WCDMA Optimization

UMTS Optimization

Prepared By Legend Technologies

Copy Rights © LEGEND Co. 2010

Course Content

• WCDMA Features – Idle Mode Behavior – Radio Link Supervision – Power control – Load sharing– Handover Capacity management– Capacity management

– Channel switching

• 3G KPIs Monitoring and analysis


WCDMA Features

• Course Objective jUpon completion of this part you be able to

• Explain the main parts of idle mode behavior E l i h t i th di li k i i d h t it• Explain what is the radio link supervision and what are its benefits

• Explain the different types of power control • Explain how can we control the capacity to maximize it• Explain how can we control the capacity to maximize it under minimum interference

• Explain Different Handover types and scenarios • Explain how and why do we need for Load sharing andExplain how and why do we need for Load sharing and• Explain the main types of channel switching we have • Explain the Main 3G KPIs and how to analyze them


WCDMA Radio Network Features


Idle Mode Behavior

• PLMN selectionPLMN selection

• Cell Selection / Reselection

i• Paging

• Location Update and Routing area update

• System Information


What is Idle Mode?

1. OFF Mode2. IDLE MODE3. CONNECTED MODE

UE in IDLE MODE has the following properties :

• UE is Powered ON , while it doesn't have connection to the Radio Network

• UE is synchronized with Radio Network and can read broadcast information , Accordingly UE can access the Network request services ., g y q

• UE is registered on the network , updating Network with its LAC , Accordingly UE becomes reachable by the network


Accordingly UE becomes reachable by the network

Services Types in Idle Mode

• Normal Service• When the UE select accepted level cell in its HPLMN

• Limited Service• When the UE didn’t find any accepted level cells at its home PLMN it selects any accepted level cell at any h PLMNother PLMN

• Operator reserved services• The operator can reserve any cell for testing only and this through two parameters cell reserved and Access classNbarred


PLMN Selection

• PLMN SelectionPLMN Selection – What is it ? And When it happens ? What are the types of PLMN selectiontypes of PLMN selection

• PLMN Selection is the process in which the UE decide which PLMN it should register in and this process happens when the Mobile turned on or when the mobile returned back from limiting service

– Automatic PLMN selectionAutomatic PLMN selection

– Manual PLMN selection


Automatic PLMN selection

• When the mobile powered onWhen the mobile powered on • The mobile uses information about the last registered PLMN (Freq, the stored neighbors before off)

• Mobile search the strongest signal cells and read its system information to get (MCC and MNC)

If h h ll i d h bil d h• If the chosen cell is accepted the mobile try to do the registration

• If the last chosen cell not available or there is no storedIf the last chosen cell not available or there is no stored info in the mobile USIM then the mobile might select any accepted PLMN automatically or manually


• In the automatic selection if no last register PLMN gexists or available the Mobile will select the PLMN that is available and allowed as follow

HPLMN if not previously selected due to RAT– HPLMN if not previously selected due to RAT

– Each PLMN in User controlled PLMNs list in the USIM, in order of priority

h i ll d li i h S i– Each PLMN in operator controlled PLMN list in the USIM, in order of priority

– Other PLMNs according to the high quality criteria randomly h i i CPICH RSCP i 95dBthe minimum CPICH RSCP power is ‐95dBm

– Other PLMNs that don’t fulfill high quality criteria


Initial Cell Selection – Automatic Mode

USIM

HPLMNI

St t ll

f1

Strongest cell

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8x 107

‐40

‐20

0

20

40

60

80

Frequency

Power Spe

ctrum M

agnitude

(dB)

II

USIMI

IIPLMN

PLMN

A B C D E FPLMN

III

USIMI

IIPLMN

IIIPLMNPLMN

PLMN0

20

40

60

80

Power Spe

ctrum M

agnitude

(dB)

IV

2110 2170 MHz

III II

IIIPLMNPLMN

PLMNPLMN0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8

x 107‐40

‐20

Frequency

PLMN

PLMNPLMN ‐20

0

20

40

60

80

Power Spe

ctrum M

agnitude

(dB)

V

PLMN APLMN BPLMN D

PLMN BPLMN EPLMN D


PLMNPLMN0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8

x 107‐40

FrequencyPLMN E PLMN A

Manual PLMN Selection

• UE displays all the available PLMNS afterUE displays all the available PLMNS after carriers scanning

