12 umts-edch ws12

8/13/2019 12 Umts-edch Ws12

1/32

Enhanced Uplink Dedicated Channel (EDCH)

High Speed Uplink Packet Access (HSUPA)

u EDCH Background & Basics

u Channels/ UTRAN Architecture

u Principles: scheduling, handover

u Performance Results

8/13/2019 12 Umts-edch Ws12

2/32

UMTS Networks 2Andreas Mitschele-Thiel, Jens Mckenheim Nov. 2011

Background

u E-DCH is a Rel-6 feature with following targets

u Improve coverage and throughput, and reduce delay of the uplink

dedicated transport channelsu Priority given to services such as streaming, interactive and background

services, conversational (e.g. VoIP) also to be considered

u Full mobility support with optimizing for low/ medium speed

u Simple implementation

u Special focus on co-working with HSDPA

u Standardization started in September 2002

u Study item completed in February 2004

u Stage II/ III started in September/ December 2004

u Release 6 frozen in December 2005/ March 2006

u Various improvements have been introduced in Rel-7 & Rel-8

8/13/2019 12 Umts-edch Ws12

3/32


E-DCH Basics

E-DCH is a modification of DCH Nota shared channel, such asHSDPA in the downlink !!

u PHY taken from R99

u Turbo coding and BPSK modulation

u Power Control

u 10 msec/ 2 msec TTI

u Spreading on separate OVSF code, i.e. code mux with existing PHYchannels

u MAC similarities to HSDPA

u Fast scheduling

u Stop and Wait HARQ: but synchronous

u New principles

u Intra Node B softer and Inter Node B soft HO should be supported forthe E-DCH with HARQ

u Scheduling distributed between UE and NodeB

8/13/2019 12 Umts-edch Ws12

4/32


E-DCH Scheduling

u UE sends scheduling information

u MAC-e signaling

u On E-DPCCH: happy bit

u NodeB allocates the resources

u Absolute/ relative scheduling grants

u Algorithms left open from standards

u Depending on the received grants, UE decides on transmission

u Maintains allocated resources by means of internal serving grantsu Selects at each TTI amount of E-DCH data to transmit

u Algorithms fully specified by UMTS standard

DATA

UE NodeB

UE detects

data in buffer

Scheduling information

Schedulertakes UE for

scheduling

Scheduling grant

Scheduling information

Scheduling grant

Scheduling grant

8/13/2019 12 Umts-edch Ws12

5/32


UMTS Channels with E-DCH

Cell 1

UE

Cell 2

R99 DCH (in SHO)u UL/DL signalling (DCCH)u UL/DL CS voice/ data

Rel-5 HS-DSCH (not shown)u DL PS service (DTCH)u DL signalling (Rel-6, DCCH)

Rel-6 E-DCH (in SHO)

UL PS service (DTCH)

UL Signalling (DCCH)

= Serving

E-DCH cell

8/13/2019 12 Umts-edch Ws12

6/32


E-DCH Channels

u E-DPDCH

u Carries the data traffic

u Variable SF = 256 2u UE supports up to 4 E-DPDCH

u E-DPCCH

u Contains the configuration as used on E-DPDCH

u Fixed SF = 256

u E-RGCH/ E-HICH

u E-HICH carries the HARQ acknowledgements

u E-RGCH carries the relative scheduling grants

u Fixed SF = 128

u Up to 40 users multiplexed onto the same channel by using specificsignatures

u E-AGCH

u Carries the absolute scheduling grants

u Fixed SF = 256

8/13/2019 12 Umts-edch Ws12

7/32


Timing Relation (UL)

E-DPDCH/ E-DPCCH time-aligned to UL DPCCH

Uplink DPCCH

Subframe #0

E-DPDCH/

E-DPCCH

3 Tslot(2 msec)

Subframe #1 Subframe #2 Subframe #3 Subframe #4

10 msec

CFN

15 Tslot(10 msec)

CFN+1

0.4 Tslot(1024 chips)

148chips

Downlink DPCH

10 msec TTI

2msec TTI

CFN

8/13/2019 12 Umts-edch Ws12

8/32


HSUPA UE Categories

When 4 codes are transmitted, 2 codes are transmitted with SF2 and 2 with SF4

UE Category 7 supports 16QAM

E-DCHCategory

Max. num.Codes

Min SF EDCH TTI Maximum MAC-eTB size

Theoretical maximum PHYdata rate (Mbit/s)

