2. Review
Parameters Optimization is an important step
after RF Optimization
Service quality and network resources
utilization will be improved after Parameters
Optimization
4. Objectives
Understand the procedure of
Parameters Optimization
Master the contents of Parameters
Optimization
Upon completion of this course,you will be able to:
7. Data Input and Find Problems
From the Input Data to find out the Problems such as
“Call Setup Success Rate Low”, “Handover Success Rate Low “
or “ Drop Call Rate High” etc.
10. Determine Parameter Values
List Parameters Changing Form
( Original Parameter Values vs. New Parameter Values)
List Parameters Changing MML Command
Note : Maybe some Tradeoff considerations need taking into account
to assure the maximal improvement in the whole view such as
“coverage and capacity”,“ fast and stable”, “improvement and risk” ,
“cost (or efforts) and gain”, etc.
12. Prepare Test Plan and Implement Changing
Prepare Test schedule , Routes, Tools and be ready to get
Information .
Change Parameters and Make Records.
14. Parameters Optimization Contents
Mobile Management Parameters Optimization
Power Control Parameters Optimization
Power Configuration Parameters Optimization
Load Control Parameters Optimization
Note: Because there are a lot of parameters , it is not possible to introduce
every parameter . Only some parameters about network optimization are
mentioned here and maybe more parameters need to be added in the future.
15. Mobile Management Parameters
Optimization
Cell Selection & Reselection
The changing of cell on which UE camped in Idle mode or in Cell FACH ,
Cell PCH ,URA PCH states. That assures UE camping the most suitable cell ,
receiving system information and establishing a RRC connection on a best
serving cell.
Handover
The changing of cells with which UE connected in DCH mode.
That assures seamless coverage and load balancing.
16. Cell Selection & Reselection Procedure
Initial
Cell Selection
Any Cell
Selection
go here
when no
USIM in
the UE
USIM inserted
Camped on
any cell
go here whenever a
new PLMN is
selected
1
no cell information
stored for the PLMN
cell information
stored for the PLMN
Stored
information
Cell Selection
no suitable cell found
no suitable
cell found
Cell Selection
when leaving
connected
mode
suitable cell found 2
suitable
cell found
Camped
normally
suitable cell found
no suitable
cell found
leave
idle mode
return to
idle mode
Connected
mode
Cell
Reselection
Evaluation
Process
suitable
cell found
trigger
no suitable
cell found
1
Cell Selection
when leaving
connected
mode
no acceptable cell found
acceptable
cell found
acceptable
cell found
suitable
cell found 2
leave
idle mode
return to
idle mode
Connected
mode
(Emergency
calls only)
Cell
Reselection
Evaluation
Process
acceptable
cell found
trigger
no acceptable
cell found
NAS indicates that
registration on selected
PLMN is rejected
(except with cause #14
or #15 [5][16])
17. Cell Selection Criteria (S Criteria)
The cell selection criterion S is fulfilled when:
for FDD cells: Srxlev > 0 AND Squal > 0
for TDD cells: Srxlev > 0
Where:
Squal = Qqualmeas – Qqualmin
Srxlev = Qrxlevmeas - Qrxlevmin - Pcompensation
When UE wants to select an UMTS cell , the cell should be
satisfied with S Criterion.
19. Cell Re-selection Measure Condition
use Squal for FDD cells and Srxlev for TDD for Sx
1. If Sx > Sintrasearch, UE need not perform intra-frequency measurements.
If Sx <= Sintrasearch, perform intra-frequency measurements.
If Sintrasearch, is not sent for serving cell, perform intra-frequency measurements.
2. If Sx > Sintersearch, UE need not perform inter-frequency measurements.
If Sx <= Sintersearch, perform inter-frequency measurements.
If Sintersearch, is not sent for serving cell, perform inter-frequency measurements.
3. If Sx > SsearchRAT m, UE need not perform measurements on cells of
RAT"m".
If Sx <= SsearchRAT m, perform measurements on cells of RAT "m".
If SsearchRAT m, is not sent for serving cell, perform measurements on cells of
RAT "m".
20. Cell Reselection Criteria (R Criteria)
1) All cells should be satisfied with S Criteria.
2) Select the Cell with the highest R value using the following method to compute.
Rs = Qmeas,s + Qhysts
Rn = Qmeas,n - Qoffsets,n
The cells shall be ranked according to the R criteria specified above, deriving Qmeas,n and
Qmeas,s and calculating the R values using CPICH RSCP, P-CCPCH RSCP and the averaged received signal
level for FDD, TDD and GSM cells, respectively.
