OWA333010 WCDMA HSPA+ Principles RAN11 ISSUE1.11.Ppt [Last Saved by User]

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OWA333010 RNC RAN10 Issue 1.11

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Liangjie/41026 2009-10-30 Mijia/43064 Update

Liangjie/41026 2009-11-30 Mijia/43064 Update

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HSPA+ Principle

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About This Coursel This course introduces principles and some key

technologies of HSPA+.


Referencesl 3GPP Release 7 Specification References:

p 3GPP TS 25.211: Physical channels and mapping of transport channels onto physical channels (FDD)

p 3GPP TS 25.212: Multiplexing and channel coding (FDD)

p 3GPP TS 25.213: Spreading and modulation (FDD)

p 3GPP TS 25.214: Physical layer procedures (FDD)

p 3GPP TS 25.308, "UTRA High Speed Downlink Packet Access (HSPDA); Overall description"

p 3GPP TS 25.309: FDD Enhanced Uplink

p 3GPP TS 25.301: Radio Interface Protocol Architecture

p 3GPP TS 25.302: Services provided by the physical layer

p 3GPP TS 25.321: Medium Access Control (MAC) protocol specification


Contents1. HSPA+ Overview

2. Key Technologies of HSPA+


HSPA+ Introductionl HSPA refers to HSDPA and HSUPA which are introduced in

3GPP Release 5 and Release 6. It can provide significant

throughput, latency, and capacity gains on the downlink and

uplink, compared to Release 99.

l HSPA+ (also known as HSPA evolution) is introduced in

3GPP Release 7. It is an enhancement to HSPA.


Goals for HSPA+ in Release7l Reduced service delay

l Increase peak data rates

l Improve spectrum efficiency

l Increase system capacity

l Reduce UE power consumption


Room to Improve Release 6

l Release 6 (HSDPA and HSUPA) already provides high-speed wireless access to large number of users.

l But there is room for even more improvements:p Use of multiple antenna techniques (MIMO) to increase peak data rate

and system capacity

p Higher order modulation scheme to improve downlink spectral efficiency and peak data rate

p Adapt system behavior to match application requirements to reduce interference and to extend UE battery life

p Expand use of high speed HS-PDSCH channel beyond DTCH and DCCH, extend it to the CELL_FACH state.


HSPA+ Features in Release 7

l Downlink enhanced L2

l Downlink 64QAM

l MIMO (Multiple Input Multiple Output)

l Enhanced CELL_FACH operation

l CPC (Continuous Packet Connectivity)


MIMO and DL 64QAM

l MIMO

p MIMO increases transmission rates through space

multiplexing and improves channel qualities through space

diversity. The network side can dynamically select single- or

dual-stream transmission according to channel conditions. The

peak rate at the MAC layer can reach 28 Mbit/s.

l DL 64QAM

p DL 64QAM allows the use of 64QAM in HSDPA to increase

the number of bits per symbol and thus to obtain higher

transmission rates. The peak rate at the MAC layer can reach

21 Mbit/s.


Enhanced CELL_FACH Operation

l Enhanced CELL_FACH operation

p Enhanced CELL_FACH operation allows the use of HSDPA

technologies for the UEs in the CELL_FACH, CELL_PCH, and

URA_PCH state. The purpose is to increase the peak rates in

these states and reduce the signaling transmission delay

during service setup or state transition with the result

improving the user experience.


DL Enhanced L2

l This feature allows Uu L2 to use flexible PDU size on RLC

layer and segmentation on MAC layer. The feature

prevents the L2 from becoming the bottleneck of higher Uu

rate increased by MIMO and 64QAM.

l DL enhanced L2 is the precondition of MIMO, 64QAM and

enhanced CELL_FACH operation.


CPC (Continuous Packet Connectivity)

l CPC allows the uplink and downlink transmissions to take place at periodic intervals. This feature reduces the transmitted power (and thus increases the UE battery life) because the UE does not have to monitor and transmit overhead channels every TTl. This reduction in the transmitted power also helps to increase the uplink capacity by decreasing the total interference. This improvement is especially significant when there are users who transmit data infrequently as VoIP users.

l CPC feature consists of DL DRX, UL DTX and HS-SCCH less operation.


