE-RAB Failed to Setup List (O)Criticality Diagnostics (O)


Dedicated Radio Bearer Modification


Dedicated Radio Bearer Release


Reference: Parameter description

For detail, please refer to the notes.

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2 LTE ERAN6.0 Connection Management Feature ISSUE 1.00