• All the available PLMNs will appear regardless• All the available PLMNs will appear regardless it is allowed or not and ignoring the forbidden LACsLACs


f2

•

PLMN APLMN B

HPLMN

f1Strongest cell

40

60

80

ectrum

Magnitude

(dB)

•

fn

PLMN E0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8

x 10 7

‐40

‐20

0

20

Frequency

Power Sp


Roaming

• It is the services in which the user will be ableIt is the services in which the user will be able to obtain services from another PLMN – Same country (national roaming)– Same country (national roaming)

– Another country (international roaming)

E 30 i t th UE t t l t it• Every 30 minutes the UE try to reselect its home PLMN


Cell Search

StartStart

Detecting slot synchronizationDetecting slot synchronization

Detecting frame synchronization and primary scrambling code groupDetecting frame synchronization and primary scrambling code group

Detecting primary scrambling and read system information g p y g y

End


SCH

Broadcast ChannelsPilot ChannelSCH

P-CCPCH

PICH Pilot Symbol Data (10 symbols per slot)

1 timeslot = 2560 Chips = 10 symbols = 20 bits = 666.667 uSec

Pilot Channel

P-CCPCH 1 2 3 4 5 6 7 8 9 1 1 1 1 10P CCPCH 1 2 3 4 5 6 7 8 9 10

11

12

13

14

0

1 Frame = 15 slots = 10 mSec

CPICH always take code 0 from SF 256code 0 from SF 256tree


Cell selection procedure

• Squal = Qqualmeas – qQualMin (For WCDMA)Squal = Qqualmeas qQualMin (For WCDMA)– Qqualmeas is CPICH Ec/No

qQualMin is minimum required Ec/No– qQualMin is minimum required Ec/No

• Srxlev = Qrxlevmeas ‐ qRxlevMin – Pcompensation (F ll ll )(For all cells)– Qrxlevmeas is CPICH RSCP

– qRxlevMin is minimum required RSCP


– Pcompensation=Max(maxTXpowerUL‐P , 0)Pcompensation Max(maxTXpowerUL P , 0) • P is maximum O/P power of the UE accoring to its class

• maxTXpowerUL is maximum power used in accessing

• The cell consider as accepted if p– Squal > 0 and

– Srxlev > 0Srxlev 0



• Cell selection occurs whenCell selection occurs when• When UE is switched on

• When UE in idle mode has had a number of failed RRC connection request

• When a UE returns to idle mode from the connection d h l ( ll FACH) f bmode on common channel (cell‐FACH) after a number

of failed cell update

• UE returns to idle mode from connected mode (cell‐UE returns to idle mode from connected mode (cellDCH)

• When a UE returns to idle mode after an emergency ll


call on any PLMN

Cell reselection procedure

• When it occursWhen it occurs – When cell on which it is camping is no longer suitablesuitable

– When there is any neighbor with better quality than the selected onethan the selected one

– When the UE in the limited service state on an acceptable cell p

– When the UE is in cell _FACH state


• According to the cell reselection criteria. In order to perform cell ranking, the UE measures the serving cell and neighbor cells listed in SIB11 according to the measurement rules .

i. Measurement rules for cell reselection

f h

Si S h C l h i f f d

1. Intra frequency measurements starts when Squal <= Sintrasearch

SintraSearch : Controls when intra‐frequency measurements are performed

(0 dBm)


2. Inter frequency measurements starts when S l Si S h

Sintersearch : Controls when intra‐frequency measurements are performed (0 dBm)

Squal <= SinterSearch

3. GSM measurements starts when

sRatSearch : Controls quality Threshold at which GSM measurements are

Squal <= sRatSearchOR Srxlev <= SHcsRat

performed (4 dBm)

SHcsRat : Controls Signal Strength Threshold at which GSM measurements

are performed (3 dBm)



Qq almeas (EcN0 dB)GSM measurements can also be triggered

by low RSCPQqualmeas (EcN0, dB)

14

Qrxlevmeas (RSCP, dBm)by low RSCP

sRatSearch = 4dB

-14

qQualMin = -18 sHcsRat = 3dB (negative values arei t t d 0)

-112

Time (s)WCDMA WCDMAWCDMA & GSM

qRxLevMin+P = -115 interpreted as 0)

