Lte epc kp is and signalling (sf)

18
LEKS_SF_1 Multimedia over IP Based on SIP Response codes 1xx Provisional response 2xx Success 3xx Redirection 4xx Request failure 5xx Server failure 6xx Global failure PSTN SIP Proxy RTP Real-time Transport Protocol SDP Session Description Protocol SIP Session Initiation Protocol TCP Transmission Control Protocol UA User Agent UAC UA Client UAS UA Server UDP User Datagram Protocol UE User Equipment URI Uniform Resource Identifier VoIP Voice over IP Media Stream Alice Bob REGISTER sip: [email protected] contact:<sip:201.32.7.1> 200 OK INVITE sip: [email protected] bob ? INVITE sip: bob@ 201.32.7.1 bob@ 201.32.7.1 ! 200 OK 200 OK ACK BYE bpis.se Location Service SIP Registrar SIP URI: sip:[email protected] SIP proxy bob@ 201.32.7.1 SIP proxy INVITE sip: [email protected] apis.se SIP URI: sip:[email protected] 200 OK 200 OK 180 Ringing 180 Ringing 180 Ringing SIP Traffic Case 100 Trying 100 Trying DNS lookup Ringback Ringtone Bob answers Bob hangs up PSTN Breakout IP L2 / L1 TCP UDP AS Application Server DNS Domain Name System FQDN Fully Qualified Domain Name ISUP ISDN User Part Lx Layer x MG Media Gateway MGC Media Gateway Controller PCM Pulse Code Modulation PSTN Public Switched Telephone Network RFC Request for Comments RTCP Real-time Control Protocol SIP [RFC 3261] - Allows UAs to: register current IP address of the UA in the network set up, modify and release logical links - Can carry payload from other protocols (SDP, ISUP...) - Open to extensions (new methods, responses, headers, header values) SDP [RFC 2327, 3264] - Describes real-time multimedia sessions - Carried by e.g. SIP RTP [RFC 3550, 3267] - End-to-end transport of real-time data - Sequence numbers - Timestamps SIP User Agent Can act as: - Client (UAC), or - Server (UAS) SIP SIP SIP Any DNS SIP URI IP addr. Stores IP address [or FQDN] per subscriber authentication authorization service access implements policies routes requests Receives registrations 200.1.1.1 201.32.7.1 Audio over RTP 5000 5001 RTCP 6544 6545 Video over RTP 7654 7655 RTCP 10002 10003 [RFC 3263] sip:[email protected] Session The media stream(s), Dialogue a peer-to-peer SIP relationship between two UAs RTCP [RFC 3550] - Reports quality on RTP session port port H.248 [RFC 3015] Used by MGCF to control resources in MGW DNS SIP Proxy Server SIP Proxy Server Location Service SIP Registrar S I P RTP RTCP Real-time app. SIP URI: sip:[email protected] SIP ISUP RTP PCM H.248 SIP MGC MG Control plane (Signalling) User plane (Transmission) Any Eg. VoIP

Transcript of Lte epc kp is and signalling (sf)

Page 1: Lte epc kp is and signalling (sf)

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Multimedia over IP Based on SIP

Response codes 1xx – Provisional response 2xx – Success 3xx – Redirection 4xx – Request failure 5xx – Server failure 6xx – Global failure

PSTN

SIP Proxy

RTP Real-time Transport Protocol SDP Session Description Protocol SIP Session Initiation Protocol TCP Transmission Control Protocol UA User Agent UAC UA Client UAS UA Server UDP User Datagram Protocol UE User Equipment URI Uniform Resource Identifier VoIP Voice over IP

Media Stream

Alice Bob

REGISTER sip: [email protected]

contact:<sip:201.32.7.1>

200 OK

INVITE sip: [email protected]

bob ?

INVITE sip: bob@ 201.32.7.1

bob@

201.32.7.1 !

200 OK 200 OK

ACK

BYE

bpis.se

Location

Service SIP

Registrar

SIP URI:

sip:[email protected]

SIP proxy

bob@ 201.32.7.1

SIP proxy

INVITE sip: [email protected]

apis.se SIP URI:

sip:[email protected]

200 OK

200 OK

180 Ringing 180 Ringing

180 Ringing

SIP Traffic Case

100 Trying

100 Trying

DNS

lookup

Ringback

Ringtone

Bob answers

Bob hangs up

PSTN Breakout

IP

L2 / L1

TCP UDP

AS Application Server DNS Domain Name System FQDN Fully Qualified Domain Name ISUP ISDN User Part Lx Layer x MG Media Gateway MGC Media Gateway Controller PCM Pulse Code Modulation PSTN Public Switched Telephone Network RFC Request for Comments RTCP Real-time Control Protocol

SIP [RFC 3261]

- Allows UAs to:

register current IP address of the UA in the network

set up, modify and release logical links

- Can carry payload from other protocols (SDP, ISUP...)

- Open to extensions (new methods, responses, headers,

header values)

SDP [RFC 2327, 3264]

- Describes real-time multimedia sessions

- Carried by e.g. SIP

RTP [RFC 3550, 3267]

- End-to-end transport of real-time data

- Sequence numbers

- Timestamps SIP User Agent

Can act as:

- Client (UAC), or

- Server (UAS)

SIP

SIP

SIP

Any

DNS

SIP URI IP addr.

