Mobility_Strategy_IDLE-MODE
Same Cell 1 Same Cell
priority priority
LTE
Hi-Low Cell
Low-Hi Cell
3 2 priority
priority 6
WCDMA
5
Hi-Low Cell 4 Low-Hi Cell
priority 5 priority
RSCP
- Cell detection for reselection is considered when minimum cell power is achievable
- For equal priority neighbor and serving cells, use ranking criteria Rn > Rs
- For higher priority neighbor cell, measurement is started immediately
- For lower priority neighbor cell, measurement is started when SRXLEV(s) < Threshold
- Reselection is triggered when a tReselectionRAT has lapsed
- In this scenario, Cell(s) and Cell(n) have no idea on UE (RRC_IDLE) location as reselection is initiated by the UE.
1. Inter-freq reselection for same cell priority (LTE to LTE):
o Cell detection is considered when Qrxlevmin(n) is achievable
o Detection measurement is started when SRXLEV(s) < SnonintraSearch
o Reselection happens If SRXLEV(n) > (SRXLEV(s) + Qhyst) for a duration of tReselectionEUTRA
Where:
• SRXLEV(s) = Qrxlevmeas(s) – Qrxlevmin(s)
• SRXLEV(n) = Qrxlevmeas(n) – Qrxlevmin(n)
• S-nonintraSearch(s), Qrxlevmin(s), Qhyst, Cell Priority(s) in SIB3
• Qrxlevmin(n), Cell Priority(n) and tReselectionEUTRA in SIB5
2. Inter-freq reselection for Hi-Low cell priority (LTE to LTE):
o Cell detection is considered when Qrxlevmin(n) is achievable
o Detection measurement is triggered when SRXLEV(s) < SnonintraSearch
o Reselection happens if SRXLEV(s) < threshServLow and SRXLEV(n) > threshXLow for a duration of
tReselectionEUTRA
Where:
• SRXLEV(s) = Qrxlevmeas(s) – Qrxlevmin(s)
• SRXLEV(n) = Qrxlevmeas(n) – Qrxlevmin(n)
• Qrxlevmin(s), Cell Priority(s) and threshServLow in SIB3
• Qrxlevmin(n), Cell Priority(n), tReselectionEUTRA and threshXLow in SIB5
3. Intra-Freq reselection for same cell priority (LTE to LTE):
o Cell detection is considered when Qrxlevmin(n) is achievable
o Detection measurement is triggered when SRXLEV(s) < SintraSearch
o Reselection happens if SRXLEV(n) > (SRXLEV(s) + Qhyst) for a duration of tReselectionEUTRA
Mobility_Strategy_IDLE-MODE
Where:
• SRXLEV(s) = Qrxlevmeas(s) – Qrxlevmin(s)
• SRXLEV(n) = Qrxlevmeas(n) – Qrxlevmin(n)
• SintraSearch, Qrxlevmin(s), Qhyst, Cell Priority(s), tReselectionEUTRA in SIB3
• Qrxlevmin(n), Cell Priority(n) in SIB4
4. IRAT reselection for Hi-Low cell priority (LTE to WCDMA):
o Cell detection is considered when Qrxlevmin(n) is achievable
o Detection measurement is triggered when SRXLEV(s) < SnonintraSearch
o Reselection happens if SRXLEV(s) < threshServLow and SRXLEV(n) > threshXLow for a duration of
tReselectionUTRA
Where:
• SRXLEV(s) = Qrxlevmeas(s) – Qrxlevmin(s)
• SRXLEV(n) = Qrxlevmeas(n) – Qrxlevmin(n)
• Qrxlevmeas(s) and Qrxlevmin(s) in RSRP power
• Qrxlevmeas(n) and Qrxlevmin(n) in RSCP power
• Cell Priority(s), Qrxlevmin(s) and threshServLow in SIB3
• Cell Priority(n), Qrxlevmin(n), tReselectionUTRA and threshXLow in SIB6
5. IRAT reselection for Low-Hi cell priority (WCDMA to LTE):
o Cell detection is considered when Qrxlevmin(n) is achievable
o Detection measurement is started immediately when minimum cell power requirement is achieved
o Detection measurement is stopped when SRXLEV(s) > s-PrioritySearch1
o Reselection happens if SRXLEV(n) > threshXHigh
Where:
