WCDMA Radio Optimization

WCDMA Radio Optimization

Contents Radio planning planning optimizat optimization ion ............ .................. ............ ............ ............ ............ ............ ...... 3-14 Quality of Service .............................................................. 15-22 Measurement and statistics collection ............................... 23-29 KPI .................................................................................... 30-32 Accessibility....................................................................... Accessibility....................................................................... 33-38 Retainability....................................................................... 39-44 Integrity Integrity ............ .................. ............ ............. ............. ............ ............ ............ ............ ............ ............ .......... .... 45-47 HSDPA-HSU HSDPA-HSUPA PA ............. ................... ............ ............ ............ ............ ............ ............ ............ ......... ... 48-55

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Contents Radio planning planning optimizat optimization ion ............ .................. ............ ............ ............ ............ ............ ...... 3-14 Quality of Service .............................................................. 15-22 Measurement and statistics collection ............................... 23-29 KPI .................................................................................... 30-32 Accessibility....................................................................... Accessibility....................................................................... 33-38 Retainability....................................................................... 39-44 Integrity Integrity ............ .................. ............ ............. ............. ............ ............ ............ ............ ............ ............ .......... .... 45-47 HSDPA-HSU HSDPA-HSUPA PA ............. ................... ............ ............ ............ ............ ............ ............ ............ ......... ... 48-55

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Radio planning optimization

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Antenna height  

Since WCDMA performance is interference limited the cell dominance areas should be kept as controlled as possible lf the antenna is located “too high” (no proper tilting) then  The cell gathers more traffic and external interference and thus the “effective” capacity is decreased  Produced interference decreases the capacity of the surrounding network  Also surrounding network’s service probability is negatively effected

Antenna azimuth  

Natural obstacles and buildings should be used to create good dominance areas for WCDMA cells This improves the SHO performance and decrease interference  Example of a UMTS cell, that is naturally bordered (wall effect) by buildings

Antenna height simulation  

When re-using the GSM sites, analysis should be made whether the UMTS antennas should be positioned lower This analysis is done with simulations and visiting the site locations in practise Part of network reused few +40meter GSM antenna heights

High UMTS antenna positions lowered to 25-35m

Dominance areas become clear, so less interference is introduced and HO performance is better.  Capacity is increased and performance enhanced!

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Antenna tilt  





ln addition to antenna height, downtilting is very important physical means for interference minimizing in WCDMA Basic rule of designing antenna tilt is that the height of the antenna should be selected with respect to the wanted amount of cell range If the cell range with respect to available antennas and their tilting with a feasible amount of tx-power becomes too large to suit the network plan, then the antenna must be lowered According to experience, the analysis should start with the optimum tilting and not by reducing the tx-powers of the cell, which can be optimized after the tiltings are done Horizontal plane h

Antenna tilt 

According to experience even 15 degrees of downtilting is not impossible (lf the radiation pattern of the antenna supports it), although in practice not very often needed.



There has also been lot of discussion of a potential need to change the tilts often during the network lifecycle (even regularly)



However practice have not shown such need if the tilts are design well from the start with help from simulations



But once WCDMA gets congested this might be given another look (Remote tilts).

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Sectorisation  

According to simulations and analysis, sectorisation of WCDMA site helps to improve capacity of the network However, as permissions for additional antennas are quite hard to come by, e.g. 6-sector sites might be very rare Antenna 3 Other to own dB cell Beam interference width ratio, i



Sectorisation can increase the capacity if correct beamwidth antennas are selected and SHO properly controlled

Served users

Soft handover overhead

UL coverage probability (outdoor to indoor) For 8/64/144 kbps

OMNI CASE Omni

0.79

240

28%

70/32/40%

THREE SECTORS CASE 120 900 650

1.33 1.19 0.88

0

441 461 575

39% 35% 34%

85/50/59% 87/55/62% 86/59/62%

FOUR SECTOR CASE 1200 900 650 330

1.72 1.49 1.09 0.92

489 510 604 691

54% 51% 41% 40%

90/62/68% 92/67/72% 92/70/71% 88/65/64%

SIX SECTOR CASE 120 900 650 330

2.18 1.97 1.43 1.15

0

593 627 758 880

64% 59% 55% 48%

95/75/79% 96/80/82% 96/80/81% 93/76/76%

Served users in DL

UL coverage probability (outdoor to indoor) for 8/64/144 hbps

Master head amplifier 





The MHA can be used in WCDMA in the uplink direction to compensate for the cable losses and thus reducing the required mobile station’s transmit powers Using MHA the performance in uplink can be improved also in WCDMA systems. However in practice if the network turns to downlink limited then the MHA won’t help

Other to Served own cell users in interference UL ratio, I

THREE SECTORED CASE, 65O antenna No MHA With MHA

0.60 0.61

1038 1064

807 746

93/78/78% 95/82/82%

FOUR SECTTORED CASE, 65O antenna No MHA With MHA

0.73 0.73

1089 1107

884 846

96/86/85% 98/89/89%

SIX SECTORED CASE, 33O antenna no MHA with MHA No MHA 4dB cable losses WITH mha 4 DbN CABLE LOSSES