Stores IP address

[or FQDN]

per subscriber authentication

authorization

service access

implements policies

routes requests

Receives

registrations

200.1.1.1 201.32.7.1

Audio over RTP 5000

5001 RTCP

6544

6545

Video over RTP 7654

7655 RTCP

10002

10003

[RFC 3263]

sip:[email protected]

Session

The media stream(s),

Dialogue

a peer-to-peer SIP relationship between two UAs

RTCP [RFC 3550]

- Reports quality on RTP session

port port

H.248 [RFC 3015]

Used by MGCF to control

resources in MGW

DNS

SIP Proxy Server

SIP Proxy Server

Location Service

SIP Registrar

S

I

P RTP RTCP

Real-time app.

SIP URI:

sip:[email protected]

SIP ISUP

RTP PCM

H.248 SIP

MGC

MG

Control plane (Signalling)

User plane (Transmission)

Any

Eg. VoIP

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IP-CAN PDN 1: IMS

PCC Policy and Charging Control PCEF Policy and Charging Enforcement Function PCRF Policy and Charging Rules Function PGW Packet Data Network Gateway PDN Packet Data Network QoS Quality of Service RTSP Real Time Streaming Protocol SDF Service Data Flow SGSN Serving GPRS Support Node SGW Serving Gateway SIP Session Initiation Protocol SPR Subscriiption Profile Repository TDF Traffic Detection Function UDR User Data Repository VoIP Voice over IP

AF AF

Node that uses PCC, e.g.:

• Media Server or CSCF

For Operator Controlled Services

GW PCEF Audio + Video over IP

One IP-CAN Session

Two IP-CAN Bearers

Three SDFs: Signaling, Audio, Video)

ADC Application detection and Control AF Application Function APN Access Point Name CSCF Call Session Control Function DPI Deep Packet Inspection eNB Evolved Node B EPS Evolved Packet System E-UTRAN Evolved UTRAN GGSN Gateway GPRS Support Node GW Gateway IP-CAN IP Connectivity Access Network LTE Long Term Evolution MMtel Multimedia Telephony OCS Online Charging System OFCS Offline Charging System

SIP

Default EPS Bearer

eNB PGW SGW

EPS

IP-CAN

Bearers

”Session Based Service”

PCEF

PDN 2: Internet

Video Streaming

Email

File Transfer

Example:

• One IP-CAN Bearer

• 3 Service Data Flows

SDFs identified e.g. with DPI

SDF

Dedicated EPS Bearer

IP-CAN

Session

PCRF SPR/ UDR

TDF IP-TV

MMtel

APN X

APN Y

Gx Rx

OFCS OCS

IP-CAN Problems Ro

Gy Gz

MME

HSS

1

1 1

1

1 2

1

1 3

1

1 4 1

1 5

HNW

VNW

1

1 6

1

1 8

1

1 9

KPI: Session setup success rate

RRC establishment S1 link establishment ERAB establishment

System events and counters

1

1 7

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E-UTRAN Key Performance Indicators, KPI

PDN

Packet Data Network

IMS / Internet

PCRF

HPLMN VPLMN

Provides QoS

and charging rules

• QoS aware packet routing

• UP anchor:E-UTRAN 2G / 3G

eNB SGW PGW

• QoS aware packet routing

• User IP-address allocation

• Policy Enforcement Point

MME HSS • Radio Base Station

• Radio Resource Mgmt

• Mobility

• Security (e.g. Authentication)

• Bearer Mgmt • Subscriber

database

Accessibility :

The probability for an end-user to

be provided with an E-RAB at

request. (%)

A1=InitialEPSBEstabSR=

A2=AddedEPSBEstabSR=

RRC.ConnEstabAtt.Cause

RRC.ConnEstabSucc.Cause

S1SIG.ConnEstabAtt

S1SIG.ConnEstabSucc

ERAB.EstabInitAttNbr.QCI

ERAB.EstabInitSuccNbr.QCI

ERAB.EstabAddAttNbr.QCI

ERAB.EstabAddSuccNbr.QCI

Retainability:

How often an end-user

abnormally looses an E-RAB

during the time the E-RAB is used.

(Release/time)

R1QCI=x=

R2=

ERAB.RelActNbr.QCI

ERAB.SessionTimeUE

ERAB.SessionTimeQCI.QCI

Integrity:

The degree to which a service is

provided without excessive

impairments such as throughput,

latency and packet loss.

