technology_WCDMA_introduction [Mode de compatibilité]

WCDMA/HSPA network setting overview

Summary

• WCDMA/HSPA/HSPA+ key concept

• Cell planning difference between 2G/3G

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• Link budget difference between 2G/3G

• optimization

Cell planning difference 2G/3G• GSM

• Planning is focused on coverage• Performance depend on C/I• Capacity fixed on available 200k channel

• WCDMA• Cell breathing � coverage decreases as network loading

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• Cell breathing � coverage decreases as network loading increases

• Higher noise rise (UL)• Lower Tx power per user (DL)

• Capacity is interference limited• Planning is focused on Ec/Io, soft handover %, SC

allocation, neighbor list,…..

Optimization• Excessive propagation is a problem in WCDMA

• Pilot pollution• need more tilt as traffic increases

• Soft/softer HO• Avoid excessive HO regions (used up traffic CE)

• Shared antenna system• more tilt (e.g., 2~4deg) than GSM

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• more tilt (e.g., 2~4deg) than GSM• Co-located GSM/3G sites

• GSM/WCDMA, WCDMA/WCDMA neighbor• Load balancing• Interference management

• PSC planning (code and index)• Critical for neighbor list and high sites etc

UMTS Radio Planning

• CDMA systems show a certain relationbetween capacity and coverage, so thenetwork planning process itself depends notonly on propagation but also on cell load.Thus, the results of network planning aresensitive to the capacity requirements. UMTS

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sensitive to the capacity requirements. UMTSforces radio network planners to abandon thecoverage first, capacity later approach.

• Furthermore, for a given design load, due tothe large difference in services bit rates andQoS requirements, UMTS networks exhibitseveral cell ranges possibilities.

Cell Range

GSM UMTS

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speech/data SF=256SF=32SF=8

coverage (EM power >threshold) coverage, load, services, interferenceCell range highly depends on

Codes

• All W-CDMA users occupy the same frequency atthe same time, thus frequency and time are notused as discriminators.

• W-CDMA operates by using CODES to discriminatebetween users. The receiver will ‘hear’ all the

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between users. The receiver will ‘hear’ all thetransmitter signals mixed together, but by using thecorrect code sequence, it can decipher the requiredtransmission channel and the rest is backgroundnoise.

• Spreading sequences are actually unique streamsof 1 and -1 which compose the code associatedwith a user. Therefore, users are discriminatedthanks to spreading codes.

Channelization Codes

Channelization Codes : Users data is modulated by a channelization code. The orthogonality properties of OVSF enable the UE to recover its bits without being interfered by other users. This is true only if

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interfered by other users. This is true only if the system is synchronous, which is the case in downlink, but not in uplink. Thus, the OVSF codes are not used to separate users in uplink and therefore different users can use the same code. But they can be used to distinguish the different physical channels of one user.

Scrambling codes

• The scrambling operation is used for base stationand mobile station identification. In downlink, thesame scrambling code can be used on differentchannels in a cell, but different scrambling codesare used in different cells. In uplink, scramblingcodes are used to differentiate users.

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codes are used to differentiate users.• Scrambling codes reduce the interference between

neighboring cells in downlink since samechannelization codes are used.

• It is important to maintain good cross-correlationproperties between the different scrambling codesin order not to decode an interferer.

• Similar to the reuse of frequency in GSM,scrambling codes are reused.

Scrambling codes

• The number of SC used in uplink 2^24 ----No Uplink SC planning

• The number of SC used in DL is 512-----

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• The number of SC used in DL is 512-----Dowlink SC planning based on neighboring relations.

Codes

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WCDMA/HSPA/HSPA+

• WCDMA• Max traffic ch code = 512 (total) – 40 (CCH) = 472

• HSPA• Fixed SF=16• Hybrid ARQ

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• Hybrid ARQ• No fast power control, no soft HO• Adaptive modulation/coding (QPSK or 16QAM)• PS scheduler depending on Ec/Nt, QoS

• HSPA+• DC-HSDPA• MIMO support for QPSK/16QAM• 64QAM for some MS categories

HSDPA

Radio Resource Allocation

Dedicated Channel

Dedicated Channel

Dedicated Channel

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Shared Channel

DCH/DSCH

DCH transmitted on DPCHFixed SF (SF determines the channelisation code).Power controlled, support for SHO, highest rate – 2 Mbps.