Category 1 1 SF4 10 msec 7110 0.71

Category 2 2 SF4 10 msec/2 msec

14484/2798

1.45/1.4


Category 4 2 SF2 10 msec/

2 msec

20000/

5772

2.0/

2.89


Category 6 4 SF2 10 msec/2 msec

20000/11484

2.0/5.74

Category 7(Rel.7)

4 SF2 10 msec/2 msec

20000/22996

2.0/11.5

8/13/2019 12 Umts-edch Ws12

9/32


E-DCH UTRAN Architecture

MAC-c/sh

MAC-d

RLC

RRC PDCP

Logical Channels

Transport Channels

MAC-b

BCH

BCCHDCCHDTCH

SRNC

CRNC

NodeB

DCH

Upper phy

DSCH

FACH

Evolution from Rel-5

E-DCH functionality is

intended for transport of

dedicated logical

channels (DTCH/ DCCH)

MAC-hs

HS-DSCH

w/oMAC-c/sh

MAC-dflows

MAC-e

MAC-es

MAC-dflows

EDCH

E-DCH in Rel-6

Additions in RRC toconfigure E-DCH

RLC unchanged

(UM & AM)

New MAC-es entity with

link to MAC-d

New MAC-e entity located

in the Node B

MAC-e entities from

multiple NodeB may serve

one UE (soft HO)

8/13/2019 12 Umts-edch Ws12

10/32


MAC-e/es in UE

MAC-e/es Functions

u Priority handling

u Per logical channel

uMultiplexing

u MAC-d flow concept

u Mux of data from multipleMAC-d flows into singleMAC-e PDU

u Scheduling

u Maintain scheduling grant

u E-TFC selectionu HARQ handling

Cf. 25.309

MAC-es/e

MAC Control

Associated Uplink Signalling:E-TFCI, RSN, happy bit

(E-DPCCH)

To MAC-d

HARQ

MultiplexingE-TFC Selection

Associated SchedulingDownlink Signalling

(E-AGCH / E-RGCH(s))

Associated ACK/NACKsignaling

(E-HICH)

UL data(E-DPDCH)

8/13/2019 12 Umts-edch Ws12

11/32


MAC-e in NodeB

MAC-e Functions

u Per user

u HARQ handling:ACK/ NACKgeneration

u De-multiplexing

u E-DCH control:Rx/ Tx controlsignals

u E-DCH scheduling for allusers

uAssign resources

(scheduling grants)

u Iub overload control

Cf. 25.309

MAC-e

MAC Control

E-DCH

AssociatedDownlink

Signalling

AssociatedUplink

Signalling

MAC-d Flows

De-multiplexing

HARQ entity

E-DCH

Control

E-DCHScheduling

Common RG

UE #2

UE #N

UE #1

8/13/2019 12 Umts-edch Ws12

12/32


MAC-es in SRNC

MAC-es

MAC Control

FromMAC-e inNodeB #1

To MAC-d

Disassembly

Reordering QueueDistribution

Reordering QueueDistribution

Disassembly

Reordering/

Combining

Disassembly

Reordering/

Combining

Reordering/

Combining

FromMAC-e inNodeB #k

MAC-d flow #1 MAC-d flow #n

MAC-es Functions

u Queue distribution

u Reordering

u Per logical channel

u In-sequence delivery

u Macro-diversity

combining:

frame selection

u Disassembly

Cf. 25.309

8/13/2019 12 Umts-edch Ws12

13/32


Data Flow through Layer 2

MAC-es PDUMAC-e header

DATAHeader

DATA

DATA

DDI N PaddingO t

RLC PDU:

MAC-e PDU:

DDI N DATA

MAC-d PDU:

DDI

RLC

MAC-d

MAC-e/es

PHY

TSN DATA DATAMAC-es PDU:

DATA

u DDI: Data Description

Indicator (6bit)

u MAC-d PDU size

u Log. Channel ID

u Mac-d flow ID

u N: Number of MAC-d PDUs

(6bit)

u TSN: Transmission Sequence

Number (6bit)

8/13/2019 12 Umts-edch Ws12

14/32


Hybrid ARQ Operation

u N-channel parallel HARQ with stop-and-wait protocol

u Number of HARQ processes N to allow uninterrupted E-DCH transmissionu 10 msec TTI: 4

u 2 msec TTI: 8

u Synchronous retransmissions

u Retransmission of a MAC-e PDU follows its previous HARQ (re)transmissionafter N TTI = 1 RTT

u Incremental Redundancy via rate matching

u Max. # HARQ retransmissions specified in HARQ profile

New Tx 2 New Tx 3 New Tx 4 Re-Tx 1 New Tx 2 Re-Tx 3 New Tx 4 Re-Tx 1 Re-Tx 2New Tx 1

