HSPA

1Telecom IsraelTechnical Tutorial

November 7th, 2006

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University

Understanding HSPA

Understand HSPA:High-Speed Packet Access For UMTS

Understand HSPA:High-Speed Packet Access For UMTS

Telecom IsraelTechnical Tutorial

November 7th, 2006

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University

Understanding HSPA

About QUALCOMM University

QUALCOMM University (QU) offers the advanced technology training solutions you need to stay on the cutting edge of wireless technology.

Visit the QU website for more information about individual training products, international training centers, and distance learning opportunities, along with a complete list of classesall developed by QUALCOMM, the pioneers of CDMA.

QUALCOMM University: www.qualcommuniversity.comQUALCOMM: www.qualcomm.com


November 7th, 2006

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Understanding HSPA

Where Can I Learn More?

WCDMA HSDPA: Protocols and Physical Layer (1 day)

WCDMA HSUPA: Protocols and Physical Layer (1 day)

Want to learn more?QUALCOMM University offers additional in-depth technical training related to this course. To learn more about this or related topics, sign up for the following courses.

To check out the schedules for these courses and enroll, go to:

www.qualcommuniversity.com


November 7th, 2006

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Understanding HSPA

UMTS Courses from QUALCOMM University

For the latest information on all QUALCOMM University courses, visit www.qualcommuniversity.com.


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Understanding HSPA

Tutorial Objectives

Provide telecommunication professionals with the basic understanding of HSPA, the high speed packet access technologies (HSDPA, HSUPA), and related applications, network architecture, and deployments.

The talk will present: the market drivers for UMTS HSPA the basic enabling techniques and terminology associated

with HSPA

the basic operations of HSPA the HSPA implementation and performances


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Understanding HSPA

HSPA Motivations

Market Drivers


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Understanding HSPA

Increasing Wireless Internet Traffic Demands Higher Data Rates

3G Enables Wider Options of Services

EducationEducationFinancialFinancial

InformationInformation

BusinessBusiness

Audio on demandVideo on demandGames on demandNetwork GamesReservation services

Database accessE-mail/Fax/WebLocation Based ServicesEmergency Call LocatingSafety Credit verification

Stock tradingWireless bankingFinancial news

Interactive shoppingE-commerce

Remote learningRemote library access

Remote language laboratory

WorkgroupsRemote LAN accessVideoconferencing

and manyothers

Entertainment


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Understanding HSPA

CDMA2000 1xCDMA2000 1xMore Capacity, High Speed Data

Capacity/Quality

Roaming

Mobility

AMPS

TDMAGSMPDC

cdmaOneIS-95A

cdmaOne IS-95B

cdmaOne IS-95B

Medium Speed Data

Multi-ModeMulti-Mode

Global Roaming

1G 2G 3G (IMT-2000)2.5G

Multi-BandMulti-Band

Multi-NetworkMulti-Network

GPRSGPRS

CDMA2000 1xEVCDMA2000 1xEV

WCDMAWCDMA

Time

IMT-2000 aims to achieve Anywhere, Anytime Communications

Key Features: Commonality Compatibility High quality Small terminals Worldwide roaming Multimedia Wide range of services

3G (IMT-2000)


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Understanding HSPA

GPRS GPRS

EDGEEDGE

WCDMA (R99)WCDMA (R99)

HSDPA/HSUPA(Rel5 / Rel6)

HSDPA/HSUPA(Rel5 / Rel6)

Peak Data Rate

Spec

tral

Effi

cien

cy

Rich Voice Video Telephony

MM streaming MM sharing Wireless

Broadband Access Interactive Gaming VoIP with AMR-WB

Text Messaging Speech GSM GSM

Push-to-Talk Customized

Infotainment Multimedia

Messaging

Data ServicesEvolution

Evolved 3G

Voice & Limited Data

Medium Speed Data

Voice & High Speed Data

3G Enables Advanced Data Services


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Understanding HSPA

HSPA for Higher Speed

Data Rate Demand for higher peak

data rates

Delay Lower latency

Capacity Better capacity and throughput Better spectrum efficiency Finer resource granularity

Coverage Better coverage for higher data

rate

What are the requirements for HSPA?