WCDMA & GSM


( )measurements measurementsmeasurements measurements

• When the UE triggers a cell reselectionsWhen the UE triggers a cell reselections procedure it starts ranking for the cell satisfy S‐criteria (Squal > 0 and Srxlev > 0) and theS criteria (Squal > 0 and Srxlev > 0) and the ranking will be according R‐criteria

– R(serving)= Qmeas(s)+qHyst(s)

– R(neighbor)= Qmeas(n)‐qOffset(s,n)


• Qmeas: is the quality value of the receivedQmeas: is the quality value of the received signal which is derived from

• CPICH Ec/No orCPICH Ec/No or

• CPICH RSCP

• qHyst(s): hystersis value sent to mobile inqHyst(s): hystersis value sent to mobile in system information used to delay the reselection as possible on the LA boardersreselection as possible on the LA boarders – qHyst1 if the ranking based on CPICH RSCP

qHyst2 if the ranking based on CPICH Ec/No


– qHyst2 if the ranking based on CPICH Ec/No

• qOffset(s,n): is the offset between the serving andqOffset(s,n): is the offset between the serving and the neighbor cell also used to shift the cell boarder

– qOffset1sn : if the ranking based on RSCP, there q g ,are 2 qOffset1sn one for WCDMA neighbor and the other one for GSM neighbor.

– qOffset2sn : if the ranking based on Ec/No

• qualMeasQuantity is the parameter that determine if we will do the ranking based on RSCP or Ec/No

• The UE reslect the better cell if it stay better for time


interval more than Treselection

UMTS to UMTS cell ReselectionReselection

Qmeas(n)

qOffset2sn=0R(n)

Qmeas (dBm)

qOffset2sn 0

qHyst2 = 4

Qmeas(s)

R(s)

Qmeas(s)

treSelection

Cell reselection time

R(n)>R(s)


UMTS to GSM cell Reselection

Qmeas (dBm)

Qmeas(n)

qOffset1snqRxLevMin*

qRxLevMin*+

R(n)

qHyst1

qsHcsRat

Qmeas(s)

R(s)

RankingWCDMA&GSMmeasurements

Qmeas(s)

treSelectionCell reselection

time


R(n)>R(s)* Pcompensation is assumed to be 0

• FACH‐connected cell reselection – During the FACH‐connected mode the UE use secondary

common control physical channel (SCCPCH)

– The parameters used to control the measurementThe parameters used to control the measurement fachMeasOccaCycLenCoeff and interFreqFddMeasIndicator

– fachMeasOccaCycLenCoeff (K) used to show when the UE has to do this measurment this value should be greater than 0 andto do this measurment this value should be greater than 0 and this value send to mobile via system information

– FACH measurment occasions are defined as being the frame where the following equation is fulfilled

SFN= C‐RNTI mod n*2^K

C RNTI is the cell UE identity (16 bits) & n is the frame number 0 1 2


C-RNTI is the cell UE identity (16 bits) & n is the frame number 0,1,2,….

– InterFreqFddMeasIndicator is a value set to TrueInterFreqFddMeasIndicator is a value set to True or False if it set to True the UE will perform the reselection criteria on inter frequency or inter RAT and if it is set false it will not do


Location area Update and Routing area UpdateRouting area Update

• After a UE has found a suitable cell it tries to make PLMN registration.

• If the LAI or RAI read on system informationIf the LAI or RAI read on system information has been changed then the UE tries to do RA or LA registration Updateor LA registration Update

• During the idle mode when the UE changes its location or routing area it should do LAU orlocation or routing area it should do LAU or RAU

LAU d RAU d b CN


• LAU and RAU managed by CN

• Types of Updates P i di– Periodic

• Occurs periodically after timer T3212 for LAU or T3312 for RAU the value of the timer sent to the UE overfor RAU, the value of the timer sent to the UE over BCCH in the IMSI attach or in RAU , it is CN parameter, when the UE is in connected mode and the timer

i d th th UE it til t idl d i texpired then the UE wait until enter idle mode again to perform the periodic LA

– NormalNormal • Occurs when the UE change its LA or RA, the UE discover the changes after comparing the new Cell RAC


or LAC with the stored values in the USIM

– IMSI attach and detachIMSI tt h h th UE ti t d i th• IMSI attach occurs when the UE activated in the same LA in which it was before deactivation and the detach occurs when UE deactiated

• This function used to prevent unnecessary paging for the off UEs

IMSI h i i l f i d i i d b• IMSI attach is an optional function and it is managed by cell parameter called ATT sent to UE over BCCH