The offset Qoffset1s,n is used for Qoffsets,n to calculate Rn, the hysteresis Qhyst1s is used
for Qhysts to calculate Rs.
If an FDD cell is ranked as the best cell and the quality measure for cell selection and re-selection is set to CPICH
Ec/No, the UE shall perform a second ranking of the FDD cells according to the R criteria specified above, but
using the measurement quantity CPICH Ec/No for deriving the Qmeas,n and Qmeas,s and calculating the R values
of the FDD cells. The offset Qoffset2s,n is used for Qoffsets,n to calculate Rn, the hysteresis Qhyst2s is used for
Qhysts to calculate Rs.. Following this second ranking, the UE shall perform cell re-selection to the best ranked
FDD cell.
In all cases, the UE shall reselect the new cell, only if the following conditions are met:
- the new cell is better ranked than the serving cell during a time interval Treselection.
- more than 1 second has elapsed since the UE camped on the current serving cell.
23. Cell Reselection from GSM to UMTS
If the 3G Cell Reselection list includes UTRAN frequencies, the MS shall, at least every 5 s
update the value RLA_C for the serving cell and each of the at least 6 strongest non-serving
GSM cells.
The MS shall then reselect a suitable (see TS 25.304) UTRAN cell if its measured RSCP value
exceeds the value of RLA_C for the serving cell and all of the suitable (see 3GPP TS 03.22) non-
serving GSM cells by the value XXX_Qoffset for a period of 5 seconds and, for FDD, the UTRAN
cells measured Ec/No value is equal or greater than the value FDD_Qmin. In case of a cell
reselection occurring within the previous 15 seconds, XXX_Qoffset is increased by 5 dB.
where Ec/No and RSCP are the measured quantities.
FDD_Qmin and XXX_Qoffset are broadcast on BCCH of the serving cell. XXX indicates
other radio access technology/mode.
Note:The parameters required to determine if the UTRAN cell is suitable are broadcast on
BCCH of the UTRAN cell. An MS may start reselection towards the UTRAN cell before
decoding the BCCH of the UTRAN cell, leading to a short interruption of service if the
UTRAN cell is not suitable.
Cell reselection to UTRAN shall not occur within 5 seconds after the MS has reselected a
GSM cell from an UTRAN cell if a suitable GSM cell can be found.
If more than one UTRAN cell fulfils the above criteria, the MS shall select the cell with the
greatest RSCP value.
25. Handover Procedure
Node B
Node B
Node B
Intra-frequency cells
–Neighbor cells both from same NodeB or
other NodeBs
Measurement reportMeasurement report
Handover decisionHandover decision
measurement controlmeasurement control
Measurement and filteringMeasurement and filtering
Handover executionHandover execution
28. Soft Handover Event – 1A
1A (Add a cell in Active Set)
)2/(10)1(1010 11
1
aaBest
N
i
iNewNew HRLogMWMLogWCIOLogM
A
−−⋅⋅−+
⋅⋅≥+⋅ ∑=
MNew : the measurement result of the cell entering the reporting range.
CIONew : the individual cell offset for the cell entering the reporting range
if an individual cell offset is stored for that cell. Otherwise it is equal to 0.
Mi : measurement result of a cell not forbidden to affect reporting range in
the active set.
NA : the number of cells not forbidden to affect reporting range in the
current active set.
MBest : the measurement result of the cell not forbidden to affect reporting range
in the active set with the highest measurement result, not taking into account
any cell individual offset.
W : a parameter sent from UTRAN to UE.
R1a : the reporting range constant.
H1a : the hysteresis parameter for the event 1a.
29. Soft Handover Event – 1B
1B (Remove a cell from Active Set)
)2/(10)1(1010 11
1
bbBest
N
i
iOldOld HRLogMWMLogWCIOLogM
A
+−⋅⋅−+
⋅⋅≤+⋅ ∑=
MOld : the measurement result of the cell leaving the reporting range.
CIOOld : the individual cell offset for the cell leaving the reporting range if
an individual cell offset is stored for that cell. Otherwise it is equal to 0.
Mi : measurement result of a cell not forbidden to affect reporting range in the
active set.
NA : the number of cells not forbidden to affect reporting range in the current
active set.
MBest : the measurement result of the cell not forbidden to affect reporting range
in the active set with the lowest measurement result, not taking into account
any cell individual offset.
W : a parameter sent from UTRAN to UE.
R1b : the reporting range constant.
H1b : the hysteresis parameter for the event 1b.