HSPA+ Capable UE CategoriesHS-DSCH category

Supported Modulations Without MIMO

Supported Modulations with MIMO

Category 13QPSK, 16QAM, and 64QAM None

Category 14

Category 15QPSK and 16QAM QPSK and 16QAM

Category 16

Category 17QPSK, 16QAM, and 64QAM QPSK and 16QAM

Category 18


Contents2. Key Technologies of HSPA+

2.1 Downlink Enhanced L2

2.2 Downlink 64QAM

2.3 MIMO

2.4 Enhanced CELL_FACH Operation

2.5 CPC


Limitation of Original L2 Functionl MIMO and 64QAM increase the DL rates on the Uu

interface. The original DL L2 function cannot adapt to such

high rates. To prevent L2 from becoming the bottleneck of

network performance, 3GPP Release 7 introduces

enhancements to L2.


Downlink Enhanced L2 in Release 7l Downlink enhanced L2 includes the following two features:

p Improving the RLC entity to support flexible RLC PDU sizes

p Adding a new entity, the MAC-ehs, implementing data

segmentation at the MAC layer, and supporting the

multiplexing of multiple priority queues


Flexible RLC PDU sizel With introduction of flexible RLC PDU sizes, the RLC layer

will not segment higher-layer packets with sizes less than

maximum RLC PDU size (the maximum RLC PDU size is

configurable and maximum value is 1500 bytes). Thus, the

RLC layer can flexibly adapt to variations in traffic volume

and reduce the overhead of the RLC PDU header.


MAC-hs Entity (UTRAN side) in Release 6

MAC-hs

MAC – Control

HS-DSCH

TFRC selection

Priority Queue distribution

Associated Downlink Signalling

Associated Uplink Signalling

MAC-d flows

HARQ entity


Priority Queue

Priority Queue

Priority Queue

Priority Queue

Scheduling/Priority handling


MAC-ehs Entity (UTRAN side) in Release 7

MAC-ehs

MAC – Control

HS-DSCH

TFRC selection


Associated Downlink Signalling

Associated Uplink Signalling

MAC-d flows

Priority Queue

Scheduling/Priority handling

Priority Queue

Priority Queue

Segmentation

Priority Queue MUX

HARQ entity

Segmentation

Segmentation




2.2 Downlink 64QAM

2.3 MIMO


2.5 CPC


Modulation Modes for HSPA+l Three modulation modes can be used for HS-PDSCH

64QAM allows more bits per Symbol to be transmitted

Higher peak rate achieved in good channel condition


CQI Mapping Table Change for 64QAM

CQI TBS Codes Modulation

1 136 1 QPSK…

25 14424 10 16-QAM

26 15776 10 64-QAM

27 21768 12 64-QAM

28 26504 13 64-QAM

29 32264 14 64-QAM64-

l 64QAM configuredl 64QAM not configured

CQI TBS Codes Modulation

1 137 1 QPSK…

25 14411 10 16-QAM

26 17237 12 16-QAM

27 21754 15 16-QAM

28 23370 15 16-QAM

29 24222 15 16-QAM16-


HS-SCCH Change for 64QAM

Channelization Code Set

Modulation Scheme0: QPSK

1: 16QAM

MUX

HS-SCCH part 1

Channelization Code SetLast bit: 0:16QAMLast bit 1: 64QAM

Modulation Scheme0: QPSK1: QAM

MUX

HS-SCCH part 1

l Release 6 l Release 7


Prerequisites for Downlink 64QAMl UE capability

p UE category 13, 14, 17 and 18 can support downlink 64QAM.

l Service type

p 64QAM modulation mode is only used for HSPDA service.

l Cell capability

p The Serving cell must support downlink enhanced L2 and 64

QAM.




2.2 Downlink 64QAM

2.3 MIMO


2.5 CPC


What is MIMO?l MIMO: Multiple Input Multiple Output

Transmitter ReceiverWireless Channel

… …

N M

Channel Condition Feedback


What can MIMO provide?l 2×2 MIMO can increase peak data rate to 28Mbps

Transmitter ReceiverWireless Channel

Channel Condition Feedback

Data Stream 1

Data Stream 1


Effect of Channel Condition to MIMO

l MIMO operation is affected by channel condition of UE.

l Only when the channel conditions are good, two parallel

data streams can be carried in different transmitters. This is

dual-stream case. Otherwise only one data stream is carried

even though two transmitters are used. This is single-

stream case.


