IFHO Optimization Radio Network Optimization – Cairo team
Agenda : • • • • • • •
Handover Procedures Compressed Mode Compressed Mode Events IFHO (Event 2b) Examples Proposed Values for Trial Recommendations
Handover Procedures For Handover to be executed , there are some procedures that handover have to go through. These procedures can be summarized in 3 phases :
Measurements
RNC
Evaluation
RNC
Execution
Handover Procedures Specifies the rules that control UE Measurements
1. Cells Triggered the event •Synch. Info Admisssion CTRL
Code Allocation
Power CTRL
2. Active Set EC/N0
Compressed Mode
• •
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 where measurements can be performed
Compressed Mode methods ? 1. 2.
Spread Factor /2 : SF is reduced by 2 so the same amount of data can be transmitted in half the time Higher Layer Scheduling : with respect to Compressed mode schedule , HLS will decrease the bit rate for Compressed mode frames .
Compressed Mode Events 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 = maxTxPowerUl Note: ( 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.
2.
Event 2f Measured Ecno
>
Measured RSCP
>
Event 6b Measured UE TX Power <
usedFreqThresh2dEcno+serviceOffset2dEcno +usedFreqRelThresh2fEcno AND usedFreqThresh2dRscp +serviceOffset2dRscp +usedFreqRelThresh2fRscp ueTxPowerThresh6b
Note That: All Conditions were Checked before Compressed Mode Exit .
Compressed Mode Events 2d Event 2f Event
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
IFHO Event (2b) In Case that , UE has entered Compressed Mode AND Connection Quality hasn’t recovered but Continued degradation Then, Hotype : IFHO_PREFFERED
Hotype : IRAT_PREFFERED
IFHO (Event 2b) Attempted
IRAT HO (Event 3a) Attempted
•
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 satisfied F2 Cell Measured Rscp > NonUsedFreqThresh4_2bRscp + serviceOffset2dRscp F2 Cell Measured Ecn0 > NonUsedFreqThresh4_2bEcno+serviceOffset2dEcno
Examples - 1 Assume that : NonUsedFreqThresh4_2bRscp = -95 NonUsedFreqThresh4_2bEcno = - 9
hotype : IFHO_PREFFERED
Rscp= -97 usedFreqThresh2dRSCP = -97 Then,Compressed Mode Entered Rscp= -100 UsedFreqRelThresh4_2bRscp = -3 Then ,Event 2b is Triggered
Rscp= -94 usedFreqRelThresh2fRscp = 3 Then, Compressed Mode Exit
If IEF Neighbour Rscp > -95 AND Its IEF Neighbour Ecn0 > -9 Then 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 )
Examples - 2 Assume that : NonUsedFreqThresh4_2bRscp = -95 NonUsedFreqThresh4_2bEcno = - 9
hotype : IFHO_PREFFERED
Ecn0= -12 usedFreqThresh2dEcn0 = -12 Then,Compressed Mode Entered Ecn0= -13 UsedFreqRelThresh4_2bEcn0 = -1 Then ,Event 2b is Triggered
Ecn0= -10 usedFreqRelThresh2fEcno = 2 Then, Compressed Mode Exit
If IEF Neighbour Rscp > -95 AND Its IEF Neighbour Ecn0 > -9 Then 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 : F1 f1 F2 Parameter hotype
Example Value IFHO_PREFFERED
UsedFreqThresh2dEcn0 UsedFreqThresh2dRscp UsedFreqRelThresh2fEcn0 UsedFreqRelThresh2fRscp UsedFreqRelThresh4_2bRscp
- 12 -92 2 3
Parameter hotype
Example Value IFHO_PREFFERED - 12 -97 2 3
-3
UsedFreqThresh2dEcn0 UsedFreqThresh2dRscp UsedFreqRelThresh2fEcn0 UsedFreqRelThresh2fRscp UsedFreqRelThresh4_2bRscp
UsedFreqRelThresh4_2bEcn0
-1
UsedFreqRelThresh4_2bEcn0
-1
NonusedFreqThresh4_2bRscp
- 95
NonusedFreqThresh4_2bRscp
- 95
NonusedFreqThresh4_2bEcn0
-9
NonusedFreqThresh4_2bEcn0
-9
-3
Recommendations • For IFHO Optimization ,The following steps are recommended to be followed : 1. 2. 3. 4.
Identify 2_nd Carrier Cells For 1_st Carrier , Identify border cells with 2_nd Carrier Cells . Define IEF Neighbor list (recommended to be small) With respect to field measurements , i. set Compressed Mode events (2d/2f) Thresholds ii. Set IFHO event (2b) Thresholds
Thank You !