30. Soft Handover Event – 1C
1C (A non-active primary CPICH becomes better than an active
primary CPICH. If Active Set is not full ,add the non-active cell into
active set .Otherwise use the cell substitute the active cell . )
2/1010 1cInASInASNewNew HCIOLogMCIOLogM ++⋅≥+⋅
MNew : the measurement result of the cell not included in the active set.
CIONew : the individual cell offset for the cell becoming better than the cell in the active
set if an individual cell offset is stored for that cell. Otherwise it is equal to 0.
MInAS : the measurement result of the cell in the active set with the highest
measurement result.
MInAS : the measurement result of the cell in the active set with the lowest
measurement result.
CIOInAS : the individual cell offset for the cell in the active set that is becoming worse
than the new cell.
H1c : the hysteresis parameter for the event 1c.
31. Soft Handover Event – 1D
1D (Change of best cell. If the chosen cell is not in Active Set ,
add the cell into Active Set and modify measurement control
.Otherwise only modify measurement control. )
2/1010 1dBestBestNotBestNotBest HCIOLogMCIOLogM ++⋅≥+⋅
MNotBest : the measurement result of a cell not stored in "best cell"
CIONotBest : the cell individual offset of a cell not stored in "best cell" .
MBest: the measurement result of the cell stored in "best cell".
CIOBest : the cell individual offset of a cell stored in "best cell" .
H1d : the hysteresis parameter for the event 1d.
32. Soft Handover Parameters
Parameter Name Description Default Setting
IntraRelThdFor1A Relative thresholds of soft handover for Event 1A (R1a) 10 , namely 5dB (step 0.5)
IntraRelThdFor1B Relative thresholds of soft handover for Event 1B (R1b) 10 , namely 5dB (step 0.5)
Hystfor1A, Hystfor1B,
Hystfor1C, Hystfor1D
Soft handover hysteresis (H1x) 6,namely 3dB (step 0.5) for H1a .
8,namely 4dB(step 0.5) for H1b,
H1c,H1d.
CellIndividalOffset Cell CPICH measured value offset; the sum of this
parameter value and the actually tested value is used for
UE event estimation. (CIO)
0
WEIGHT Weighting factor, used to determine the relative
threshold of soft handover according to the measured
value of each cell in the active set.
0
TrigTime1A,TrigTime1B,
TrigTime1C,TrigTime1D
Soft handover time-to-trigger parameters (event time-to-
trigger parameters. Only the equation are always
satisfied during the trigger time, the event will be
triggered).
D640, namely 640ms .
FilterCoef Filter coefficient of L3 intra-frequency
measurement
D5 ,namely 5
34. Intersystem Handover Measure
1) Use Inter-frequency measurement reporting Event 2D ,2F
to reflect the currently used frequency quality.
Event 2d: The estimated quality of the currently used frequency is below a certain threshold.
The variables in the formula are defined as follows:
QUsed is the quality estimate of the used frequency.
TUsed 2d is the absolute threshold that applies for the used frequency and event 2d.
H2d is the hysteresis parameter for the event 2d.
Event 2f: The estimated quality of the currently used frequency is above a certain
threshold.
The variables in the formula are defined as follows:
QUsed is the quality estimate of the used frequency.
TUsed 2f is the absolute threshold that applies for the used frequency and event 2f.
H2f is the hysteresis parameter for the event 2f.
2/22 ddUsedUsed HTQ −≤
2/22 ffUsedUsed HTQ +≥
35. Intersystem Handover Measure
2 ) When Received 2D reports ( that means the currently used frequency signal is poor ) , RNC
sends Measurement Control (ID3) to let UE begin to measure other system signal . UE will
send measurement result reports periodically . When Received 2F reports (that means the
currently used frequency signal is not poor), RNC sends Measurement Control (ID3,but
different contents) to let UE stop measuring other system signal .
3) When received the periodical reports , RNC use the following formula to judge whether should
handover UE to another system .
Mother_RAT + CIO > Tother_RAT + H/2
Tother_RAT : the inter-system handover decision threshold;
Mother_RAT : the inter-system (GSM RSSI) measurement result received by RNC;
CIO: Cell Individual Offset, which is the inter-system cell setting offset;
H : refers to hysteresis,
If the formula is met, a trigger-timer called TimeToTrigForSysHo will be started, and a handover decision will be
made when the timer times out;
Note: if the inter-system quality satisfies the following condition before the timer times out:
Mother_RAT + CIO < Tother_RAT - H/2
The timer will be stopped, and RNC will go on waiting to receive the next inter-system measurement report.
The length of the trigger-timer is called time-to-trigger.