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Understanding HSPA

UMTS Data Rate Evolution

Uplink Peak Data Rate (Typical Deployment)

Downlink Peak Data Rate (Typical Deployment)

GSM 9.6 kbps 9.6 kbpsGPRS 20 kbps 40 kbpsEDGE 60 kbps 120 kbps

WCDMA Release 99 64 kbps 384 kbpsHSDPA - Release 5 384 kbps 10 Mbps*HSUPA - Release 6 1.4 Mbps (early deployment) 10 Mbps


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Understanding HSPA

Applications Benefiting from HSPA

Voice-over-IP (VoIP)- Low latency, Quality of Service (QoS) control, fine resource

granularity and improved capacity

Video Telephony (in Packet Switched domain)- Low latency, Quality of Service (QoS) control, high data rates

and improved coverage and capacityGaming

- Low latency, fast resource allocation

Video Share / Picture Share- High Uplink data rates and improved coverage

and capacity

File Uploading (large files)- High Uplink data rates and improved coverage

and capacity

Delay Sensitive Error

Tolerant

Delay Tolerant Error

Sensitive


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Understanding HSPA

Part I: Understanding HSDPA


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Understanding HSPA

Review - UMTS Network Architecture

Core Network

UserEquipment

UTRAN

Mobile EquipmentUSIM

Node B

Node B

Node B

RNC

RNC

HLR/AuC

Node B

Node B

Node B

GMSCPSTN/ISDN

SGSN GGSN Internet

MSC/VLR

Node B

Node B

Uu

Iucs

Iups

Iub

Iub

Iur


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Understanding HSPA

Review - UMTS Protocol Stack

Mobility Management (MM)

Radio Resources Control (RRC)

Supplementary Services (SS)

Short Message Services (SMS)

Layer 2

Physical Layer (L1)

Non-Access Stratum

Access Stratum

GPRS Mobility Management (GMM)

Session Management (SM)

Radio Link Control (RLC)

Medium Access Control (MAC)

Connection Management (CM)

Call Control (CC)

Short Message Services (SMS)

Circuit Switched Packet Switched


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Understanding HSPA

Review - Release 99 Channels


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Understanding HSPA

Review RRC Modes and States

UTRAN Connected Mode

CELL_FACH

CELL_PCHURA_PCH

Idle Mode(Camping on a UTRAN cell)

Channels: PCH, No UplinkMobility: URA UpdateCalls: PS (no data transfer)DRX Mode

CELL_DCH

Channels: PCH, No UplinkMobility: Cell UpdateCalls: PS (no data transfer)DRX Mode

Channels: FACH, RACHMobility: Cell UpdateCalls: PS Dedicated logical channels, but common transport and physical channelsNo DRX Mode

Channels: Downlink DCH, Uplink DCHMobility: HandoverCalls: PS, CS

Channels: PCH, No UplinkMobility: Location/Routing Area UpdateCalls: None, PS call might be in context preserved state DRX Mode

Establish RRCConnection

Release RRCConnection Establish RRC

Connection

Release RRCConnection


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Understanding HSPA

Release 99 Principles

How is Packet Data Managed in Release 99? DCH (Dedicated Channel)

Spreading codes assigned per user Closed loop power control Macro diversity

FACH (Common Channel) Common spreading code Header defines user No closed loop power control

DSCH (Downlink Shared Channel) not implemented for FDD Common spreading code shared by many users User assignment by Physical Layer signaling Closed loop power control with DPCH

10


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DCH/FACH Comparison Summary

Mode DCH FACHChannel Type Dedicated Common

Power Control

Closed Inner Loop at 1500 Hz -

Slower Outer Loop

None or slow (based on

measurement report)

Soft Handover Supported Not Supported

Setup Time High Low

Suitability for Bursty Data Poor Good

Data Rate Medium Low

Radio Performance Good Poor

How do we do Packet Data in Release 99


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Understanding HSPA

What will HSDPA Address?

