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WCDMA Radio Optimization
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CCoonntteennttss Radio planning optimization ................................................ 3-14
Quality of Service .............................................................. 15-22
Measurement and statistics collection ............................... 23-29
KPI .................................................................................... 30-32
Accessibility....................................................................... 33-38
Retainability....................................................................... 39-44
Integrity ............................................................................. 45-47
HSDPA-HSUPA ................................................................ 48-55
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RRaaddiioo ppllaannnniinngg ooppttiimmiizzaattiioonn
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AAnntteennnnaa hheeiigghhtt � 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
AAnntteennnnaa aazziimmuutthh � Natural obstacles and buildings should be used to create good
dominance areas for WCDMA cells � This improves the SHO performance and decrease interference
AAnntteennnnaa hheeiigghhtt ssiimmuullaattiioonn � 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
� Example of a UMTS cell, that is naturally bordered (wall effect) by buildings
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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AAnntteennnnaa ttiilltt � 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
AAnntteennnnaa ttiilltt � 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).
h
Horizontal plane
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SSeeccttoorriissaattiioonn � 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
� Sectorisation can
increase the capacity if correct beamwidth antennas are selected and SHO properly controlled
MMaasstteerr hheeaadd aammpplliiffiieerr � 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
Antenna 3 dB
Beam width
Other to own cell
interference ratio, i
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
1200
900
650
1.33 1.19 0.88
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 1200
900
650
330
2.18 1.97 1.43 1.15
593 627 758 880
64% 59% 55% 48%
95/75/79% 96/80/82% 96/80/81% 93/76/76%
Other to own cell
interference ratio, I
Served users in
UL
Served users in
DL
UL coverage probability (outdoor to indoor) for
8/64/144 hbps 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
0.88 0.90
0.88
0.90
1124 1132
1109
1132
1052 1021
1057
1016
97/87/86% 98/90/90%
95/83/82%
98/90/90%
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MMaasstteerr hheeaadd aammpplliiffiieerr � 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
TTrraannssmmiitt ppoowweerr iinnccrreeaassee
MHA is sometimes called as Tower Mounted Amplifier (TMA)
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TTrraannssmmiissssiioonn ppoowweerrss � 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)
TTrraannssmmiissssiioonn ppoowweerrss � 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.
Max power-11 …13dB BCH
Max power-12…-13dB FACH
Max power-11 …12dB SCH
Max power-11 …-13 dB PCH
Max power-10dB CPICH
43 dBm Max power of the Node B
Allocated power Channel
Typical DL power recommendations
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RReeccaallll:: SSoommee ccoonnttrrooll cchhaannnneellss � 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.
TTrraannssmmiissssiioonn ppoowweerrss • 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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CCaarrrriieerr aaddddiittiioonn � 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
DL Capacity gain Carrier
configuration Dense Urban 350m
Urban 550m
Suburban 1700m
Rural 7km
1C>2C 92% 87% 77% 60% 2C>3C 41% 37% 27% 15%
IInnddoooorr ccoovveerraaggee aassppeeccttss � 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
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PPiilloott ppoolllluuttiioonn � 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
PPiilloott ppoolllluuttiioonn � 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
PPiilloott ppoolllluuttiioonn � 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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NNeeiigghhbboouurr cceellll rreellaattiioonnss
� 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
NNeeiigghhbboouurr cceellll rreellaattiioonnss
� 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
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� Incilude the missing cell to neighbour list if it’s wanted to active set or change cell plan if FIO
SSHHOO ooppttiimmiissaattiioonn � 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
SSHHOO ooppttiimmiissaattiioonn � 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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SSHHOO ooppttiimmiissaattiioonn � 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
SSuummmmaarryy KKPPII
Indicator KPI KPI target example Coverage Measured RSCP > -88 dBm over 97% of area
(value should be adapted based on required margins)
Interference Measured Ec/No > -9 dB over 95% of area Cell overlap Cell overlay < 3 cells over 95% of area
Cell Overshoot No cell detected above -111 dBm (CPICH RSCP)
Integrity of cell coverage
No cell fragmentation detected
Qualitative
Best server plot Clean boundary without un-necessary change of best server
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QQuuaalliittyy ooff SSeerrvviiccee
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QQuuaalliittyy ooff SSeerrvviiccee –– ddeeffiinniittiioonnss ((11)) 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>>.