IP Throughput for a single QCI:

(kbps)

Downlink

Uplink

DRB.IPThpDl.QCI

DRB.IPThpUl.QCI

E-UTRAN IP Latency.(ms)

Downlink

DRB.IPLatDl.QCI

Availability:

E-UTRAN Cell Availability (%)

CellAvailability=

RRU.CellUnavailableTime.cause

Mobility:

E-UTRAN Mobility. (%)

MobilitySuccessRateQCI=x=

HO.ExeAtt

HO.ExeSucc

HO.PrepAtt.QCI

HO.PrepSucc.QCI

EPS Bearer = Radio Bearers + S1 Tunnel + S5/8 Tunnel

P-GWS-GW Peer

Entity

UE eNB

EPS Bearer

Radio Bearer S1 Bearer

End-to-end Service

External Bearer

Radio S5/S8

Internet

S1

E-UTRAN EPC

Gi

E-RAB S5/S8 Bearer

SRB

DRB

TS 32.450

SR Success Rate QCI Quality Cllass Indicator IP Internet Protocol QoS Quality of Service PDN Packet Data Network IMS Internet Multimedia Subsystem RRU Radio Remote Unit UP User Plane

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E-UTRAN Key Performance Indicators, KPI

Accessibility:

100

QCI.InitAttNbrERAB.Estab

QCIr.InitSuccNbERAB.Estab

EstabAttS1SIG.Conn

EstabSuccS1SIG.Conn

CausetabAtt.RRC.ConnEs

CausetabSucc.RRC.ConnEs

1

QCI

cause

QCI

cause

BEstabSRInitialEPSA

100

QCIAddAttNbr.ERAB.Estab

QCI.AddSuccNbrERAB.Estab

2

QCI

QCI

stabSRAddedEPSBEA

Retanability:

. .1

. .

QCI x

QCI x

QCI x

ERAB RelActNbr QCIR

ERAB SessionTimeQCI QCI

. .

2.

QCI

ERAB RelActNbr QCI

RERAB SessionTimeUE

Integrity:

xQCIxQCI IPThpDlDRBThpDownlink .

xQCIxQCI IPThpUlDRBThpUplink .

IP Throughput for a single QCI:

xQCIxQCI IPLatDlDRBLatDownlink .

E-UTRAN IP Latency (ms)

Availability:

100_

]ime.[causeavailableTRRU.CellUn-t_periodmeasuremencause

periodtmeasuremenbilityCellAvaila

Mobility:

%100.QCIHO.PrepAtt

c.QCIHO.PrepSuc

HO.ExeAtt

HO.ExeSuccRateSuccessMobility

xQCI

xQCI

xQCI

TS 32.450

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EPC Key Performance Indicators, KPI

PDN

Packet Data Network

IMS / Internet

PCRF

HPLMN VPLMN

Provides QoS

and charging rules

• QoS aware packet routing

• UP anchor:E-UTRAN 2G / 3G

eNB SGW PGW

• QoS aware packet routing

• User IP-address allocation

• Policy Enforcement Point

MME HSS • Radio Base Station

• Radio Resource Mgmt

• Mobility

• Security (e.g. Authentication)

• Bearer Mgmt • Subscriber

database

Accessibility :

EPS Attach Success Rate (%)

The ratio of the number of

successfully performed EPS

attach procedures to the number

of attempted.

EASR=

MM.EpsAttachAtt.Type

MM.EpsAttachSucc.Type

Dedicated EPS Bearer Creation

Success Rate (%)

The ratio of the number of

successfully performed dedicated

EPS bearer creation procedures

by PGW to the number of

attempted.

DEBCSR=

SM.CreationPGWInitBearerAtt

SM.CreatationPGWInitBearerSucc

Dedicated Bearer Set-up Time by

MME (Mean) (Second)

Describes the valid time per

dedicated bearer set-up procedure

by MME and is used to evaluate

service accessibility.

DBSTM=

SM.EstabActDedicatedEpsBearer

TimeMean

Service Request Success Rate

(%)

Describes the ratio of the number

of successfully performed service

request procedures by UE to the

number of attempted service

request.

SRSR=

SM.EpsServiceReqAtt

SM.EpsServiceReqSucc

Mobility:

Inter-RAT Outgoing Handover

Success Rate (EPS->GSM) (%)

Inter-RAT Outgoing Handover

Success Rate (EPS->UMTS) (%)

Inter-RAT Outgoing Handover

Success Rate (EPS->CDMA2000)

(%)

Inter-RAT Incoming Handover

Success Rate (GSM->EPS) (%)

Inter-RAT Incoming Handover

Success Rate (UMTS ->EPS) (%)

Inter-RAT Incoming Handover

Success Rate (CDMA2000->EPS)

(%)

Tracking Area Update Success

Rate (%)

Utilization KPI:

Mean Active Dedicated EPS

Bearer Utilization

EPS Bearer = Radio Bearers + S1 Tunnel + S5/8 Tunnel

P-GWS-GW Peer

Entity

UE eNB

EPS Bearer

Radio Bearer S1 Bearer

End-to-end Service

External Bearer

Radio S5/S8

Internet

S1

E-UTRAN EPC

Gi

E-RAB S5/S8 Bearer

SRB

DRB

TS 132455

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EPC Key Performance Indicators, KPI TS 132455

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TAC Tracking Area Code PLMN Public Land Mobile Network TAI Tracking Area Identity ECM EPS Connection Managemen ID Identityt

S1 Setup

Used to take a new eNB into

service. eNB already

configured so the purpose is

to inform the MME about the

main parameters.

S1 Setup & Initial Attach

MME 1

Weight 100

1

1

S1AP Initiating Message S1 Setup

(eNB ID, TAC (1..256)

12.122.122.5

eNB ID = Global eNB

ID + TAC (PLMN, TAI)

+ IP#.