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0.88 0.90

1124 1132

1052 1021

97/87/86% 98/90/90%

0.88

1109

1057

95/83/82%

0.90

1132

1016

98/90/90%

Master head amplifier  

  



Increases uplink coverage/capacity in low loaded network Compensates for feeder and combiner losses in the uplink direction, increasing coverage for suburban, rural and road sites where antennas are in very high positions and the feeder lines are long Allows UEs to reduce transmission power level With heavily loaded network (i.e. high interference) the benefit of the mast head amplifier is negligible Also in downlink limited 3G networks (DL oriented traffic, users in cell edge, DL tx-power per user low e.g. in for high bit rate indoor users) the usage of mast head amplifier is not justified Needs extra space in the masts and increase the wind load

MHA is sometimes called as Tower Mounted Amplifier (TMA)

Transmit power increase

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Transmission powers  



 

Default transmission powers are determined by the equipment vendors. In initial phase of the planning  Transmission powers of TCHs and CCHs needs to be set  Maximum UE transmission power is to be defined In DL the power tuning between TCHs and CCHs has effect on network performance  More power to CCHs —> better channel estimation, which improves the Eb/No performance and thus improves coverage  More power to TCHs —> better capacity  Rule of thumb: 15-20% of DL total power is used for CCHs Maximum UE transmission power should be set to 21-24 dBm (network operation and battery life) Most important control channel is the common pilot channel (CPICH)

Transmission powers   

Also other control channels beside CPICH need power (for example BCH) to enable correct functioning of the system All the other common control channels are powered in relation to the P-CPICH The goal of allocating power to the common channels is to find a minimum power level needed for each channel to secure the network operation and to provide the same cell coverage area as with CPICH, but not to waste any capacity left for the traffic channels.

Typical DL power recommendations Channel

Allocated power

Max power of the Node B

43 dBm

CPICH

Max power-10dB

PCH

Max power-11 …-13 dB

SCH

Max power-11 …12dB

FACH

Max power-12…-13dB

BCH

Max power-11 …13dB

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Recall: Some control channels   



  

PCH: Paging channel initiates the communication from network side SCH: Synchronization channel FACH: Forward access channel carries control information to terminals that are known to be located in the given cell. ls used to answer to the UL RACH message. BCH: Broadcast channel carries network specific information to the given cell (random access slots for UL, antenna configuration etc) PICH: Paging indicator channel is used to provide sleep mode operation for UE AICH: Acquisition indicator channel is used to indicate the reception of RACH CCPCH: Primary and secondary common control physical channels (P-CCPCH and S-CCPCH) are physical channels that carry BCH, FACH and PCH.

Transmission powers • • • • • •

P-CCPCH transmitted with activity factor 0,9 S-CCPCH transmitted with activity factor 0,25 SCHs transmitted with activity factor 0,1 AICH, PICH and CPICH are transmitted continuously The BCH is transmitted on the P-CCPCH and FACH and PCH on the S-CCPCH The BCH is transmitted on the P-CCPCH continuously expect during the 256 first chips, when the P-SCH and S-SCh are transmitted we can assume 0,1 activity factor for the SCHs and 0,9 for the P-CCPCH Channel

Allocated power

Power out of the total common channel powers

Power out of the maximum Node B transmission power (20W)

P-SCH

0,331W

S-SCH

0,224W

PICH

0,1W

AICH

0,126W

P-CCPCH

0,245W

S-CCPCH

1,165W

CPICH

1W

31%

5%

All common ch.

3,191W

100%

16%

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Carrier addition  



Adding a carrier to less transmit power per carrier, if no additional PA is installed Additional carrier can also be used for e.g. optimisation of indoor coverage with clever network planning and parametrisation (not with power reduction) Even with less transmit power, there is a capacity gain possible especially for high traffic areas (low cell range)  Actual gain produced is heavily dependent on the traffic mix

Carrier configuration 1C>2C 2C>3C

Dense Urban 350m 92% 41%

DL Capacity gain Urban Suburban 550m 1700m 87% 37%

77% 27%

Rural 7km 60% 15%

Indoor coverage aspects 



 

Most of the UMTS users are indoors. Therefore good indoor coverage is vital for UMTS success In GSM indoor coverage is pretty straightforward to plan. However this is not the case with WCDMA Indoor coverage provided from outdoor base stations is highly sensitive to cell load increase in WCDMA If outdoor users is given a high-data rate bearer this can result in loss of coverage to users indoors INDOOR COVERAGE ANALYSIS • Consider different RAB / coverage scenarios • Carefully estimate the effect of cell loading to the coverage • Use repeaters if possible • Assess the need for indoor sites • Carry out real-life verification of the planning - 10 -