QQuuaalliittyy ooff SSeerrvviiccee –– ddeeffiinniittiioonnss ((22)) User domain: throughput, accuracy, dependability (reliability, availability), … Provider domain: delay, loss, utilisation, …
QQuuaalliittyy ooff SSeerrvviiccee––ddeeffiinniittiioonnss ((33)) QoS and NP, Performance network (ITU Rec. E800)
User QoS Requirements
QoS offered by Provider
QoS achieved by User
QoS experienced By Users
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QQuuaalliittyy ooff SSeerrvviiccee aanndd uusseerr ssaattiissffaaccttiioonn
RRaaddiioo AAcccceessss BBeeaarreerr QQooSS
Commercial offer Competition Trends
User expectations in terms of QoS
Technical QoS Non-technical QoS
Network performance
Terminal performance
Sales points Customer care
Users satisfaction
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RRaaddiioo AAcccceessss BBeeaarreerr � 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.
UUMMTTSS QQooSS CCllaasssseess 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
UUMMTTSS QQooSS CCllaasssseess Traffic Class Properties
Conversation class Minimum fixed delay, no buffering, symmetric traffic, guaranteed bit rate
Streaming class Minimum variable delay, buffering allowed, asymmetric, guaranteed bit rate
Interactive class Moderate variable delay, buffering allowed, asymmetric traffic, no guaranteed bit rate
Background class Big variable delay, buffering allowed, asymmetric traffic, no guaranteed bit rate
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UUMMTTSS QQooSS PPaarraammeetteerrss
Parameter Explanation
Maximum bit rate Defines the maximum bit rate when delivering information between end points of UMTS bearer (<2Mbps)
Guaranteed bit rate Defines the bit rate that the UMTS bearer must carry between its end points
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
SSoommee vvaalluueess ooff QQooSS UUMMTTSS ppaarraammeetteerrss ccllaasssseess
Traffic class Conversation Streaming Interactive Background Maximum throughput (kb/s)
<2048
Scheduling Yes/No Max. SDU size (octers)
<_ 1500 or 1502
Corrupted SDU delivery
Yes/No
Residual BER 5* 10-2, 10-2, 5* 10-3, 10-4,
10-6
5* 10-2, 10-2, 5* 10-3, 10-3,
10-4, 10-5, 10-6
4* 10-3, 10-5,
6* 10-8
4* 10-3, 10-5,
6* 10-8 SDU error rate 10-2, 7*10-3,
10-3 10-4, 10-5
10-1, 10-2, 7* 10-3, 10-3,
10-4, 10-5
10-3, 10-4, 10-6
10-3, 10-4, 10-6
Transfer delay (ms)
100 –maximum value
250 – maximum value
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QQooSS NNeeggoottiiaattiioonn
QQooSS iinn UUMMTTSS
� 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
E2E service request
Maximum bit rate Guaranteed bit rate Transfer delay QoS negotiable (y/n)
RRM: Admission control
Maximum bit rate Guaranteed bit rate Transfer delay QoS negotiable (y/n)
UMTS bearer service: Request for UMTS QoS Class
RAB assignment request
QoS negotiation
RAB assignment response
UMTS Bearer service with negotiated QoS
Radio bearer and radio link establishment
UE UTRA
(NB, RNC) CN
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QQooSS iinn UUMMTTSS � 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
QQooSS iinn UUMMTTSS � 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 rate
384 kbps 64 kbps 12 kbps
Allowed THPs THP 1 (e.g. for e-mail download)
THP 2 (e.g. for file tranfer)
THP 3
Maximum bit rate
Maximum SDU size
Residual BER
Transfers Delay
Guaranteed bit rate
Delivery order
SDU Error Ratio
Delivery of errorneous
Maximum bit rate
Maximum SDU size
Residual BER
Transfers Delay
Guaranteed bit rate
Delivery order
SDU Error Ratio
128 kbps
1500
10^ -6
NA
64 kbps
yes
1%
NO
SF=16
Map to Transport formats
1/3 turbo encoder
Interleaver=40 or 80 msec
SF=16
Use Acknowledged RLC
Set appropriate threshold for
Use Acknowledged RLC
Parameters Interactive Class Radio Resource mapping
- 22 -
QQooSS iinn UUMMTTSS
- 23 -
MMeeaassuurreemmeenntt aanndd ssttaattiissttiiccss ccoolllleeccttiioonn
- 24 -
MMeeaassuurreemmeenntt ttoooollss ttyyppoollooggyy
AA.. FFiieelldd mmeeaassuurreemmeennttss
DDrriivvee tteesstt eeqquuiippmmeenntt
PPoooorr CCoovveerraaggee eexxaammppllee
Measurement tools
Field Measurements
System Measurements
OMC counters
Passive capture tools
Calls generators
Generic
Specific
measures and
softwares
Controler
GPS
Energy
Mobile QoS test equipment
Processing
External antennas
Man to machine interface
- 25 -
PPoooorr CCeellll DDoommiinnaannccee eexxaammppllee
PPiilloott PPoolllluuttiioonn eexxaammppllee
- 26 -
EExxaammppllee ooff nneeiigghhbboorr mmiissssiinngg ((EEcc//IIoo))
CCoorrnneerr eeffffeecctt ((EEcc//IIoo))
- 27 -
QQVVOOIICCEE
BB.. SSyysstteemm mmeeaassuurreemmeennttss
OOMMCC mmeeaassuurreemmeennttss
PSTN / ISDN
Cellular Network
Post processing
Data collection
QVS
QVP-Server
QVP-Client
3 parts: QVM (QV Mobile), QVS (QV Stationary) et QVP (QV Post processing).