Release 99 Downlink Limitations Limited Peak Data Rate

Maximum implemented Downlink of 384 kbps

Capacity and Throughput Modulation and coding

QPSK Convolution coding (R=1/2, 1/3) or turbo coding (R=1/3)

Link adaptation due to channel conditions Fast closed inner loop power control, but Slower outer loop

Minimum TTI of 10 ms Slow Rate and Type Switching

11


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Understanding HSPA

HSDPA Goals

9 Higher Data Rate9 Higher User / Cell Throughput9 Lower Latency


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Understanding HSPA

HSDPA Enabling Technologies

How will HSDPA address the limitations of Release 99? Extension of DSCH Multi-Code operation Adaptive modulation and coding

QPSK and 16-QAM Coding from R=1/3 to R=1 Fast feedback of channel condition

Improve transmission efficiency Fast retransmission and Physical Layer HARQ

Fast resource management Node B scheduling

Reduce transmission latency 2 ms TTI

12


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Understanding HSPA

Common Channel for Data

Common Channel for data transfer using the HS-PDSCH

HS-PDSCH


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Understanding HSPA

Multi-Code Operation

Fixed Spreading Factor SF=16 (Typical Spreading Factor for 128 kbps in Release 99)

1-15 codes can be reserved for HS-PDSCH Can be TDM or CDM between users

Up to 15 codes reserved for HS-PDSCH transmission

User #1 User #2 User #3 User #42 ms (3 slots)

13


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Understanding HSPA

Adaptive Modulation and Coding

Coding from R=1/3 to R=1 HSPDA supports 16-QAM modulation

4 bits per symbol versus 2 bits per symbol with QPSK


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Understanding HSPA

Link Adaptation versus Power Control

Release 99 Use fast power control with

fixed data rate (DCH)

HSDPA Adapt the modulation and

coding to the link quality

Rate #1 Rate #2 Rate #3 Rate #2 Rate #1 Rate #2Rate #2

Switchinglevels

Channel quality (C/I)Fast Link adaptation:

time

Rate #3: e.g. 16-QAM, R=3/4

Rate #2: e.g. QPSK, R=3/4

Rate #1: e.g. QPSK, R=1/2

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Understanding HSPA

Scheduling Comparison

RNC

Node B

RELEASE 99SchedulingRLC ARQResource Allocation

RELEASE 5 (HSDPA)RLC ARQResource Allocation

RELEASE 5 (HSDPA)SchedulingLink AdaptationHARQResource Allocation


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Understanding HSPA

HSDPA Scheduling and Retransmissions

Scheduling Done at the Node B No interaction with the RNC Based on channel quality feedback from the UE

Retransmissions HARQ (link level retransmissions) Done at the Node B Based on UE feedback (ACK/NACK) Soft combining at the UE

15


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Hybrid Automatic Repeat Request (HARQ)

Scheme combining ARQ and Forward Error Correction

FEC decoding based on all unsuccessful transmissions

Stop-and-Wait (SAW) protocol Two basic schemes:

Chase Combining same data block is sent at each retransmission

Incremental Redundancy (IR) Additional Redundant Information sent at each retransmission


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Understanding HSPA

HARQ Illustration

NAK

NAK

ACK

PassFa

il

16


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Understanding HSPA

Comparison Summary

Mode DCH FACH HSDPAChannel Type Dedicated Common Common

Power ControlClosed Inner Loop at 1500 Hz - Slow

Outer LoopNone

Fixed Power with link

adaptationSoft Handover Supported Not Supported Not Supported

Suitability for Bursty Data Poor Good Good

Data Rate / Traffic Volumn Medium Low High


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Understanding HSPA

UMTS Network Architecture with HSDPA

Core Network

UserEquipment

UTRAN


Node B

Node B

Node B

RNC

RNC

HLR/AuC

Node B

Node B

Node B

GMSCPSTN/ISDN

SGSN GGSN Internet

MSC/VLR

Node B

Node B

Uu Iub

Iub

Iups

IucsHardware and Software Changes

Software Changes

Iur

17


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Understanding HSPA

HSDPA Protocol Stack


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Understanding HSPA

HSDPA Channels

New HSDPA ChannelsTransport Channel

High Speed Downlink Shared Channel (HS-DSCH) Downlink Transport Channel

Physical Channels High Speed Shared Control Channel (HS-SCCH)