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DSCH transmitted on PDSCHVariable SF.Always DCH associated.DSCH is shared by several users (single or multi-code

transmission).Power controlled (DPCCH), no support for SHO.

User Throughput Management

PowerPowerControlControl

Data Power

Unused Power Data

Unused

Same Throughput

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RateRateAdaptationAdaptation

Data Power

100% Power

100%

HSDPA Channel Operation

HS-SCCHDownlink Transfer Information(UEid, OVSF,...)

HS-PDSCHData Transfer(PS I/B)

2ms

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

OVSFcodes

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DPCHUpper Layer Signaling

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

DPCHUpper Layer Signaling

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

OVSF Code Tree ReservationSF4

SF8

SF16

SF32

SF64

SF128

HS-PDSCH

HS-SCCH

HSDPAHSDPA

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SF4

SF8

SF16

SF32

SF64

SF128

SF256

cmCH. . .

HS-PDSCH

HS-SCCH

. . .

. . .

. . .

HSDPA + R4HSDPA + R4

Scheduler Behavior

FAIR RR CQI PROPORTIONAL FAIR

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FAIR RR CQI PROPORTIONAL FAIR

AMC Principles

QPSK ¼QPSK ½QPSK 400

500

600

700

800

Thr

ough

put (

kbps

)

AMC IllustrationUE Category Reported CQI

AM

CA

MC

2ms

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QPSK ¾16QAM ½16QAM ¾-20 -15 -10 -5 0 50

100

200

300

Ior/Ioc (dB)

Thr

ough

put (

kbps

)

CodingRate

ModulationScheme

Number ofOVSF Codes

AM

CA

MC

2ms

Selected TFRC

Channel coding• Allowed combinations form TFRC (Transport Format and

Resource Combination).• Given sufficiently good channel conditions, a single user

may simultanously reveive 15 parallel multi-codes .

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UE CategoriesHS-DSCH Category

HS-PDSCH Max Number

Inter-TTI Min Interval

Modulation Max Peak Rate

Category 1 5 3 QPSK & 16-QAM

1.2 Mbps


1.2 Mbps


1.8 Mbps


1.8 Mbps


3.6 Mbps

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• QPSK mandatory for HSDPA capable UE

• 16-QAM optional

QAM


3.6 Mbps


7.3 Mbps


7.3 Mbps


10.2 Mbps


14.4 Mbps

Category 11 5 2 QPSK only 0.9 Mbps

Category 12 5 1 QPSK only 1.8 Mbps

UE Capabilities and Max Bit Rates

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soft

CQ

I

Soft CQI vs C/I - Pedestrian_a 1 RX

Category 6 UE CQI Mapping Table

CQI Value

HS-PDSCH Number

RLC Throughput

Modulation

0 out of range

1 1 0 kbps QPSK

2 1 0 kbps QPSK

3 1 0 kbps QPSK

4 1 0 kbps QPSK

5 1 144 kbps QPSK

6 1 144 kbps QPSK

7 2 144 kbps QPSK

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-10 -8 -6 -4 -2 0 2 4 6 8 1010

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C/I (dB)so

ftC

QI

8 2 288 kbps QPSK

9 2 288 kbps QPSK

10 3 432 kbps QPSK

11 3 576 kbps QPSK

12 3 720 kbps QPSK

13 4 864 kbps QPSK

14 4 1008 kbps QPSK

15 5 1296 kbps QPSK

16 5 1440 kbps 16-QAM

... ... ... ...