Specific • Alcatel: RNO • Siemens: SPOTS • Ericsson: TEMS Analyser • …
Generic • APIC from Metrica • MyCom from MYCom • AirCom • NetAct SQM: Nokia • OVPI: HP (for IP equipments)
- 28 -
KKPPII pprroocceessssiinngg ttoooollss
AAnnaallyyssiiss bbaasseedd oonn OOMMCC--RR ccoouunntteerrss Analysis tools using these counters (generally they are specific). Example: RNO or NPA of Alcatel, SPOTS from Siemens, etc.
• BiVision • ADC/Metrica, • NetAct (Nokia, for 3G)
• UTRAN Network and service Analyzer (Tektronix)
• Actix
Commercial tools:
- 29 -
PPaassssiivvee ttoooollss eexxaammpplleess • 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.
GGIISS ddiissppllaayy
- 30 -
KKPPII
- 31 -
OOppttiimmiizzaattiioonn pprroocceessss
NNeettwwoorrkk ssttaattiissttiiccss • 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)
KKPPII ddeeffiinniittiioonn • 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
Performance measurements
Performance analysis
Network tuning
Update of parameters, site
configuration
Key Performance Indicators (KPI)
• Reasons that lead to otimisation: – Improve the performance – Business reasons (cost-effective) – Troubleshooting
- 32 -
KKPPII EExxaammppllee 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
- 33 -
AAcccceessssiibbiilliittyy
- 34 -
AAcccceessssiibbiilliittyy :: ccaallll sseett--uupp
AAcccceessssiibbiilliittyy wwoorrkkffllooww
WWoorrsstt ppeerrffoorrmmiinngg cceellll ffoorr CCSS aanndd PPSS
RAB Assignment
Random Access
MS Originating Call Setup
RRC Connection Setup
Service Request Authentication
Security
Performance Measurements
Performance Analysis
Recommendation &
Implementation
Verification of changes
Other M
odules
pmTotNoRrcConnectCsSucc pmTotNoRrcConnectPsSucc pmNoRabEstablishAttempt<RAB> pmNoRabEstablishSuccess<RAB> pmNoPageDiscardCmpLoadC pmNoPagingAttemptUtranRejected
Idle mode RRC Connection Random Access NAS RAB Assignment
Squal, Srxlev, qQualmin, qRxLevMin, maxTxPowerUl, t3212, t3312, aichPower, powerOffsetP0, preambleRetransMax, constantValueCprach
Alarms Cell Availability Counters
� � �
� � � �
� > <
> < × � � �
� � � �
� ×
RAB Attempt bEstablish pmmTotNoRa RAB uccess EstablishS pmTotNoRab
Cs ConnectReq pmTotNoRrc CsSuccess ConnectReq pmTotNoRrc
100
� � �
� � � �
� > <
> < × � � �
� � � �
� × RAB Attempt bEstablish pmmTotNoRa
RAB uccess EstablishS pmTotNoRab Ps ConnectReq pmTotNoRrc
PsSuccess ConnectReq pmTotNoRrc 100
- 35 -
SSeerrvviiccee ssuucccceessss sseett uupp rraattee ((CCSS))
SSeerrvviiccee ssuucccceessss sseett uupp rraattee ((PPSS))
pmTotNoRrcConnectReqCsSucc pmTotNoRrcConnectReqCs
pmTotNoRabEstablishSuccessSpeech pmmTotNoRabEstablishAttemptSpeech x 100x
Speech
pmTotNoRrcConnectReqCsSucc pmTotNoRrcConnectReqCs
pmTotNoRabEstablishSuccessCS64 pmmTotNoRabEstablishAttemptCS64 x 100x
Circuit-Switched 64
Circuit-Switched 57
pmTotNoRrcConnectReqCsSucc pmTotNoRrcConnectReqCs
pmTotNoRabEstablishSuccessCS57 pmmTotNoRabEstablishAttemptCS57 x 100x
