HSDPA Overview_ 3G.ppt

Date Presentation / Author

NSN 3G Network

RAN Workshop

HSDPA Overview


Outline

HSDPA Aktivasi HSDPA di Nokia RAN Parameter HSDPA di Nokia RNC Resource Allocation untuk HSDPA di Nokia

RAN


HSDPA Part of 3GPP release 5 specifications System of new physical channels for UTRAN Downlink data rates up to 14.4 Mbit/s per user It uses shared channel concept -Rather than constantly allocating and deallocating

dedicated channels to individual users, users share a high bandwidth channel - the HS-DSCH (High Speed Downlink Shared Channel).

-It allows the system to operate with a “fat pipe” Fixed SF16 multicode transmission


Three Keys Technical of HSDPA

Data rates are optimized dynamically during the session according to radio link quality. This ensures highest possible data rates to end-users.

To improve QoS data Packets are further compressed and BTS schedules data transmission instead of RNC. Fast interleaving(2ms).

Data retransmission is handled by BTS. UE combines correct bits from original transmission and re transmission (Hybrid ARQ). This provides fastest possible response.

HSDPA

Adaptivemodulation and

coding Fastscheduling

Fast retransmission


1. Adaptive Modulation and Coding (AMC)

16 QAM (Quadrature Amplitude Modulation)

QPSK (Quadrature Phase Shift Keying)

Q

1011 1001

10001010

0001 0011

00100000

0100 0110

01110101

1110 1100

11011111

I

QPSK

2 bits / symbol480 kbit/s/HS-PDSCH

10 00

0111

Q

I

16QAM

4 bits / symbol 960 kbit/s/HS-

PDSCH


Adaptive Modulation and Coding (AMC) 1symbol=2 bits 1 channel SF16 in QPSK = (symbol x chiprate)/16 = (2 x 3840)/16 = 480 kbps 1 fat pipe = 5 codes = 5 x 480 x (3/4) = 1.8 Mbps

1symbol=4 bits 1 channel SF16 in 16 QAM = (symbol x chiprate)/16 = (4 x 3840)/16 = 960 kbps 1 fat pipe = 5 codes = 5 x 960 x (3/4) = 3.6 Mbps


Adaptive Modulation and Coding

QPSK

1/4

Modulation EffectiveCode rate

2/4

3/4

16

SF

16

16

2/4

3/4

16

16

1.2 Mbit/s

Data rate(10 codes)

2.4 Mbit/s

3.6 Mbit/s

4.8 Mbit/s

7.2 Mbit/s

1.8 Mbit/s

Data rate(15 codes)

3.6 Mbit/s

5.3 Mbit/s

7.2 Mbit/s

10.7 Mbit/s

600 kbit/s

Data rate(5 codes)

1.2 Mbit/s

1.8 Mbit/s

2.4 Mbit/s

3.6 Mbit/s

4/4*16 4.8 Mbit/s 7.2 Mbit/s2.4 Mbit/s

4/4*16 9.6 Mbit/s4.8 Mbit/s

16QAM

14.4 Mbit/s

Note: * In theory


Node BRNC

PacketsScheduler

& Buffer

ARQ &

Coding

ACK/NACK & Feedback Decoding

Flow Control

Terminal

ARQ

Decoding

Soft Buffer

& Combining

ACK/NACK & Feedback Generation

• Fast Transmission Time Interval (TTI) reduced from 10 ms to 2 ms

2. Fast Scheduling


Schedulers• The scheduler schedules the information that will be sent from the

Node B to the UE.• The scheduler requires important information from the uplink HS-

DPCCH

Scheduler

QoS and Subscriber ProfileWho is the subscriber? Platinum, Gold,Silver, Normal.What type of service is the subscriber allowed? High priority, Best effort

Uplink FeedbackCQI and Ack/Nackinformation

Node B buffer statusHow much dataHow fast is the data arriving

User HistoryHow long has userbeen waiting

Available Radio ResourcesPowerCodes

Traffic ModelWhat type of traffic model shouldbe used - according to periodof the day – Peak/Off Peak

