Introduction to KPI’s for
UMTS
•For more detailed information see T035 course.
Revision of protocol stack
•Relay
•Relay
•Relay
•MM/SM
•MM/SM
•RRC
•NBAP
•RANAP
•NBAP
•RLC
•RLC
•MAC
•SSCF-UNI
•Physical
•Channels
•Physical
•Channels
•W-CDMA
•W-CDMA
•UE
•RRC
•Node B
•SSCOP
•AAL2
•ATM
•MAC
•GTP-C
•SCCP
•SCCP
•MTP3-b
•MTP3-b
•SSCF-UNI
•SSCF-NNI
•SSCOP
•AAL2
•ATM
•RNC
•RANAP
•GTP-C
•SSCF-NNI
•UDP
•SSCOP
•SSCOP
•IP
•AAL5
•AAL5
•AAL5
•ATM
•SGSN
KPI’s for UMTS
RRC 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
•RNC
•U
E
•RRC Connection request-TM
Just some of many counters
•RRC Connection Set up-UM
•RRC Connection Set up Complete-AM
•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
•RNC
•RRC Connection request
•U
E
•UE identity
•Cause
•Protocol error
•CHOICE
•IMSI
•TMSI + LAI
•PTMSI + RAI
•This message can indicate
message rrcConnectionRequest :
whether a protocol error
occurred.
initialUE-Identity tmsi-and-LAI : {
tmsi '10000111011100001001000101101011'B,
lai {
plmn-Identity {
mcc {
234
mnc {
20
lac '0000010010110000'B
establishmentCause originatingHighPrioritySignalling,
protocolErrorIndicator noError
1.RRC Connection Set up message
•Uplink
•Power control
•Information
•Up Link Scrambling
Code
•Long
•0……16,777,215
•1….max 6
•TPC step size
•Power offsets from
pilot
•Number DPDCH
•Spreading Factor
•Power Control
•Algorithm
•1 OR 2
•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 UMTS
NBAP 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)
Node B
RNC
FPs
ALCAP
NBAP
NBAP
ALCAP
FPs
AAL2
AAL5
AAL5
AAL5
AAL5
AAL2
ATM
ATM
ATM
ATM
ATM
PVC
ATM
•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.
PVC
SVC
•Common Functions of NBAP include:
•Common transport channel
establishment, reconfiguration and
removal.
•Logical Operation and Maintenance
resource control.
•Measurement handling of Common
Channels.
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
•NEW NODE B-must have SC
etc
•RNC
•NBAP:UL initiating Message Id: audit required
•NBAP DL initiating message id audit ‘start’
•With the Cell update
message, the RNC assigns:
•Primary SC
•NBAP UL successful outcome id audit ‘ end of audit’(local cell
•Common channels
id)
•Primary Synchronization
•NBAP DL initiating Id –cell set up
•Cell id = a Primary SC, Common Channels
Channel
•Secondary synchronization
channel
•For each cell
•Common Pilot channel
•NBAP UL successful Outcome
•NBAP:DL initiating Message
id SIB update
•NBAP UL successful Outcome SIB update
•Common Control Physical
channel (CCPCH) that
carriers the broadcast channel
•UE
•Node
•RNC
B
•RRC Connection Request
•NBAP
•Radio link setup request
•Step size
•NBAP
•Minimum and Maximum DL power
•Power offsets PO1, PO2, PO3
•TPC Step Sizes: 0.5,1,1.5, 2dB
•R
•N
•C
•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.