Can serve 1..6 PLMN

S1AP Successful Outcome S1

Setup (MME, GUMMEI, relative

MME Capacity)

Relative MME Capacity (load balancing) 0 .. 255

Weight factor = probability to be choosen.

2

3 S1AP Unsuccessful Outcome S1

Setup (cause) =

• Semantic error

• CPU Overload

• HW Failure

• Unknown PLMN

• Unspecified

Example: Out of 3 UE attaches, eNB will

forward 2 attaches to MME-1 and 1 attach to

MME-2. If in case MME-1 is down, then all

calls will be routed to MME-2.

MME 2

Weight 50

MME Pool MME 1 wants to move

Ue’s:

RRC: Cause ”Load

Balancing TAU”.

ECM connected Ue’s.

UE:

RRC: TAU

eNB:

Choose MME 2

DNS

UE: Attach (not initial)

GUMMEI

eNB:

eNB: IP# GUMMEI

If no answer select new

MME …

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LEKS_SF_8 TEID Tunneling Endpoint ID F-TEID MME IP + TEID

Initial Attach

HSS eNB MME

Initial Attach

The subscriber need to

register to the network.

NAS EMM Attach Request

(IMSI/GUTI/S-TMSI, PDP ESM Request)

Update Location (”Service Granted”, PDN

IP#, QoS)

Origin @ Realm

Destination

@ Realm

Uu S1 MME

S11 S5/S6

S6a (DIAMETER)

SGW

DNS Result Code:

Successful or Failure.

AMBR for Subscriber and

APN (PGW).

UL: 10 Mbps

DL: 100 Mbps

Charging Info.

QoS defined by QCI eg. 9

= Best Effort.

Default

Bearer

PGW Create Session Req.

(F-TEID, EBI=x, ) Req./Resp.

CP IP#

UP IP#

CP IP#

UP IP# Create Session

Resp..(S1-U, SGW F-

TEID = xx + yy )

Allocate UE IP#

if dynamic.

1 1 MME get full control of UP

routing and can change route

due to mobility or load in

core.

Initial Ctx Setup Req.(E-RAB id, TEID,

Attach Accept, Activate Default B. Req) Attach Accept, Default B. Req.

EMM

T3412=20dH

for TAU.

GUTI, QCI=9,

UE IP#,

DRB

(SRB = 1)

Attach Complete Modify Bearer Req.

2

2 Inform SGW about UP eNB

IP# and TEID for S1-U

RRC CONNECTION REQUEST

Idle

Mode

Connected

Mode

RRC CONNECTION SETUP Config. of UE

Protocols…

RRC CONNECTION SETUP

COMPLETE SRB 1

SRB 0

pmRrcConnEstabAtt +

pmRrcConnEstabSucc +

RRC Con. Setup

logical S1 connection

S1 Signalling Connection Establishment

RRC CONNECTION

SETUP COMPLETE NAS ’Attach Request’

INITIAL UE MESSAGE

RRC S1AP

DOWNLINK NAS

TRANSPORT

NAS UE identity Request’

DL INFORMATION TRANSFER

pmS1SigConnEstabAtt +

pmS1SigConnEstabSucc +

MME

E-RAB Establishment (Initial)

RRC CON.

RECONFIG. COMPLETE

INITIAL CONTEXT SETUP REQUEST

Includes a list of E-RABs to be setup

RRC S1AP

RRC CONNECTION

RECONFIGURATION

pmErabEstabAttInit +

Stepped for each E-RAB

received in the list of E-

RABs to be setup

INITIAL CONTEXT SETUP RESPONSE

Authentication and security mode procedures

pmErabEstabSuccInit +

Stepped for each initial

E-RAB that has been

successfully established

MME

3

3

4

4

Initial E-RAB Establishment Success Rate [%]:

pmErabEstabAttInit

pmErabEstabSuccInit pmS1SigConnEstabSucc

pmRrcConnEstabAtt

pmRrcConnEstabSucc = X X

pmS1SigConnEstabAtt X 100

Added E-RAB Establishment Success Rate [%]:

pmErabEstabAttAdded

pmErabEstabSuccAdded

= X 100

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After successful Attach:

UE ctx Release & Service Request

MME

HSS

SGW

PGW

MME

HSS

SGW

PGW

UE ctx Release due to inactivity

IP #

GTP-U

RRC

MAC:C-RNTI

(S-RNTI)

GTP-U

GTP-C

IMSI

MME IP#

GTP-C

CP #

UP #

CP #

UP #

TEID=1

TEID=xx TEID=0

TEID =yy

UP #

IP#

IP #

UE timer in eNB expires and buffer

empty… t=10 .. 60 .. 120 s

UE ctx Release Req.