pmTotNoRabEstablishSuccessPacketStream + pmRabEstablishSuccessPacketStream128 pmTotNoRabEstablishAttemptPacketStream + pmRabEstablishAttemptPacketStream128 100 x (Y) x
pmTotNoRrcConnectReqPsSuccess PmTotNoRrcConnectReqPs Where Y =
Packet-Switched Data Streaming
Packet-Switched Data Interactive
pmTotNoRabEstablishSuccessInteractive pmTotNoRabEstablishAttemptPacketInteractive + HS1_HardHO_Flow 100 x (Y) x
pmTotNoRrcConnectReqPsSuccess pmTotNoRrcConnectReqPs Y x
Where
HS1_HardHO_Flow= pmNoOutgoingHsHardHoAttempt – pmNoHsHardHoReturnOidSource -pmNoIncomingHsHardHoAttempt - pmNoHsHardHoReturnOldChTarget
- 36 -
IIddllee mmooddee ppaaggiinngg
RRaannddoomm aacccceessss:: pprreeaammbbllee ddeetteeccttiioonn 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):
RRaannddoomm aacccceessss:: AAIICCHH ddeetteeccttiioonn Percentage of getting AICH but no RRC connection setup, excluding cell (re)selection:
Successful First and Repeated Page attempts of total number of first attempts, Paging success rate in aMSC
NPAAG1RESUCC + NPAG2RESUCC NPAG1GLTOT + NPAG1LOTOT
100 x
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 that RNC
pmNoPreambleFalseDetection or
x100% pmNoPreambleFalseDetection pmPositiveMessages
x100% No of AICH_ACK-No of RRC connection setup-No of cell (re)selection during RRC establishment No of AICH_ACK
- 37 -
AAddmmiissssiioonn ccoonnttrrooll:: DDLL ttrraannssmmiissssiioonn ccaarrrriieerr ppoowweerr
AAddmmiissssiioonn ccoonnttrrooll:: UULL RRSSSSII
AAddmmiissssiioonn ccoonnttrrooll:: AAiirr IInntteerrffaaccee SSppeeeecchh EEqquuiivvaalleenntt ((AASSEE))
pmTransmittedCarrierPoweri x
pmTransmittedCarrierPoweri
i 2 �
102
�=0
� 102
�=0
Average DL TX power for a cell-carrier:
DL transmission carrier power
[pmAverageRssii x (0.5xi – 110.5)]
pmAverageRssii
� 62
�=0
� 62
�=0
Average UL RSSI for a cell-carrier:
Average UL ASE for a cell: pmSumOfSampleAseUI
pmNoOfSampleAseUI
Average DL ASE for a cell: pmSumOfSampleAseDI
pmNoOfSampleAseDI
- 38 -
AAddmmiissssiioonn ccoonnttrrooll:: ccooddee aallllooccaattiioonn 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):
AAddmmiissssiioonn ccoonnttrrooll:: ccoommpprreesssseedd mmooddee How many users are in compressed mode? Well the average number of users in compressed mode for a cell:
AAddmmiissssiioonn ccoonnttrrooll:: llooaadd sshhaarriinngg
pmNoDIChCodeAllocFailureSF128
pmNoDIChCodeAllocAttemptSF128 x100%
pmSumCompMode
pmSampesCompMode
Ratio between RRc connection returning and redirection due to load sharing for a cell:
pmNoDirRetrySuccess
pmNoDirectionRetryAtt x100%
The failures can be observed by the successful rate of directed retry to GSM for a cell:
pmNoOfReturingRrcConn
pmNoLoadSharingRrcConn
- 39 -
RReettaaiinnaabbiilliittyy
- 40 -
SSeerrvviiccee rreettaaiinnaabbiilliittyy wwoorrkkffllooww
DDrrooppppeedd ccaallll rraattee CCSS
DDrrooppppeedd ccaallll rraattee PPSS
Performance Measurements
Performance Analysis
Recommendation &
Implementation
Verification of changes
Other M
odules
pmSystemRabRelease<RAB> pmNormalRabRelease<RAB> pmNoSysRelSpeechULSynch pmNoOfTermSpeechCong pmNoSysRelSpeechSoHo