ACK

ACK

NACK

NACK

NACK

NACK

8/13/2019 12 Umts-edch Ws12

15/32


E-DCH UE Scheduling

u UE maintains internal serving grant SG

u SG are quantized Maximum E-DPDCH/ DPCCH power ratio (TPR), which are

defined by 3GPPu Reception of absolute grant: SG = AG

u No transmission: SG = Zero_Grant

u Reception of relative grants: increment/ decrement index of SG in the SGtable

u AG and RG from serving RLS can be activated for specific HARQ processes for

2msec TTIu UE selects E-TFC at each TTI

u Allocates the E-TFC according to the given restrictions

u Serving grant SG

u UE transmit power

u Provides priority between the different logical channels

8/13/2019 12 Umts-edch Ws12

16/32


Scheduling Grant Table

Index Scheduled

Grant37 (168/15)

2*6

36 (150/15)2*6

35 (168/15)2*4

34 (150/15)2*4

33 (134/15)2*4

32 (119/15)2*4

31 (150/15)2*2

30 (95/15)2*4

29 (168/15)2

14 (30/15)2

13 (27/15)2

12 (24/15)2

11 (21/15)2

10 (19/15)2

9 (17/15)2

8 (15/15)2

7 (13/15)2

6 (12/15)2

5 (11/15)2

4 (9/15)2

3 (8/15)2

2 (7/15)2

1 (6/15)2

0 (5/15)2

u Scheduling grants are max.

E-DPDCH/ DPCCH power ratio (TPR traffic to pilot ratio)

u Power Ratio is related to UE datarate

u Relative Grants

u SG moves up/ down when RG = UP/DOWN

uAbsolute Grants

u SG jumps to entry for AG

u 2 reserved values for ZERO_GRANT/INACTIVE

8/13/2019 12 Umts-edch Ws12

17/32


Timing Relation for Scheduling Grants

u AG and RG associated with specific uplink E-DCH TTI, i.e. specific HARQ process

u Association based on the timing of the E-AGCH and E-RGCH.Timing is tight enough that this relationship is un-ambiguous.

u Example: 10msec TTI

1 2 3 4 1 2 3

E-RGCH

E-AGCH

E-DCH

HARQ process

number

Scheduling

decision

Load

estimation, etc

AG applied to this

HARQ process

RG interpreted relativeto the previous TTI inthis HAR rocess.

8/13/2019 12 Umts-edch Ws12

18/32


Scheduling Information

u Happy bit signaling

u One bit status flag send on E-DPCCH at each TTI

u Criterion for happy bit

u Set to unhappy if UE is able to send more data than given withexisting serving grant

u Otherwise set to happy

u Scheduling Information Reporting

u Content of MAC-e reportu Provides more detailed information (log. channel, buffer status,

UE power headroom)

u Will be sent less frequently (e.g. every 100 msec)

u Parameters adjusted by RRC (e.g. reporting intervals, channels toreport)

8/13/2019 12 Umts-edch Ws12

19/32


HSUPA Scheduling

EDCH NodeB Scheduler

QoS Parameters

Throughput bounds

Feedback from UE

Scheduling InformationReports

Other constraints

NodeB decoding capabilities

Iub bandwidth limit

UE capabilities

Radio resources

UL Load (interference)

Allocate (absolute/ relative) Scheduling

Grants (max. allowed power offsets)

UE allocates transport formats according to

the allocated grants

8/13/2019 12 Umts-edch Ws12

20/32


NodeB Load Scheduling Principle

E-DCH scheduler constraint

u Keep UL load within the limit

Scheduler controls:

u E-DCH load portion of non-serving

users from other cells

u E-DCH resources of each serving user

of own cellPrinciples:

u Rate vs. time scheduling

u Dedicated control for serving users

u Common control for non-serving

users

Note: Scheduler cannot exploit fast fading !

Non E-DCH

Non-serving

E-DCH users

Serving

E-DCH users

UL Load UL Load

target

UE #1

UE #m

8/13/2019 12 Umts-edch Ws12

21/32


Rate Scheduling

u UEs are continuously active

u Data rate is incremental increased/decreased by relative scheduling grants

u No synch between UEs required

u Load variations can be kept low

u For low to medium data rates

Time Scheduling

u UEs are switched on/ off by absolutescheduling grants

u UEs should be in synch

u Load variations might be large

u For (verry) high data rates

E-DCH Scheduling Options

time

rate

time

rate

UE1UE2 UE3 UE1

UE1

UE2

UE3

8/13/2019 12 Umts-edch Ws12

22/32


Non-scheduled Mode

u Configured by the SRNC

u UE is allowed to send E-DCH data at any time

u Signaling overhead and scheduling delay are minimized

u Support of QoS traffic on E-DCH, e.g. VoIP & SRB

u Characteristics

u Resource given by SRNC:

u Non-scheduled Grant = max. # of bits that can be included in a MAC-e PDU

u UTRAN can reserve HARQ processes for non-scheduled transmission

u Non-scheduled transmissions defined per MAC-d flow

u Multiple non-scheduled MAC-d flows may be configured in parallel

u One specific non-scheduled MAC-d flow can only transmit up to the non-

scheduled grant configured for that MAC-d flow

u Scheduled grants will be considered on top of non-scheduled

transmissionsu Scheduled logical channels cannot use non-scheduled grant

u Non-scheduled logical channels cannot transmit data using Scheduling Grant

8/13/2019 12 Umts-edch Ws12

23/32


E-DCH Power Control Tx Power of E-DPCCH/ E-DPDCH

u E-DCH is power-controlled the same way as R99 DCH

u E-DPCCH/ E-DPDCH power controlled with offsets relative to DPCCH

u DPCCH still under closed inner/ outer loop power controlu E-DPCCH/ DPCCH offset signaled by RRC

u E-DPDCH/ DPCCH offset adjusted according to selected E-TFC

u Reference PO/ reference E-TFCI signaled by RRC

u Calculated for other E-TFCI from reference PO (specified in standard)

u Additional offset DHARQ in HARQ profile for each MAC-d flow to satisfydifferent QoS requirements

u E-DCH quality control loop

u Each MAC-es PDU received by the SRNC contains indication of how many

retransmissions were required to decode it

u Measure of the received E-DCH quality

u SRNC may react as followsu Update SIR target setting for DPCCH via DCH FP signaling

u Signal new power offset settings to UE/ NodeB via RRC signaling

8/13/2019 12 Umts-edch Ws12

24/32


E-DCH Operation in Soft Handover

u Macro-diversity operation on multiple NodeBs

u Softer handover combining in the same NodeB

u Soft handover combining in RNC (part of MAC-es)

u

Independent MAC-e processing in both NodeBsu HARQ handling rule: if at least one NodeB tells ACK, then ACK

u Scheduling rule: relative grants DOWN from any NodeB haveprecedence

NodeB 1 NodeB 2

UE

scheduling grant

HARQ ACK/ NACK

scheduling grant

HARQ ACK/ NACK

8/13/2019 12 Umts-edch Ws12

25/32


Mobility Handling

u The UE uses soft handover for associated DCH as well as for E-DCH

u Using existing triggers and procedures for the active set update

(events 1A, 1B, 1C)u E-DCH active set is equal or smaller than DCH active set

u New event 1J: non-active E-DCH link becomes better than active one

u The UE receives AG on E-AGCH from only one cell out of the E-DCHactive set (serving E-DCH cell)

u E-DCH and HSDPA serving cell must be the same

u Hard Handover, i.e. change of serving E-DCH cell

u Using RRC procedures, which maybe triggered by event 1D

u Could be also combined with Active Set Update

8/13/2019 12 Umts-edch Ws12

26/32


Mobility Procedures

Inter-Node B serving E-DCH cell change within E-DCH active set

Note: MAC-e still established in both NodeBs !

NodeB NodeB

MAC-e

NodeB NodeB

MAC-e

ServingE-DCH

radio link

ServingE-DCH

radio link

s t

SRNC SRNC

MAC-es MAC-es

MAC-e MAC-e

8/13/2019 12 Umts-edch Ws12

27/32


Serving E-DCH Cell Change

SRNC=

DRNC

Target serving

E-DCH cell

UE

RL Reconfiguration Prepare

RL Reconfiguration Ready

Radio Bearer Reconfiguration

Radio Bearer Reconfiguration Complete

Source serving

E-DCH cell

If new NodeB

Synchronous

Reconfiguration

with TactivationRL Reconfiguration Commit

Serving E-DCH cell

change decision

i.e. event 1D

RL Reconfiguration Prepare

RL Reconfiguration Ready

RL Reconfiguration Commit

UE receives now

AG & dedicated RG

from target cell

u Handover of E-DCH scheduler controlu No changes in UL transport beareru No MAC-es RESET