(cause=user inactivity) Modify Bearer Req.(Scope

Indication=1, EBI=x)

Scope => delete EBI +

transport TEID (S1-U) Mod.B.Resp.( cause=req.

accept, EBI=x)

UE ctx Rel. Command

(cause=normal release) 1

1

Normal for the MME even

if radio conection with UE

lost…

UE ctx Release Complete 2

2 RRC, C-RNTI, S1-U

But Default Bearer and other ctx

remains…

CP IP#

UP IP#

CP IP#

UP IP#

pmErabRelMme +

pmErabRelMmeAct +

Normal release: pmErabRelNormalEnb +

Abnormal release: pmErabRelAbnormalEnb +

pmErabRelAbnormalEnbAct +

MME Initiated ERAB Release

ERAB Rel. Resp.

ERAB Release COM.

(ERAB’s)

MME

UL DL

DRB and S1-U Releasad

eNB Initiated

ERAB Rel. Indication. DRB and S1-U Releasad

pmErabRelMmeAct +

pmUeCtxtRelMmeAct +

pmErabRelMme +

pmUeCtxtRelMme +

Normal release: pmErabRelNormalEnb +

pmUeCtxtRelNormalEnb +

MME Initiated UE Ctx Release

UE Ctx Rel. Com.

MME

eNB Initiated

DRB and S1-U Releasad

UE Ctx Rel. Complete

pmErabRelAbnormalEnbAct +

pmUeCtxtRelAbnormalEnbAct +

Abnormal release: pmErabRelAbnormalEnb +

pmUeCtxtRelAbnormalEnb +

UE Ctx Rel. Req. (cause)

UE Ctx Rel. Com.

UE Ctx Rel. Complete

E-RAB Release Rate [drops/s]:

= pmSessionTimeUe

pmErabRelRelAbnormalEnbAct + pmErabRelMmeAct

UE Session Time

Data

Transfer

Time

In session

Out of

session In session

100

msec 100

msec

pmSessionTimeUe +

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UE ctx Release & Service Request UE Service Request

After S1AP ctx release the UE remain attached…

and by sending a ”Service Request” on NAS the

con. Is resumed…

HSS eNB MME

Initial UE Message (S-TMSI, TAI, Service Req.(KASME)

Uu S1 MME S6a (DIAMETER)

Default

Bearer PGW

Initial Ctx Setup Req.(E-RAB id, TEID)

Attach Accept, Default B. Req.

SRB = 1

Attach Complete

Opt. Auth. Info

SGW Initial Ctx Setup Resp.(E-RAB id, TEID)

Modify Bearer Req.(TEID, F-TEID, EBI=x,

S1-U eNB F-TEID) Update Bearer Req(IMSI,EBI=x, QCI,

Charging ID, AMBR)

Update Bearer Response

IP # GUTI

GUTI

Modify Bearer Resp.(cause=Req.Accept,

PGW F-TEID, EBI)

Create Bearer Req.(create new TFT)

ERAB Mod.Req (ERAB ID, QoS, new TFT)

(DRB = x)

ERAB Mod. Resp.(ERAB ID, QoS)

2

2 ERAB modification on S1

1

1 SGW confirms S1-U can

be used for payload…

3

3 Start UE activity timer…

KASME Access Security Management

PCRF

IP-CAN Session

Modification

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Dedicated Bearer Setup

If required by the QoS parameters a dedicated bearer will

be setup…

Dedicated Bearer Setup

SPR eNB MME

S1AP Init.Msg(ERAB Setup, ERAB ID=y) NAS Activate

Dedicated EPS Beraer Context Req.(RAB=Y)

Uu S1 MME

Default

Bearer RAB ID = x

Active

PGW

Create Bearer Req.(EBI=Y,

new TFT(PCC Rules))

SGW

NAS Activate Ded.B. Ctx Req.(RAB=Y)

S1AP Succ. Outcome ERAB Setup (ERAB ID=Y)

APN-AMBR

UE-AMBR

TFT

ARP

L-EBI

IP # GUTI

GUTI

PCRF

SIP(SDP) Codec

MPEG-4

SPR Subscriber Profile Respository SDP Session Description Protocol SIP Session Initiating Protocol APN Access Point Name TFT Tranport Format Template L-EBI Linked EPSBearerId

Subscriber browsing on internet (default bearer). Finds streaming video. PCRF detects SDP=new codec and authorizes a dedicated bearer…

PCC Rule

QoS

Default

NGBR

QCI 5 - 9

Dedicated

NGBR GBR

QCI 5 - 9 QCI 1 - 4

APN-AMBR

UE-AMBR

APN

IP#

ARP

GBR

MBR

TFT

ARP

L-EBI

NAS Activate Ded.B. CTx. Resp.(RAB=Y)

NAS Activate Dedicated B. Ctx Resp(RAB ID = Y)

Create Bearer Resp..(EBI=Y, new TFT )

Multimedia Session (Browsing Best Effort), Streaming Video (GBR)

Dedicated Beraer (RAB ID=Y) and Default Bearer (RAB ID = X) active

Example VoLTE: Two ”default” and one dedicated.

Default 1: SIP signalling QCI = 5 (priority 1) IP# A with max 100 ms delay UE-PGW with max packet loss < 10 -6

Dedicated : VoIP QCI = 1 (priority 2) linked to Default 1 (L-EBI) GBR.

”Default 2”: smart phone traffic (video, chat, email, browser etc) QCI = ) (lowest priority) IP# B with max 300 ms delay UE-PGW with packet loss 10-6

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Inter eNB HO over X2

When Ue changes its geographic position a

HO is required – ideally over X2.

