kpi's for umts
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Introduction to KPI’s for UMTS
•For more detailed information see T035 course.
•W-CDMA
•MM/SM
•SSCF-UNI
•AAL2
•SSCOP
•RRC
•RLC
•MAC
•AAL5
•SSCOP
•RANAP
•SCCP
•SSCF-NNI
•GTP-C
•AAL5
•IP
•ATM
•SSCF-UNI
•AAL2
•SSCOP
•NBAP•RRC
•RLC
•MAC •SSCF-NNI
•AAL5
•SSCOP
•SCCP
•RANAP
•MTP3-b
•UDP
•GTP-C•NBAP
•Physical
•Channels
•MM/SM
•UE •Node B •RNC •SGSN
•Relay •Relay
•Physical
•Channels
•Relay
•W-CDMA •ATM •ATM
•MTP3-b
Revision of protocol stack
KPI’s for UMTSRRC Connection
Number of RRC connection requests
Number of RRC connection set up
Number of successful RRC connection establishments
Number of RRC failures
Number of release requests on Iu per cause
Just some of many counters
•UE
•RRC Connection Set up-UM
•RNC
•RRC Connection Set up Complete-AM
•RRC Connection request-TM
•UE
•RRC Connection request •RNC
•UE identity
•Cause
•CHOICE
•IMSI
•TMSI + LAI
•PTMSI + RAI
•RRC establishment Cause
•Originating Conversational Call
•Originating Streaming
•Originating Interactive
•Originating Background
•Terminating Conversational Call
•Terminating Streaming
•Terminating Interactive
•Terminating Background
•Emergency Call
•Inter-RAT Cell reselection
•Registration
•Detach
•Originating High Priority Signalling
•Originating Low PrioritySignalling
•Terminating High Priority Signalling
•Terminating Low PrioritySignalling
•Protocol error
•This message can indicate whether a protocol error occurred.
message rrcConnectionRequest :
initialUE-Identity tmsi-and-LAI : {
tmsi '10000111011100001001000101101011'B,
lai {
plmn-Identity {
mcc {
2 3 4
mnc {
20
lac '0000010010110000'B
establishmentCause originatingHighPrioritySignalling,
protocolErrorIndicator noError
1.RRC Connection Set up message
•Uplink
•Power control
•Information
•Power Control
•Algorithm
•1 OR 2
•TPC step size
•Power offsets from pilot
•Up Link Scrambling Code
•Long
•0……16,777,215
•Number DPDCH
•1….max 6
•Spreading Factor•4, 8, 16, 32, 64, 128, 256
•Size of CRC
•Beta Parameters •Information the UE requires from the Network (NOT A COMPLETE LIST)
•Transport /Logical channel/ Physical Number
•RNC
KPI’s for UMTSNBAP Radio – Link Management
Successful NBAP radio link setups
Number of failed NBAP radio-link setups
Number of successful NBAP radio link deletions
Number of failed NBAP radio link deletions
Just some of many NBAP counters
The Node B Application Part (NBAP)The Node B Application Part (NBAP)
Dedicated functions of NBAP include:
• Dedicated transport channel establishment, reconfiguration and removal.
• Downlink power control.
• Measurement handling of dedicated radio channels.
• Some control of compressed mode operations
AAL2
ALCAPNBAP
AAL5AAL5
FPs
ATM ATM ATM
AAL2
ALCAP NBAP
AAL5 AAL5
FPs
ATMATMATM
PVC
PVC
SVC
Node B RNC
•The NBAP protocol is transmitted over the Iub interface on its own PVC
AAL5 on ATM.
•The NBAP procedures can be split into two types, common and
dedicated. The common procedures are not related to a particular UE,
where the dedicated procedures are related to a specific UE context.
•Common Functions of NBAP include:
•Common transport channel establishment, reconfiguration and
removal.
•Logical Operation and Maintenance resource control.
•Measurement handling of Common Channels.
•RNC
•NBAP:UL initiating Message Id: audit required
• For each cell
•NBAP DL initiating message id audit ‘start’
•NBAP UL successful outcome id audit ‘ end of audit’(local cell id)
•NBAP DL initiating Id –cell set up
•Cell id = a Primary SC, Common Channels
•NBAP UL successful Outcome
•NBAP:DL initiating Message
id SIB update
•NBAP UL successful Outcome SIB update
•With the Cell update message, the RNC assigns:
•Primary SC
•Common channels
•Primary Synchronization Channel
•Secondary synchronization channel
•Common Pilot channel
•Common Control Physical channel (CCPCH) that carriers
the broadcast channel
•NEW NODE B-must have SC etc
•R
•N
•C
•Minimum and Maximum DL power
•Power offsets PO1, PO2, PO3
•TPC Step Sizes: 0.5,1,1.5, 2dB
•UE •Node B
•RNC
•RRC Connection Request
•NBAP •NBAP•Radio link setup request
•Step size
•Power adjustment is contained in the RADIO LINK SETUP REQUEST
(NBAP). It cannot be reconfigured during
connection.