29 5 3024 kbps 16-QAM

30 5 3024 kbps 16-QAM

Target BLER ≤ 10%

HSUPA

• Release 99: Dedicated channels in Downlink and Uplink

• HSDPA (Release 5)• Shared downlink channel (TDMA), implementing

new techniques

WCDMA – HSDPA – HSUPA

DL DPCH 1

UL DCH 1

DL DPCH 2

UL DCH 2

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• Uplink remains unchanged

• HSUPA (Release 6)• Downlink identical to HSDPA• Implementing the same techniques (more or less)

in the Uplink

HS-DSCH

UL A-DCH 1

HS-DSCH

UL A-DCH 2

HS-DSCH

UL E-DCH 1

HS-DSCH

UL E-DCH 2

Same principles as HSDPA…• HSUPA is the uplink counterpart of HSDPA• Thanks to link adaptation methods (shorter TTI,

HARQ, fast scheduling…), it achieves:• Higher peak data rates (up to 5.6 Mbps) and cell

capacity• Reduced latency…

• Fast HARQ (Hybrid Automated Repeat Request)• The RBS can rapidly request retransmission of

erroneously received data, which implies increased robustness

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robustness• Higher error probability is supported

• Faster TTI (Transmission time interval): 2ms instead of 10ms

• Allows reduction of latency and increased cell throughput

• Tighter resource control, allowing additional capacity• Fast Scheduling

• The system rapidly adapts to interference variations and re-allocates resources between UEs

• Controlled by Node B instead of RNC

2 ms

… but UL and DL are fundamentally different• Shared channel in HSDPA,

Dedicated channels in HSUPA• Shared resource:

• Power and code for HSDPA• Interference headroom for HSUPA

• Scheduling applies to:

Shared Resource

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• Scheduling applies to:• User data rate in HSDPA• Interference level in HSUPA

• Power control• Soft handover• Higher order modulations

Soft Handover

Resource sharing: HSDPA vs. HSUPA

HSDPA

Release 99

Dow

nlin

k P

ower

, cod

e sp

ace

Upl

ink

Inte

rfer

ence

Interference headroom for HSUPA

Release 99 in-cell interference

Inter-cell interference

RoT

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Common channels

Dow

nlin

k P

ower

, cod

e sp

ace

Upl

ink

Inte

rfer

ence

Thermal Noise

Inter-cell interference

Cell A

Cell B Cell CCell B

Cell C

Cell A

Load Control• The Rise-over-Thermal (RoT) is monitored by

the serving Node B

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• Absolute grant can increase or decrease the E-DPDCH power, i.e. the data rate

• Relative grant can only hold or decrease the E-DPDCH power, i.e. the data rate, in order to limit the amount of inter-cell interference

New channels• Downlink

• E-AGCH (Absolute Grants Channel for E-DCH scheduling)• E-HICH (HARQ ACK/NACK Indicator Channel)• E-RGCH (Relative Grants Channel for E-DCH scheduling)

• Uplink• E-DPDCH (E-DCH user data)• E-DPCCH (E-DCH control information: E-TFCI, happy bit,

RSN)

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Planet Modules for WCDMA/HSPA+

• Traffic map generator

• Subscriber Manager

• WCDMA Analysis Module (RCSP, Pilot

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• WCDMA Analysis Module (RCSP, Pilot coverage, service coverage, handover state….), Monte Carlo

• Scrambling code planning

Simulation

• Network analysis: Suitable for intial Network coverage planning and CPICH analysis (Coverage and pollution). This algorithm is an UMTS link budget based on load assumptions (Noise rise)

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• Monte Carlo : Provides comprehensive analysis of the network including Power limits, codes limits, Throuphout, channel element limits.

Traffic MapA traffic map is used to determine areas that• Currently carry high voice traffic• Currently carry high data traffic

A Traffic map is used as an input for WCDMA analysis, it will give the number of subscribers to include in analysis.Typically, we will have

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to include in analysis.Typically, we will have one traffic map per service.

The input of the traffic Map are :

• Population data or subscriber data• Nework data (obtained from the switch)

Subscriber Manager

The subscriber Manager module is designed to define the types of subscribers, their equipements, services and associated quality of service.

