LTE Call Processing and Handover

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Customer Training Center
Jaeho, Lee
Distribution
EnglishED01

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Network Architecture
UTRAN
GERAN
SGSN
MME
E-UTRANUE
Serving
Gateway
HSS
LTE-Uu
S1-U
S1-MME
S3
S6a
S11
S10
S4
S12
PDN
Gateway
PCRF
Operator’s IP
Services
Ex) IMS. PSS etc
S5 SGi
Gx
Rx
LTE Network Architecture

4/73
Protocol Stack
UE Control Plane
UE User Plane
L1
MAC
RLC
PDCP
RRC
NAS
L1
MAC
RLC
PDCP
RRC
L1
L2
IP
SCTP
S1-AP
Relay
L1
L2
IP
SCTP
S1-AP
L1
L2
IP
UDP
GTP-C
L1
L2
IP
UDP
GTP-C
L1
L2
IP
UDP
GTP-C
L1
L2
IP
UDP
GTP-C
NAS
LTE-Uu S1-MME S11 S5/S8a
UE eNB MME S-GW P-GW
SGi
L1
MAC
RLC
PDCP
IP
App
L1
MAC
RLC
PDCP
L1
L2
UDP/IP
GTP-U
Relay
LTE-Uu S1-U S5/S8
L1
L2
UDP/IP
GTP-U
L1
L2
UDP/IP
GTP-U
Relay
L1
MAC
UDP/IP
GTP-U
IP
UE eNB S-GW P-GW

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eNB Software Architecture
• CPS (Call Processing Software): LTE Control & Bearer Protocol processing
• OAM (Operation and Maintenance): eNB Operation and Maintenance
• MW (Middleware): IPC and Redundancy function
• IPRS (IP Routing Software): Routing protocol operation
• NP SW (Network Processor Software): Packet forwarding function
• OS (Operating System): Embedded Linux
• DD (Device Driver): initializing and setting the devices

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Call Software Blocks (1/3)
ECCB
GTPB
PDCB
RLCB
MACB
Other eNB
EPC
PHY
UE
S1-c
X2-c
S1-u
X2-u
ECS (eNB Control
Subsystem)
EDS (eNB Data
Subsystem)
LTE eNB
LEGEND :
(UDP port)Control (IPC)
Traffic
SCTB
ECMM
ESCM
ERCM
ERRM
ECCM
EHCM
Uu
ECCB
ECMB
Interface

7/73
ECMB (eNB Common Management Block)
Initiate eNB and set the common channel
Transmit system information for initiating UE
Load Control for cell and system overload
ECCB (eNB Call Control Block)
Radio Resource Management, Call Admission Control
RRC/S1-AP ASN.1 Interface, X2-AP ASN.1 Interface
Control the basic call access, S1-AP Paging, Handover call control, Call Trace
SCTB (Stream Control Transmission protocol Block)
S1-C/X2-C SCTP Interface (Association setup/release), S1/X2 AP message
Transmission

8/73
GTPB (GPRS Tunneling Protocol Block)
GPRS(General Packet Radio Service) Tunneling Protocol for data access on S1-U or
X2-U.
PDCB (Packet Data Convergence protocol Block)
Header compression and decompression on IP packet stream, Ciphering, Integrity
DL/UL data forwarding on Handover
PDCP sequence number maintenance, Timer based PDCP SDU discard
RLCB (Radio Link Control Block)
Radio Link control and ARQ(Automatic Repeat Request)
RLC SDU concatenation/segmentation/reassemble, In sequence delivery, RLC re-
establishment
RLC PDU re-segmentation, Paging
MACB (Medium Access Control Block)

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Main ID and S1/X2 Procedure

10/73
E-UTRAN Identifiers (1/3)
eNB-Related ID

11/73
UE-Related ID on S1 (for UE-associated signaling)
UE-Related ID on X2 (for X2 Handover)

12/73
Other EPS IDs

13/73
S1 Interface: Procedures (1/2)
Class 1 Procedures
Sender expects response from receiver

14/73
S1 Interface: Procedures (2/2)
Class 2 Procedures
Sender does not expect response

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X2 Interface: Procedures
Class 1 Procedures
Class 2 Procedures

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S1 Setup between eNB and MME
Objective
To setup the S1AP connection
Exchange configuration information

18/73
X2 Setup between eNB and eNB
Objective
To setup the X2AP connection
Exchange configuration information
Neighbor PCI info is exchanged for supporting Automatic PCI Selection