KPI-Number of failed NBAP radio-link
setups- Major problem
•PO1: TFCI
•PO2: TPC
•PO3: Pilot bits
•ALL KPI’s
•UE
•Node B
•RNC
•1. RACH: CCCH: RRC CONNECTION REQUEST <TM>
•RRC
•RRC
•2. RADIO LINK SETUP REQUEST
•NBAP
•NBAP
•Start RX
•3. RADIO LINK SETUP RESPONSE
•NBAP
•4. ESTABLISH REQUEST (AAL2)
•ALCAP
•5. ESTABLISH CONFIRM (AAL2)
•ALCAP
•6. DOWNLINK SYNCHRONISATION
•DCH-FP
•7. UPLINK SYNCHRONISATION
•DCH-FP
•NBAP
•ALCAP
•ALCAP
•DCH-FP
•DCH-FP
•Start TX
•8. FACH: CCCH: RRC CONNECTION SETUP <UM>
•RRC
•L1
•9. INSYNCH IND
•L1
•NBAP
•RRC
•RRC
•10. RADIO LINK RESTORE INDICATION
•11. DCCH: RRC CONNECTION SETUP COMPLETE <AM>
•NBAP
•RRC
KPI’s for UMTS
Node B – Radio
Wideband received power
Transmitted carrier power
Just some of many counters
Received Total Wideband Power
(RTWP)
•If RTWP(dBM) < Max UP
Interference level
•RRC is accepted
•Max Up Inter= -112 to -50 step 0.1
•NBAP - Received Total Wideband Power
•R
•N
•C
•CCCH/RACH Connection Request
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 UMTS
RNSAP– Radio Link Management
Node B
Number of successful RNSAP radio link set up
Node B
Number of failed RNSAP radio link setups
Node B
Just some of many RNAP counters
Node B
Iub
Iu-CS
RNC
Iur
Node B
Uu
Node B
RNC
MSC/VLR
D
Gs
Iu-PS
SGSN
HLR
Gr
Gn
GGSN
UE
•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.
KPI’s for UMTS
RRC 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 UMTS
RAB 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 UMTS
Quality 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
Dedicated
Channels
Common Channels
Shared Channels
DCH
FACH
RACH
CPCH
DSCH
USCH
Uplink
Downlink
Both
DL
UL
UL
DL
UP TDD only
Fast
Power
Control
Yes
No
No
Yes
Yes
Yes
Soft
Handover
Yes
No
No
No
No
No
Suited
for
Medium or Large
Data amounts
Small
Small
Small or
Medium
Medium or
large
Medium or
large
Suited for
bursty
data
No
Yes
Yes
Yes
Yes
Yes
CELL_FACH state
•UL or DL traffic
Cell_DCH
Threshold
Cell_FACH
•Downsizing
timer
•Upsizing
CELL_FACH state
•Idle
•Release
•Establish shared
mode
Shared
Connection
connection
•Add token
•Remove
token
•CELL_DCH
•AO
•AO
upsize
downsize
•CELL_FACH
KPI’s for UMTS
Quality 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 UMTS
Hard 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
UMTS FDD Neighbour types
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
Hard Handover
During an HHO the used radio frequency of UE
changes
Break before make handover
Not 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
Decision to HO to GSM
Eb/No
Cell 1
Eb/No
Cell 2
Threshold
-20dB
Threshold
Counter
Decision to HO
to GSM
Node B
Iub
R
N
C
Iu-CS
HLR
3G
MSC
MAP
SS7
Network
BTS
BSC
A-bis
2G
MSC
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
•10ms
•10ms
•10ms
•Extra Power needed
for compressed mode
•Normal Frame
Gap
•Normal Frame
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 UMTS
Power 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
Initial DL traffic channel power
When a traffic channel is setup it is done
at a certain DL power.
•Power
for SHO
•Common Channel Power
•Call
•Maximum
•Power
Admission
•Power
for
Overhead
Example
•Power for
•Data
= 33 + ( -13) – (- 10)
•Power for
= +30dB
speech
= 33 + ( -13) - (-15)
•Power For
= +35dB
signalling
•Power
Power = DL CPICH power + Ec/No target
– UE received CPICH pilot
KPI’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 UMTS
Quality 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 UMTS
IRM 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 UMTS
IRM 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
IRM scheduling
KPI’s for UMTS
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
Good radio
conditions
Target
SHO
•384kbps
•User rate
reduction
•384kbps
KPI’s for UMTS
Radio Measurements
Uplink RSSI
CPICH Ec/No measurements
Compressed mode configuration success
Compressed mode configuration failure
Just some of many counters
KPI’s for UMTS
Node B –ATM
Node B – PCM
Number of received cells (AAL2)
Loss of incoming signal
Number of lost packets(AAL2)
Alarm indication signal
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
•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?
Just some of many counters
KPI’s for UMTS
Node B –ATM
•If you had the following KPI’s.
Number of error AAL2 packets
Number of invalid CID(AAL2)
Number of lost packets(AAL5)
Number of error AAL5 packets
Give a list of problems?