HSDPA with MIMO in Release 7l Operation is similar to Release 5 HSDPA, but with different signaling:

p Via HS-DPCCH UE reports

n Channel Condition

n Preferred antenna weight

n Dual stream or single stream preference

p Based on UE report, NodeB

n Determines number of data streams, TB size, modulation and coding scheme and antenna weighting

n Informs UE of the decision via HS-SCCH

l NodeB transmits the data via HS-PDSCH channel.

l Upon receiving the data, UE sends ACK/NACK via HS-DPCCH.


Illustration of 2× 2 MIMO

Pre-coding

Pilot for channel estimation


Pre-codingl In single-stream case pre-coding is used to achieve

transmit diversity. It is similar to closed-loop transmit diversity.

l In dual-stream case pre-coding is used to reduce the interference between two streams and try to make them orthogonal.

l Four predefined antenna weighting vectors are used, identified by PCI (Pre-coding Indicator). NodeB decides which weighting vector is used and inform UE.


Pilots for Channel Estimationl On each antenna, a common pilot channel is transmitted.

It is used to estimate the channels between NodeB and UE.

l In 2×2 MIMO mode the channel between transmitter and receiver can be expressed as the following format, where hi,j is the estimate of the channel between the physical antenna i at the base station and the antenna j at the UE.

=

2,2

2,1

1,2

1,1

hh

hh

H


HS-DPCCH Signalingl UE reports on HS-DPCCH

p Preferred number of transport blocksn 2 TBs = dual stream transmission

n 1 TBs = single stream transmission

p Channel Quality Indicator (CQI)n Type A: provide CQI for each TB when 2 TBs are preferred

n Type B: provide CQI when only one TB should be sent

p Preferred pre-coding (Pre-coding Control Indication: PCI)n Indicate 1 of 4 predefined pre-coding vectors

p ACK/NACKn If one TB was transmitted, UE sends one ACK or NACK

n If two TBs were transmitted, UE reports one out of four possible values for ACK/ACK, ACK/NACK, NACK/ACK, NACK/NACK

n Each TB is acknowledged independently.


Two Types of CQI Feedbackl Two types of CQI is reported by UE: type A and type B

l In type A report, UE indicates:

p Preferred pre-coding vectors (2 bits)

p Preferred number of TBs per TTI

p CQI (8 bits)

n “Old” 31-level CQI report, if one TB is preferred

n “New” 255-level CQI report, if two TBs is preferred

l In type B report, UE indicates:

p Preferred pre-coding vectors (2 bits)

p CQI (5 bits)


Two Types of CQI Feedback (continued)

Type A Type A Type A Type A Type B Type A Type A Type A Type BType A Time

Configurtion N/M = 4/5, CQI feedback cycle = 1 (2ms)

Type A Type A Type B Time

Configuration N/M = 2/3, CQI feedback cycle = 4 (8ms)

l NodeB Configures UE to use N type A reports every period

of M CQI reports. UE uses type B in remaining time.

l The following are two examples for type A/B reporting:


HS-SCCH Signaling – Part 1l New HS-SCCH format Part 1

p Transmitted in the first slot of the 3-slot HS-SCCH TTI

p Supports single stream (8 bits) or dual streams (12bits)

p For dual stream operation (12 bits)

n Channelization code set (7 bits)

n Modulation Scheme and number of TBs (3 bits)

n Pre-coding vector (2 bits)


HS-SCCH Signaling – Part 2l Transmitted in the second and third slots of the HS-SCCH

TTI

l Supports single stream (12 bits) or dual stream (20 bits)

l For dual stream transmission (20 bits):

p Transport block size (6 bits per TB)

p HARQ IDs (4bits)

p Redundancy version (2 bits per TB)


Prerequisites for MIMOl UE capability

p UE category 15, 16, 17, 18, 19 and 20 can MIMO

l Service type

p MIMO modulation mode is only used for HSPDA service.

l Cell capability

p The Serving cell must support downlink enhanced L2 and

MIMO.




2.2 Downlink 64QAM

2.3 MIMO


2.5 CPC


Purpose of Enhanced CELL_FACH Operationl The RRC states of a UE in connected mode include

CELL_DCH, CELL_FACH, CELL_PCH, and URA_PCH. HSPA significantly increases the maximum achievable uplink and downlink data rates, but only for UEs in CELL_DCH states.

l The purpose of the Enhanced CELL_FACH feature is to extend the use of HSDPA function to the CELL_FACH, CELL_PCH, and URA_PCH state as well, allowing a more flexible allocation of resources, increased data rates, and reduced transmission delays. So far RAN11 only supports HSDPA in CELL_FACH.