• X2 HO prep X2AP to create tunnel

• S1AP path switch to update MME for

new S1-U

• MME needs to inform SGW.

Inter-eNB Handover over X2 & S1 HO

MME Uu S1 MME

PGW

X2AP SN Status Transfer, eRAB, PDCP SN

SGW

X2AP Succ. Outcome ”HO prep” UL/DL TEID…

GUTI

X2AP Handover Prep. Target Cell ID,

GUMMEI, eRAB, QoS

Source Target

S1AP ”DL NAS Trasnport” TAU Accept, new GUTI

S1AP ”Path Switch Req.”

CellID, TAC, RABID

GTP-C Update UP Resp.

UL GTP-U

GTP-C Update UP Req.

EBI, S1-U eNB TEID

S1AP Succ. Outcome

”Path Swtich Req” X2AP X2AP ”UE ctx Release”

S1AP ”UL NAS Transport”, Cell ID, TAU, old GUTI

RSRP

time

sintrasearch

Qmeas(n)

R(n)

R(s)

Qmeas(s)

qHyst(s)

qoffset(s)

tReselectionEutra

Qrxlevmeas [dBm] =

measured RSRP

Qrxlevmin [dBm] = minimum

required rx signal strength (SIB

3) (-140 to -44)

pMaxServingCell [dBm]= max

UL tx power (SIB 1 serving or

SIB 3 inter freq neighbor) (-33

to 33 or 1000) (36.101)

P [dBm] = UE max power

capability (23 dBm) (36.101)

RRC Meas. Report (Event A3) pmHoPrepAttLteIntraF +

Handover Prep.

HO Req.

HO Ack.

Source Target

pmHoPrepSuccLteIntraF +

RRC Con. Reconfig. pmHoExeAttLteIntraF +

Handover Exec.

RACH Procedure

Source Target

pmHoExeSuccLteIntraF +

RRC Con. Reconfig. Complete

Path Switch

Req./ Resp. UE ctx Rel.

T300 = Time UE waits for RRC Req.Resp (ms)

T301= Time UE waits for RRC Re-estab.Req (ms)

T310= Started after receiving N310 (”out of synch”)

T311 = Started after initiating con.re-establish proc. (if expired and no suitable cell go to RRC IDLE) (sec.)

Page 13: Lte epc kp is and signalling (sf)

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Inter-eNB Handover over X2 & S1 HO S1 HO

Whitout X2 we need S1HO.

• eNB trigger HO based on

measurements from UE

• HO preparations

• HO resource allocation

and modification of S1-U

KPI

Handover Prep. = eNB

”outgoing leg”

Relocation Proc. = ”MME

”incoming leg” (resource

allocation)

MME Uu S1 MME

PGW

S1AP Succ. Outcome HO Prep. (RRC Con. Reconfig. Info, Target PCI)

SGW

S1AP Handover Resource Alloc., ERAB ID, TEID

GUTI

S1AP Handover Prep. Target Cell ID, TAC

Source Target

S1AP ”UE ctx Release” cause = succ. HO”

S1AP Succ. Outcome

(RRC Con. Reconfig Info)

S1AP ”MME status transfer” UL/DL PDCP SN (source forward info to target)

GTP-C Modify B. Req. (MME switch the S1-U

DL TEID, UL not changed)

GTP-C Mod. B. Resp.(S1 SGW F-TEID,

GTP-U TEID)

S1AP ”HO Notification” CGI, TAI

S1AP ”Source eNB sends HO command to UE” and ”Status Transfer Message to MME (PDCP SN)

UE arrives…

S1AP ”UE ctx Release”

RRC Meas. Report (Event A3) pmHoPrepAttLteIntraF +

Handover Prep.

HO Req.

HO Command

Source

pmHoPrepSuccLteIntraF +

MME

RRC Con. Reconfig. pmHoExeAttLteIntraF +

Handover Exec.

RACH Procedure

Source

pmHoExeSuccLteIntraF +

RRC Con. Reconfig. Complete

UE ctx Rel.

MME

Target

SGW

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Dedicated Bearer Release & Detach Dedicated Bearer Release

Here, triggered by the NW e.g

UE inactivity timer exp in

SGW…

Or UE by means of the Bearer

Resource Modification or PDN

Disconnect procedure.

The DEACTIVATE EPS

BEARER CONTEXT

REQUEST message contains

an ESM cause :

#8: operator determined

barring

#36: regular deactivation

#38: network failure

#39: reactivation requested or

#112: APN restriction value

incompatible with active EPS

bearer context

MME SGW

S1AP (ERAB Release ERAB ID) NAS Deact. D. B.

ctx Rel. (RAB ID, ESM cause)

Delete Bearer Req (EBI)

”No cause value” NAS Deact. D.B. ctx Rel

Start the timer T3495 and wait for UE

resp. If no resp. resend 5 times, then

deactivate EPS locally…

S1AP Succ. Outcome

NAS Deact. D.B. ctx

Resp. S1AP (ULNASTransport, NAS Deact. Dedicated

EPS B. Resp (RAB ID) Delete Bearer

Resp.(cause = Req.