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Monte Carlo Algorithm• Planet’s Monte Carlo Simulation tool is based

on• creating semi-random patterns of users based

on traffic map distribution,bearers, and equipment, then repeating this process for a specified number of times. Each repetition of the pattern generation process is a run.

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the pattern generation process is a run.• Repeating the runs helps you determine how

the network performs under a variety of conditions with a variety of subscribers and equipment.

• Statistically, each individual run is of little value. However, over many Monte Carlo runs, the average result provides a realistic representation of the network.

MONTE CARLO Simulation

Monte Carlo Simulations

• A Monte carto Simulation is based on many runs. On Each run, the subscribers are spread on different locations.

• A big number of runs allow to cover all the possible positions of subscribers.

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possible positions of subscribers.• The final result is obtained using averages on

the individual results• The algorithm will stop when the convergence

factor is reached

Monte Carlo run• A monte Carlo run will spread the subcribers

over a geographical area according to thedensity of the traffic map. The number ofmobiles to be spread is computed from thetraffic map

• The mobiles that belong to services with

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• The mobiles that belong to services withhighest priority will be placed and connected tothe network first

• During a run, the algorithm will try to serve oneby one the number of simultaneous mobilesuntil a constraint is broken (Noise Rise Maxreached, Maximal Power of Node B reached,CE, OVSF Codes..)

Monte Carlo Run : No. of Subscribers Spread(Step 1)

• Qty of Subscribers to spread comes from Traffic map, and Erlang per Subscriber value.

• Its is computed for Both Circuit or Packet switched traffic.• CS: E.g. 1000 voice subscribers in the traffic map, for 25 mErlang

per subscriber, returns 1000 x 0.025 = 25 subscribers spread in the analysis

• PS: For Packet Users, we need a representation of the amount of

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• PS: For Packet Users, we need a representation of the amount of time that a connection is active, in much the same way as the 'Erlangs per subscriber' is for Circuit traffic. So we calculate a value of 'packet data Erlangs per subscriber' based on the Session type (which basically provides the proportions of activity/no-activity in a session), the Service (which gives the amount of data transferred per user, plus overheads), and the bearers used (which provide the amount of time that it takes to transfer that data). The combination of these items gives us the activity representation for a single user.

Monte Carlo run : Placing subscribers(Step 2)

The simulation places the subscribers atrandom locations using the traffic mapdensities, and determines the subscriber types

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densities, and determines the subscriber typesfrom the definitions in the Subscriber Manager.

Monte Carlo run : Power ControlUMTS is based on Power control un Uplink and

Downlink Directions• UL: The BS will indicate to each mobile the

required power to be used in order to meet Eb/N0 requirements on UL. This power will depend on the position of the mobile and the used service,

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used service, • Limitation of UL interferences• DL : The BS will transmit on the trafic channel

dedicated for Mobile Mi, the power required to obtain a DL Eb/N0 equal to the

Pnode_B=PCPICH+PSCH/CCH+∑ PTch(Mi)Limitation of DL interferences

Monte Carlo run : UL Coverage(Step 3)Generates uplink analyses : This uses the random

subscriber pattern to determine the number ofsubscribers that can be served, while taking intoaccount the impact of each served subscriber on thenetwork.

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A subcriver can be served on Uplink if:• The power required to communicate with the BS is

below the value of the maximal power of the Mobile.• Admission control : The current noise rise

(Generated by all served mobiles) of the BS is belowthe Noise rise Max

Noise Rise= 10.log{1/(1-L)}

Monte Carlo run : DL Coverage(Step 4)

�A mobile is covered on Downlink if these radio conditions are verified:

• Pilot Coverage (Ec/I0 > Ec/I0 Threshold)

Generates downlink analyses : To do this, the simulation uses the best serving sector information determined in the uplink analysis

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• Pilot Coverage (Ec/I0 > Ec/I0 Threshold)• Service Coverage(Eb/N0 at least equal to Eb/N0

Threshold)�Additional conditions are considered to connect

Mobiles on DL• The Power of the Node-B is below the Max• Number of OVSF codes• Number of CE• Throughout of the Site

Last Run

• On the last run of the simulation, the simulation tool also generates two additional types of data:

• Operating points— These are the results of the simulation divided by sector, carrier, and

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the simulation divided by sector, carrier, and subscriber type. Planet averages these and uses them to create analysis layers.