UL out of Synch Congestion control, SHO functions IFHO functions IRAT Handovers
ReleaseConnOffset maxTxPowerUl,SirMax, MinPwrRl, treselection, timetotrigger1, reportingrange1
pmNoSystemRab ReleaseSpeech
(pmNoNormalrAB ReleaseSpeech + pmNoSystemRab ReleaseSpeech)
pmNoSystemRabReleaseCs64
(pmNoNormalRab ReleaseCs64 + pmNoSystemRab ReleaseCs64)
pmNoSystemRabReleaseCsStream
(pmNoNormalrRab ReleaseCsStream + pmNoSystemRab ReleaseCsStream)
Speech
Circuit-switched Streaming
Circuit-switched 64
100x
100x
100x
Packet Switched data Streaming
pmNoSystemRabReleasePacketStream + pmNoSystemRabReleasePacketStream128 (pmNoNormalRabReleasePacketStream + pmNoSystemRabReleasePacketStream + pmNosystemRabReleasePacketStream128)
100x
pmNoSystemRabReleasePacket (pmNoNormalRabReleasePacket + pmNoSystemRabReleasePacket) 100x
Packet Switched data Interactive
- 41 -
MMiinnuutteess ppeerr ddrroopp CCSS
MMiinnuutteess ppeerr ddrroopp PPSS
HHaannddoovveerr ffaaiilluurree rraattee The following formula shows the failure rate for RL addition/replacement to active set
Sp_U_User
pmNoSystemRabReleaseSpeech 100x x number of minutes
Cs64_U_User
pmNoSystemRabReleaseCs64 100x x number of minutes
Cs57_U_User
pmNoSystemRabReleaseCsStream 100x x number of minutes
Circuit-switched Streaming
Circuit-switched 64
Speech
Pstr_P8_U_User
pmNoSyatemRab ReleasePacketStream + pmNoSystemRab ReleasePacketStream128 100 x No of minutes
Plntdch_U_User+PlntHs_U_User+PlntFach_U_User
pmNoSystemRab ReleasePacket 100 x No of minutes
PlntHs_U_User
pmNoSystemRab ReleaseHs 100 x No of minutes
Packet Switched data Streaming
Packet Switched data Interactive
Packet Switched data Interactive HS
pmNoTimesCellFailAddToActSet
(pmNoTimesCellFailAddToAct + pmNoTimesRlAddToActSet 100x
- 42 -
HHaannddoovveerr ffaaiilluurree rraattee:: HHSS cceellll cchhaannggee The following metric measures the success rate for HS Cell Change in target cell
HHaannddoovveerr ffaaiilluurree rraattee:: oouutt ooff ssyynncchhrroonniizzaattiioonn Shows fraction of drop due to uplink Out of Sync reason.
HHaannddoovveerr ffaaiilluurree rraattee:: mmiissssiinngg nneeiigghhbboorr
100x
(pmNoSysRelSpeechULSynch)
(pmNoNormalRabReleaseSpeech + pmNoSystemRabReleaseSpeech) 100x
pmNoSysRelSpeechSoHo
(pmNoSystemRabReleaseSpeech + pmNoNormalRabReleaseSpeech) 100x
pmNoSysRelSpeechNeighbr
(pmNoSystemRabReleaseSpeech + pmNoNormalRabReleaseSpeech) 100x
Shows fraction of speech drop due to missing neighbour reason when a non-valid cell cannot ne added to active set.
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.
pmHsCcSuccess
pmHsCcAttempt
- 43 -
IInntteerr--ffrreeqquueennccyy hhaannddoovveerr ffaaiilluurree rraattee ((CCSS)) Drop due to IHO failure for speech: Outgoing IFHO failure when UE failed to return to present active set.
IInntteerr--ffrreeqquueennccyy hhaannddoovveerr ffaaiilluurree rraattee ((PPSS))
pmFailNonBlindInterFreqHoFailRevertCsSpeech12
pmAttNonBlindInterFreqHoCsSpeech12 100x
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.