•Values are: O.5, 1, 1.5 and 2 dB
•Downlink DPCCH power offsets
•With the DL DPCCH are the TFCI, Pilot and TPC. These can be transmitted at different power levels.
•PO1: TFCI
•PO2: TPC
•PO3: Pilot bits
KPI-Number of failed NBAP radio-link setups- Major problem
•UE •Node B •RNC
•RRC•1. RACH: CCCH: RRC CONNECTION REQUEST <TM>
•2. RADIO LINK SETUP REQUEST
•3. RADIO LINK SETUP RESPONSE
•6. DOWNLINK SYNCHRONISATION
•7. UPLINK SYNCHRONISATION
•11. DCCH: RRC CONNECTION SETUP COMPLETE <AM>
•8. FACH: CCCH: RRC CONNECTION SETUP <UM>
•4. ESTABLISH REQUEST (AAL2)
•5. ESTABLISH CONFIRM (AAL2)
•Start RX
•RRC
•NBAP•NBAP
•NBAP•NBAP
•ALCAP
•ALCAP
•ALCAP
•ALCAP
•DCH-FP•DCH-FP
•DCH-FP •DCH-FP
•RRC
•RRC
•RRC
•RRC
•Start TX
•10. RADIO LINK RESTORE INDICATION•NBAP•NBAP
•9. INSYNCH IND•L1 •L1
•ALL KPI’s
KPI’s for UMTSNode B – Radio
Wideband received power
Transmitted carrier power
Just some of many counters
•R
•N
•C
•CCCH/RACH Connection Request
•NBAP - Received Total Wideband Power
•If RTWP(dBM) < Max UP Interference level
•RRC is accepted
•Max Up Inter= -112 to -50 step 0.1
Received Total Wideband Power (RTWP)
UL RTWP
Received total wideband power, including nose generated in the receiver. This measurement is used to filter RRC CONNECTION REQUESTS. If the RNC is going to accept message or not.
The overall UL interference received in a cell is evaluated with the UL RTWP with is measured by the node B and reported to the RNC through NBAP common measurement.
On the RACH reception, before allocating SRB, the RNC compares the RTWP with the maximum UL interference level parameter to decide whether to accept the RRC connection OR not.
Parameter Range default
Max UPLINK Interference
-112 …..50 (Step 0.1) -50
KPI’s for UMTSRNSAP– Radio Link Management
Number of successful RNSAP radio link set up
Number of failed RNSAP radio link setups
Just some of many RNAP counters
•The Radio Network Subsystem Application Part (RNSAP)
•The RNSAP protocol is mainly used for:
•Basic mobility procedures used in soft handover and relocation.
•Carrying RRC messages, bridging the gap between SRNC and CRNC.
•Establishment and release of dedicated channels between RNCs, as well as reconfiguration of existing channels.
Node B
Node B
Node B
Node B
Node B
Node B
RNC
RNC
MSC/VLR
SGSN
HLR
GGSN
Gs
Iu-CS
Gn
Iu-PS
Iub
Iur
Gr
D
UE
Uu
KPI’s for UMTSRRC Radio Link management
Number of successful RRC active set updates per cell
Number of successful RRC active set updates per RNC
Number of failed RRC active set updates per cell
Number of failed RRC active set updates per RNC
Active set size
Number of RRC state transitions from Cell_FACH to cell_DCH
Number of RRC state transitions from Cell_DCH to cell_FACH
Number of calls in cell_FACH state
Just some of many counters
KPI’s for UMTSRAB Management
Number of successful radio bearer establishments per cell
Number of successful radio bearer establishments per RNC
Number of refused radio bearer establishments per cell
Number of refused radio bearer establishments per RNC
Number of successful RAB releases
Number of failed RAB releases
Number of RAB failures due to UE capabilites
Just some of many counters
KPI’s for UMTSQuality of service
Number of successful downsizing per cell
Number of successful downsizing per RNC
Number of successful up sizing per cell
Number of successful up sizing per RNC
Just some of many counters
DedicatedChannels
Common Channels Shared Channels
DCH FACH RACH CPCH DSCH USCH
UplinkDownlink
Both DL UL UL DL UP TDD only
FastPower Control
Yes No No Yes Yes Yes
SoftHandover
Yes No No No No No
Suitedfor
Medium or LargeData amounts
Small Small Small or Medium
Medium or large
Medium or large
Suited for bursty
data
No Yes Yes Yes Yes Yes
CELL_FACH stateCELL_FACH state
•Downsizing timer
•Upsizing
•UL or DL traffic
Threshold
Cell_DCH
Cell_FACH
CELL_FACH stateCELL_FACH state
•Idle mode
•CELL_DCH
•CELL_FACH
•AO upsize
•AO downsize
•Add token•Remove token
•Establish shared connection
•Release Shared Connection
KPI’s for UMTSQuality of service
Number of free downlink channelization codes
Percentage of time a cell is congested
Percentage of time a cell is congested due to OVSF codes
Percentage of time a cell is congested due to power
Number of RAB assignments rejected for high priority users