• Discrete subscriber information — Planet compiles snapshots of each subscriber’s status on each run of the simulation

Rapid Planning

• It is a link budget that provide simplified analysis for uplink and Downlink loading.

• Detailed Subscriber information is not required. Nominal subscriber information is used instead

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Nominal subscriber information is used instead

• This algorithm will not provide information about the use of power, OVSF codes and channel elements since traffic map is not used.

• Can be used for Initial Network planning and if the network is not loaded.

HSUPA in Planet 5.2

• As part of the WCDMA tool, HSUPA is being implemented in Planet 5.2

• On top of the existing Rel99, HSDPA and Rel99&HSDPA carrier types, two new carrier

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Rel99&HSDPA carrier types, two new carrier types have been created:

• HSPA• Rel99&HSPA

• HSPA = HSDPA (Downlink) + HSUPA (Uplink)

Network Settings - Carriers

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Network Settings - FRC

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Network Settings - FRC• FRC: Fixed Reference Channel• A FRC represents an E-DCH channel configuration• They have been used for testing purposes

FRCTTI

Length (ms)

Number of CodesCoding

rate

Max Data Rate

HSUPA UE

CategorySF2 SF4 SF16

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(ms)rate Rate

(kbps)CategorySF2 SF4 SF16

1 2 0 2 0 0.71 1353 2

2 2 2 0 0 0.71 2706 4

3 2 2 2 0 0.71 4059 6

4 10 0 1 0 0.53 508 1

5 10 0 2 0 0.51 980 2,3

6 10 2 0 0 0.51 1960 4,5

7 10 0 0 1 0.29 69 1

Downlink channels• Although HSUPA is an

uplink technology, new downlink channels are necessary

• E-AGCH• E-HICH

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• E-HICH• E-RGCH

• They are combined under HSUPA Control Channels and their power is specified in the sector settings, along with the other common channels

Uplink Noise Rise• DPCH Noise Rise: Noise due to Release 99

and HSDPA subscribers• Total Uplink Noise Rise: Total noise, including

HSUPA traffic

E-DPCH Noise Rise Total Uplink Noise Rise (dB)

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Upl

ink

Inte

rfer

ence

Thermal Noise

DPCH Noise Rise

E-DPCH Noise Rise

DPCH Noise Rise (dB)

Total Uplink Noise Rise (dB)

Uplink Noise Rise• All uplink layers

are based on the Total uplink noise rise

• What is the DPCH Noise

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DPCH Noise Rise for?

E-DCH Layers• FRC Coverage probability

• Only for selected data rates• Based on slow fading standard deviation (clutter types GUI)

and required Ec/No for the FRC (Network settings)• Max Achievable data rate

• This is the data rate of the best FRC that achieves the cell edge coverage probability (Services GUI: typically 85%)

• Average data rate

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• Average data rate• This takes all selected FRCs into account and calculates the

average data rate based on each FRC’s coverage probability

E-DCH LayersE-DCH – Coverage for FRC1

E-DCH – Max Achievable Data Rate

E-DCH – Coverage for FRC1

E-DCH – Max Achievable Data Rate

E-DCH – Average Data RateE-DCH – Average Data Rate

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Monte -Carlo simulation• HSUPA is supported by the Monte-Carlo tool• As a result,

• HSPA carriers will spread HSDPA subscribers• Rel99&HSPA carriers will spread Release 99

subscribers and HSDPA subscribers and HSUPA subscribers

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• Noise Rise• The noise rise output of the Monte Carlo simulation

includes the DPCH Noise Rise and HSUPA traffic• The Total Noise Rise defined in the sector settings

(including HSUPA traffic) will be used by the layers

Documents

technology_WCDMA_introduction [Mode de compatibilité]