u Handover of HS-DSCH serving cellu DL transport bearer setupu MAC-hs RESET

8/13/2019 12 Umts-edch Ws12

28/32


E-DCH RRM Principle

E-DCH resources controlled by

uUL load targetu E-DCH non-serving load portion

NodeB schedules E-DCH usersaccording to RNC settings

u Priority for non E-DCH traffic

RNC still controls non E-DCH loadportion

u By means of e.g. admission/congestion control

u Based on an estimate of non-EDCH loadNon E-DCH

Non-serving

E-DCH users

Serving

E-DCH users

UL Load UL Load

target

Non E-DCH

load portion

8/13/2019 12 Umts-edch Ws12

29/32


User Throughput vs. Aggregate Cell Throughput

u 36 cells network

u UMTS composite channel

model

u FTP traffic model (2 Mbyte

upload, 30 seconds thinking

time)

uMaximum cell throughputreached for about 78 UEs

per cell

u Cell throughput drops if #UEs

increases further since the

associated signaling channel

consume UL resources too

#UEs/cell1

2

3

4

5

6

7

8

910

1 UE/ cell

2

3

4

5

6

7

8

1012

1416182022

240

200

400

600

800

1000

1200

1400

1600

1800

2000

200 400 600 800 1000 1200 1400 1600 1800

AverageUserThroughput[kbps]

Aggregate Cell Throughput [kbps]

10ms TTI 2ms TTI

8/13/2019 12 Umts-edch Ws12

30/32


Single User Performance

uAverage user throughput

(RLC layer) for different

channel profiles

u 1 UE in the network

u 1 target HARQ transmission

u For AWGN channel

conditions:

u

10ms TTI: up to 1.7 Mbps(near theoretical limit of 1.88

Mbps)

u 2ms TTI: up to 3.6 Mbps

(below theoretical limit 5.44

Mbps)

u E.g. due to restrictions

from RLC layer (window

size, PDU size)

0

500

1000

1500

2000

2500

3000

3500

4000

AWGN PedA3 PedA30 VehA30 VehA120

Scenario

AverageUserThroughput[kbps]

2ms TTI 10ms TTI

8/13/2019 12 Umts-edch Ws12

31/32


References

u Papers

u A. Ghosh et al: Overview of Enhanced Uplink for 3GPP W-CDMA, Proc.

IEEE VTC 04/ Milan, vol. 4, pp. 22612265u A. Toskala et al: High-speed Uplink Packet Access, Chapter 13 in

Holma/ Toskala: WCDMA for UMTS, Wiley 2010

u H. Holma/ A. Toskala (Ed.): HSDPA/ HSUPA for UMTS, Wiley 2006

u Standards

u TS 25.xxx series: RAN Aspects

u TR 25.896: Feasibility Study for Enhanced Uplink for UTRA FDD

u TR 25.808: FDD Enhanced Uplink; Physical Layer Aspects

u TR 25.309/ 25.319 (Rel.7 onwards): Enhanced Uplink: Overall

Description (Stage 2)

8/13/2019 12 Umts-edch Ws12

32/32


Abbreviations

ACK (positive) Acknowledgement

AG Absolute Grant

AM Acknowledged (RLC) Mode

AMC Adaptive Modulation & Coding

BO Buffer Occupancy

CAC Call Admission Control

CDMA Code Division Multiple Access

DBC Dynamic Bearer Control

DCH Dedicated Channel

DDI Data Description Indicator

DPCCH Dedicated Physical Control Channel

E-AGCH E-DCH Absolute Grant Channel

E-DCH Enhanced (uplink) Dedicated Channel

E-HICH E-DCH HARQ AcknowledgementIndicator Channel

E-RGCH E-DCH Relative Grant Channel

E-TFC E-DCH Transport Format Combination

FDD Frequency Division Duplex

FEC Forward Error Correction

FIFO First In First Out

FP Framing Protocol

GoS Grade of Service

HARQ Hybrid Automatic Repeat Request

IE Information Element

MAC-d dedicated Medium Access Control

MAC-e/es E-DCH Medium Access Control

Mux Multiplexing

NACK Negative Acknowledgement

NBAP NodeB Application Part

OVSF Orthogonal Variable SF (code)

PDU Protocol Data Unit

PHY Physical Layer

PO Power Offset

QoS Quality of Service

QPSK Quadrature Phase Shift Keying

RB Radio Bearer

RG Relative Grant

RL Radio Link

RLC Radio Link Control

RLS Radio Link Set

RRC Radio Resource Control

RRM Radio Resource Management

RV Redundancy Version

SDU Service Data Unit

SF Spreading Factor

SG Serving Grant

SI Scheduling Information

TNL Transport Network Layer

TPR Traffic to Pilot Ratio

TTI Transmission Time Interval

UM Unacknowledged (RLC) Mode

12 umts-edch ws12

Documents