– If ATT set to 1 it means the UE should do IMSI attach and detach

– When the UE is turned on it sent registration request indicate IMSI attach to find out if the LA changed or not if changed it


send normal LA update

Paging

• Is the process through it the CN inform the UE there is a service request or RAN inform all the UEs that the System information has been updated also to initiate the channel switch from URA‐PCH to Cell‐FACH state

• Paging occurs in the following states – Idle

– URA‐PCH

– Cell‐FACH

Copy Rights © LEGEND Co. 2010– Cell‐DCH

• Paging in Idle mode and URA‐PCH – PICH and S‐CCPCH are used to page the UE

• PICH used to tell the UE when to read S‐CCPCH

• S‐CCPCH used to carry RRC message type1 which i l d l i i f d h b f iincludes actual paging info and the number of times the WCDMA RAN will retransmit the paging (noOfPagingRecordTransm)


• DRXDRX – In the Idle mode the UE should in order to save its power consumption to listen to the PICH in certainpower consumption to listen to the PICH in certain predefined times

288 bits for paging indication 12 bits (undefined)

b1b0 b287 b288 b299

One radio frame (10 ms)


– 288 bits are divided to number of PIs each PI288 bits are divided to number of PIs each PI related to one paging group and each paging group related to one user

– The number of PIs in a PICH frame is given by parameter named PichMode

• If PichMode is 72 that mean we have 72 PIs and each one 4 bits

Th UE it PI i i i– The UE monitors one PI in one paging occasion per DRX cycle

• The length of DRX cycle is given by 2^k * 10(ms)


• The length of DRX cycle is given by 2^k 10(ms)

• Where k is the DRX cycle Length coefficient defined byWhere k is the DRX cycle Length coefficient defined by cnDRXcycleLengthCS (PS)

• Different DRX cycle for CS, PS and URA‐PCH


• Paging in cell‐FACH and cell‐DCHPaging in cell FACH and cell DCH– When the establish connection between UE and RAN is existing Paging type 2 message are sent toRAN is existing Paging type 2 message are sent to the user it is carried on DCCH so it is only for one user.

• Updated System information – RRC message “paging type1” sent to the UE in theRRC message paging type1 sent to the UE in the idle mode to inform it about the updated SI


System Information


• The UE read System information whenThe UE read System information when – Powered on

Cell change in idle mode or Cell FACH– Cell change in idle mode or Cell‐FACH

– UE informed that change occurred in system information while it is in idle mode or Cell‐FACHinformation while it is in idle mode or Cell‐FACH

– UE switches from Dedicated mode to Common ModeMode.

– Timer expires for SIBs with expiration time.



Radio Connection Supervision


Radio Connection Supervision

• Supervision of the UE in State Cell‐FACH andSupervision of the UE in State Cell FACH and URA‐PCH

• Supervision of the UE in Cell‐DCH


• What is the radio link supervisionWhat is the radio link supervision Is the algorithm supervises the radio connection

between the UE and the UTRAN during all thebetween the UE and the UTRAN during all the

connected states, the reason of this is to check if the

UTRAN till t l th UE t d t tUTRAN still control the UE or not and to prevent

undue charging and increase the efficiency of

resources usage.

Occurs in both of Uplink and Downlink


Supervision in Cell‐FACH and URA‐PCHURA PCH

• In CELL FACH state, supervision is provided by monitoring _ , p p y gperiodic Cell Update messages sent by the UE. The timer cchWaitCuT is started whenever the UE enters the CELL FACH state or upon transmission of a Cell UpdateCELL_FACH state, or upon transmission of a Cell Update CONFIRM message to the UE. The timer is stopped if the UE enters CELL_DCH state and is reset to zero (but not stopped) upon receipt of a Cell Update from the UE. Upon expiry of the timer, the overall release of the connection shall be triggered. The time set on cchWaitCuT is longer thang

the one set on timer t305. The timer t305 indicates how often the UE has to send a Cell Update message.