Downlink Control Channel

High Speed Physical Downlink Shared Channel (HS-PDSCH) Downlink Data Channel

High Speed Dedicated Physical Control Channel (HS-DPCCH) Uplink Control Channel

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Understanding HSPA

HSDPA Channels (continued)


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Understanding HSPA

HSDPA Operation Overview

1. Each UE reports channel quality on HS-DPCCH.

2. The Node B determines which and when each UE is to be served.

3. The Node B informs the UE to be served via HS-SCCH.

4. Then deliver the data to the UE via HS-DSCH.

5. The UE sends feedback (ACK/NAK) back to Node B on HS-DPCCH.

HSDPA Operation

3dTower.emf

Node B

HS-D

PCCH

HS-D

SCH

HS-S

CCH

P-CP

ICH

UE

HS-DPCCH

HS-DSCH

HS-SCCH

P-CPICH

19


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Understanding HSPA

HSDPA Channel Operation Timeline


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Understanding HSPA

HS-PDSCH

High Speed Physical Downlink Shared Channel (HS-PDSCH) Carries UE data Up to 15 HS-PDSCH may be assigned simultaneously

UE capability indicates maximum number of codes it supports

Uses Spreading Factor = 16

20


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Understanding HSPA

HS-DPCCH

High Speed Dedicated Physical Control Channel (HS-PDCCH)

1st slot carries ACK or NAK for received HS-DSCH blocks 2nd and 3rd slots carry Channel Quality Indicator (CQI)

UE measures Downlink CPICH channel quality CQI indicates the highest data rate for error rate < 10% Frequency of CQI reports configured by UTRAN

DTX during ACK/NAK and CQI slots if nothing to send Uses Spreading Factor = 256

HS-DPCCHUplink Channel

CQI

2 ms3 slots

ACK/NAK


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Understanding HSPA

HS-SCCH

High Speed Shared Control Channel (HS-SCCH) 1st part carries modulation information

OVSF code assignment Modulation scheme

2nd part carries transport block size, Hybrid ARQ parameters UE Identity encoded over each part

UE decodes each part independently

UE assigned up to 4 HS-SCCHs to monitor Uses Spreading Factor = 128

21


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Understanding HSPA

Data Rate Example

Question:

Assuming a transport block size of 320 bits, what HSDPA data rate can be achieved by a single UE using the channel allocation timing shown above?


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Understanding HSPA

Data Rate Example (cont.)

Answer:320 bits are transmitted every 10 ms, so the maximum data rate is 32 kbps.

22


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Understanding HSPA

Theoretical HSDPA Maximum Data Rate

How do we get from 32 kbps to 14.4 Mbps? Multi-code transmission Consecutive assignments using multiple Hybrid

Automatic Repeat Request (HARQ) processes Lower coding gain 16-QAM


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Understanding HSPA

Multi-code Transmission

Data Rate with 15-code Multi-code32 kbps X 15 = 480 kbps

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Understanding HSPA

Consecutive Assignments

Data Rate with Consecutive Assignments480 kbps X 5 = 2.4 Mbps


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Understanding HSPA

Hybrid Automatic Repeat Request (HARQ)

Hybrid Automatic Repeat Request (HARQ) Each HSDPA assignment is handled by a HARQ process

HARQ Processes run in Node B and UE Up to 8 HARQ processes per UE Number configured by Node B when HSDPA operations begin