Drop due to IFHO failure for PS streaming and others: Outgoing IFHO failure when UE failed to return to present active set.
pmFailNonBlindInterFreqHoFailRevertPsInteractiveLess64
pmAttNonBlindInterFreqHoPsInteractiveLess64 100x
pmFailNonBlindInterFreqHoFailRevertPsInteractiveGreater64
pmAttNonBlindInterFreqHoPsInteractiveGreater64 100x
pmFailNonBlindInterFreqHoFailRevertStreamingOther
pmAttNonBlindInterFreqHoStreamingOther 100x
Drop due to IFHO failure for PS greater than 64 kbps: Outgoing IFHO failure when UE failed to return to present active set.
- 44 -
IIRRAATT hhaannddoovveerr
IIRRAATT hhaannddoovveerr
CCoonnggeessttiioonn
pmNoSuccessOutIratHoSpeech
pmNoAttOutIratHoSpeech 100x
The following metric measures hard handover success rate between UtranCell and target GSM cell for speech calls. The formula is considering the GsmRelation.
pmNoSuccessOutIratHoCs57
pmNoAttOutIratHoCs57 100x
The following metric measures hard handover success rate between UtranCell and target GSM cell for streaming calls. The formula is considering the GsmRelation.
pmNoSuccessOutIratHoMulti
pmNoAttOutIratHoMulti 100x
The following metric measures hard handover success rate between UtranCell and target GSM cell for Multi-RAB calls. The formula is considering the GsmRelation.
pmNoOutIratCcReturnOldCh
pmNoOutIratCcAtt 100x
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.
(pmNoOfTermSpeechCong)
(pmNoNormalRabReleaseSpeech + pmNoSystemRabReleaseSpeech) 100x
(pmNoOfTermSpeechCong)
(pmNoNormalRabReleaseCs64 + pmNoSystemRabReleaseCs64) 100x
Shows fraction of video call drop due to cogestion action
Shows fraction of speech drop due to cogestion action
- 45 -
IInntteeggrriittyy
- 46 -
SSeerrvviiccee iinntteeggrriittyy wwoorrkkffllooww
BBLLEERR 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.
TThhrroouugghhppuutt
Performance Measurements
Performance Analysis
Recommendation &
Implementation
Verification of changes
pmFaultyTransportBlocksBcUl pmTransportBlocksBcUl pmNoOfSwDownNgCong PmNoOfSwDownNgAdm PmDl Traffic volume counters
BLER, power, SIR parameters Throughput
Test the settings Check statistics If not OK, roll back
BLER counters and Down Switching counters
100x
pmDlTrafficVolume<RAB> pmSum<RAB>RabEstablish
pmSamples<RAB>RabEstablish *ROPsec
Throughput =
Average throughput per cell and RAB in the DL, excluding HSDPA:
Actual Bitrate per RAB
Nominal Bitrate per UeRc=x RABEfficiency =
The RAB efficiency can also be checked
RAB efficiency excluding HSDPA
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).
pmFaultyTranspoertBlocksBcUL
pmTransportBlocksBcUI
- 47 -
PPaayyllooaadd ccoouunntteerrss
Radio Connection
type
UL Payload counter DL Payload counter
Speech pmUITrafficVolumeCs12 pmUITrafficVolumeCs12 PS64/64 pmUITrafficVolumePs64 pmUITrafficVolumePs64 PS64/128 pmUITrafficVolumePs128 pmUITrafficVolumePs128 PS64/384 pmUITrafficVolumePs384 pmUITrafficVolumePs384 CS 57.6
(streaming) pmUITrafficVolumeCs57 pmUITrafficVolumeCs57
CS 64 (UDI) pmUITrafficVolumeCs57 pmUITrafficVolumeCs57 Speech/PS 64 multirab
pmUITrafficVolumeCs12Ps64 pmUITrafficVolumeCs12Ps64
PS Common
pmUITrafficVolumePsCommon pmUITrafficVolumePsCommon
- 48 -
HHSSDDPPAA--HHSSUUPPAA
- 49 -
HHSSPPAA KKeeyy ffeeaattuurreess--AAMMCC
HHSSPPAA KKeeyy ffeeaattuurree –– SSyysstteemm rreessoouurrccee
AMC could improve radio bandwidth and fit for high speed radio transmission.