Cell Update Message will be sent either when t305 expires or when the UE change its serving cellwhen the UE change its serving cell

In URA PCH state the UE sent URA_Update Message instead of Cell_ Update as in Cell FACH case

CCHWAITCUT

T305 expires Cell Update Confirmation

Overall Connection Release

CCHWAITCUT starts Cell Update

MessageCCHWAITCUT Expire

UE Enters

CCHWAITCUT Reset

Timer Should stopped if UE Enters CELL-DCH


UE Enters Cell FACH

Supervision in Cell‐DCH

• In CELL DCH state the Radio ConnectionIn CELL_DCH state, the Radio Connection Supervision functionality is provided by means of two different algorithms: the Radio Link Setof two different algorithms: the Radio Link Set Supervision algorithm, located in the RBS, supports the Radio Connection Supervisionsupports the Radio Connection Supervision Evaluation algorithms, located in the SRNC


The Radio Link consider failed if and only if radio link failure


The Radio Link consider failed if and only if radio link failure indication send from the 2 RBSs

• Radio Connection Supervision (RCS)Radio Connection Supervision (RCS) Evaluation The Radio Connection Supervision Evaluation algorithm keeps track of theEvaluation algorithm keeps track of the synchronization status of the whole radio connection by assigning a tag to every RLSconnection by assigning a tag to every RLS.


• Radio Link Set (RLS) Supervision( ) p

The RLS Supervision function supervises the synchronization status of the RLS provided by the RBS to the radio connection, d t h t th SRNC Wh O tS I dand reports any changes to the SRNC. When nOutSyncInd

number of consecutive frames are out‐of‐sync a timer rlFailureT is started and at expiry the RLS is considered out‐of‐sync and Radio Link Failure is reported to the SRNC. When the RLS is out‐of‐sync and nInSyncInd number of frames are in‐sync, the RLS is considered in‐sync and Radio Link Restorein sync, the RLS is considered in sync and Radio Link Restore is reported to the SRNC.


• Uplink DPDCH/DPCCHUplink DPDCH/DPCCH

Coded Data, 10 x 2^k bits, k=0…6 (10 to 640 bits)

Dedicated Physical Data Channel (DPDCH) Slot (0.666 mSec)

I

Pilot (FSW: is some of Pilot Bits) FBI TPCDedicated Physical Control Channel (DPCCH) Slot (0.666 mSec)

QTFCI

1 2 3 4 5 6 7 8 9 10 11 12 13 14 151 2 3 4 5 6 7 8 9 10 11 12 13 14 15



• The connection is considered lost by the RCS when the last RLS, for the connection, has been out‐of‐sync , , yfor a time given by the parameter dchRcLostT. For a connection that includes HSDPA, the PS part of the connection is considered lost by the RCS when the RLS that contains the Serving HS‐DSCH cell, has been out of sync for a time given by the parameterout‐of‐sync for a time given by the parameter hsDschRcLostT. This means that when the hsDschRcLostT timer expires, an Iu Release will behsDschRcLostT timer expires, an Iu Release will be requested to the PS CN and when the dchRcLostT timer expires, an Iu Release will be requested to all


involved CNs.

SRNC Radio Link Restore

d hR L t T St tRadio Link out of sync sent to SRNC

dchRcLost T Starts

T.S 1 T.S 15Number of Bad frames = nOutSyncInd Good

Number of good frames = nInSyncInd

……………………….

Bad Frame #1

lF il T

Good Frame

UE sends FSW in each

What is the BER of this frame (CRC decoding)

rlFailure T starts

rlFailure T Expires

N.B if number of good frame that decoded by NB before rlFailureT timer expiration equal to nInSyncInd then the RL id k d th ti h ld t d


UE sends FSW in each Time Slot in DPCCH

RL consider ok and the timer should stopped

Power Control


Power Control types

Power controlPower control

Uplink Downlink

Initial PowerOpen Loop Power Control

Closed Loop Power Control

Initial Power settings for Power

Closed loop Power control


Setting Of common Channel PowerPower

Channel Name Parameter Name Default Power Setting

Meaning

CPICH PrimaryCpichPower 300 30dBm

BCH bchPower ‐31 ‐3.1dB

AICH aichPower ‐6 ‐6dB

FACH (control) maxFach1Power 18 1.8dBFACH (control) maxFach1Power 18 1.8dB

FACH (Traffic) maxFach2Power 15 1.5dB

PCH pchPower ‐4 ‐0.4dB

PICH i hP 7 0 7dBPICH pichPower ‐7 ‐0.7dB

P‐SCH schPower1 ‐18 ‐1.8dB

S‐SCH schPower2 ‐35 =3.5dB


Open Loop Power Control

• UL SIRUL SIR – SIR=Ec/No X SF

= RSCP/RTWP X SF= RSCP/RTWP X SF

= RSCP‐RTWP + 10log SF

– RSCP=SIR + RTWP – 10log SFSIR h t t l d d i d Ch l• SIR has target value depend on service and Channel

• SF has value related to the used service


RACH preamble Power setting

• P‐PRACH = RSCP + LossesP PRACH = RSCP + Losses. – RSCP = SIR+RTWP – 10log SF.