The UE HARQ process is responsible for: Attempting to decode the data Deciding whether to send ACK or NAK Soft-combining of retransmitted data

The Node B HARQ process is responsible for: Selecting the correct bits to send according to the selected retransmission

scheme and UE capability

24


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Understanding HSPA

Lower Coding Gain

R=1/3 Turbo Coding and QPSK Modulation


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Understanding HSPA

Lower Coding Gain (continued)

Data Rate with Rate 1 Turbo Coding and QPSK Modulation2.4 Mbps X 3 = 7.2 Mbps

25


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Understanding HSPA

16-QAM

Data Rate with 16-QAM7.2 Mbps X 2 = 14.4 Mbps


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Understanding HSPA

Theoretical HSDPA Maximum Data Rate

Review: How do we get to 14.4 Mbps? Multi-code transmission

Node B must allocate all 15 OVSF codes of length 16 to one UE

Consecutive assignments Node B must allocate all time slots to one UE UE must decode all transmissions correctly on the first transmission

Lower Coding Gain Effective code rate = 1

Requires very good channel conditions to decode

16-QAM Requires very good channel conditions

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Understanding HSPA

Inter-TTI Interval

Inter-TTI Interval = 2

HS-SCCH

HS-PDSCH 1.. .

.

.

.HS-PDSCH N

HS-DPCCH

CQI

.

.

.

.

.

.

.

.

.

.

.

.

ACK ACK ACK

2 ms

1 2 3 4 5 6 7 8


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Understanding HSPA

Retransmissions

HS-SCCH

HS-PDSCH 1.. .

.

.

.HS-PDSCH 15

HS-DPCCH

10 ms minimum retransmit interval

.

.

.

.

.

.

.

.

.

NAK ACK ACK ACK ACK ACK

.

.

.

.

.

.

.

.

.

ACK

1 2 3 4 5 6 7 8 9 10

2 ms

.

.

.

.

.

.

.

.

.

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Understanding HSPA

ACK/NAK Repetitions


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Understanding HSPA

Node B Implementation Considerations

Node B Considerations OVSF Code Allocation Power Allocation CQI Report Processing Scheduler HSDPA Cell Re-pointing Procedure Compressed Mode

28


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Understanding HSPA

OVSF Allocation

SC

CPC

H

HS-

SCC

H


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Understanding HSPA

Node B Transmit Power Allocation

Tota

l ava

ilabl

e ce

ll po

wer

Tota

l ava

ilabl

e ce

ll po

wer

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Understanding HSPA

CQI Report Processing

UE measures CPICH strength Measurement reference period is 3 slots, ending 1 slot before CQI is

sent

UE reports index into CQI Table Highest data rate for which UE can guarantee error rate < 10%

Node B may filter CQI reports Varying CQI means UE is in a fast changing environment Steady CQI means UE is in a stable environment


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Understanding HSPA

Node B Scheduler

User #1 User #2User #3 User #4

HS -DSCH TTI(3 slots = 2 ms)

User #1 User #2 User #2 User #3 User #1 User #4 User #4 User #2 User #1

User #1 User #2User #3 User #4

15 codes reserved for HS-PDSCH

transmission

Pure Time Division Multiplexing

Combined Code and Time Division Multiplexing

30


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Understanding HSPA

HSDPA Cell Re-pointing Procedure


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Understanding HSPA

HSUPA Performance

Maximum Theoretical Data Rate: 14.4 Mbps

15 codes 16QAM Consecutive assignments (Inter-TTI spacing of 1) Coding Rate of 1

Practical Peak Data Rate: 10.0 Mbps

Full capability UE Good RF conditions (High Cell Geometry) Single UE

Dedicated HSDPA carrier

31


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Understanding HSPA

Part II: Understanding HSUPA


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Understanding HSPA

Release 99 Uplink Packet Data

How is Uplink Packet Data handled in Release 99?