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Attach Procedure (1/2)
UE Source eNB MME S-GW
EPC
4. Initial UE Message(+ Attach Requet)
NAS procedure( Nas security, Authentication )
7. Initial Context Setup Request (+ Attach Accept)
2. RRC Connection Setup
1. RRC Connection Request
3. RRC Connection Setup Complete
5. Create Session Request
6. Create Session Response

20/73
Attach Procedure (2/2)
EPC
10. UE Capbility Info Indication
13. RRC Connection Reconfiguration
8. UE Capability Enquiry
9. UE Capability Information
12. Security Mode Complete
11. Security Mode Command
14. RRC Connection Reconfiguration Complete
15. Initial Context Setup Response
18. Modify Bearer Request
19. Modify Bearer Response
16. Uplink Information Transfer 17. Uplink NAS Transport
Uplink Data

21/73
Detach Procedure(1/2) – w/o RRC Connection
EPC
4. Initial UE Message(+ Detach Requet)
9. UE Context Release Command
2. RRC Connection Setup
1. RRC Connection Request
3. RRC Connection Setup Complete (+ Detach Request)
6. Delete Session Response
7. Downlink NAS Transport (+ Detach Accept)
8. Downlink Information Transfer(+ Detach Accept)
10. RRC Connection Release
11. UE Context Release Complete
5. Delete Session Request

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Detach Procedure (2/2) – w RRC Connection
EPC
2. Uplink NAS Transport(+ Detach Requet)
7. UE Context Release Command
1. Uplink Information Transfer (+ Detach Request)
4. Delete Session Response
5. Downlink NAS Transport (+ Detach Accept)
6. Downlink Information Transfer(+ Detach Accept)
8. RRC Connection Release
9. UE Context Release Complete
3. Delete Session Request

23/73
LTE Measurement Report Events
Intra-LTE measurement events
Event A1 - Serving becomes better than threshold.
=> release the measurement gap.
Event A2 - Serving becomes worse than threshold.
=> setup measurement gap.
Event A3 - Neighbour becomes offset better than serving.
=> trigger Intra-LTE handover
=> execute ANR
Event A4 - Neighbour becomes better than threshold.
Event A5 - Serving becomes worse than threshold1 and neighbour becomes
better than threshold2.
Inter-RAT measurement events
Event B1 - Inter RAT neighbour becomes better than threshold.
Event B2 - Serving becomes worse than threshold1 and inter RAT neighbour
becomes better than threshold2.
=> trigger Inter-RAT handover

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Measurement Signaling & Info
MeasurementReport
UE EUTRAN
Measurement Reporting from the UE
Measurement Report message has Physical Cell Id (PCI) info of neighbor cell.
Execute handover using PCI of Measurement Report message received from eNB.
In case of neighbor cell of CDMA2000, preRegistrationStatusHRPD information is
included requested interworking- HRPD.
Cell Global Id (CGI) information is included as requested from eNB.
ANR function is executed using CGI information from UE on eNB.

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Handover Classification
Intra-RAT Handover
Intra-eNB Handover
Inter-eNB Handover over X2
Inter-eNB Handover over S1 (Intra-MME)
Inter-eNB Handover over S1 (Inter-MME)
Inter-RAT Handover
CDMA2000, GERAN, UTRA, etc.

26/73
Handover Procedure [signaling]

27/73
Handover Procedure [event-triggering]

28/73
Handover Procedure [measurement]
RSRP [dBm] : Reference Signal Received Power
Absolute value, not related to Payload
RSSI [dBm] : Received Signal Strength Indicator
Received power of center 6RB (1.08MHz)
Directly proportional to Payload
RSRQ [dB] : RSRP/RSSI ratio
Inversely proportional to Payload
– Using for handover of cell loading
frequency
0
RSSI [dBm] : 6RB power
(6RB=72subcarrier=1.08MHz)
BW = 10MHz
RSRP [dBm] : carrier powerRS carrier data carrier

29/73
Handover Interruption Time

30/73
Intra-LTE / Inter-eNB X2 Handover
EPC
1. MeasurementReport
Target eNB
Downlink/Uplink data Downlink/Uplink data
3. HANDOVER REQUEST ACKNOWLEDGE
5. SN STATUS TRANSFER
4. RRCConnection-
Reconfiguration
(mobilityControlinfo)
Data forwarding
6. Synchronization/UL allocation and timing advance
7. RRCConnectionReconfigurationComplete
Forwarded data
Uplink data
Forwarded data
Downlink data
Down/Uplink data Down/Uplink data
Uplink data
Downlink data
8. PATH SWITCH REQUEST
End marker
End marker
10. Modify Bearer Response11. PATH SWITCH
REQUEST
ACKNOWLEDGE
12. UE CONTEXT RELEASE
2. HANDOVER REQUEST