Losses = CPICH Power CPICH RSCP– Losses = CPICH_Power – CPICH_RSCP.

– P_PRACH = SIR_TARGET_RACH + RTWP – 10 log SF + CPICH Power (pimaryCpichPower) –+ CPICH_Power (pimaryCpichPower) –CPICH_RSCP.

– SIR TARRGET RACH – 10log SF + C is constantSIR_TARRGET_RACH 10log SF + C is constant parameter called (constantValueCprach)


ConstantValueCprach PrimaryCPICHPower andConstantValueCprach , PrimaryCPICHPower and RTWP are sent to the UE through BCCH

Now the UE can transmit the Preamble using P PRACH l l d V lP_PRACH calculated Value


Power Ramping


Parameter Range Default Description

PowerOffsetPO 1 to 8 3 3dB

PowerOffsetPpM ‐5to10 ‐4 ‐4dB

PreambleRetansMax1 to 64 8 8 step of increase

before thePreambleRetansMax before the recalculation of P_PRACH

MaxPreambleCycle 1 to 32 4 4 trials for P_PRACH calculation before giving access failure


RACH Message Power

Random Access Message (10, 20, 40, or 80 bits per slot)

RACH Data Slot (0.666 mSec)

I

Pilot (8 bits)

RACH Message Slot (0.666 mSec)

QTFCI (2 bits)

Control Part Power = P_PRACH+ PowerOffsetPpm

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15



Control Power/ Data Power = 20 log (GFc/GFd)Control Power/ Data Power = 20 log (GFc/GFd)

G i d d i f l d lGFc: is standard gain factor related to control

part

GFd: is standard gain factor related to data part

This 2 parameters will be different according toThis 2 parameters will be different according to the type of carried information


Gain Factor Range Default

GF (C t l) 0 t 15 11GFc (Control) 0 to 15 11

GFd (Control) 0 to 15 15

GFc (Data) 0 to 15 10

GFd (D t ) 0 t 15 15GFd (Data) 0 to 15 15


FACH Power Setting

• As mentioned earlier FACH power is initiallyAs mentioned earlier FACH power is initially reserved relative to CPICH power

The question Now is that do every part of FACH h h h dmessage has the same power as the reserved

value 20 to 1256 bits0, 2, or 8 bits

DataTFCI or DTX Pilot

0, 8, or 16 bits


• TFCI Power = FACH Power + FO1TFCI_Power = FACH_Power + FO1– FO1 Default Value is 0 dB

• Pilot_Power = FACH_Power + FO2 – FO2 Default Value is 0 dB


Initial Setting of DL_DPDCH

In case of inter frequency non blind handover cBackoff


will be replaced by cNbifho (modified parameter to enhance the performance of IFHO

Data 2TFCIData 1 TPC

DPDCH

Pilot

DPDCH DPCCH DPCCH

Default Values PO1 (00) Step 0.25 Value 0dB ( ) pPO2 (12) Step 0.25 Value 3dB PO3 (12) Step 0.25 Value 3dB


Downlink Power Ramping

Upper Power Limit

P_DL_DPDCH Calculated

2nd power step size

Upper Power Limit

1st power steps x steps

2nd power step size

Lower Power LimitUsed only when the NBAP indicates it should be used via parameter first RLS indicator

2nd power increase Inner loop 1st power Ramp

RLS indicator


Setting of initial UL_DPDCH powerpower

• Power UL DPCCH initial=• Power_UL_DPCCH_initial=

PrimaryCpichPower + RTWP+uLInitSirTarget ‐10l (SF DPCCH) + CPO10log(SF_DPCCH) + CPO

–RSCP_PCPICH (dBm)DPCCH_power_offset Sent to UE by RBS in RRC connection setup Message