DCH (Dedicated Channel) Variable spreading factor Closed loop power control Macro diversity (soft handover)

RACH (Common Channel) Common spreading code Fixed (negotiated) spreading factor No closed loop power control No soft handover

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Release 99 Uplink Limitations

Large Scheduling Delays Slow scheduling from RNC

Large Latency Transmission Time Interval (TTI) durations of 10/20/40/80 ms RNC based retransmissions in case of errors

Limited Uplink Data Rate Deployed peak data rate is 384 kbps

Limited Uplink Cell Capacity Typically about 800 kbps


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Understanding HSPA

High Speed Uplink Packet Access (HSUPA)

Set of high speed channels is received at the Node B. Interference is shared by multiple users. Several users may be allowed to transmit at given data rate

and power on a fast scheduling.

33


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Understanding HSPA

Enhancements Provided by HSUPA

How will HSUPA address the limitations of Release 99?

Higher Peak Data Rate in Uplink Enable new services and improve user perception

Improved Uplink Coverage for higher Data Rates

Improved Uplink Cell Capacity

Reduced Latency

Fast Scheduling and Resource Control Increase resource utilization and efficiency

Quality of Service (QoS) support Improve QoS control and resource utilization


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Understanding HSPA

How are Enhancements Achieved?

Improved Cell Capacity

Higher Peak Data RatesReduced Latency

Improved QoS Support

Faster Resource Control

Release 99 UL DCH HSUPA

Minimum TTI of 10 ms

Smaller TTI of 2 ms

Slow UL rate switching

(RNC based)

Fast UL data ratecontrol in the Node B

Improved Physical Layer performance

through HARQ

Multiplexing of transport channels at Physical Layer

Multiplexing of logical channels at MAC layer

Slow mechanism to request resources

Fast mechanism to request UL resources

Dedicated resource allocation for latency sensitive applications

Dedicated resource allocation that could

not be used efficiently

New Transport Channel

New Physical Channels

34


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Understanding HSPA

HSUPA vs. HSDPA

HARQ with Fast Retransmission at Layer 1

Fast Node-B SchedulerMany-to-One

Rise-over-Thermal (RoT)

Fast Node-B SchedulerOne-to-Many

Shared Node-B Power and Code

Fast Power ControlSoft Handover

Rate/Modulation AdaptationSingle Serving Cell

Dedicated Channel with Enhanced Capabilities

New high-speed Shared Channel

HSUPAHSDPA


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Understanding HSPA

Rise-over-Thermal Noise

Determination of grant for the UE

(At NodeB)

NodeB

UL Interference Level(RoT measure)

UE Data Rate

Interference from other UEs

Grant Received from NodeB

UE Transmit Power

2

3

1

5

4

In order to decode received data correctly, a minimum SINR shall be guaranteed at the Node B receiver.

Rise-over-Thermal is a measure of the Uplink load.

1. By increasing the number of transmitting UEsand their transmit power, the level of interference in the Uplink band increases.

2. This interference is perceived by the Node B receiver as noise, affecting the SINR.

3. The Node B controls the interference level by adjusting the UE grant assignments.

4. When the UE receives a new grant, it uses it in combination with available UE transmit power and the amount of data in the buffer

5. to determine the data rate and the corresponding transmit power.

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Understanding HSPA

Node B Scheduler for HSUPA

The HSUPA scheduler addresses the trade-off between:

Several users that want to transmit at

high data rate all the time

3dTower.emf

Node B

Satisfying all requested grants while preventing overloading and

maximizing resource utilization

and


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Understanding HSPA

Rise-over-Thermal Loading

load

RoTOverload

margin

Target Load

Possible additional load with HSUPA

R99 UL

R6 UL

With the introduction of HSUPA, a lower Uplink margin for preventing overload situations can be used, thanks to the fast resource allocation and control mechanisms in the Node B.

36


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Understanding HSPA

HSUPA Channel Operation

1. The UE sends a Transmission Request to the Node B for getting resources.

2. The Node B responds to the UE with a Grant Assignment, allocating Uplink band to the UE.

3. The UE uses the grant to select the appropriate transport format for the Data Transmission to the Node B.

4. The Node B attempts to decode the received data and send ACK/NAK to the UE. In case of NAK, data may be retransmitted.

