HSDPA Fundamentals

Section 1

Objectives
After this section, you will be able to

Describe HSDPA introduction technological context

List HSDPA main concepts and benefits

List HSDPA target applications and services

Compare HSDPA approach with existing technologies

Describe HSDPA future evolutions

Contents
Packet Data Services Trends & Technologies
High Speed Data Services Landscape
Standard Evolution
Theoretical Peak User Data Rates
What is HSDPA?
HSDPA Key Points
HSDPA Main Concepts and Benefits
HSDPA Market Applications
HSDPA vs. R4
Radio Resource Allocation
User Throughput Management
HSDPA vs. 1x EV-DO
Spectral Efficiency
What comes next?
Beyond HSDPA

Packet Data Services Trends &

Technologies

High Speed Data Services Landscape

Mobility

GPRS

EGPRS

UMTS

HSDPA

Emerging
Technologies
OFDM
Emerging
Technologies

WiFi
Bluetooth
Dial-Up

Broadband

10Base-T

Throughput

100Base-T

T-1

Standard Evolution
2G

3G

PDC

GSM

GPRS

W-CDMA

HSDPA

EDGE
IS136
1xEV-DV

IS95A

IS95B

3xEV-DV

1xRTT

1xEV-DO

Theoretical Peak User Data Rates

Enhanced UE

HSDPA

UE Category 6

3.6M

HSDPA

3.1M

1xEV-DV

EGPRS

2.4M

1xEV-DO

0.38 M

2M

W-CDMA

0.31 M

1xRTT

14.4M

What is HSDPA?

HSDPA Key Points

Radio Access
Technology

Downlink
Only

High
Throughputs

Low
Latency

Shared
Channels

PS
Dedicated

HSDPA Main Concepts & Benefits

HSDPA
No Fast Power Control (100% of available power used)
No Variable Spreading (SF = 16)
No Soft Handover (for DL user data channel)
Time & Code Multiplexing of User Data (Shared Channel)
Adaptive Modulation & Coding (Rate Adaptation)
Fast Retransmission / Scheduling Layer in NodeB
Short Radio Framing (2ms)

Higher User
Data Rates

Lower Service
Response Time

Higher Packet
Data Capacity

Better End-User Perceived Quality

Better Services
Availability

HSDPA Market Applications

Business Market

Consumer Market

Virtual Office

Multiplayer Gaming

Corporate VPN

Video Streaming & TV

Remote Applications / Tools

Advertising / News Broadcast

Web Browsing

Music & Video Downloads

Massive Downloads

Web Surfing

...

...

Working Anywhere!

Having Fun!

HSDPA vs. R4

Radio Resource Allocation

Dedicated Channel
Dedicated Channel
Dedicated Channel

Shared Channel

User Throughput Management

Same Throughput

Unused

Power
Control

Unused Power

Data

Data Power

Rate
Adaptation

100%
100% Power

HSDPA vs. 1xEV-DO

Spectral Efficiency

Peak Data Rate

3.6 Mbps (Cat. 6)

14.4 Mbps (Cat. 10)

2.4 Mbps

Modulation on Data
Channel

QPSK/16QAM

QPSK/8PSK/16QAM

Channel Coding

Turbo 1/3

Turbo 1/3

L1 Retransmission

HARQ

HARQ

Transmission
Interval

2 ms

1.6 ms

Sector Throughput

depending on load
and environment

depending on load
and environment

1.25MHz

1.25 MHz

1.25MHz

5 MHz

1xRTT
Voice & Data

1.25MHz

Bandwidth/Carrier

1xEV-DO Data

time

HSDPA Data
5 MHz

1xEV-DO

1 x 5 MHz
Carrier

HSDPA

3 x 1.25MHz
Carrier

1xEV-DO

UMTS
Voice & Data

HSDPA

What comes next?