Accept, EBI) PGW

Default

Bearer RAB ID =

x Active

HSS

eNB MME Uu S1 MME S11 S5/S6 SGW PGW

Delete B. Req.

(TEID, EBI)

Detach

Normally triggered by

the UE power off…

Delete B.

Req./Resp.

Delete B. Resp..

(cause= Req. Accept) S1AP DL NAS Transport (Detach

Request)

S1AP UL NAS Transport (Detach

Accept)

UE ctx Release Req./Resp. DIAMETER Notification

Req./Answer

X CP IP#

UP IP# CP IP#

UP IP# X X

IP # X

+ ppt ”Failure Cases…”

Page 15: Lte epc kp is and signalling (sf)

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RRC Connection Problems CCCH SRB 0 RLC-SAP TM

DCCH SRB 1 RLC-SAP AM

BCCH : BCH : PBCH

MIB (DL bandwidth/# RB)

RS RSRP

RSRQ

PSS (0, 1, 2) 5 ms loop that gives slot synch

To detect the 10 ms frame start SSS (0 .. 167)

PDCCH CRC : for me?

PDSCH : DL-SCH : BCCH

SIBs (tell UE how to behave)

PRACH : RACH

preamble

PCFICH

Indicates the size of the DCI

(1, 2, 3, or 4 OFDM symbols)

PDCCH

DCI UL Assignment: (UE ID,

PRBs, MCS, HARQ id, TPC)

PUSCH : UL:SCH : CCCH

RRC Connection Request (cause …)

CRC

24

TrBlk

RNTI

data

Input data vector for

a CRC, masked with

RNTI

If ERR ~= 0 then either an error has occurred or

the input CRC has been masked.

MAC-IDs

UL : RA_RNTI

DL : P-RNTI, SI-RNTI

UL/DL : C-RNTI

PCFICH

PDCCH

PDSCH : DL : SCH : CCCH

RRC Connection Response

(UE ID, DCCH, …)

RACH: MAC Rand. Acc. Preamble

(RA-RNTI, preamble index)

Error Not sent/Not received

UL-SCH/CCH: RRC Con. Req (temp

C-RNTI, NAS UE ID=IMSI or TMSI

1

2 Error RRC Con. Reject

( cause=?, wait time)

RRC Security Mode Command

3 Error RRC Security Mode

Failure (cause ?)

RRC Con. Reconfig.

4 Error RRC Con. Re-est. Req.

(cause =”reconfig. failure”

RRC Con. Re-establ. (new

SRB 1, new security ctx).

RRC Con. Re-establ. Compl. OK!

Error RRC Con. Re-

establ. Reject (cause ?)

5

or ...

Failure!

1

2

3

4

5

Error on Uu: interference on DL-SCH, coverage? High TA? Solution:

partial freq. Reuse!

eNB CPU overload?

Typically cell congested, no radio resources. ? =

• ”reconfig. Failure”

• ”HO failure”

• ”other reason” - wait time second before new request (1 .. 16)

Typically due to problem in handset during ciph/integr. Procedure….

Sent instead of ”RRC Con. Reconfig. Complete”. eNB must take

decision what to do…

RLC AM used for RRC sign. but ACK never received (not sent or

interference?). If repeated eNB drops the con. And release UE…

If S1AP cause = ”failure in Uu procedure” or ”release due to EUTRAN”

possible caused by AM errordue to interference or problem in UE

power control…

freq

(power)

Page 16: Lte epc kp is and signalling (sf)

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SCH Shared Channell QoS Quality of Service TTI Transmission Time Interval VoIP Voice over IP RRC Radio Resource Control PRB Physical Resource Block MCS Modulation and Coding Scheme RI Rank Indicator PMI Precoding Matrix Indicator MIMO Multiple Input Multiple Output PAPR Peak to Average Power

MAC-Scheduler Purpose:

• Efficient SCH(Data) Resources

Assignments

Consideration

• Traffic Volume, QoS (Buffer

Status, Priority…)

• Channel Condition

Scheduling Interval

• Dynamic Scheduling by MAC :

One TTI (1ms : One Sub-

frame)

• Semi-Persistent for VoIP :

Multiple TTIs by RRC

Resource Assignment :

• PRBs & MCS

MIMO

• RI and PMI

Freq.

Time.

DL OFDMA:

High Throughput

High PAPR

UL SC-FDMA:

Fair Throughput

Low PAPR saves battery…

RE Mapping Cell Specific

Scrambling

Layer

Mapping

(symbols

mapped on

1,2,3,4

layers)

Modulation

(QPSK,

xQAM)

Precoding

(mapping to

1, 2or

4antenna

ports) RE Mapping

OFDM

(IFFT)

OFDM

(IFFT) Code word, qo

Pseudo

Random bit

sequence

Depends on selected tx mode:

•Single antenna tx

• tx diversity

• spatial multiplexing (MIMO)

• beamforming

X

i

.

.

.

.

Y

i

.

.

.

.

Code

word, q1

(if MIMO)

1 modulation

Symbol -> RE

antenna

ports

.

.

.