3dTower.emf

Node B

REQ

GRAN

T

DATA

ACK/

NAK

UE

HSUPA Operation


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Understanding HSPA

HSUPA Channel Operation (continued)

1. Transmission Request

The UE requests data transmission by means of the Scheduling Information (SI), which is determined according the UE Power and Buffer Data availability.

The scheduling information is sent in-band to the Node B.

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2. Grant Assignment

The Node B determines the UE Grant by monitoring Uplink interference (RoT at the receiver), and by considering the UE transmission requests and level of satisfaction.

The grant is signaled to the UE by new grant channels.


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3. Data Transmission

The UE uses the received grant and, based on its power and data availability, selects the E-DCH Transport Formatand the corresponding Transmit Power.

Data are transmitted by the UE on together with the related control information.

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4. Data Acknowledgment

The Node B attempts to decode the received data and indicates to the UE with ACK/NAK if successful.

If no ACK is received by the UE, the data may be retransmitted.


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Understanding HSPA

UMTS Network Architecture with HSUPA

Core Network

UserEquipment

UTRAN


Node B

Node B

Node B

RNC

RNC

HLR/AuC

Node B

Node B

Node B

GMSCPSTN/ISDN

SGSN GGSN Internet

MSC/VLR

Node B

Node B

Uu Iub

Iub

Iups

IucsHardware and Software Changes

Software Changes

Iur

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Understanding HSPA

HSUPA Protocol Stack


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Understanding HSPA

HSUPA Uplink Channels

New HSUPA Uplink Channels:

Enhanced Uplink Dedicated Channel (E-DCH) Uplink Transport Channel

E-DCH Dedicated Physical Data Channel(E-DPDCH) Uplink Physical Channel

E-DCH Dedicated Physical Control Channel(E-DPCCH) Uplink Control Channel

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Understanding HSPA

HSUPA Downlink Channels

New HSUPA Downlink Channels:

E-DCH Hybrid ARQ Indicator Channel (E-HICH) Downlink Physical Channel

E-DCH Absolute Grant Channel (E-AGCH) Downlink Physical Channel

E-DCH Relative Grant Channel (E-RGCH) Downlink Physical Channel


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Understanding HSPA

HSUPA Channel Mapping

Rel. 99

Rel. 5

Rel. 6

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Uplink Channels

E-DPDCH Carries the payload. May include a scheduling

request from UE to Node B.

E-DPCCH Carries control information

required to decode the payload carried by E-DPDCH.

Carries an indication from UE to indicate to the Node B whether the assigned resources are adequate.

SI

TTI

PAYLOADHD


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Downlink Channels

E-AGCH The absolute grant carries maximum

allowed E-DPDCH/DPCCH ratio. Carries information that controls HARQ

process.

E-RGCH The relative grant carries a simple

command to increase (UP), Decrease (DOWN), or keep (HOLD) the current grant.

E-HICH Gives feedback to the UE about previous

data transmission, carrying Acknowledge (ACK) or Not Acknowledge (NAK).

Up / Down / Hold

TTI

ACK/NAK

TTI

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HSUPA Channel Timing


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HSUPA Features (continued)

Shorter TTI of 2 ms In HSUPA both 10 ms and 2 ms TTI are supported

A shorter TTI allows reduction of the latency and increasing the average and peak cell throughput

A tighter resource control can be implemented, thus allowing for additional capacity

Higher Peak Data Rate For a 10-ms TTI UE, peak data rate is limited to 2 Mbps

Higher peak data rates can be achieved with a 2-ms TTI UE

5.76 Mbps is the maximum peak data rate for HSUPA

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Hybrid-ARQ N-channel Stop-and-Wait