Benefits of Enhanced CELL_FACH Operationl UE can reduce the state transitions from CELL_FACH to

CELL_DCH

l UE can receive high speed downlink traffic (data or

signaling) in CELL_FACH.

l UL transmission is still possible in CELL_FACH and uplink

traffic (data or signaling) is carried on RACH. (as in Release

6)


Logical Channel Mapping in Enhanced CELL_FACH

DTCH BCCHDCCH CCCH

FACH HS-DSCH

RAN10 RAN11


UE Reception in Enhanced CELL_FACHl UE can decode HS-SCCH using:

p Dedicated H-RNTI (from prior dedicated RRC signaling)

p Or an H-RNTI selected from list of common H-RNTI in SIB5

l UE use HS-SCCH channelization code from SIB5.

l UE decodes HS-PDSCH to receive DL data transmissions.

p BCCH/CCCH/DTCH/DCCH

l No Uplink ACK/NACK or CQI is transmitted.


State Transition – Idle to CELL_FACH/CELL_DCHl UE procedures in state transition from idle to CELL_FACH/CELL_DCH

1. Read system information in SIB5

2. Sends an RRC Connection Request on PRACH to request PS service

3. Selects an H-RNTI from common H-RNTI listed, HS-SCCH channelization

code from SIB5.

4. Monitor HS-SCCH using selected common H-RNTI.

n Decode HS-PDSCH to receive RRC Connection Setup.

5. Transitions to CELL_FACH or CELL_DCH based on the reconfiguration

message.

n Uses new assigned H-RNTI for further HS-PDSCH reception.

6. May receive subsequent data in CELL_FACH or CELL_DCH




2.2 Downlink 64QAM

2.3 MIMO


2.5 CPC


CPC Motivation

l CPC allows packet data users to remain in CELL_DCH

state to a larger extent, thus avoiding frequent packet

connection re-establishments.

l CPC motivation is mainly to allow more efficient use of

continuous packet data connections:

p Higher capacity

p Lower UE battery consumption


What is CPC?

l CPC adds three main features:

p UL DTX (discontinuous uplink transmission)

p DL DRX (discontinuous downlink reception)

p HS-SCCH less operation

l These three features are optional

p UL DTX can be used alone or in combination with other CPC features.

p DL DRX can be used only if UL DTX is used.

p HS-SCCH less operation can be used alone or in combination with other CPC features.


Preconditions for CPC Configuration

l UE is in CELL_DCH state.

l No DCH is configured.

l Downlink traffic is carried by HS-DSCH and uplink traffic is

carried by E-DCH.

l SRB (Signaling radio bearer) is carried by HSPA.

l F-DPCH is configured.


Basic Concepts of UL DTX

l UL DTX includes the following features:

p UL DPCCH DTX

p E-DCH transmission restriction

p CQI reporting DTX


UL DPCCH DTX

Release 6 UL DPCCH

Release 7 UL DPCCH DTX


UL DPCCH DTX Activation/Deactivationl UL DPCCH DTX activation and deactivation

DTX at UE_DTX_cycle_1 (Initial state)

DTX at UE_DTX_cycle_2

UL DTX Configured in

RRC?

UL DTX enabled UL DTXdeactivated

UL DTX Active

DTX activationorder

DTX deactivationorder

Data to transmit

No E-DCH data for Inactivity_threshold_for_UE_DTX_cycle_2 TTIs

No UL DTX

Enabling_delayelapse

N

Y


UL DPCCH DTX Operation

l When UL DTX is active:

p UE shall transmit the uplink DPCCH in a slot if there is:

n HARQ-ACK/NACK transmission on HS-DPCCH

n CQI transmission on HS-PDSCH

n E-DCH transmission

p Otherwise, UL DPCCH shall be transmitted based on:

n Two periodic (DTX_cycle) transmission gaps


UL DPCCH DTX Operation (continued)

l Two cycles of UL DPCCH DTX


CQI Reporting DTX

l CQI reporting DTX

UE_DTX_cycle

CQI DTX timerLast HS-DSCH activity on the

downlink

CQI DTX timer expires

CQI feedback cycleNormal CQI reporting Does not coincide with UE_DTX_cycle

No CQI reporting

DPCCH additional transmissions(When CQI is transmitted)


E-DCH transmission restriction

l UL DTX supports configurable E-DCH transmission start

time restrictions

p It can enable DRX at NodeB to save NodeB processing power.