Cood CQI
Bad CQI
High Code Effective Rate
Low Code Effective Rate
Good coverage Bad coverage
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
DCH Code For R99 and HSPA access and traffic channel
HSPA Maximum Code
HSPA Minimum Code
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.
Reasonable resource allocation can improve throughput performance
Resource allocation
Power resource Threshold for R99 load control, which should not be allocated too much to avoid no power for HSPA user
- 50 -
HHSSPPAA KKeeyy ffeeaattuurree--SScchheedduulliinngg
MMoobbiilliittyy mmaannaaggeemmeenntt
Transmission slot 2 ms
Data transmission slot
UE1
UE2 UE3
- 51 -
SSaammppllee mmeessssaaggee ffllooww ttoo bbeeggiinn HHSSDDPPAA ooppeerraattiioonn
SSaammppllee mmeessssaaggee ffllooww ttoo ssttoopp HHSSDDPPAA ooppeerraattiioonn
UE Bode B RNC
UTRAN decides to start HSDPA for the UE
User plan data can flow on the HS-DSCH
Measurement Control message (Setup Event 1d)
Measurement Report message (Report Event 1d)
Radio link reconfiguration prepare
Radio link reconfiguration ready
Radio link reconfiguration commit
Radio Bearer Reconfiguration message
Radio Bearer Reconfiguration Complete message
1
2
3
4
UE Bode B RNC
UTRAN decides to stop HSDPA but keep DCH for the UE due to: • Low Downlink data activity • High UE mobility
User plane data only flows on the DCH
Radio link reconfiguration prepare
Radio link reconfiguration ready
Radio link reconfiguration commit
Radio Bearer Reconfiguration message
Radio Bearer Reconfiguration message
1
2
3
- 52 -
CCeellll cchhaannggee ttrriiggggeerriinngg wwiitthh eevveenntt 11dd
DDiiffffeerreenncceess aabboouutt iinnffoorrmmaattiioonn ccoolllleeccttiioonn bbeettwweeeenn RR9999 aanndd HHSSPPAA
Time-to- Cell change
HS-DSCH on Cell 1 HS-DSCH on
Cell 2
Cell 1 Ec/No
A B C
Hysteresis
Time
- 53 -
HHSSPPAA ddiimmeennssiioonniinngg ooppttiimmiizzaattiioonn
HHSSPPAA OOppttiimmiizzaattiioonn ttaarrggeett –– IImmpprroovvee CCQQII
� -9dB -15 dB - -9dB � -15dB Equipment Ec/Io
Good Fair Poor User experience
CQI�15 15>CQI�9 9>CQI CDI
Make sure that CQI is distributed as appropriate proportion. Cell edge throughput requirement could be fulfilled in the door coverage area.
CQI
HSPA RF optimization target R99 RF optimization target
RSCP & Ec/Io
Make sure that cell gets target coverage probability
- 54 -
PPeerrffoorrmmaannccee OOppttiimmiizzaattiioonn PPrroocceedduurree
IInntteerr--ffrreeqq HHaannddoovveerr iiss tthhee mmoosstt ddiiffffiiccuulltt ffoorr HHSSPPAA mmoobbiilliittyy ooppttiimmiizzaattiioonn
Problem Analyze • Code congestion • Power overload • HSPA subscriber number overload • lub bandwidth congestion • Unsupported configuration by UE
KPI Collection DT/CQT/Statistics
Performance optimization • Modify the load balance policy • Carry out smart admission algorithm such as DRD or Downsize Access • Power and lub bandwidth congestion means the capacity should be expanded • The higher bit rate such as 13.6K DCH channel can help to improve access performance
The three kind of KPI of should be paid more attention HSPA CALL SUCCESS RATIO HSPA HANDOVER SUCCESS RATIO HSPA THROUGHPUT PERFORMANCE
- 55 -
HHSSPPAA TThhrroouugghhppuutt OOppttiimmiizzaattiioonn
The Power and Codes available for HS-PDSCH, the lub bandwidth and RF environment of UE position will all impact throughput user got.
DATA
DATA
DATA
DATA
CQI
CQI
CQI
CQI
The air environment
condition
The web sever performance.
GSN Process ability
The data should be delivered
Available lub backhaul for HSPA The Data Power to be transmitted
Available Codes for HSPA Available Power for HSPA
App Sever
Node B
Firewall
SGSN/GGSN
RNC
Check point
- 56 -