Pilot pollution  

Pilot pollution is faced on a certain area when there is no clearly dominant CPICHs over the others. The pilot pollution creates an abnormally high level of interference, which is likely to result in the performance problems  Increased interference level  Poor service quality, decreased throughput or increased delay  Decreased service access  Frequent changes in Active Set and potential risk for unnecessary handovers.  Higher non-controllable load

Pilot pollution  

The yellow dots represent points where 4-5 CPICHs were received within 6dB window As Active Set size is typically 3, in this situation the rest of the Pilots produce unnecessary interference

Pilot pollution 

   

Pilot pollution can be (at least partly) avoided by planning the CPICH powers and SHO parameters so that throughout the network there is only 2-3 CPICHs available for the UE’s, strong enough to be included in the Active Set. All CPICH outside Active Set should be clearly weaker Antenna design, height and tilt are selected carefully Balanced UL & DL SCH/DCH power adjustments

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Neighbour cell relations 



 



The Monitored Set is also called as a Neighbour List. This list can be defined in network planning and it can be later changed in network optimization. The list of neighbours play an important role since WCDMA is interference limited. Insufficient planning of neighbour relations will lead to unnecessary high interference  E.g. if suitable SHO candidate is not in the monitore set and thus it is not selected to active set then it’s turning to a “pilot poIIuter”  On the other hand, unnecessary neighbours increase signalling and effects the SHO selection negatively Accurate neighbour relations planning is much more important than in GSM In GSM it is possible to “hide” cell planning mistakes by frequency planning, in CDMA the such inaccuracies will effect the system capacity The effort saved in frequency planning is spent in more detailed cell planning

Neighbour cell relations 







The parameters to control the neighbour relations and the algorithms how system evaluates neighbours for cell lists, depend on vendor  minimum CPICH RSCP or Ec/lo  Ec/lo margin  maximum number of neighbours A neighboring set (or monitored set) is defined for each cell  Utilise planning tools automatised functions and check with drive tests  Optimise according to CPICI-l coverage and SHO parameters UE monitors the neighboring set that may contain  Intra-frequency monitored list: Cells on the same WCDMA carrier (Soft HO)  Inter-frequency neighbor list: Cells on another WCDMA carrier (hard HO)  Inter-system neighbor list: For each neighboring PLMN Missing neighbour can be detected during drive tests  If the best cell shown in the 3G scanner does not enter the active set missing neighbour - 12 -



Incilude the missing cell to neighbour list if it’s wanted to active set or change cell plan if FIO

SHO optimisation  





Soft/Softer HO planning and correct operation is one of the most important means of optimizing WCDMA networks The importance is high because of the high biterate (pathloss sensitive) and RT (delay sensitive) RABs SHO is measured in terms of probability, the percentage of all connections that are in SHO state The probability is effected by network planning and parameter settings

SHO optimisation SHOs have effect to the network performance Advantages  Required to avoid near-far effects  Coverage increases when more distant users can connect  Capacity can be “increased” if more users can be connected  Alongside with PC, SHO is the main interference migitation means in WCDMA Inconvenient  Requires more connections, thus eats DL transmission power and decreases capacity  Introduces more interference to DL  Increases the traffic in lub 40% SHO probability1.4 times the traffic! 

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SHO optimisation 

 

 

Probability for soft HO should be set to 30-50% and for softer HO to 5-15%, depending on the area  Too high SHO% results in excess overlapping between cells —> other-cell interference increases —> capacity decreases  Too high SHO% also leads to poorly utilised network capacity (unnecessary links)  With too low SHO% the full potential of network is not utilised and transmission powers cannot be minimized —> trouble with interference SHO performance is planned with a planning tool and optimised by measurements in live network. In early stage SHO% can be planned high, since the traffic density is smaller. With increasing traffic coverage decreases and SHO areas become smaller. SHO% can be tuned with related parameters and dominance areas SHO most important in urban areas due to serious shadowing

Summary KPI Indicator

KPI

Coverage

Interference

Measured RSCP > -88 dBm over 97% of area (value should be adapted based on required margins) Measured Ec/No > -9 dB over 95% of area

Cell overlap

Cell overlay

< 3 cells over 95% of area

Qualitative

Cell Overshoot

No cell detected above -111 dBm (CPICH RSCP) No cell fragmentation detected

Integrity of cell coverage Best server plot

KPI target example

Clean boundary without unnecessary change of best server

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Quality of Service

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Quality of Service – – definitions (1) QoS (ITU-T): << The collective effect of service performance which determines the degree of satisfaction of a user of the service>>. Network Performance, NP (ITU-T): << The ability of a network portion to provide the functions related to communication between users>>.