37. Parameters Optimization Contents
Mobile Management Parameters Optimization
Power Control Parameters Optimization
Power Configuration Parameters Optimization
Load Control Parameters Optimization
38. Power Control Parameters Optimization
Power Control Characteristics
Minimize the interference in the network, thus improve
capacity and quality
Maintain the link quality in uplink and downlink by adjusting
the powers
Mitigate the near far effect by providing minimum required power
level for each connection
Provides protection against shadowing and fast fading
39. Power Control Classification
Open Loop Power Control
Open loop power control is used to determine UE’s initial uplink transmit power in PRACH and
NodeB’s initial downlink transmit power in DPDCH. It is used to set initial power reference values for
power control.
Outer Loop power control
Outer loop power control is used to maintain the quality of communication at the level of bearer service quality
requirement, while using as low power as possible.
Inner loop power control (also called fast closed loop power control)
Inner loop power control is used to adjust UE’s uplink / NodeB’s downlink Dpch Power every one slot in
accordance with TPC commands. Inner loop power control frequency is 1500Hz.
40. Open Loop Power Control - Uplink
BCH£ ºCPICH channel powerBCH£ ºCPICH channel power
UL interference leveUL interference leve
Constant ValueConstant Value
Measure CPICH_RSCPMeasure CPICH_RSCP
and determine the initialand determine the initial
transmitted powertransmitted power
RACHRACH
Preamble_Initial_Power = Primary CPICH TX power - CPICH_RSCP
+ UL interference + Constant Value
where Primary CPICH TX power , UL interference and Constant Value are broadcasted
in the System Information , and CPICH_RSCP is the measured value by UE 。
41. Open Loop Power Control - Downlink
DCHDCH
Measure CPICH Ec/I0Measure CPICH Ec/I0
RACH reports theRACH reports the
measured valuemeasured value
Determine the downlink initial powerDetermine the downlink initial power
controlcontrol
where R is the user bit rate. W is the chip rate (3.84M).
Pcpich is the Primary CPICH transmit power.
Eb/Io is the downlink required Eb/Io value for a bearer service.
(Ec/Io)cpich is measurement value reported by the UE.
a is downlink cell orthogonal factor.
Ptotal is the current cell’s carrier transmit power measured at the NodeB
and reported to the RNC.
))/(( total
o
c
CPICH
o
b
Pcpich
I
E
P
W
R
I
E
P ×−××= α
43. Outer Loop Power Control
SRNC DRNC
Set SI RSet SI R
t ar gett ar get
Set SI R t ar getSet SI R t ar get
Set SI R t ar getSet SI R t ar get
Macr o di ver si t yMacr o di ver si t y
combi ni ngcombi ni ng
Outer loop control is used to setting SirTarget (Signal to Interference Ratio Target) for inner loop power
control. It is divided into uplink outer loop power control and downlink outer loop power control.
The uplink outer loop power control is controlled by SRNC (serving RNC) for setting a target SIR for each
UE. This target SIR is updated according to the estimated uplink quality (Block Error Ratio/ Bit Error Ratio).
If UE is not in DTX (Discontinuous Transmission)status (that means RNC can receive uplink traffic data),
RNC will use Bler (Block Error Ratio) to compute SirTarget . Otherwise , RNC will use Ber (Bit Error Ratio)
to compute SirTarget.
The downlink outer loop power control is controlled by the UE receiver to converge to required link quality
(BLER) set by the network (RNC) in downlink.
45. Inner Loop Power Control
The inner-loop power control adjusts the UE or NodeB
transmit power in order to keep the received
signal to interference ratio (SIR) at a given SIR target,‑ ‑
SIRtarget.
It is also divided into uplink inner loop power control and
downlink inner loop power control.
46. Uplink Inner Loop Power Control
UTRAN behaviour
The serving cells (cells in the active set) should estimate signal-to-interference ratio
SIRest of the received uplink DPCH. The serving cells should then generate TPC
commands and transmit the commands once per slot according to the following rule: if
SIRest > SIRtarget then the TPC command to transmit is "0", while if SIRest < SIRtarget
then the TPC command to transmit is "1".
UE behaviour
Upon reception of one or more TPC commands in a slot, the UE shall derive a single
TPC command, TPC_cmd, for each slot, combining multiple TPC commands if more
than one is received in a slot. This is also valid when SSDT transmission is used in the
downlink. Two algorithms shall be supported by the UE for deriving a TPC_cmd. Which
of these two algorithms is used is determined by a UE-specific higher-layer parameter,
"PowerControlAlgorithm", and is under the control of the UTRAN. If
"PowerControlAlgorithm" indicates "algorithm1", then the layer 1 parameter PCA shall
take the value 1 and if "PowerControlAlgorithm" indicates "algorithm2" then PCA shall
take the value 2.