CRC 24 Code Block

Segmentati

on

FEC

Turbo

Coding

R = 1/3 To detect

bit errors If input >

6144 bits Bit error

correction

Sub block

Interleaving

Rate

Matching

Code Block

Concatenati

on

To achieve

high throuput

and error

correct

coding by

HARQ

Add

segmentet

blocks...

1 TB

PDU

S

P1

P2

”Code Word”

MAC PHY

Output

Assignment

(DL)

Grant (UL)

Scheduler

Data related inputs

•HARQ retransmissions

•Data buffer (DL)

User related inputs

•UE capabilities

•UE measurement gaps

•Sync status

QoS

translation

•UE prioritization

•Resource

Allocation

•PDCCH resources

•Buffer estimation

(UL)

•RB and symbols

•DL Power

Power Control

CQI (DL)

PMI(DL)

RI(DL)

MCS (DL)

QCI table

•Priorities

•LCGs

SINR(UL)

RRC Connection

Request (UL)

• UL interference based on i.e eNB sharing of load over X2 with max

20ms

• 3G quality can be measured DL/UL with ded. Ch’s. LTE user are

distributed in time x freq. Test mobiles can never measure UL quality.

• Satisfy latency and packet error loss characteristics of each QCI class

• Satisfy Guaranteed Bit Rate (GBR), Minimum Bit Rate (MBR)

• Enforce downlink maximum bit rate for sum of downlink bearers

• new users are admitted only when QoS requirements of existing and newly added

users/bearers can be met.

• perform frequency selective and frequency diverse scheduling (localized and

distributed virtual resource blocks) depending upon channel conditions,

QoS requirements etc.

• Adapt TB size, MIMO and rank depending on CQI, PMI and RI from UEs plus data buffers

• Higher priority to HARQ re-tx versus new tx…

RSRQ = NRB x RSRP

RSSI

Page 17: Lte epc kp is and signalling (sf)

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Radio Quality Downlink

UL Scheduling Req.

• Power Headroom

• Buffer Status Reporting (long and Short)

The three most important tasks in LTE prelaunch radio parameter planning are:

1 Physical Cell Identity (PCI) allocation

2 Physical Random Access Channel (PRACH) parameter planning, and

3 Uplink reference signal (RS) sequence planning

During/after launch are:

4: UL Power control

5: Handover thresholds

6: Paging (MME/eNB paging capacity)

7: Control Channel planning

Also SI-time-to-release and DRX-cycle should be configured…

MIMO

MIMO

PCI

PCI

PCI

PR

AC

H

Attach Request

Connected Mode UE UL RS

Handover thresholds

UL PC

MME P

a

g

i

n

g

UL Path Loss

DL Path Loss

Uplink Budget, 64

kbps, 2 RB’s, 3-

sector macro-cell

Downlink Budget,

1 Mbps, Antenna

Diversity, 10 MHz,

46 dBm ”When needed”

~ 100 Hz

UMTS CPICH

GSM RSSI

dB/dBm

t

RSRQ

RSRP

RSRQ bad while RSRP

stable = increasing DL

interference

Both RSRQ and RSRP bad

= path loss…

t1

t1 + t

Timing Advance, TA

To synch tx/rx of UL radio

(UE/eNB) in time domain

eNB sends TA value in RACH responce.

TA = 0 .. 1287 = UE sent RACH at max 200 km

distance = cell range of 100 km.

TA = 0,52 μs = 156 m

MAC timing advance command values between 0

and 63.

Using the 64 index values, a distance of 64 x

156m

= 10 km so ± 5km at 3600km/h.

PRACH Planning

839 preamble sequences available

Paging (MME/eNB paging capacity)

The process of TA dimensioning contains two main tasks:

• TA dimensioning for the MME

• TA dimensioning for the RBS

Number of ZC sequences required per cell, for a

given random access radius. A cell requires five

ZC sequences per cell for up to 7.3km radius,

which is typically sufficient for urban and

suburban macro cells. This results in sequence

reuse factor of at least 839/5 ≈ 167 cells, hence

allows for easy planning process.

Paging Failures

• defective handsets;

• insufficient coverage;

• wrong settings for broadcast cell (re)selection parameters like S0

criteria.

Page 18: Lte epc kp is and signalling (sf)

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Performance

• ”Call Drops” due to Uu

MME

Opt: RRC Con. Release

(cause=”unspecified”) UE ctx Rel. Request

(”failure due to EUTRAN”)

UE ctx Rel. Command

(cause=”normal release”)

UE ctx Rel. Complete

May not be seen as dropped from for the user… since UE

moves in/out from IDLE. Takes 1 – 2 seconds to setup

RRC…

Makes sence to distinguis between subscriber level (QoE)

and service level (NW).

• Should we aggregate per QCI?

• Aggregate per handset?

”Uu failure or radio connection lwith UE lost”

Coverage? Interference? Handset?

Permanent

interference due to

ext. Source?

MAC Scheduler

Algorithm?

Buildings, tunnels? Parameter errors

e.g. missing

neighbours?

Protocol? Measurements?

QoE

2000 2010 2020

User-paid

revenues

Traffic growth Non user-paid

revenues

Voice-centric

pay-per minute

X 100%