Quality of Service – – definitions (2) User domain: throughput, accuracy, dependability (reliability, availability), … Provider domain: delay, loss, utilisation, … User QoS Requirements

QoS offered by Provider

QoS experienced By Users

QoS achieved by User

Quality of Service –definitions (3) QoS and NP, Performance network (ITU Rec. E800)

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Quality of Service and user satisfaction Commercial offer

Competition

Trends

User expectations in terms of QoS

Users satisfaction

Technical QoS

Network performance

Non-technical QoS

Terminal performance

Sales points

Radio Access Bearer QoS

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Customer care

Radio Access Bearer   

  

Main task of the UTRAN is to create and maintain RAB for communication between UE and CN. RAB is build up in order to give for CN elements an illusion about fixed communication path to UE. The network builds up the end-to-end QoS connection from small pieces, which compose a complete chain without bottlenecks These pieces are called Bearers When the connection is set up, the network elements negotiate the QoS requirements of the bearers set up between them The result is a compromise, in which the QoS requirements and network’s capacity is taken into account.

UMTS QoS Classes Traffic Class

Example application

Conversation class

Speech and video calls

Streaming class

Real-time streaming video

Interactive class

Web surfing

Background class

File downloading, e-mails

UMTS QoS Classes Traffic Class

Properties

Conversation class

Minimum fixed delay, no buffering, symmetric traffic, guaranteed bit rate Minimum variable delay, buffering allowed, asymmetric, guaranteed bit rate Moderate variable delay, buffering allowed, asymmetric traffic, no guaranteed bit rate Big variable delay, buffering allowed, asymmetric traffic, no guaranteed bit rate

Streaming class

Interactive class

Background class

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UMTS QoS Parameters Parameter

Explanation

Maximum bit rate

Defines the maximum bit rate when delivering information between end points of UMTS bearer (<2Mbps) Defines the bit rate that the UMTS bearer must carry between its end points

Guaranteed bit rate

Allowed transfer delay Set the limits for delay (>80ms) QoS negotiable

QoS of some services are not negotiable (speech), packet data services admit various QoS classes

Some values of QoS UMTS parameters classes Traffic class

Conversation Streaming Interactive

Background

Maximum <2048 throughput (kb/s) Scheduling Yes/No Max. SDU size <_ 1500 or 1502 (octers) Corrupted SDU Yes/No delivery Residual BER 5* 10-2, 10-2, 5* 10-2, 10-2, 4* 10-3, 10- 4* 10-3, 105, 5, 5* 10-3, 10-4, 5* 10-3, 10-3, 10-6 10-4, 10-5, 10-6 6* 10-8 6* 10-8 SDU error rate 10-2, 7*10-3, 10-1, 10-2, 10-3, 10-4, 10-3, 10-4, 10-3 7* 10-3, 10-3, 10-6 10-6 10-4, 10-5 10-4, 10-5 Transfer delay (ms)

100 –maximum 250 – maximum value value

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QoS Negotiation UTRA (NB, RNC)

UE

CN

E2E service request

Maximum bit rate Guaranteed bit rate Transfer delay QoS negotiable (y/n)

UMTS bearer service: Request for UMTS QoS Class Maximum bit rate Guaranteed bit rate Transfer delay QoS negotiable (y/n) RAB assignment request RRM: Admission control

Radio bearer and radio link establishment

QoS negotiation RAB assignment response

UMTS Bearer service with negotiated QoS

QoS in UMTS 







In early UMTS Release 99 all conversational and streaming class traffic were offered over the CS bearer  Voice  RT multimedia (e.g. videotelephony) In early Release 99 only Interactive and background class traffic utilisises the PS bearer Release 4 capable networks introduce some streaming class traffic on PS bearer as well Release 5 brings along a full portofolio of PS bearers also utilised for conversation traffic

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QoS in UMTS 

  

The QoS over the air interface is implemented by matching each radio bearer with a transport channel whose format set defines the QoS parameters The mapping is performed during the establishment of the RAB RNC performs the mapping of RAB characteristics to actual resource requirements (vendor dependent) Example of mapping for web service, which belongs to the interactive class

Parameters

Interactive Class

Radio Resource mapping

Maximum bit rate

128 kb s

SF=16

Maximum SDU size

1500

Ma to Trans ort formats

Residual BER

10 -6

1/3 turbo encoder

Transfers Dela

NA

Interleaver=40 or 80 msec

Guaranteed bit rate

64 kb s

SF=16

Deliver order

es

Use Acknowled ed RLC

SDU Error Ratio

1%

Set appropriate threshold

Deliver of errorneous

NO

Use Acknowled ed RLC

QoS in UMTS   

Operators can define the wanted QoS profile (in HLR) per subscriber Users can be categorised (QoS differentiation) for various tariffing schemes Traffic handling priorities can be set (THP)

Business Remote office Basic free time Traffic class All four allowed All four allowed Only converational (voice calls) and background Max bit rate 400 kbps 800 kbps 64 kbps Guaranteed bit 384 kbps 64 kbps 12 kbps rate Allowed THPs THP 1 (e.g. for THP 2 (e.g. for THP 3 e-mail file tranfer) download)

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QoS in UMTS

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Measurement and statistics collection

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Measurement tools typology Field Measurements Generic Measurement tools

OMC counters Specific System Measurements

Passive capture tools Calls generators

A. Field measurements Drive test equipment measures and softwares

GPS

Controler

Energy Processing

Mobile QoS test equipment

Man to machine interface

Poor Coverage example

- 24 -

External antennas

Poor Cell Dominance example

Pilot Pollution example

- 25 -

Example of neighbor missing (Ec/Io)

Corner effect (Ec/Io)

- 26 -

QVOICE QVS

PSTN / ISDN Cellular Network

QVP-Server

Data collection Post processing

QVP-Client

3 parts: QVM (QV Mobile), QVS (QV Stationary) et QVP (QV Post processing).

