understand hspa - high-speed packet access for umts
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Telecom IsraelTechnical Tutorial
November 7th, 2006
Page 1
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 classes—all developed by QUALCOMM, the pioneers of CDMA.
QUALCOMM University: www.qualcommuniversity.comQUALCOMM: www.qualcomm.com
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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
Telecom IsraelTechnical Tutorial
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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 streamingMM sharingWireless Broadband AccessInteractive GamingVoIP with AMR-WB
Text MessagingSpeech GSM GSM
Push-to-TalkCustomized InfotainmentMultimedia 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
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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 conditionsFast closed inner loop power control, butSlower outer loop
• Minimum TTI of 10 ms• Slow Rate and Type Switching
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Understanding HSPA
HSDPA Goals
Higher Data RateHigher User / Cell ThroughputLower 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
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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)
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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
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Understanding HSPA
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 Combiningsame 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
PassFail
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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
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 Iub
Iub
Iups
IucsHardware and Software Changes
Software Changes
Iur
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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-DPCCH
HS-DSCH
HS-SCCH
P-CPIC
H
UE
HS-DPCCH
HS-DSCH
HS-SCCH
P-CPICH
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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
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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
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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.
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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
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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
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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
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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
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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
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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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Understanding HSPA
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.
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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
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Understanding HSPA
HSUPA vs. HSDPA
HARQ with Fast Retransmission at Layer 1
Fast Node-B Scheduler“Many-to-One”
Rise-over-Thermal (RoT)
Fast Node-B Scheduler“One-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.
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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
GRANT
DATA
ACK/NAK
UE
HSUPA Operation
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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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HSUPA Channel Operation (continued)
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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HSUPA Channel Operation (continued)
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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HSUPA Channel Operation (continued)
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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UMTS Network Architecture with HSUPA
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 Iub
Iub
Iups
IucsHardware and Software Changes
Software Changes
Iur
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HSUPA Protocol Stack
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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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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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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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HSUPA Features (continued)
• 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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HSUPA Features (continued)
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 Features (continued)
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
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