Measured by the UE

cPO= -30 to 30 in 0.5 dB steps default = 0 (0 dB) PrimaryCpichpower = -100 to 500 in 0.1 dB steps default = 300 (30 dBm)ulInitSirTarget : has different values for different services e.g. SRB =5.7dB; RAB with SF=4 = 9.2 ; RAB with SF=16 or 8 = 8.2 dB


e.g. SRB 5.7dB; RAB with SF 4 9.2 ; RAB with SF 16 or 8 8.2 dB and for RAB with SF= 32 or higher =4.9

• Uplink DPDCH/DPCCHp /

Coded Data, 10 x 2^k bits, k=0…6 (10 to 640 bits)Dedicated Physical Data Channel (DPDCH) Slot (0.666 mSec)

I

Pilot FBI TPCDedicated Physical Control Channel (DPCCH) Slot (0.666 mSec)

QTFCI

1 2 3 4 5 6 7 8 9 10 11 12 13 14 151 2 3 4 5 6 7 8 9 10 11 12 13 14 15



P_DPDCH power calculation

DPCCH power/ DPDCH power = Bc/Bd

DPCCH power – DPDCH power= 20 log (Bc/Bd)

DPDCH power = DPCCH power‐ 20log(Bc/Bd)DPDCH power DPCCH power 20log(Bc/Bd) Bc: DPCCH gain factor Bd: DPDCH gain factor


Radio Bearer DPCCH gain Factor DPDCH gain factor DPDCH power

Signaling 11 15 DPCCH power +2.7

Speech 11 15 DPCCH power + 2.7

CS 64 8 15 DPCCH power + 5.46

PS 64/64 8 15 DPCCH power + 5.46p

PS 64/384 8 15 DPCCH power + 5.46


Inner loop power control

• Up Link inner loop power controlUp Link inner loop power control

DPDCH/DPCCH (pilot + Data +TFCI +TPC + Data)

TPC_Command = (UP) or (Down)

DPCCH (Pilot + TFCI + TPC)

DPDCH RBS measure SIR UL RLS of _ _the pilot Data then compare it with Target value


DPCCH TPC_cmd=‐1 (Down) or +1 (UP)

DPCCH change = TPC X TPC_cmd dB

DPDCH power related to DPCCH power

SIR_UL_RLS>= SIR_TARGET TPC command = “down” SIR_UL_RLS < SIR_TARGET TPC command = “UP”


UL Power control during compressed modecompressed mode

10 mSec Frames (15 slots)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 1511 12 13 14 15

( )

Normal Operation

1 2 3 4 12 13 14 1511 12 13 14 15

Compressed-Mode; single-frame method1 2 3 4

Transmission Gap

Compressed period used for IRAT measurements and BSIC decoding and

3

Compressed period used for IRAT measurements and BSIC decoding and confirmation


SIR_target in CM

SIR_target + 1dB

SIR_target + 0.5dB

1 2 3 4 12 13 14 1513 14 15 1 2 3 4 14 15

SIR_target

Transmission Gap

3 14 15


TPC command in CM

TPC = 1 dB

TPC = 2 dB

1 2 3 4 12 13 14 1513 14 15 1 2 3 4 14 15

Transmission Gap

3 14 15

Recovery Period 7 slotsRecovery Period 7 slots after the Gap

pilot = 10 log (Npilot,prev/Npilot,curr)


DPCCH= TPC X TPC_cmd + Pilot

Down link inner loop power controlcontrol

DPDCH/DPCCH (pilot + Data +TFCI +TPC + Data)

DPCCH (Pilot + TFCI + TPC)

DPDCH

MS measureTPC_Command = (UP) or (Down)

MS measure SIR_DL_RLS of the pilot Data then compare it with


Target value

TPC command (UP or Down)

present power P(K)= P(k 1) + Ptpc(K)present power P(K)= P(k‐1) + Ptpc(K)

P_TPC(K) = +1 dB if (TPC_CMD is Up) or -1 dB if (TPC CMD is down)

SIR_UL_RLS>= SIR_TARGET TPC command = “down” SIR_UL_RLS < SIR_TARGET TPC command = “UP”

Up) or -1 dB if (TPC_CMD is down)


Downlink Power Balancing

SRNCPower Drift

RBS 2 UE


RBS 1

8 frame cycle

Frame 1 Frame 2 Frame 3 Frame 4 Frame 5 Frame 6 Frame 7 Frame 8

Reference value

SRNC

RBS 1 RBS 2

At the beginning of each cycle a reference power, which is the average of all radio link powers is calculated.