B. System measurements OMC measurements Specific • Alcatel: RNO • Siemens: SPOTS • Ericsson: TEMS Analyser •…

Generic • APIC from Metrica • MyCom from MYCom • AirCom • NetAct SQM: Nokia • OVPI: HP (for IP equipments)

- 27 -

KPI processing tools Commercial tools:

• BiVision • ADC/Metrica, • NetAct (Nokia, for 3G) • UTRAN Network and service Analyzer (Tektronix)

• Actix

Analysis based on OMC-R counters Analysis tools using these counters (generally they are specific). Example: RNO or NPA of Alcatel, SPOTS from Siemens, etc.

- 28 -

Passive tools examples • • • • •

HP : Ovis (data services tests, producers KPIs). RamCom : Network Consultant (A, Gb, Gi, Gn, Iub, Iur, Gi and Gn interfaces) Trafica (NetAct from Nokia) Ipanema : Ipanema (2,5 G and 3G data traffic). Cigale (Astellia): 2 and 3G traffic.

GIS display

- 29 -

KP I

- 30 -

Optimization process Performance measurements Update of parameters, site configuration

Key Performance Indicators (KPI)

Network tuning

• Reasons that lead to otimisation:

Performance analysis

– Improve the performance – Business reasons (cost-effective) – Troubleshooting

Network statistics • • • •

Network statistics are collected from different network elements with counters Different types of counters are used KPIs are needed to provide information of the network performance Raw counter data too detailed to be used in monitoring and optimisation (Some counters can be used as KPIs)

KPI definition • •

•

•

KPIs are composed from several counters KPI categories – Accessibility – Retainability – Integrity Documentation of KPIs is important – Same KPI can be defined from different counters or formula can be incorrect Measurement period must be reasonable – Too much averaging if too long – Not enough statistical information if too short - 31 -

KPI Example

Optimisation based on KIPs: • Optimisation is performed for each category • Find the worst performing cells • Find the reasons behind the poor performance • Make the changes in the network • Monitor the performance after the changes

- 32 -

Accessibility

- 33 -

Accessibility : call set-up MS Originating Call Setup Random Access RRC Connection Setup Service Request Authentication Security

RAB Assignment

Accessibility workflow

Performance Measurements

Alarms Cell Availability Counters

Performance Analysis

Idle mode RRC Connection Random Access NAS RAB Assignment

Recommendation & Im lementation

Verification of changes

Squal, Srxlev, qQualmin, qRxLevMin, maxTxPowerUl, t3212, t3312, aichPower, powerOffsetP0, preambleRetransMax, constantValueCprach

O t h e r M o d u l e s

pmTotNoRrcConnectCsSucc pmTotNoRrcConnectPsSucc pmNoRabEstablishAttempt pmNoRabEstablishSuccess pmNoPageDiscardCmpLoadC pmNoPagingAttemptUtranRejected

Worst performing cell for CS and PS  pmTotNoRrc ConnectReq CsSuccess  pmTotNoRab EstablishS uccess < RAB >  ×   100 ×  pmTotNoRrc ConnectReq Cs pmmTotNoRa bEstablish Attempt RAB < >  

 pmTotNoRrc ConnectReq PsSuccess  pmTotNoRab EstablishS uccess < RAB >  ×   100 ×  pmTotNoRrc ConnectReq Ps   pmmTotNoRa bEstablish Attempt < RAB >

- 34 -

Service success set up rate (CS) Speech 100x

pmTotNoRrcConnectReqCsSucc x pmTotNoRrcConnectReqCs

pmTotNoRabEstablishSuccessSpeech pmmTotNoRabEstablishAttemptSpeech

Circuit-Switched 64 100x


pmTotNoRabEstablishSuccessCS64 pmmTotNoRabEstablishAttemptCS64

Circuit-Switched 57 100x


pmTotNoRabEstablishSuccessCS57 pmmTotNoRabEstablishAttemptCS57

Service success set up rate (PS) Packet-Switched Data Streaming 100 x (Y) x

pmTotNoRabEstablishSuccessPacketStream + pmRabEstablishSuccessPacketStream128 pmTotNoRabEstablishAttemptPacketStream + pmRabEstablishAttemptPacketStream128

Where Y =

pmTotNoRrcConnectReqPsSuccess PmTotNoRrcConnectReqPs

Packet-Switched Data pmTotNoRabEstablishSuccessInteractive 100 x (Y) x pmTotNoRabEstablishAttemptPacketInteractive + HS1_HardHO_Flow