UE CapabilitySee UE categories

Users are scheduled according to theirrequirements for transmission by theNode B over the air interface


3. Fast Retransmission

• Retransmissions handled in BTS in layer 1

• Retransmission process Hybrid Automatic Retransmission reQuest (HARQ)

• Note: HSDPA does not support soft handover

Retransmission between

• UE and BTS by layer 1

• UE and RNC by RLC

• UE and data server by TCP

• Fast Transmission Time Interval (TTI) reduced from 10 ms to 2 ms


HSDPA Activation Hardware requirements HSDPA requires the following hardware: . In the base transceiver station (BTS), at least one WSPC

card is required. . In the radio network controller (RNC), all data and macro

diversity combining units (DMCUs) must be of type CDSP-C Software requirements The RNC and BTS software have to be upgraded to RAS05

level for basic HSDPA. The new features require RAS05.1.


HSDPA Activation Activation in RNC 1. Check Service Pool Information 2. Change Pool Allocation based on RNC Capacity

step 3. Execute the Pool Change (restart RNC, restart

DMPG, or Performed a controlled DMPG state change)

Activation in WBTS HSDPA support can be enabled or disabled with a cell-

specific management parameter HSDPAenabled.


HSDPA Activation HSDPA Activation Document

Adobe Acrobat Document


HSDPA Parameter in RNC

Fixed power is allocated for HSDPA transmissions (HS-DSCH). AMC is used instead of fast PC.

Associated UL HS-DPCCH is under fast PC loop. Different power levels for ACK and CQI part.

Transmit power of associated DL HS-SCCH is tuned adaptively

CCH

DCH + CCH

Variable power

Ptx Offset

Ptx Target

DCH + CCH

HSDPA power

PC headroom

Fixed power

PC headroom

Fixed power for HSDPA transmissions.

Controlled with a cell-specific parameter

CCH

R’99 DCH only R’5 DCH+HSDPA


Share of HSDPA and DCH bandwidth on Iub

HSDPA only pipe

Shared pipe

Shared HSDPA AAL2 Allocation Size - SHAS

Shared HSDPA Flow Control Allocation SizeSHFCAS


Shared HSDPA Allocation Size WBTS Parameter SharedHSDPAallocation Indicates the guaranteed bit rate in the Iub for HSDPA traffic Reservation only made when the first HSDPA user enters the cell If the DCH reservation is high so that the requested capacity is not available,

then the largest possible available capacity will be allocated If new HSDPA users arrive in the cell the reservation will be upgraded if

possible to the full value of the configured SharedHSDPAallocation size The value of the parameter depends on the priority required for the HSDPA

traffic – if HSDPA traffic is not as important as DCH traffic then assign a low value

300Kbps is the recommended minimum size 1Mbps is the recommended size for a 1+1+1 site with only 1 WSPC

Mandatory creation parameter Range 0 to 7.2 Mbps in 0.1 Mbps steps


Shared HSDPA Flow Control Allocation Size WBTS parameter SharedHSDPAFlowControlAllocation Indicates the maximum data rate the RNC may use to send mac-d

data on the Iub DCH traffic has strict priority except for the reserved capacity allocated

by the SharedHSDPAallocation parameter Initially this parameter could be set at 1.25 X average air interface

throughput Maximum value should be Total Iub capacity – signalling traffic

requirements Too high DCH usage and aggressive setting of SHFCAS will result in

mac-d data buffering at AAL2 level Buffer overflow will cause the RLC layer to retransmit data in Ack

mode By monitoring HOs and buffer overflows and comparing the

retransmission distributions on the mac-hs and RLC layer can provide a rough indication about the feasibility of the SHFCAS setting


Number Of Overbooked HSDPA Users WBTS parameter NbrOfOverbookedHSDPAUsers The parameter defines the allowed number of

MAC-d flows if the Shared HSDPA AAL2 allocation has failed.