Just some of many counters
KPI’s for UMTSHard Handover
Number of 3G to 2G handover requests per cell
Number of 3G to 2G handover requests per RNC
Number of failures
Just some of many counters
Intra-Frequency: UMTS to UMTS- Same Carrier
Inter-Frequency: UMTS to UMTS- Between Carriers
Inter-Mode: UMTS to UMTS- Between FDD and TDD Modes
IRAT: UMTS to GSM
IRAT: GSM to UMTS
UMTS FDD Neighbour typesUMTS FDD Neighbour types
Hard HandoverHard Handover
During an HHO the used radio frequency of UE changes
Break before make handoverNot seamless
UE stops transmission on one frequency before it moves to another frequency
CAN Make it more seamless
Use of compressed mode if:Both frequencies use overlapping compressed mode
gaps and switch is done during gap-seamless
Eb/No Cell 1
Eb/No Cell 2
Eb/No
Threshold
Threshold
Counter
Decision to HO to GSM
-20dB
Decision to HO to GSM
RNC
3GMSC
2GMSC
BSC
Iub
Iu-CS
A-bis
Node B
BTS
Intersystem reporting events:
3A – the estimated quality of the current used UTRAN frequency is below a certain threshold and and the estimated quality of the other system is above a certain threshold
3B - The estimated quality of the other system is below a certain threshold
3C – The estimated quality of the other system is above a certain threshold
3D – Change to best cell in other system
SS7 Network
HLR
MAP
•Normal Frame •Normal Frame
•Extra Power needed for compressed mode
•10ms •10ms •10ms
Gap
Compressed Frame
•Same amount of data is transmitted in a shorter time.
•10log10(15 slot/7 slot gap) = 2.7dB
•With 7 slot gap in 15 slot frame
KPI’s for UMTSPower Management
Cell power used for speech calls
Cell power used for data calls
Cell power used for signalling
Cell power used for miscellaneous
TX power
Just some of many counters
•Power for SHO
•Power for Overhead
•Call Admission
•Power
•Common Channel Power
•Power For signalling
•Power for speech
•Power for
•Data•Maximum
•Power
Initial DL traffic channel power
When a traffic channel is setup it is done at a certain DL power.
Power = DL CPICH power + Ec/No target – UE received CPICH pilot
Example
= 33 + ( -13) – (- 10)
= +30dB
= 33 + ( -13) - (-15)
= +35dB
KPI’sKPI’s
• If one speech circuit is configured for 3dbm of power. How much power in dBm will 100 connections take in dBm?
KPI’s for UMTSQuality of service
Number of successful IRM scheduling downgrades per cell
Number of failed IRM scheduling downgrades per cell
Just some of many counters
KPI’s for UMTSIRM scheduling
The principle of IRM scheduling is that when experiencing power shortage:
When the UE leaves the centre of the cell and reaches the cell edge it is a way to AVOID a DROP CALL.
•Reducing power by reducing user bit rate and increasing process gain.
•Process gain = 10 log 384000/User bit rate
KPI’s for UMTSIRM scheduling
The bearer downgrade maybe triggered by observing the BLER. When this exceeds a threshold, bad radio conditions are detected. If these radio conditions remain bad during a period of time, bearer fallback is triggered.
RNC
Checks BLER
KPI’s for UMTSIRM scheduling
Is based on detection of bad radio conditions due to layer 1. BLER increase for a period of time.
The RNC reduces the Transport Format Combination set so limits the user bit rate.
•BLER Target
Good radio conditions
•384kbps •384kbps
SHO
•User rate reduction
KPI’s for UMTSRadio Measurements
Uplink RSSI
CPICH Ec/No measurements
Compressed mode configuration success
Compressed mode configuration failure
Just some of many counters
KPI’s for UMTSNode B –ATM
Number of received cells (AAL2)
Number of lost packets(AAL2)
Number of error AAL2 packets
Number of invalid CID(AAL2)
Number of received cells (AAL5)
Number of lost packets(AAL5)
Number of error AAL5 packets
Loss of cell delineation
Just some of many counters
Node B – PCM
Loss of incoming signal
Alarm indication signal
•Question?
•If you are receiving an AIS alarm. What is the problem?
•What other KPI’s will show?
•If you had a loss of signal in one direction. What KPI will be set in the
other?
KPI’s for UMTSNode B –ATM
Number of error AAL2 packets
Number of invalid CID(AAL2)
Number of lost packets(AAL5)
Number of error AAL5 packets
•If you had the following KPI’s. Give a list of problems?