• SRXLEV(s) = Qrxlevmeas(s) – Qrxlevmin(s)
• SRXLEV(n) = Qrxlevmeas(n) – Qrxlevmin(n)
• Qrxlevmeas(s) and Qrxlevmin(s) in RSCP power
• Qrxlevmeas(n) and Qrxlevmin(n) in RSRP power
• Qrxlevmin(s) in W-SIB3
• s-PrioritySearch1, threshXHigh , Cell Priority(s), Cell Priority(n), Qrxlevmin(n) in W-SIB19
6. Inter-freq reselection for Low-Hi cell priority (LTE to LTE):
o Cell detection is considered when Qrxlevmin(n) is achievable
o Detection measurement is started immediately when minimum cell power requirement is achieved
o Detection measurement is stopped when SRXLEV(s) > SnonintraSearch
o Reselection happens when SRXLEV(n) > threshXHigh and
o Reselection occurs after expiry of tReselectionEUTRA
Where:
• SRXLEV(s) = Qrxlevmeas(s) – Qrxlevmin(s)
• SRXLEV(n) = Qrxlevmeas(n) – Qrxlevmin(n)
• Qrxlevmin(s), Cell Priority(s) in SIB3
• Qrxlevmin(n), Cell Priority(n), tReselectionEUTRA and threshXHigh in SIB5
Mobility_Strategy_CONNECTED-MODE
Synchronizing HO & Reselection Settings
Cell(s) will send an RRCConnectionRelease message
to UE with redirection info containing “EUTRA-
1
TargetFreqInfo”. UE will be RRC_IDLE for a moment
and UE will establish a new RRCConnection to Cell(n)
as a new user.
LTE
1
4 2
WCDMA
4
3
- In handover scenario, both Cell(s) and Cell(n) knows the location of the UE (RRC_Connected) as resources are
initially reserved before the connected state UE is handed off from Cell(s) to Cell(n)
- In redirection scenario, only the Cell(s) knows the location of the UE as there is no initial preparation
performed between the Cell(s) and Cell(n) when moving the UE
- After an event is triggered, a measurement report is sent by UE to eNB, after time-to-trigger, where
afterwards eNB decides to allow a handover to the UE.
1. Inter-freq handover for Hi-Low cell priority (LTE to LTE):
• A2 event is triggered when Qrxlevmeas(s) + Hyst < Threshold
• A3 event is triggered when Qrxlevmeas(n) – Hyst > Qrxlevmeas(s) + Offset
• A4 event is triggered when Qrxlevmeas(n) – Hyst > Threshold
• A5 event is triggered when (Qrxlevmeas(n) – Hyst > Threshold2) and (Qrxlevmeas(s) + Hyst <
Threshold1)
• After expiry of timeToTrigger, UE sends measurement report and eNB decides whether to allow HO
Where:
• Hyst, Offset, Threshold is found in RRCConnectionReconfiguration message
2. Intra-freq handover for same cell priority (LTE to LTE):
• A2 event is triggered when Qrxlevmeas(s) + Hyst < Threshold
• A3 event is triggered when Qrxlevmeas(n) – Hyst > Qrxlevmeas(s) + Offset
• After expiry of timeToTrigger, UE sends measurement report and eNB decides whether to allow HO
3. IRAT handover for Hi-Low cell priority (LTE to WCDMA):
• A2 event is triggered when Qrxlevmeas(s) + Hyst < Threshold
• B1 event is triggered when Qrxlevmeas(n) – Hyst > Threshold
• B2 event is triggered when (Qrxlevmeas(n) – Hyst > Threshold2) and (Qrxlevmeas(s) + Hyst <
Threshold1)
Where:
• Qrxlevmeas(s) is RSRP
• Qrxlevmeas(n) is RSCP
• IRAT redirection for Low-Hi cell priority (WCDMA to LTE):
4. IRAT redirection for Low-Hi cell priority (WCDMA to LTE):
• B1 event is triggered when Qrxlevmeas(n) – Hyst > Threshold
Mobility_Strategy_CONNECTED-MODE
Synchronizing HO & Reselection Settings
UE will be handed over to F2
being the cell with better A5
Inter-Freq threshold @ -104dBm.