Beyond HSDPA

Throughput
&
Capacity

Release 6

Release 7

MIMO

Release 7

OFDM

Main Technological Concepts

Section 2

Objectives
After this section, you will be able to

List HSDPA key features

Describe HSDPA channel operation

Describe AMC schemes

Describe HARQ process

Describe NodeB Scheduler structure

Describe Iub Flow Control mechanism

HSDPA Key Features

NodeB Role
RNC

Capacity Request
Control FP

Capacity Allocation
Control FP

Data FP

Flow Control
Dynamically fills the Queues of each UE

Queue IDs

Scheduler
Fills the TTIs with one or more users based on their priority and
feedback information

HARQ Processes
Retransmissions handling, TFRC selection, AMC

Feedback Reception

Radio Transmission

HSDPA New Channel Structure

HSDPA Channel Operation

UE #1
UE #2
UE #3
UE #4
UE #5

OVSF
codes

HS-PDSCH
Data Transfer
(PS S/I/B)

DPCH
Upper Layer Signaling

HS-DPCCH
Feedback Information
(ACK/NACK, CQI)

2ms

HS-SCCH
Downlink Transfer Information
(UEid, OVSF,...)

DPCH
Upper Layer Signaling

HS-DPCCH
Feedback Information
(ACK/NACK, CQI)

OVSF Code Tree Reservation

SF4

HSDPA

SF8
SF16
SF32

HS-PDSCH

SF64
HS-SCCH
SF128

SF4

HSDPA + R4

SF8
SF16
SF32

...

HS-PDSCH

SF64

...

SF128

...

SF256

HS-SCCH

...

cmCH

Adaptive Modulation and Coding

AMC Principles
UE Category

Reported CQI

AMC Illustration
800
700

Throughput (kbps)

2ms

AMC

600
500

QPSK
QPSK
QPSK
16QAM
16QAM

400
300
200
100

Coding
Rate

Modulation
Scheme

Number of
OVSF Codes

Maximum Throughput

-20

-15

-10

-5

Ior/Ioc (dB)

Modulation Schemes
16QAM
Q

QPSK
1011

1001

0001

0011

Q
10

1010

1000

0000

00

0010
I
I

1110

1100

0100

0110

1111

1101

0101

0111

4 bits per symbol

960kbps per OVSF
1920 bits per TTI

11

01

2 bits per symbol

480kbps per OVSF
960 bits per TTI

UE Categories
HS-DSCH Category

HS-PDSCH Max Number

Inter-TTI Min Interval

Modulation

Max Peak Rate

Category 1

QPSK & 16-QAM

1.2 Mbps

Category 2

QPSK & 16-QAM

1.2 Mbps

Category 3

QPSK & 16-QAM

1.8 Mbps

Category 4

QPSK & 16-QAM

1.8 Mbps

Category 5

QPSK & 16-QAM

3.6 Mbps

Category 6

QPSK & 16-QAM

3.6 Mbps

Category 7

10

QPSK & 16-QAM

7.3 Mbps

Category 8

10

QPSK & 16-QAM

7.3 Mbps

Category 9

15

QPSK & 16-QAM

10.2 Mbps

Category 10

15

QPSK & 16-QAM

14.4 Mbps

Category 11

QPSK only

0.9 Mbps

Category 12

QPSK only

1.8 Mbps

QPSK mandatory for HSDPA capable UE

16-QAM optional

UE Capabilities and Max Bit Rates

Category 6 UE CQI Mapping Table
CQI Value

HS-PDSCH Number

RLC Throughput

Modulation

out of range

0 kbps

QPSK

0 kbps

QPSK

0 kbps

QPSK

0 kbps

QPSK

144 kbps

QPSK

144 kbps

QPSK

144 kbps

QPSK

288 kbps

QPSK

288 kbps

QPSK

10

432 kbps

QPSK

11

576 kbps

QPSK

12

720 kbps

QPSK

13

864 kbps

QPSK

14

1008 kbps

QPSK

15

1296 kbps

QPSK

16

1440 kbps

16-QAM

...

...

...

...

29

3024 kbps

16-QAM

30

3024 kbps

16-QAM

Target BLER 10%

Hybrid Automatic Repeat Query

Multiple HARQ Processes

UE
Category

HSDSCH

Retransmission
Management

Soft Bits
Combining

Soft Bits
Combining

HARQ
HARQ
HARQ
HARQ
HARQ
HARQ
HARQ
HARQ

Soft Bits
Combining

HARQ
Processes

Category 1

Category 2

Category 3

Category 4

Category 5

Category 6

Category 7

Category 8

Category 9

Category 10

Category 11

Category 12

Stop And Wait Principles

HARQ

Wait for Transmission

UE is Scheduled

Update RV Parameters

TB

HARQ

TB

HARQ

Transmit Data
HSDSCH
Wait for ACK/NACK Reception

ACK

ACK/NACK/DTX?

