IFHO OptimizationRadio Network Optimization – Cairo team

Agenda :

• Handover Procedures• Compressed Mode • Compressed Mode Events• IFHO (Event 2b)• Examples• Proposed Values for Trial• Recommendations

Handover ProceduresFor Handover to be executed , there are some procedures that handover haveto go through.These procedures can be summarized in 3 phases :

Measurements

Evaluation

Execution

RNC

RNC

Handover ProceduresSpecifies the rules that control UE Measurements

1. Cells Triggered the event•Synch. Info

2. Active Set EC/N0Admisssion CTRL

Code Allocation

Power CTRL

• When degradation happens to 3G Signal , UTRAN looks forward to check inter Frequency neighbors if they can Survive the Call .

• UE inters Compressed Mode in order to perform Measurements on Other Frequency Cells

What are Compressed Mode Properties ?transmission and reception are stopped for a short time and inter frequency measurements are then performed on other frequency or RAT, After the time is over the transmission and reception resumes. To make sure that the data is not lost, the data is compressed in the frame making empty space wheremeasurements can be performed

Compressed Mode methods ?1. Spread Factor /2 : SF is reduced by 2 so the same amount of data can be transmitted in half the time 2. Higher Layer Scheduling : with respect to Compressed mode schedule , HLS will decrease the bit rate for

Compressed mode frames .

Compressed Mode

Continuously , Connection Quality is monitored by RNC on both UL (Event 6d) and DL (2d Event)If Event 2d OR Event 6d was Triggered , Then Compressed Mode Entered

Event 2d Compressed Mode Entered Event 6d

1. Event 2d : Measured Ecno < usedFreqThresh2dEcno + serviceOffset2dEcno OR Measured RSCP < usedFreqThresh2dRSCP + serviceOffset2dRSCP

2. Event 6d : Measured UE TX Power = maxTxPowerUlNote: ( serviceOffset2d ) used to have different 2dThreshold / RAB .

Compressed Mode Events

During Compressed Mode the Connection quality is still under Monitoring if it recovers back so , if Event 2f (DL) and Event 6b (UL) were Triggered , Then Compressed Mode Exit

1. Event 2f Measured Ecno > usedFreqThresh2dEcno+serviceOffset2dEcno +usedFreqRelThresh2fEcno AND Measured RSCP > usedFreqThresh2dRscp +serviceOffset2dRscp +usedFreqRelThresh2fRscp

2. Event 6b Measured UE TX Power < ueTxPowerThresh6b

Note That: All Conditions were Checked before Compressed Mode Exit .

Compressed Mode Events

To avoid Ping Pong effects , both of Time To Trigger & Hysteresis Parameters are defined .TimeToTrigger2dEcn0 , TimeToTrigger2fEcn0, TimeToTrigger2dRscp , TimeToTrigger2fRscp ,TimeToTrigger6d , TimeToTrigger6b.

Used FreqThresh2dEcn0,UsedFreqThresh2fEcno , UsedFrequencyThresh2dRscp , UsedFrequencyThresh2dRscp , UsedFreqThresh6b

Compressed Mode Events2d Event

2f Event

In Case that , UE has entered Compressed Mode AND Connection Quality hasn’t recovered but Continued degradation Then,

• Event 2b : Measured Ecn0 < usedFreqThresh2dEcno + serviceOffset2dEcno +UsedFreqRelThresh4_2bEcno OR Measured RSCP < usedFreqThresh2dRSCP + serviceOffset2dRscp +UsedFreqRelThresh4_2bRscp OR Measured RSCP < usedFreqThresh2dRSCP + serviceOffset2dRscp +UsedFreqRelThresh4_2bRscp + utranRelThreshRscp For IFHO to be executed , the following Conditions on F2 Cell should be satisfiedF2 Cell Measured Rscp > NonUsedFreqThresh4_2bRscp + serviceOffset2dRscpF2 Cell Measured Ecn0 > NonUsedFreqThresh4_2bEcno+serviceOffset2dEcno

IFHO Event (2b)

IFHO (Event 2b) Attempted

IRAT HO (Event 3a) Attempted

Hotype : IFHO_PREFFEREDHotype : IRAT_PREFFERED

Assume that :NonUsedFreqThresh4_2bRscp = -95 hotype : IFHO_PREFFEREDNonUsedFreqThresh4_2bEcno = - 9

Examples - 1

Rscp= -97usedFreqThresh2dRSCP = -97Then,Compressed Mode Entered

Rscp= -100UsedFreqRelThresh4_2bRscp = -3Then ,Event 2b is Triggered

Rscp= -94usedFreqRelThresh2fRscp = 3Then, Compressed Mode Exit

If IEF Neighbour Rscp > -95 ANDIts IEF Neighbour Ecn0 > -9Then IFHO will be executed

The above example , shows a 3G Signal that entered Compressed mode due to bad RSCP and – using parameters – the example describes its alternatives ( Compressed Mode Exit and IFHO Execution )

Assume that :NonUsedFreqThresh4_2bRscp = -95 hotype : IFHO_PREFFEREDNonUsedFreqThresh4_2bEcno = - 9

Examples - 2

Ecn0= -12usedFreqThresh2dEcn0 = -12Then,Compressed Mode Entered

Ecn0= -13UsedFreqRelThresh4_2bEcn0 = -1Then ,Event 2b is Triggered

Ecn0= -10usedFreqRelThresh2fEcno = 2Then, Compressed Mode Exit

If IEF Neighbour Rscp > -95 ANDIts IEF Neighbour Ecn0 > -9Then IFHO will be executed

The above example , shows a 3G Signal that entered Compressed mode due to bad Ecn0 and – using parameters – the example describes its alternatives ( Compressed Mode Exit and IFHO Execution )

Proposed Values for Trial :

Parameter Example Value

hotype IFHO_PREFFERED

UsedFreqThresh2dEcn0 - 12UsedFreqThresh2dRscp -92UsedFreqRelThresh2fEcn0 2UsedFreqRelThresh2fRscp 3UsedFreqRelThresh4_2bRscp -3

UsedFreqRelThresh4_2bEcn0 -1

NonusedFreqThresh4_2bRscp - 95

NonusedFreqThresh4_2bEcn0 - 9

f1F2F1

Parameter Example Value

hotype IFHO_PREFFERED

UsedFreqThresh2dEcn0 - 12UsedFreqThresh2dRscp -97UsedFreqRelThresh2fEcn0 2UsedFreqRelThresh2fRscp 3UsedFreqRelThresh4_2bRscp -3

UsedFreqRelThresh4_2bEcn0 -1

NonusedFreqThresh4_2bRscp - 95

NonusedFreqThresh4_2bEcn0 - 9

Recommendations• For IFHO Optimization ,The following steps are recommended to be followed :

1. Identify 2_nd Carrier Cells2. For 1_st Carrier , Identify border cells with 2_nd Carrier Cells .3. Define IEF Neighbor list (recommended to be small)4. With respect to field measurements ,

i. set Compressed Mode events (2d/2f) Thresholds ii. Set IFHO event (2b) Thresholds

Thank You !