RSRP >
ThreshXHigh =
-106
IRAT Resel
RSRP >
IRAT HO
ThreshXHigh = -
112
If UE has RxLevmeas = -111 in RRC_IDLE while at F3, it will stay at F3
because reselection setting ThreshServLow = -112. But when UE
goes to RRC_Connected at F3 with A2-IRAT threshold at -110, UE Assuming that for F3Cell2:
will be handed over to F4 because the current RxLevmeas is lower A2-IRAT = -110
than the A2-IRAT threshold. This will cause signaling with RAN and ThreshServLow = -108
possibly with CN as well during HO. ThreshXHigh = -112
While if reselection setting for F3, ThreshServLow = -108 and UE When UE is RRC_IDLE with RxLevmeas = -111 while at F4Cell1, then a
RxLevmeas = -111, a reselection to F4 is triggered before UE reselection is triggered because UE RxLevmeas is better than
becomes RRC_Connected, therefore UE will establish its call on F4 ThreshXHigh of F3Cell2 .
thus will not cause any HO signaling between F3 and F4.
When UE, while at F3Cell2, gets RRC_Connected with RxLevmeas = -111,
Note: in this case, UE will be handed over back to F4Cell1 because its current
IRAT-HO signaling causes undue issues to the UE because UE will go RxLevmeas is worse than the A2-IRAT threshold of F3Cell2 at -110. Then
into compressed mode while scanning for other frequencies in after the call, when UE gets RRC_IDLE, UE will reselect again to F3Cell2.
preparation for IRAT-HO. This causes ping-pong effect and unnecessary HO signaling.
While if reselection setting for F3Cell2 is changed to ThreshXHigh = -106
and UE RxLevmeas = -111, UE will stay at F4Cell1 and possibly gets
RRC_Connected while at F4Cell1. Thus avoiding user experience issues
brought by ping-pong effect and compression during freq. scan for HO
preparation.
Mobility Parameters (Connected Mode)
Configurations of Intra-RAT Events
Ofs and Ofn, which are considered during inter-frequency handovers
• The Cell.QoffsetFreq parameter specifies Ofs.
• Cell.QoffsetFreq (0 dB)
• Range: (-24, -22, -20, -18, -16, -14, -12, -10, -8, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16,
18, 20, 22, 24)
• The EutranInterNFreq.QoffsetFreqConn parameter specifies Ofn.
• EutranInterNFreq.QoffsetFreqConn (0 dB)
• Range: (-24, -22, -20, -18, -16, -14, -12, -10, -8, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16,
18, 20, 22, 24)
Ocs and Ocn
• The Cell.CellSpecificOffset parameter specifies Ocs.
• Cell.CellSpecificOffset (0 dB)
• Range: (-24, -22, -20, -18, -16, -14, -12, -10, -8, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16,
18, 20, 22, 24)
• The EutranIntraFreqNCell.CellIndividualOffset parameter specifies Ocn for intra-frequency neighboring cells.
• EutranIntraFreqNCell.CellIndividualOffset (0 dB)
• Range: (-24, -22, -20, -18, -16, -14, -12, -10, -8, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16,
18, 20, 22, 24)
• The EutranInterFreqNCell.CellIndividualOffset parameter specifies Ocn for inter-frequency neighboring cells.
• EutranInterFreqNCell.CellIndividualOffset (0 dB)
• Range: (-24, -22, -20, -18, -16, -14, -12, -10, -8, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16,
18, 20, 22, 24)
Mobility Parameters (Connected Mode)
Off, which applies only to event A3
• The IntraFreqHoGroup.IntraFreqHoA3Offset parameter specifies Off for intra-frequency event A3.
• IntraFreqHoGroup.IntraFreqHoA3Offset (2)
• Range: (-15 ~ 15), Unit: 0.5dB
• The InterFreqHoGroup.InterFreqHoA3Offset parameter specifies Off for inter-frequency event A3.