Where Yx

pmTotNoRrcConnectReqPsSuccess pmTotNoRrcConnectReqPs

HS1_HardHO_Flow= pmNoOutgoingHsHardHoAttempt – pmNoHsHardHoReturnOidSource -pmNoIncomingHsHardHoAttempt - pmNoHsHardHoReturnOldChTarget

- 35 -

Idle mode paging Successful First and Repeated Page attempts of total number of first attempts, Paging success rate in aMSC 100 x

NPAAG1RESUCC + NPAG2RESUCC NPAG1GLTOT + NPAG1LOTOT

Paging intensity per cell in a RNC (if RNC, LA and RA consist of exact same cells): pmCnlnitPagingToldleUeLa + pmCninitPagingToldieUeRa + pmCnlnitPagingToldleUe Measurement period x total number of cells in tha t RNC

Random access: preamble detection Number/percentage of false detections, which is the case that preamble is detected but there is no enough energy in message part, due to noise on the random access channel for a carrier (it could be due to loss of AICH, wrong recognition of preamble or loss of RACH message part after the UE sends message out):

pmNoPreambleFalseDetection or pmNoPreambleFalseDetection x100% pmPositiveMessages

Random access: AICH detection Percentage of getting AICH but no RRC connection setup, excluding cell (re)selection:

No of AICH_ACK-No of RRC connection setup-No of cell (re)selection during RRC establishment No of AICH_ACK

- 36 -

x100%

Admission control: DL transmission carrier power DL transmission carrier power Average DL TX power for a cell-carrier: 102



i pmTransmittedCarrierPower i x 2

=0



102

 pmTransmittedCarrierPower i

=0



Admission control: UL RSSI Average UL RSSI for a cell-carrier: 62



[pmAverageRssi i x (0.5xi – 110.5 )]

=0



62

 pmAverageRssi

i

=0



Admission control: Air Interface Speech Equivalent (ASE) Average UL ASE for a cell:

Average DL ASE for a cell:

- 37 -

pmSumOfSampleAseUI pmNoOfSampleAseUI

pmSumOfSampleAseDI pmNoOfSampleAseDI

Admission control: code allocation Code allocation failure for SFn, where n is the spreading factor for a cell could be found in the following formula (as an example the SF 128 was used):

pmNoDIChCodeAllocFailureSF128

x100%

mNoDIChCodeAllocAttem tSF128

Admission control: compressed mode How many users are in compressed mode? Well the average number of users in compressed mode for a cell:

pmSumCompMode pmSampesCompMode

Admission control: load sharing Ratio between RRc connection returning and redirection due to load sharing for a cell:

pmNoOfReturingRrcConn mNoLoadSharin RrcConn

The failures can be observed by the successful rate of directed retry to GSM for a cell:

pmNoDirRetrySuccess mNoDirectionRetr Att

- 38 -

x100%

Retainability

- 39 -

Service retainability workflow

Performance Measurements


Recommendation & Im lementation

pmSystemRabRelease pmNormalRabRelease pmNoSysRelSpeechULSynch pmNoOfTermSpeechCong pmNoSysRelSpeechSoHo


ReleaseConnOffset maxTxPowerUl,SirMax, MinPwrRl, treselection, timetotrigger1, reportingrange1

O t h e r M o d u l e s

UL out of Synch Congestion control, SHO functions IFHO functions IRAT Handovers

Dropped call rate CS Speech 100x

pmNoSystemRab ReleaseSpeech (pmNoNormalrAB ReleaseSpeech + pmNoSystemRab ReleaseSpeech)

Circuit-switched 64 100x

pmNoSystemRabReleaseCs64 (pmNoNormalRab ReleaseCs64 + pmNoSystemRab ReleaseCs64)

Circuit-switched Streaming 100x

pmNoSystemRabReleaseCsStream (pmNoNormalrRab ReleaseCsStream + pmNoSystemRab ReleaseCsStream)

Dropped call rate PS Packet Switched data Streaming 100x

pmNoSystemRab ReleasePacketStream + pmNoSystemRab ReleasePacketStream128 (pmNoNormalRabReleasePacketStream + pmNoSystemRabReleasePacketStream + pmNosystemRabReleasePacketStream128)

Packet Switched data Interactive 100x

pmNoSystemRab ReleasePacket (pmNoNormalRab ReleasePacket + pmNoSystemRab ReleasePacket)

- 40 -

Minutes per drop CS Speech 100x

Sp_U_User pmNoSystemRab ReleaseSpeech

x number of minutes

Circuit-switched 64 100x

Cs64_U_User pmNoSystemRab ReleaseCs64

x number of minutes

Circuit-switched Streaming 100x

Cs57_U_User

x number of minutes pmNoSystemRab ReleaseCsStream

Minutes per drop PS Packet Switched data Streaming 100

Pstr_P8_U_User pmNoSyatemRab ReleasePacketStream + pmNoSystemRab ReleasePacketStream128

x No of minutes

Packet Switched data Interactive 100

Plntdch_U_User+PlntHs_U_User+PlntFach_U_User pmNoSystemRab ReleasePacket

x No of minutes

Packet Switched data Interactive HS 100

PlntHs_U_User pmNoSystemRab ReleaseHs

x No of minutes

Handover failure rate The following formula shows the failure rate for RL addition/replacement to active set 100x

pmNoTimesCellFailAddToActSet (pmNoTimesCellFailAddToAct + pmNoTimesRlAddToActSet

- 41 -

Handover failure rate: HS cell change The following metric measures the success rate for HS Cell Change in target cell