UE


Over the next 8 frames cycle the power of each RL is adjusted back to this reference value

dlPcMethod

1 no DL power balance and no inner loop power

control

2 No balancing only inner loop power control is used

3 Balancing is working

4 fixed power balancing algorithm is used fixed Dl reference value

P(K) = P(K-1) + Pbalance Pbal = +1 dB increase the power -1 dB decrease the power


Power balancing is configured to work on 8 frame cycle

Downlink power control in compressed modecompressed mode

P(K) P(K 1) Pt (K) P b l(K) P i (K) dBP(K)= P(K-1) + Ptpc(K) + P bal(K) + P sir (K) dBm

P(k 1): previous DL powerP(k-1): previous DL power Ptpc (K): +1(UP) or -1(down) X TPC

PSIR(K) = 4dB

TPC(K) = 1 dB

PSIR(K) = 3.5dB

TPC(K) = 2 dB

1 2 3 4 12 13 14 1513 14 15

Transmission Gap

1 2 3 4 14 15


Recovery Period 7 slots after the Gap

Outer Loop Power control

• The outer loop power control algorithm performed for DL in p p g pthe UE and for the UL in the RNC

• The Main idea behind the outer loop power control is to set SIR t tproper SIR target

• SIR target value change according to blerQualitytargetDl

• SIR target value should be between SIR Max 173 (17 3 dB) andSIR target value should be between SIR Max 173 (17.3 dB) and SIR min ‐82(‐8.2 dB)

• UL outer loop power control could be either jump regulator or constant step regulator by ulOuterLoopRegulator parameter

0 constant step


0 constant step1 Jump Regulator

Jump Regulator

SIRtarget= SIRtarget + ulSirStep(-x/(z*UPDOWNSTEPRATIO)+Y/Z)

Where: •ulSirStep = 0 to 50 in 0.1 step default 10 (1 dB)•X = Number of Transport blocks that have CRC OK•Z= Total Number of received Transport blocks •Y= Number of transport blocks that have CRC NG•UPDOWNSTEPRATIO= (1/blerQualityTargetUL * 0.5) -1 default value is 199value is 199 •blerQualityTargetUL = -63 to 0 default is -2 (0.01)


SIR T t 5 9 dBSIR_Target=5.9 dB

CRC=OK

Will continuo to drop until receive bad CRC

The SRNC will Update the SIR target value for the UL in resolution of 0.1 dB to prevent excessive Iub signaling.

………………………………………………………………………………….ulInitSirTaget = 4.9 SIRTarget= 4.9+1(-0/(199*1) +1/1) = 5.9


NG frame received

Step Regulator

If ulOuterLoopRegulator set to 0 the Step regulator will work d f l i f ll iIdea of step regulator is as following :

•The SIR target should increased by “ulSirStep” when one NG CRC have been Received • And decreased by “ulSirStep” if number of good CRC equal to y p g q

(1/(1.5blerQualityTargetUL) (0.5) Default 133

133 Good CRC

ulSirStepulSirStep

ulSirInitTarget


NG CRC NG CRC

Handover


Handover Type

HO Types

Hard Soft HandoverHandover Soft Handover

IRAT handover Inter Frequency HO

Core Network Hard HO Soft HO Softer HO


Soft/ Softer HO

RNC UE Measurement Control messageMeasurement Control message

DCCH Perform measurement

UE Evaluation

RNC Evaluation

ddRL addition Active Set Update

Radio Link Add/Remove / ReplaceDCCH

Active SetActive Set Update Complete Radio Link Removal

RNC Evaluation Measurement Control message


RNC Evaluation Measurement Control message

DCCH

Reported Measurement


Measurements Elaboration


RRC Measurement initial


Handover triggering type

• Event TriggeringEvent Triggering – Measurement to be sent whenever the levels of cells enters the reporting rangecells enters the reporting range

• Periodic triggering Measurement report should be sent to the RNC by– Measurement report should be sent to the RNC by the UE periodically


Event Description


Event 1A


Event 1B


Event 1C


Event 1D


Event 1E


Event 1F


Event 2D/2F

2B/2C

3A/3C


Compressed Mode


Compressed mode

• Realization MethodsRealization Methods – SF/2

Rate matching/puncturing– Rate matching/puncturing

– Higher layer scheduling



Load Control


PUC


ICAC


Cell Resource Decision


The algorithm Chooses UEs for Pre‐emption


LDR


OLC


Documents

WCDMA Optimization