DTX

Insert DTX
Indication

NACK

Reset & Free

HARQ Process

ACK/NACK

Nret = Nret + 1

YES

Nret > Nret_max

NO

HARQ Types
HARQ Blocks Decoding
New Block

Combine

Deliver to Upper Layer

YES

Update RV Database

Error?

RVBlocks

DATA

DATA

DATA

DATA

Chase
Combining

DATA

NO

Incremental
Redundancy
Combining

NACK

DATA

DATA1

NACK

NACK

DATA2

NACK

NACK

DATA3

NACK

NACK

ACK

DATA4

NACK

ACK

Constellation Rearrangement (16QAM)

Q

1011

1001

0001

0011

1110

0110

0100

1100

1010

1000

0000

0010

1010

0010

0000

1000

b=0
1110

1100

0100

0110

1111

1101

0101

0111

1011

0011

0001

1001

1111

0111

0101

1101

b=1

1000

1010

0010

0000

0010

1010

1000

0000

1001

1011

0011

0001

0110

1110

1100

0100

b=2
1101

1111

0111

0101

1100

1110

0110

0100

0111

1111

1101

0101

0011

1011

1001

0001

b=3

Transport Channels & Physical

Channels

Section 3

Objectives
After this section, you will be able to

Describe new MAC architecture and data flows

List the HSDPA coding chains main steps

Describe the structure of the new channels and Frame

Protocols

Describe the HSDPA specific radio modulation schemes

HSDPA Distributed Architecture

HSDPA Protocol Stack

HS-PDSCH

HS-SCCH

Data Transfer (PS I/B)

Downlink Transfer Information

(UEid, OVSF,...)

Introduction of MAC-hs

RNC
Iub

HS-DPCCH

DPCH

Feedback Information
(CQI, ACK/NACK)

Upper Layer Signaling

New Transport channel

HS-DSCH

New Frame Protocols

HS-DSCH

RLC
MAC-d

RLC
MAC-d

MAC-hs
PHY

UE

Uu

MAC-hs

HS-DSCH
FP

Flow control

PHY

L2
L1

Iub

NodeB

HS-DSCH
FP
L2
L1

RNC

HSDPA Layer2/Layer1 Flows

RRC (RNC)
RLC (RNC)
PCCH BCCH CCCH CTCH

MAC Control

MAC Control

MAC Control

MAC-hs
(NodeB)

DCCH DTCH

DTCH

MAC-d
(S-RNC)
MAC-c/sh
(C-RNC)

Associated
Downlink
Signaling

HS-DSCH

Associated
Uplink
Signaling

R5 L1: HSDPA (NodeB)

HS-SCCH

HS-PDSCH

HS-DPCCH

PCH

FACH

RACH

CPCH

DSCH

DCH

DCH

R4 L1: Channel Coding / Multiplexing (NodeB)

S-CCPCH

S-CCPCH

PRACH

PCPCH

PDSCH

DPCH

DPDCH/DPCCH

MAC-hs Architecture (UTRAN side)

to MAC-d or MAC-c/sh
MAC-d flows
MAC-hs

Flow Control
Scheduler

Priority Queue
Distribution
Priority
Queue

Priority Queue
Distribution

Priority
Queue

Priority
Queue

Priority
Queue

HARQ
TFRC Selection

Associated
Downlink Signaling

HS-DSCH

Associated
Uplink Signaling

Transport Channels

HSDPA Channel Configuration

Logical
Channels

Transport
Channels

DCCH

DTCH
DCCH

DTCH

DCH
DCH

DCH

DPCH

DPDCH

HS-DSCH

Layer 1

Physical
Channels

DPCCH

HS-PDSCH

HS-SCCH

HS-DPCCH

HS-DSCH Parameters
Higher Layer

RAB

RLC

Logical channel type

MAC

Layer 1

RAB DL ?kbps
DTCH

RLC mode

AM

Payload sizes, bit

320

Max data rate, bps

? (depends on UE category)

AMD PDU header, bit

16

MAC-d header, bit

MAC multiplexing

N/A

MAC-d PDU size, bit

336

MAC-hs header fixed part, bit

21

TrCH type

HS-DSCH

TB sizes, bit

NA

TFS

NA

TTI, ms

Coding type

TC

CRC, bit

24

Max number of bits/TTI after channel coding

NA

RM attribute

NA

Channel Coding

MAC-hs PDU

1 bit

3 bits

6 bits

3 bits

7 bits

1 bit

VF

QID

TSN

SID

MAC-hs Header

MAC-hs SDU

...