KPI’s for UMTS
Node B –ATM
Loss of cell delineation – Major problem – Cannot decode the HEC field- Result
cannot find any ATM cell
•LCD- loss of
speech
Iub
Node B
•5 Octet
Header
•5 Octet
Header
•48 Octet
•Payload
•5 Octet
Header
•48 Octet
•Payload
•48 Octet
•Payload
Iu-CS
R
N
C
Iu-PS
•LCD- loss of
data and
speech
•5 Octet
Header
•LCD – loss all
data
•48 Octet
•Payload
•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.
•STM-1/4/16
•PLMN may not
•Iub (E1)
•RNC
own this network
•ATM
•ROUTER
•IMA Group
•NODE B
AAL 2
•5 Octet
•48 Octet
•SDU
Header
Payload
•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:
•Mini Cell Header
•HEC •UUI •LI •CID
•5
•5
•6
•8
•What the function of
HEC
•12kbps service
•4.7kbps
KPI’s for UMTS
Node B – RACH
RACH negative acknowledgements
Number of accepted RACH
Just some of many counters
Transport Channels
Spreading/Modulation
RACH
CPCH
BCH
PCH
FACH
DSCH
DCH
PICH
AICH
DPCCH
DPDCH
PDSCH
S-CCPCH
P-CCPCH
PCPCH
PRACH
P-SCH
•Access preambles are sent using increasing power levels until a
matching response is received or the max number of preambles have
been sent
S-SCH
CPICH
AP-AICH
CD/CA-ICH
Physical Channels
SIB5 –
accessServiceClass-FDD
availableSignatureEndIndex 15
assignedSubChannelNumber '1111'B
•preambleSignature –Defines a set of allowed
signatures of the PRACH preamble part.
primaryCPICH-TX-Power 33,
prach-PowerOffset {
powerRampStep 2,
preambleRetransMax 64
Spreading/Modulation
RACH
CPCH
BCH
PCH
FACH
DSCH
DCH
PICH
AICH
DPCCH
DPDCH
PDSCH
S-CCPCH
P-CCPCH
PCPCH
PRACH
P-SCH
•rachSubChannels – Defines the set of access slots on which the mobiles
S-SCH
are authorised to transmit their access on the PRACH.
CPICH
AP-AICH
CD/CA-ICH
Physical Channels
KPI’s for UMTS
Mobility 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 Gs
HLR
SGSN
1. GPRS ATTACH REQUEST
(PTMSI/IMSI, Classmark, old RAI)
AUTHENTICATION
AUTHENTICATION
HLR
MSC
1. GMS ATTACH REQUEST
(PTMSI/IMSI, Classmark, old RAI)
AUTHENTICATION
AUTHENTICATION
With the Gs
HLR
SGSN
•GS Interface
1. GPRS ATTACH REQUEST
(PTMSI/IMSI, Classmark, old RAI)
AUTHENTICATION
AUTHENTICATION
MSC
HLR
Network Operation Modes
Network
Operation
Mode
GSM/GPRS
Attach
RA/LA
Updating
MS Paging
1
Combined functions
GSM (IMSI) Attach
performed via GPRS
Attach
Combined functions
GSM (LA) update
performed via the
RA Update
Co-ordinated
Paging for GSM and
GPRS on CCCH (PCH)
or PPCH
2
Not Combined
GSM (IMSI) Attach
performed.
GPRS Attach also
performed
Not Combined
GSM (LA) update
via A-Interface
GPRS (RA) update
via Gb-Interface
Not Co-ordinated
Paging for GSM on
CCCH (PCH)
Paging for GPRS on
CCCH (PCH)
3
Not Combined
GSM (IMSI) Attach
performed.
GPRS Attach also
performed
Not Combined
GSM (LA) update
via A-Interface
GPRS (RA) update
via Gb-Interface
Not Co-ordinated
Paging for GSM on
CCCH (PCH)
Paging for GPRS on
PPCH
Authentication
AUC/HLR
A3
Ki
RAND
A8
SGSN
SRES
(Signed response)
SRES value
Returned to
The SGSN
RAND
Kc
(Cipher Key)
Authentication Key (Ki)
(128 bits) stored in HLR/SIM
MS
SRES=SRES
Access Allowed
SRES=SRES
Access Barred
THE END