(SAW) protocol, with 4 processes for 10 ms TTI and 8 processes for 2 ms TTI

Synchronous retransmission

Separate HARQ feedback is provided per Radio-Link

3dTower.emf

Node B

3dTower.emf

Node B

DATA

DATANAK

ACK

E-DCH cells part of the Active Set


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Rate Request The UE requests grant for data transmission

Rate Control The UTRAN controls the grants for transmission on Uplink

Scheduled transmissions granted by the Node B for high speed data

Non-Scheduled transmissions granted by the RNC for delay-sensitive applications

Load Control The UTRAN monitors Rise-over-Thermal (RoT) noise at the

Node B receiver. UTRAN prevents overloading by reducing scheduled grants to UEs

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HSUPA Quality of Service (QoS)

QoS is linked to a logical channel.

Up to 15 logical channels can be multiplexed on a single MAC-e PDU.

Each logical channel may have a different QOS and a different priority level.

Priority level is considered while forming a MAC-e PDU.

Parameters affecting HSUPA performance are set as per the QoS requirements.

Air interface


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E-DCH Active Set and Mobility Support

3dTower.emf

Node B

3dTower.emf

Node B

3dTower.emf

Node B

Serving E-DCH Radio Link Set (RLS)

Serving E-DCH cell

Non-Serving Radio Links (RL)

Example with an Active Set of 4 cells

There are three different types of Radio Links in the UE Active Set:

Serving E-DCH Cell The cell from which UE receives AGCH from scheduler.

Serving (E-DCH) RLS Set of cells that contain at least the serving cell and from which the UE can receive and combine the serving RGCH.

Non-Serving RL Cell that belongs to the E-DCH Active Set but does not belong to the serving RLS and from which the UE can receive a RGCH.

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HSUPA Serving Cell Change

From the 3GPP Standards: HSUPA Serving Cell is the same as HSDPA Serving Cell


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Active Set Composition with HSUPA

E-DCH Serving Cell

Serving RL

Serving RL

Serving RLS

Non-

Serving RL

Non-Serving RL

E-DCH Active Set (max 4 cells) Other AS cell

Other AS cell

DPCH Active Set (max 6 cells)

Send AGCH

UE can combine RGCH commands from these cells

Send non-serving RGCH Is in SHO

All cells belonging to the UE AS

All cells belonging to the UE AS that

handle E-DCH

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Theoretical HSUPA Maximum Data Rate

How do we get 5.76 Mbps? Lower Coding Gain

Effective code rate = 1 Requires very good channel conditions to decode

Lower Spreading factor UE can use SF2

Multi-code transmission UE can use up to 4 codes, 2 with SF4 plus 2 with SF2 Require some power back-off at UE side

Shorter TTI Requires higher processing capabilities at terminal and Node B


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E-DPDCH with SF4 and Puncturing

Maximum payload for spreading factor of 4, TTI of 2 ms and coding rate of 1 is 1920 bits (for 960 kpbs).

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Lower Spreading Factor SF2

Maximum payload for spreading factor of 4, TTI of 2 ms and coding rate of 1 is 3840 bits (for 1920 kpbs).


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Multi-code Transmission

Use of multi-code transmission 2 x SF2 + 2 x SF4(2 x 1920 kbps) + (2 x 960 kbps) = 5760 kbps

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HSUPA UE Capabilities

2000 kbps

2000 kbps

2000 kbps

1448 kbps

1448 kbps

711 kbps

Peak rate for TTI = 10 ms*

5742 kbps

--

2886 kbps

--

1448 kbps

--

Peak rate for TTI = 2 ms

Category 6

Category 5

Category 4

Category 3

Category 2

Category 1

E-DCH Category

4

2

2

2

2

1

Max number of E-DPDCH channels

SF2 + SF 4

SF2

SF 2

SF 4

SF 4

SF 4

Minimum SF

2 & 10 ms

10 ms

2 & 10 ms

10 ms

2 & 10 ms

10 ms

Supported TTI

* Maximum Peak data rate for 10 ms E-DCH TTI operation is 2 Mbps in all configurations

HSPA

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