Value 0 can be used to switch the parameter off The amount of MAC-d flows is not restricted if the

HSDPA AAL2 allocation fails and the parameter is not used


HSDPA Parameter Another Parameter recommended for HSDPA can be

found on below documentation

More detailed parameter can be found on NED


TN_RNC_SW_2006_078


TN_3GBTS_SW_2006_0035


HSDPA_Overview


HSDPA with 16 user per cell

One WSPC unit supports max. 3 HSDPA cells.

One WSPC unit supports max. 16 HSDPA users. 1)

Those 16 HSDPA users can be divided freely between three cells.

Packet Scheduler in MAC-hs schedules all users equally regardless of their cell.-> Cells get resources depending on the amount of users and traffic in each.

Max. one HSDPA WSPC in BTS-> Max. three HSDPA cells in BTS.

4 users

4 users8 users

Note 1: The actual amount of supported HSDPA users per WSPC depends heavily on the used Uplink DCH channel speed associated with HSDPA user, see dimensioning rules

HSDPA BTS Configuration in RAS05


HSDPA with 16 user per cell

RAS05.1 The maximum number of HSPDA users

served by a single WBTS is increased to 48 (if QPSK modulation is used).

• The maximum number of HSDPA users per cell is 16.

• HS-DSCH can be transmitted to all cells in the WBTS at the same time.

• 1 WSPC per HSDPA-capable cell is needed.

16 users

16 users16 users

One WSPC unit supports one HSDPA cell. One WSPC unit (one cell) supports max. 16

HSDPA users, i.e, there will be maximum 16 users per cell.

Packet Scheduler in MAC-hs schedules all users in a cell (RAS05.1) instead of all users in the BTS (RAS05).

Cells get resources depending on the amount of users and traffic in each.

HSDPA BTS Configuration in RAS05. 1


RAS05.1 HSDPA with 16 user per cellRoll out (RAS05)• Maximum number of HSDPA users per BTS:

16• HS-DSCH is transmitted to one cell at a time

from the BTS• Time multiplexed between different cells of

the BTS• Up to 3 cells per BTS can be enabled for

HSDPA

Cell specific 1.8/3.6 Mbit/s HSDPA(QPSK/16QAM)

HSDPA

AMC

Frame SizeH-ARQ

Spreading& Multip.

High capacity (RAS05.1)• Maximum number of HSDPA users per cell:

16• HS-DSCH can be transmitted to all cells in the

BTS at the same time

• HSDPA with 16 users per cell brings the HSDPA performance gains for each cell independently of the data rate in the other cells in the same BTS

• Availability of sufficient baseband processing and transport resources required


WBTS and HSDPA (WBTS Structure)

R-bus

DSC-BUS

Iub

WAF

WTR WSM

WPAW

SP

WS

P

WS

P

DSC-BUS

WAF

WTR WSM

WPA

WS

P

WS

P

WS

P

DSC-BUS

WAF

WTR WSM

WPA

WS

P

WS

P

R-bus

T-bus

RT-bus

RR-bus

ST-bus SR-bus

WS

P

WSP-C assigned for HSDPA use. handles L1,

MAC-hs and FP

IFUIFU

AXU

IFU

WSC

CarrierInterFace

WA

MW

AM

WA

M

R-bus

WAM unit handles

Control and AAL2

functions


Requirements to Enable HSDPA on a BTS WN3.0 Software installed on the BTS Due to the capacity requirements only the WSP-C supports

HSDPA At least one WSP-C need to be installed in the BTS to support

HSDPA using 5 codes A software update for the WSP-C is required to support HSDPA No changes are required to any other units for HSDPA to be taken

into operation and their dimensioning can be done according to the normal guidelines

All types of WSP units can be combined in one cabinet All BTS types that can support the WSP-C unit will be able to

support HSDPA


The WSP-C Unit and HSDPA• Processing power on the WSP = Channel Elements• 32 CEs are required to handle the 5 code HSDPA

implementation (HS-SDCH, HS-SCCH and HS-DPCCH)

• The 32 CEs for HSDPA will be reserved from one WSP-C only

• This leaves 32 CEs available for CCH and DCH use. Reservation of the CEs for HSDPA is static and made at BTS start up if the flag is set (HSDPAenabled=1) in the RNC