MAC-hs SDU

21 bits
MAC-hs Payload

Padding

HS-DSCH Coding Chain

CRC attachment
Bit Scrambling
Code Block Segmentation

R4 Functionality

Turbo Coding
R4 Modified Functionality
HARQ Entity
Physical Channel Segmentation
HS-DSCH Interleaving
Constellation Rearrangement (16QAM)
Physical Channel Mapping

New Functionality

HS-SCCH Coding Chain

OVSF Code Set

s, r, b

TBS

Modulation Scheme
MUX

HARQ

RV Coding
MUX
CRC

CC 1/3

UEId

UE Masking

Rate Matching

CC 1/3

MUX

Puncturing

CC 1/3

UE Masking

Slot #0: Code Set, Modulation

Rate Matching

Slot #1: TBS, HARQ

TSUBFRAME = 2ms

Slot#2: RV, NDI

NDI

Physical Channels

HS-PDSCH
TSLOT = 2560 chips, Ndata bits
Data bits

Slot #0

Slot #1

Slot#2

TSUBFRAME = 2ms
Slot Format

Channel Bit Rate

Channel Symbol

SF

Bits per Subframe

Ndata

rate
0 (QPSK)

480 kbps

240 ksps

16

960

320

1 (16QAM)

960 kbps

240 ksps

16

1920

640

HS-SCCH
TSLOT = 2560 chips = 40 bits
Data bits

Slot #0

Slot #1

Slot#2

TSUBFRAME = 2ms
Slot Format

Channel Bit Rate

Channel Symbol

SF

Bits per Subframe

Bits per Slot

128

120

40

rate
0

60 kbps

30 ksps

HS-DPCCH
TSLOT = 2560 chips = 10 bits
ACK/NACK

Subframe #0

CQI

Subframe #1

Subframe #2

Subframe #3

Subframe #4

TFRAME = 10ms

Slot Format

Channel Bit Rate

Channel Symbol

SF

Bits per Subframe

Bits per Slot

256

30

10

rate
0

15 kbps

15 ksps

Radio Interface Timing

BFN

tcell

SFN
P-CPICH
2 ms

HS-SCCH#1

HS-SCCH#2
2 slots

HS-PDSCH

achNackRepetitionFactor = 2
ACK

HS-DPCCH
7,5 slots

ACK

ACK

Downlink Modulation
I

x
Scrambling

S/P

HS-PDSCH

Modulation
Mapper

OVSFhs

x
16QAM

QPSK

nk, nk+1, nk+2, nk+3

i1q1i2q2

0000
0001

0000
0001

0.4472
0.4472

0.4472
1.3416

0100

0010

1.3416

0.4472

0101

0011

1.3416

1.3416

0010

0100

0.4472

-0.4472

0011

0101

0.4472

-1.3416

0110

0110

1.3416

-0.4472

00
01

00 1 1
01 1 -1

0111

0111

1.3416

-1.3416

10

10 -1 1

1000

1000

-0.4472

0.4472

11

11 -1 -1

1001

1001

-0.4472

1.3416

1100

1010

-1.3416

0.4472

1110

1011

-1.3416

1.3416

1010

1100

-0.4472

-0.4472

1011

1101

-0.4472

-1.3416

1110

1110

-1.3416

-0.4472

1111

1111

-1.3416

-1.3416

nk, nk+1 iq

Uplink Modulation

OVSFd1

DPDCH1

x
OVSFd2

x
d

DPDCH3

x
OVSFd3

x
d

x
OVSFhs

x
hs

OVSFd1

DPDCH2

x
OVSFd2

x
d

DPDCH4

x
OVSFd3

x
d

DPDCH6

x
OVSFc

x
c

DPCCH

x
OVSFhs

x
hs

DPDCH5
HS-DPCCH
if Nmax-DPDCH = 2, 4, 6

HS-DPCCH
if Nmax-DPDCH = 0, 1, 3, 5

Scrambling

Modulation