100x

pmHsCcSuccess pmHsCcAttempt

Handover failure rate: out of synchronization Shows fraction of drop due to uplink Out of Sync reason. 100x

(pmNoSysRelSpeechULSynch) (pmNoNormalRabReleaseSpeech + pmNoSystemRabReleaseSpeech)

Handover failure rate: missing neighbor 100x

pmNoSysRelSpeechSoHo (pmNoSystemRabReleaseSpeech + pmNoNormalRabReleaseSpeech)

Shows fraction of speech drop due to HO action when a valid or non-valid cell cannot be added to active set. This includes also drop due to missing neighbour. 100x

pmNoSysRelSpeechNeighbr (pmNoSystemRabReleaseSpeech + pmNoNormalRabReleaseSpeech)

Shows fraction of speech drop due to missing neighbour reason when a non-valid cell cannot ne added to active set.

- 42 -

Inter-frequency handover failure rate (CS) Drop due to IHO failure for speech: Outgoing IFHO failure when UE failed to return to present active set.

100x

pmFailNonBlindInterFreqHoFailRevertCsSpeech12 pmAttNonBlindInterFreqHoCsSpeech12

Inter-frequency handover failure rate (PS) Drop due to IFHO failure for PS less or equal to 64 kbps: Outgoing IFHO failure when UE failed to return to present active set. 100x

pmFailNonBlindInterFreqHoFailRevertPsInteractiveLess64 pmAttNonBlindInterFreqHoPsInteractiveLess64

Drop due to IFHO failure for PS greater than 64 kbps: Outgoing IFHO failure when UE failed to return to present active set. 100x

pmFailNonBlindInterFreqHoFailRevertPsInteractiveGreater64 pmAttNonBlindInterFreqHoPsInteractiveGreater64

Drop due to IFHO failure for PS streaming and others: Outgoing IFHO failure when UE failed to return to present active set. 100x

pmFailNonBlindInterFreqHoFailRevertStreamingOther pmAttNonBlindInterFreqHoStreamingOther

- 43 -

IRAT handover The following metric measures hard handover success rate between UtranCell and target GSM cell for speech calls. The formula is considering the GsmRelation. 100x

pmNoSuccessOutIratHoSpeech pmNoAttOutIratHoSpeech

The following metric measures hard handover success rate between UtranCell and target GSM cell for streaming calls. The formula is considering the GsmRelation. 100x

pmNoSuccessOutIratHoCs57 pmNoAttOutIratHoCs57

IRAT handover The following metric measures hard handover success rate between UtranCell and target GSM cell for Multi-RAB calls. The formula is considering the GsmRelation. 100x

pmNoSuccessOutIratHoMulti pmNoAttOutIratHoMulti

The following metric measures cell change failure rate between UtranCell and target GSM cell for PS calls when the UE successfully returns to UtranCell. The formula is considering the GsmRelation. 100x

pmNoOutIratCcReturnOldCh pmNoOutIratCcAtt

Congestion Shows fraction of speech drop due to cogestion action 100x

(pmNoOfTermSpeechCong) (pmNoNormalRabReleaseSpeech + pmNoSystemRabReleaseSpeech)

Shows fraction of video call drop due to cogestion action 100x

(pmNoOfTermSpeechCong) (pmNoNormalRabReleaseCs64 + pmNoSystemRabReleaseCs64)

- 44 -

Integrity

- 45 -

Service integrity workflow Performance Measurements


BLER counters and Down Switching counters

Recommendation & Implementation

BLER, power, SIR parameters

Test the settings


Check statistics If not OK, roll back

Throughput

pmFaultyTransportBlocksBcUl pmTransportBlocksBcUl pmNoOfSwDownNgCong PmNoOfSwDownNgAdm PmDl Traffic volume counters

BLER The method for finding worst performing cells is based on top to down analysis. Initial worst 10-15 performing cells can be identified based on the Uplink Block Error rate before combining. pmFaultyTranspoertBlocksBcUL 100x

pmTransportBlocksBcUI

Throughput Average throughput per cell and RAB in the DL, excluding HSDPA: Throughput =

pmDlTrafficVolume pmSumRabEstablish

pmSamplesRabEstablish

*ROPsec

RAB efficiency excluding HSDPA The RAB efficiency can also be checked RABEfficiency =

Actual Bitrate per RAB Nominal Bitrate per UeRc=x

UeRc stands for different RAB’s UeRc=2, Speech UeRc=3, Video Call UeRc=4, Packet Common Channel UeRc=5, PS 64/64 UeRc=6, PS64/128 UeRc=7, PS 64/384 UeRc=10 multirab Speech+PS 0 or PS 64/64).