• InterFreqHoGroup.InterFreqHoA3Offset (2)
• Range: (-15 ~ 15), Unit: 0.5dB
A1 & A2 other parameters
• Hys, which is specified by InterFreqHoGroup.InterFreqHoA1A2Hyst
• InterFreqHoGroup.InterFreqHoA1A2Hyst (2)
• Range: (0 ~ 15), Unit: 0.5dB
• TimeToTrig, which is specified by InterFreqHoGroup.InterFreqHoA1A2TimeToTrig
• InterFreqHoGroup.InterFreqHoA1A2TimeToTrig (640ms)
• Range: (0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 480ms, 512ms, 640ms, 1024ms,
1280ms, 2560ms, 5120ms)
A3 other parameters
• Hys, which is specified by IntraFreqHoGroup.IntraFreqHoA3Hyst
• IntraFreqHoGroup.IntraFreqHoA3Hyst (2)
• Range: (0 ~ 15), Unit: 0.5dB
• TimeToTrig, which is specified by IntraFreqHoGroup.IntraFreqHoA3TimeToTrig
• IntraFreqHoGroup.IntraFreqHoA3TimeToTrig (320ms)
• Range: (0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 480ms, 512ms, 640ms, 1024ms,
1280ms, 2560ms, 5120ms)
NOTE:
Both intra-frequency event A3 and inter-frequency event A3 use the preceding parameters.
A4 & A5 other parameters
• Hys, which is specified by InterFreqHoGroup.InterFreqHoA4Hyst
• InterFreqHoGroup.InterFreqHoA4Hyst (2)
• Range: (0 ~ 15), Unit: 0.5dB
• TimeToTrig, which is specified by InterFreqHoGroup.InterFreqHoA4TimeToTrig
• InterFreqHoGroup.InterFreqHoA4TimeToTrig (640ms)
• Range: (0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 480ms, 512ms, 640ms, 1024ms,
1280ms, 2560ms, 5120ms)
Configurations of Inter-RAT Events
Mobility Parameters (Connected Mode)
Ofs and Ofn
• The Cell.QoffsetFreq parameter specifies Ofs.
• Cell.QoffsetFreq (0 dB)
• Range: (-24, -22, -20, -18, -16, -14, -12, -10, -8, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20,
22, 24)
• The UtranNFreq.OffsetFreq parameter specifies Ofn for neighboring UTRAN cells.
• UtranNFreq.OffsetFreq (0 dB)
• Range: (-15 ~ 15)
• The GeranNfreqGroup.OffsetFreq parameter specifies Ofn for neighboring GERAN cells.
• GeranNfreqGroup.OffsetFreq (0 dB)
• Range: (-15 ~ 15)
A1 & A2 other parameters
• Hys, which is specified by InterRatHoCommGroup.InterRatHoA1A2Hyst
• InterRatHoCommGroup.InterRatHoA1A2Hyst (2)
• Range: (0 ~ 15), Unit: 0.5dB
• TimeToTrig, which is specified by InterRatHoCommGroup.InterRatHoA1A2TimeToTrig
• InterRatHoCommGroup.InterRatHoA1A2TimeToTrig (640ms)
• Range: (0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 480ms, 512ms, 640ms, 1024ms,
1280ms, 2560ms, 5120ms)
B1 & B2 other parameters
E-UTRAN to UTRAN
• Hys, which is specified by InterRatHoUtranGroup.InterRATHoUtranB1Hyst
• InterRatHoUtranGroup.InterRATHoUtranB1Hyst (2)
• Range: (0 ~ 15), Unit: 0.5dB
• TimeToTrig, which is specified by InterRatHoUtranGroup.InterRATHoUtranB1TimeToTrig
• InterRatHoUtranGroup.InterRATHoUtranB1TimeToTrig (320ms)
• Range: (0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 480ms, 512ms, 640ms, 1024ms,
1280ms, 2560ms, 5120ms)
NOTE:
The measurement duration of offload-oriented and optimization-oriented handovers is controlled by a 3s
timer. If TimeToTrig is longer than 3s, UEs will not send measurement reports to the eNB because the
measurements are stopped before the time-to-trigger elapses. In this case, offload-oriented and optimization-
oriented handovers are not triggered.