• 1 to 3 cells are supported depending on the SW release and customer parameters –For RAS05 1 WSP-C will support HSDPA for the whole BTS


The WSP Channel Element and Common Channels

WSP Type CEs

WSPA 32

WSPC 64

WSPD 32

WSPE 16

Bearer (Kbps) CEs required

AMR voice 1

16 1

32 2

64 4

128 4

384 16WSP Type Cells CEs required for

CCHs

WSPA 8 per cell

WSPC 1 - 3 16

WSPD CEs not reduced for CCHs

WSPE CEs not reduced for CCHs

If all types of WSP units were installed in the same BTS the CCH allocation would follow this priority:

1) All CCHs to WSPA

2) WSPC if WSPA fully loaded or does not exist

3) WSPD if WSPA/C fully loaded or does not exist

4) WSPE if WSPA/C/D fully loaded or does not exist


Example Baseband Calculations 1 Sectorised 1 + 1+ 1 with 1 WSPC

WSPC has 64 CEs – 32 CEs for HSDPA -16 CEs for CCHS = 16 CEs left for use by associated channels and AMR channels

Using associated channel 16/128 for HSDPA requires 4 CEs from same WSP 16/4 = 4 rem 0 so support for 4 HSDPA users + 0 AMR users Using associated channel 384 requires 16 CEs from same WSP 16/16 =1 rem 0 so support for 1 HSDPA user and 0 AMR users

Sectorised 1 + 1+ 1 with 2 WSPC WSPC 1has 64 CEs - 32CEs for HSDPA – 16 CEs for CCH s= 16 CEs left for use by associated channels and

AMR channels WSPC 2 has 64 CEs by associated channels and AMR channels Using associated channel of 64/128 for HSDPA requires 4 CEs from same WSP WSPC 1 = 16/4 = 4 r 0 WSPC 2 = 64/4 = 16 r 0 RAS05 only supports 16 HSDPA users/NodeB (WSPC 2 fulfills this) and therefore all remaining WSPC 1 CEs

must be used for AMR so support for 16 HSDPA users and 16 AMR users Using associated channel 384 requires 16 CEs from same WSP WSPC 1 = 16/16 = 1 r 0 WSPC 2 = 64/16 = 4 so support for 5 HSDPA users and 0 AMR users


Example Baseband Calculations 2 Sectorised 1 + 1+ 1 with 3 WSPC

WSPC 1has 64 CEs - 32CEs for HSDPA – 16 CEs for CCHs = 16 CEs left for use by associated channels and AMR channels

WSPC 2 has 64 CEs left for use by associated channels and AMR channels

WSPC 3 has 64 CEs left for use by associated channels and AMR channels

Using associated channel of 64/128 for HSDPA requires 4 CEs from same WSP

WSPC 1 = 16/4 = 4 r 0 WSPC 2 = 64/4 = 16 r 0 WSPC 3 = 64/4 = 16 r 0

RAS05 only supports 16 HSDPA users/NodeB (WSPC 2 fulfills this) and therefore WSPC 1 and WSPC 3 CEs must be used for AMR

WSPC 1 = 16 CEs and WSPC 3 = 64 CEs = 80 CEs

so support for 16 HSDPA users 80 AMR users

Using associated channel 384 requires 16 CEs from same WSP

WSPC 1 = 16/16 = 1 r 0 WSPC 2 = 64/16 = 4 r 0 WSPC 3 = 64/16 = 4 r 0

so support for 9 HSDPA users and 0 AMR users


HSDPA And RNCRNC196RNC196 / 48M 85M 122M 156M 196M 300M 450M

Max HSDPA peak rate per UE [Mbit/s]

3.6

HSDPA active users per cell 16

HSDPA active users per RNC 215 375 540 700 845 1080 1620

Iu-ps HSDPA net bit rate [Mbit/s] 43 94 109 140 176 270 405

HSDPA BTS 128 192 256 320 512 512 512

HSDPA carriers 384 576 768 960 1152 1152 1152

Documents

HSDPA Overview_ 3G.ppt