- 46 -

Payload counters Radio UL Payload counter DL Payload counter Connection type Speech pmUITrafficVolumeCs12 pmUITrafficVolumeCs12 PS64/64 pmUITrafficVolumePs64 pmUITrafficVolumePs64 PS64/128 pmUITrafficVolumePs128 pmUITrafficVolumePs128 PS64/384 pmUITrafficVolumePs384 pmUITrafficVolumePs384 CS 57.6 pmUITrafficVolumeCs57 pmUITrafficVolumeCs57 (streaming) CS 64 (UDI) pmUITrafficVolumeCs57 pmUITrafficVolumeCs57 Speech/PS pmUITrafficVolumeCs12Ps64 pmUITrafficVolumeCs12Ps64 64 multirab PS pmUITrafficVolumePsCommonpmUITrafficVolumePsCommon Common

- 47 -

HSDPA-HSUPA

- 48 -

HSPA Key features-AMC Cood CQI Bad CQI

High Code Effective Rate

Good coverage

Low Code Effective Rate

Channel Quality Feedback (CQI) UE measures channel quality (SNR or Ec/No) and reports to Node B every 2ms or longer time. Node B chooses modulation scheme, transport block size and code effective rate based on CQI

Bad coverage

AMC could improve radio bandwidth and fit for high speed radio transmission.

HSPA Key feature – – System resource Resource allocation Reasonable resource allocation can improve throughput performance

OVSF Code resource

Minimum Code available for HSPA but not for R99, so this resource can’t allocated too much to avoid no code for HSPA access channel.

DCH Code HSPA Maximum For R99 and HSPA access and traffic channel Code

Power resource

Threshold for R99 load control, which should not be allocated too much to avoid no power for HSPA user

- 49 -

HSPA Minimum Code

HSPA Key feature-Scheduling Transmission slot 2 ms UE2 UE1

UE3

Data transmission slot

Mobility management

- 50 -

Sample message flow to begin HSDPA operation UE

Bode B

RNC

1

UTRAN decides to start HSDPA for the UE Measurement Control message (Setup Event 1d) 2 Measurement Report message (Report Event 1d) Radio link reconfiguration prepare 3 Radio link reconfiguration ready Radio link reconfiguration commit Radio Bearer Reconfiguration message 4

User plan data can flow on the HS-DSCH Radio Bearer Reconfiguration Complete message

Sample message flow to stop HSDPA operation UE

1

Bode B

RNC

UTRAN decides to stop HSDPA but keep DCH for the UE due to: • Low Downlink data activity • High UE mobility

Radio link reconfiguration prepare

2

Radio link reconfiguration ready Radio link reconfiguration commit Radio Bearer Reconfiguration message 3

User plane data only flows on the DCH Radio Bearer Reconfiguration message

- 51 -

Cell change triggering with event 1d Ec/No

Cell 1

Cell 2

H steresis

Time-to-

Cell chan e

HS-DSCH on Cell 1

A

HS-DSCH on

B

C

Time

Differences about information collection between R99 and HSPA

- 52 -

HSPA dimensioning optimization

HSPA Optimization target – – Improve CQI HSPA RF optimization target

R99 RF optimization target

CQI

RSCP & Ec/Io

Make sure that CQI is distributed as appropriate proportion. Cell edge throughput requirement could be fulfilled in the door coverage area.

Make sure that cell gets target coverage probability

CDI

9>CQI

15>CQI9

CQI15

User experience

Poor

Fair

Good

Equipment Ec/Io



-15dB

-15 dB - -9dB



- 53 -

-9dB

Performance Optimization Procedure The three kind of KPI of should be paid more attention HSPA CALL SUCCESS RATIO HSPA HANDOVER SUCCESS RATIO HSPA THROUGHPUT PERFORMANCE KPI Collection DT/CQT/Statistics

Performance optimization

Problem Analyze

• Modify the load balance policy

• Code congestion

• Carry out smart admission algorithm such as DRD or Downsize Access

• Power overload • HSPA subscriber number overload

• Power and lub bandwidth congestion means the capacity should be expanded

• lub bandwidth congestion • Unsupported configuration by UE

• The higher bit rate such as 13.6K DCH channel can help to improve access performance

Inter-freq Handover is the most difficult for HSPA mobility optimization

- 54 -

HSPA Throughput Optimization The Power and Codes available for HS-PDSCH, the lub bandwidth and RF environment of UE position will all impact throughput user got. Available Codes for HSPA Available Power for HSPA

Available lub backhaul for HSPA The Data Power to be transmitted Node B

DATA DATA DATA

Check oint

CQI

The air environment condition

DATA

RNC

CQI

CQI

The data should be delivered

GSN Process ability

CQI The web sever performance.

SGSN/GGSN App Sever

- 55 -

Firewall

WCDMA Radio Optimization

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