47. Uplink Inner Loop Power Control
The step size DTPC is a layer 1 parameter which is derived from the UE-specific
higher-layer parameter "TPC-StepSize" which is under the control of the UTRAN. If
"TPC-StepSize" has the value "dB1", then the layer 1 parameter DTPC shall take the
value 1 dB and if "TPC-StepSize" has the value "dB2", then DTPC shall take the value
2 dB. The parameter "TPC-StepSize" only applies to Algorithm 1 . For Algorithm 2 DTPC
shall always take the value 1 dB.
After deriving of the combined TPC command TPC_cmd using one of the two supported
algorithms, the UE shall adjust the transmit power of the uplink DPCCH with a step of
DDPCCH (in dB) which is given by:
DDPCCH = DTPC × TPC_cmd.
48. Uplink Inner Loop Power Control
Algorithm 1 for processing TPC commands
When a UE is not in soft handover, only one TPC command will be received in
each slot. In this case, the value of TPC_cmd shall be derived as follows:
- If the received TPC command is equal to 0 then TPC_cmd for that slot is –1.
- If the received TPC command is equal to 1, then TPC_cmd for that slot is
Algorithm 2 for processing TPC commands
When a UE is not in soft handover, only one TPC command will be received in
each slot. In this case, the UE shall process received TPC commands on a 5-slot
cycle, where the sets of 5 slots shall be aligned to the frame boundaries and there
shall be no overlap between each set of 5 slots.
The value of TPC_cmd shall be derived as follows:
- For the first 4 slots of a set, TPC_cmd = 0.
- For the fifth slot of a set, the UE uses hard decisions on each of the 5
received TPC commands as follows:
- If all 5 hard decisions within a set are 1 then TPC_cmd = 1 in the 5th slot.
- If all 5 hard decisions within a set are 0 then TPC_cmd = -1 in the 5th slot.
- Otherwise, TPC_cmd = 0 in the 5th slot.
49. Downlink Inner Loop Power Control
UE behaviour
The UE shall generate TPC commands to control the network transmit power
and send them in the TPC field of the uplink DPCCH. The UE shall check
the downlink power control mode (DPC_MODE) before generating
the TPC command:
- if DPC_MODE = 0 : the UE sends a unique TPC command in each slot and the
TPC command generated is transmitted in the first available TPC field in the uplink
DPCCH;
- if DPC_MODE = 1 : the UE repeats the same TPC command over 3 slots and
the new TPC command is transmitted such that there is a new command at the
beginning of the frame.
The DPC_MODE parameter is a UE specific parameter controlled by the
UTRAN.
50. Downlink Inner Loop Power Control
UTRAN behaviour
Upon receiving the TPC commands UTRAN shall adjust its downlink DPCCH/DPDCH
power accordingly. For DPC_MODE = 0, UTRAN shall estimate the transmitted TPC
command TPCest to be 0 or 1, and shall update the power every slot. If DPC_MODE =
1, UTRAN shall estimate the transmitted TPC command TPCest over three slots to be 0
or 1, and shall update the power every three slots.
56. Parameters Optimization Contents
Mobile Management Parameters Optimization
Power Control Parameters Optimization
Power Configuration Parameters Optimization
Load Control Parameters Optimization
57. Load Control Parameters Optimization
Call Admission Control (CAC)
Call admission control is used to control cell’s load by
admission/rejection request to assure a cell’s load under control.
Dynamic Channel Configuration Control (DCCC)
Dynamic Channel Configuration Control is used to dynamically
change a connection’s load to improve cell resource utilization and
control cell’s load.
59. Call Admission Control Parameters
Different service type can be configured different threshold. That means leave some
resources for important service ( or request), such as HO > Conversation > Other.
Ul(Dl)TotolKThd is used when NodeB load report is not available . It uses equivalent
12.2k _voice users number method.
60. Dynamic Channel Configuration Control
DCCC: Dynamic Channel Configuration Control aim to making full use
of radio resource (codes, power, CE )
- Configured bandwidth is fixed when no DCCC
- Configured bandwidth is changing when DCCC
- Traffic rate
Rateorband
61. DCCC Procedure
Measurement reportMeasurement report
DCCC decisionDCCC decision
Traffic Volume
measurement control
Traffic Volume
measurement control
UE and RNC MeasurementUE and RNC Measurement
DCCC executionDCCC execution
66. Summary
Parameter Optimization improves network quality and solves
network problems.
Parameter Optimization is a complicated procedure and
needs parameter and algorithm knowledge.
Parameter Optimization will be combined with other
optimization activities making network better !