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Intra-LTE / Inter-eNB S1 Handover (1/2)
EPC
Target eNB
3. HANDOVER REQUEST
5. Create Indirect Data
Forwarding Tunnel Request
8. RRCConnection-
Reconfiguration
(mobilityControlinfo)
1) Direct data forwarding
1. Decision to trigger a relocation via S1
2. HANDOVER REQUIRED
Indirect data forwarding
6. Create Indirect Data
Forwarding Tunnel Response
7. HANDOVER COMMAND
9. eNB STATUS TRANSFER
10. MME STATUS TRANSFER
2) Indirect data fowarding
11. Detach from old cell/Synchronize to new cell
12. RRCConnectionReconfigurationComplete
Forwarded data
Uplink data Uplink data
4. HANDOVER REQUEST ACKNOWLEDGE

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Intra-LTE / Inter-eNB S1 Handover (2/2)
EPC
Target eNB
Downlink data
Downlink data
End marker
End marker
13. HANDOVER NOTIFY
15. Modify Bearer Response
Forwarded data
16. Tracking Area Update procedure
17. UE CONTEXT RELEASE COMMAND
18. UE CONTEXT RELEASE COMPLETE
19. Delete Indirect Data
Forwarding Tunnel Request
20. Delete Indirect Data
Forwarding Tunnel Response

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Basic Parameters Setting

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MME Configuration (1/2)
CHG-MME-CONF : Setup information related MME
Input the MME’s status
connected S1 interface
CLI Command

35/73
SRB RLC Configuration (1/2)
CHG-SRB-QCI : Setup QoS information on SRB
CLI Command

36/73
SRB RLC Configuration (2/2)
CHG-SRB-RLC : Setup RLC information on SRB
CLI Command
The timer is for the prohibition of transmission of STATUS_STATUS on received-Entity(AM_RLC)

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SRB MAC Configuration (1/4)
CHG-LOCH-INF : Setup Logical channel information per QCI
CLI Command

38/73
CHG-TRCH-INF : Setup Transport channel information per Cell
CLI Command
Marking cell index for changing or displaying

39/73
CHG-DRX-INF : Setup DRX information per Cell
CLI Command

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CHG-DPHY-SPS
Change parameters for the operating of Dedicated semiPersistScheduling.
Cell_NUM : 0 ~ 5
PO_NOMINAL_PUSCHPERSISTENT: SPS Po parameter using power control is
-126 ~ 24, default: -80
PO_UEPUSCHPERSISTENT: SPS Po parameter’s range on Power control per UE: -
8 ~7, default: 0
CHG-DPHY-PUSCH
Change parameters for Dedicated PUSCH operaiton.
Cell NUM: 0 ~ 5
BETA_OFFSET_ACKINDEX: Set the value of multiplexing ACK/NACK and PUSCH.
Range: 0 ~ 15, default: 8
BETA_OFFSET_RIINDEX: Set the value of multiplexing RI and PUSCH
BETA_OFFSET_CQIINDEX: Set the value of multiplexing CQI and PUSCH

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CHG-ULPWR-CTRL
Change parameters for the operating of Dedicated Uplink Power Control.
Cell Number: 0 ~5
PO_UE_PUSCH: non-persistent scheduling Po parameter using PUSCH Power
control per UE. Range: -8 ~ 7, default: 0
DELTA_MCSENABLED: Usage possibility for different MCS on Power offset
Range: ci_en0/ci_en1/, default: ci_en0
ACCUMULATION_ENABLE: TPC Mode(accumulation mode/absolute mode)
Range: 0 ~ 1, default: 1(accumulation mode)
PO_UE_PUCCH: Po parameter(-8 ~ 7), default: 0
P_SRSOFFSET: This index is indicating the power offset of PUSCH and SRS:
0~15, default:7

42/73
CHG-CQI-REPORTING
Change parameters for the operating CQI Reporting
TRANSMISSION_MODE: ci_tm1,2,3,4, ~ 8. default null
– Mode 1: Single antenna port, port 0
– Mode 2: Transmit diversity
– Mode 3: Large-delay CDD
– Mode 4: Closed-loop spatial multiplexing
– Mode 5: MU-MIMO
– Mode 6: Closed-loop spatial multiplexing, single layer
– Mode 7: Single antenna port, UE-specific RS (port 5)
– Mode 8 (new in Rel-9): Single or dual-layer transmission with UE-Specific RS
Port 7 and/or 8
Select CQI on Wideband/subband.