MAC_Inactivity_ThresholdMAC_DTX_cycle

After data inactivity, UE shall wait nextMAC_DTX_cycle for sending E-DCH data

E-DCH data to sendbut not sent


Basic Concepts of DL DRX

l DL DRX feature is designed to save UE battery.

l If UL DTX is configured, RNC can also configure DL DRX.

p UE can receive the following channels discontinuously:

n HS-SCCH and HS-PDSCH

n E-AGCH and E-RGCH

p When DRX is configured, RNC will send DL data (on HS-

SCCH and HS-PDSCH) only at pre-defined periodic intervals.


DL DRX Activation/Deactivation

l DL DRX activation and deactivation

NO DRX (Initial state)

DRX at UE_DRX_cycle

UL DTX and DL DRX

Configured inRRC?

DTX/DRX enabled DL DRXdeactivated

DL DRX Active

DRX activationorder

DRX deactivationorder

No HS-SCCH/HS-PDSCH reception during Inactivity_threshold_for_UE_DRX_cycle subframesNo DL DRX

Enabling_delayelapse

N

Y


DL DRX Operation

l If DL DRX (and UL DTX) is configured and supported by

UE:

p UE shall continue to receive F-DPCH and E-HICH as

normal operation.

p UE can apply DRX to HS-SCCH and HS-PDSCH.

n If UE has not received an HS-SCCH or HS-PDSCH subframes

during the last Inactivity_Threshlod_for_UE_DRX_cycle

subframes, UE shall monitor HS-SCCH and HS-PDSCH every

DRX_cycle frames.


DL DRX Operation (continued)

subframe subframe subframe subframe subframe subframe subframe subframesubframe

subframe subframe subframe subframe subframe subframe subframe subframesubframe

HS-SCCH

HS-PDSCH

Inactivity_threshold_for_UE_DRX_cycle UE_DRX_cycle

UE shall monitor continuously HS-SCCH/HS-PDSCH UE shall monitor HS-SCCH/HS-

PDSCH every UE_DRX_cycle only

UE doesn’t monitor HS-SCCH/HS-PDSCH


E-AGCH and E-RGCH Monitoringl UE can apply DRX to E-AGCH and E-RGCH

p There are two main RRC parameters to control E-AGCH and E-RGCH

DRX: Inactivity_Threshold_for_UE_Grant_Monitoring and

UE_DRX_Grant_Monitoring.

l UE can avoid monitoring E-AGCH and E-RGCH channels except for

the following case:

p A scheduled E-DCH transmission has been performed in any of

Inactivity_Threshold_for_UE_Grant_Monitoring previous TTIs.

p UE_DRX_Grant_Monitoring is TRUE and the start of E-AGCH or E-

AGCH transmission overlaps with an HS-SCCH subframe.

p E-AGCH and E-RGCH commands overlap with an E-HICH

corresponding to a scheduled E-DCH transmission.


Basic Concepts of HS-SCCH Less Operationl Under certain conditions (for example low data rate), HS-

PDSCH (only for first transmission) can carry data without

associated HS-SCCH.

l With HS-SCCH less operation, DL OVSF codes and power

can be saved for low data rate downlink transmission.


HS-SCCH Less Operation

l If HS-SCCH less operation is configured by RRC, UE shall

behave as follows:

p UE monitors one or two pre-assigned HS-PDSCH codes

every TTI

n HS-PDSCH CRC is generated based on UE specific H-RNTI.

p UE performs a blind decoding of HS-PDSCH, trying some

predefined transport block sizes.

p The modulation mode can only be QPSK.

n Suitable for low data rate transmission


HS-SCCH Less Operation (continued)

blind decoding

NACK ACKNACK not transmitted

first transmission first retransmission second retransmission

HS-DPSCH

HS-DPCCH

HS-SCCH

HS-SCCH carries •Pointer to previous transmission•Retransmission number•Transport format•Channelization codes for HS-PDSCH


CPC Coexistence with Other HSPA+ Features

Feature UL DTX DL DRX HS-SCCH less

UL DTX N/A Compulsory Possible

DL DRX Possible N/A Possible

HS-SCCH less Possible Possible N/A

HSDPA Compulsory Compulsory Compulsory

HSUPA Compulsory Compulsory Possible

F-DPCH Compulsory Compulsory Compulsory

MIMO Possible Possible Not supported

DL 64 QAM Possible Possible No supported

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OWA333010 WCDMA HSPA+ Principles RAN11 ISSUE1.11.Ppt [Last Saved by User]

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