E-UTRAN to GERAN
• Hys, which is specified by InterRatHoGeranGroup.InterRatHoGeranB1Hyst
• InterRatHoGeranGroup.InterRatHoGeranB1Hyst (2)
• Range: (0 ~ 15), Unit: 0.5dB
• TimeToTrig, which is specified by InterRatHoGeranGroup.InterRatHoGeranB1TimeToTrig
• InterRatHoGeranGroup.InterRatHoGeranB1TimeToTrig (640ms)
• Range: (0ms, 40ms, 64ms, 80ms, 100ms, 128ms, 160ms, 256ms, 320ms, 480ms, 512ms, 640ms, 1024ms,
1280ms, 2560ms, 5120ms)
NOTE:
The TimeToTrig variable differs depending on UTRAN and GERAN. You can set TimeToTrig variable values to
control the event B1 reporting probability. For example, if the TimeToTrig variable value for E-UTRAN to UTRAN
is smaller than that for E-UTRAN to GERAN, a UE preferentially reports event B1 for a neighboring UTRAN cell,
given the same network conditions. Therefore the eNB preferentially sends a handover request to a
neighboring UTRAN cell.
Mobility Parameters (Connected Mode)
Other Parameters in Measurement Reports
A3, A4 & A5
• IntraRatHoComm.IntraRATHoMaxRprtCell (4)
• Range: (1 ~ 8), Unit: NONE
• IntraRatHoComm.IntraRATHoRprtAmount (Infinity)
• Range: (r1, r2, r4, r8, r16, r32, r64, Infinity)
• IntraRatHoComm.IntraFreqHoRprtInterval (240ms)
• Range: (120ms, 240ms, 480ms, 640ms, 1024ms, 2048ms, 5120ms, 10240ms, 1min, 6min, 12min, 30min,
60min)
• IntraRatHoComm.InterFreqHoRprtInterval (240ms)
• Range: (120ms, 240ms, 480ms, 640ms, 1024ms, 2048ms, 5120ms, 10240ms, 1min, 6min, 12min, 30min,
60min)
E-UTRAN to UTRAN event B1/B2; E-UTRAN to GERAN event B1/B2
• InterRatHoComm.InterRATHoMaxRprtCell (4)
• Range: (1 ~ 8), Unit: NONE
• InterRatHoComm.InterRATHoRprtAmount (Infinity)
• Range: (r1, r2, r4, r8, r16, r32, r64, Infinity)
• InterRatHoComm.InterRATHoUtranRprtInterval (480ms)
• Range: (120ms, 240ms, 480ms, 640ms, 1024ms, 2048ms, 5120ms, 10240ms, 1min, 6min, 12min, 30min,
60min)
• InterRatHoComm.InterRatHoGeranRprtInterval (480ms)
• Range: (120ms, 240ms, 480ms, 640ms, 1024ms, 2048ms, 5120ms, 10240ms, 1min, 6min, 12min, 30min,
60min)
The following lists the reference signal quality criteria for events B1 and B2 for E-UTRAN to UTRAN handovers.
• InterRatHoComm.InterRATHoUtranB1MeasQuan parameter specifies whether RSCP or Ec/N0 is used as the
reference signal quality type for event B1.
• InterRatHoComm.InterRATHoUtranB1MeasQuan (ECNO)
• Range: (RSCP, ECN0, BOTH)
• InterRatHoComm.InterRatHoA1A2TrigQuan parameter specifies whether RSRP or RSRQ is used as Thresh1 for event
B2. Thresh2 for event B2 is the same as that for event B1.
• InterRatHoComm.InterRatHoA1A2TrigQuan (RSRP)
• Range: (RSRP, RSRQ, BOTH)
The following lists the reference signal quality criteria for events B1 and B2 for E-UTRAN to GERAN handovers.
• The reference signal quality type for event B1 is RSSI.
• The InterRatHoComm.InterRatHoA1A2TrigQuan parameter specifies whether RSRP or RSRQ is used as Thresh1 for
event B2. Thresh2 for event B2 is the same as that for event B1.
• InterRatHoComm.InterRatHoA1A2TrigQuan (RSRP)
• Range: (RSRP, RSRQ, BOTH)