KPI’s for UMTSNode B –ATM
Loss of cell delineation – Major problem – Cannot decode the HEC field- Result cannot find any ATM cell
RNC
Iub
Iu-CS
Node B
Iu-PS
•5 Octet Header
•48 Octet
•Payload
•5 Octet Header
•48 Octet
•Payload
•5 Octet Header
•48 Octet
•Payload
•5 Octet Header
•48 Octet
•Payload
•LCD – loss all data
•LCD- loss of data and speech
•LCD- loss of speech
•RNC
•Iub (E1)•STM-1/4/16
•PLMN may not own this network
•NODE B
•ATM
•ROUTER
•IMA Group
•KPI’s for UMTS
•There are a number of KPI’s regarding Node B IMA:
•IMA group unavailable seconds
•IMA group near end failures
•IMA link violations
•etc
•You require a good understanding of ATM and SDH to understand these. Covered on
the T035 course.
AAL 2AAL 2
•5 Octet Header
•48 Octet Payload•SDU
•HEC •UUI •LI •CID
•5 •5 •6 •8
•Mini Cell Header
•SDU •Why do we use AAL2 connections?
•Packet Fill Delay
•If the size of the mini packets is set to 12 bytes what will be the PFD for:
•12kbps service
•4.7kbps•What the function of
HEC
KPI’s for UMTSNode B – RACH
RACH negative acknowledgements
Number of accepted RACH
Just some of many counters
BCH PCHCPCHRACH FACH DSCH DCH
DPDCH
DPCCH
PDSCH
S-CCPCH
P-CCPCH
PCPCH
PRACH
S-SCH
CPICH
AICH
PICH
AP-AICH
CD/CA-ICH
P-SCH
Physical Channels
Transport ChannelsSpreading/Modulation
•Access preambles are sent using increasing power levels until a matching response is received or the max number of preambles have been sent
BCH PCHCPCHRACH FACH DSCH DCH
DPDCH
DPCCH
PDSCH
S-CCPCH
P-CCPCH
PCPCH
PRACH
S-SCH
CPICH
AICH
PICH
AP-AICH
CD/CA-ICH
P-SCH
Physical Channels
Spreading/Modulation
SIB5 –
accessServiceClass-FDD availableSignatureEndIndex 15 assignedSubChannelNumber '1111'B
primaryCPICH-TX-Power 33,
prach-PowerOffset {
powerRampStep 2,
preambleRetransMax 64
•rachSubChannels – Defines the set of access slots on which the mobiles are authorised to transmit their access on the PRACH.
•preambleSignature –Defines a set of allowed signatures of the PRACH preamble part.
KPI’s for UMTSMobility Management
Number of cell updates
Number of cell update failures
Number of failed RRC security mode command procedures
Number of failed RANAP security mode command procedures
Just some of many counters
Without the GsWithout the Gs
HLRSGSN
1. GPRS ATTACH REQUEST (PTMSI/IMSI, Classmark, old RAI)
AUTHENTICATION AUTHENTICATION
MSC
1. GMS ATTACH REQUEST (PTMSI/IMSI, Classmark, old RAI)
AUTHENTICATION AUTHENTICATION
HLR
With the GsWith the Gs
HLRSGSN
1. GPRS ATTACH REQUEST (PTMSI/IMSI, Classmark, old RAI)
AUTHENTICATION AUTHENTICATION
MSC HLR
•GS Interface
Network Operation Modes
NetworkOperation
Mode
GSM/GPRSAttach
RA/LAUpdating
MS Paging
1
Combined functionsGSM (IMSI) Attach performed via GPRSAttach
Combined functionsGSM (LA) update performed via the RA Update
Co-ordinatedPaging for GSM andGPRS on CCCH (PCH)or PPCH
2
Not Combined GSM (IMSI) Attach performed.GPRS Attach alsoperformed
Not CombinedGSM (LA) update via A-InterfaceGPRS (RA) updatevia Gb-Interface
Not Co-ordinatedPaging for GSM on CCCH (PCH)Paging for GPRS onCCCH (PCH)
3
Not Combined GSM (IMSI) Attach performed.GPRS Attach alsoperformed
Not CombinedGSM (LA) update via A-InterfaceGPRS (RA) updatevia Gb-Interface
Not Co-ordinatedPaging for GSM on CCCH (PCH)Paging for GPRS onPPCH
Authentication
Authentication Key (Ki) (128 bits) stored in HLR/SIM
AUC/HLR
KiKi RANDRAND
A3A3
A8A8
SGSN
SRES(Signed response)
Kc(Cipher Key)
RAND
MS
SRES valueReturned to The SGSN
SRES=SRESAccess Allowed
SRES=SRESAccess Barred
THE END
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