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CHG-DPHY-ULSRS
Change the parameters for operating of Dedicated Uplink RS.
Cell_NUM: 0 ~ 5
SRS_HOPPING_BANDWIDTH: Set the Area that is became “hopping status of
Sounding RS. ci_hbw0 ~ hbw3, default: ci_hbw0
DURATION: Set the duration of sounding RS. If the value is ‘True’, the
transmission of Sounding RS is not stopped until disabled. If the value is ‘False’
, transmit one time. (Range: 0 ~1), default vlalue: 1
CHG-DPHY-SR
Change the parameters for operating of Dedicated Scheduling Request.
Cell NUM: 0 ~5
DSR_TRANS_MAX: Set the maximum transmittable counts of scheduling
requests until received PUSCH resource on UE.(ci_dsr_TransMax_n4 ~
8,16,32,64) , default value: ci_dsr_TransMax_n64

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DRB PDCP Configuration (1/3)
CHG-PDCP-INF : Set the PDCP information per QCI
CLI Command

45/73
CHG-ROHC-INF : Setup ROHC information per QCI
CLI Command

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CHG-SECU-INF : Set the Security Algorithm information
CLI Command

47/73
DRB RLC Configuration
CHG-RLC-INF : Set the RLC information per QCI
CLI Command

49/73
Neighbor Configuration (1/7)
The value is different for
opeartors.
Input PLMN Id of eNB operator.
Input the value same as PLMN
ID of eNB.
Creation EUTRA Neighbor – PLD update or manually input with CLI on LSM
CLI Command
Create information of E-UTRA cells located near a base station

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Parameter Description Range Value
Cell Num Cell number of Base Station 0~5 -
Relation Index Relation Index - -
Status Neighbor status EQUIP or N_EQUIP N_EQUIP
eNB ID Neighbor eNB Identity 20 or 28 BITS -
Local Cell ID Neighbor local cell ID 0 ~ 255 -
eNB Type Neighbor eNB type Macro or Home Macro
eNB MCC Mobile Country Code of
Neighbor eNB
- Ex) Korea: 450
eNB MNC Mobile Network Code of
Neighbor eNB
-
Physical Cell ID Neighbor cell PCI 0 ~ 503 -
TAC Neighbor cell TAC 2 BYTES -
PLMNs PLMN Lists supported neighbor
cell
- -

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EARFCN UL Uplink EARFCN 0 ~ 65535 -
EARFCN DL Downlink EARFCN 0 ~ 65535 -
Bandwidth UL Uplink Bandwidth n6, n15, n25, n50, n75, n100
It’s different per
operators.
Bandwidth DL Downlink Bandwidth n6, n15, n25, n50, n75, n100 It’s different per
operators.
Individual Offset Cell Individual Offset adaptable
neighbor cell.
dB-24, dB-22, dB-20, dB-18,
dB-16, dB-14, dB-12, dB-10,
dB-8, dB-6, dB-4, dB-2, dB-1,
dB0, dB1, dB2, dB3, dB4,
dB5, dB6, dB8, dB10, dB12,
dB14, dB16 dB18, dB20,
dB22, dB24
dB0
Qoffset Cell Cell Quality Offset adaptable
neighbor cell.
Same dB0
Is Remove
Allowed
Whether or not delete the
neighbor cell
TRUE or FALSE TRUE
Is Handover
Allowed
Whether or not handover to
neighbor cell
TRUE of FALSE TRUE

52/73
CDMA2000 1xRTT Neighbor creation – input remote neighbor widow or CLI
CLI Command
Create the information of CDMA2000 1xRTT Cells located near by a base station

53/73
Cell Num Cell number in base station 0~5 -
SID CDMA2000 1xRTT SID 0 ~ 32767 -
NID CDMA2000 1xRTT NID 0 ~ 65535 -
Base ID CDMA2000 1xRTT Base ID 0 ~ 65535 -
Band Class CDMA2000 1xRTT Band Class bc0, bc1, bc2, bc3, bc4,
bc5, bc6, bc7, bc8, bc9,
bc10, bc11, bc12, bc13,
bc14, bc15, bc16, bc17
-
ARFCN Neighbor cell’s ARFCN 0 ~ 2047 -
PN Offset Neighbor cell’s PN Offset
(CDMA2000’s PCI)
0 ~ 511 -
Is Remove Allowed Whether or not delete the
neighbor cell
TRUE or FALSE TRUE
Is Handover
Allowed
neighbor cell
TRUE of FALSE TRUE

54/73
Creation CDMA2000 HRPD Neighbor – input remote neighbor widow or CLI
CLI Command
Create the information of CDMA2000 HRPD Cells located near by a base station

55/73
Cell Num Cell number in base station 0~5 -
Color Code Neighbor Cell’s Color Code 0 ~ 255 -
BSM ID Neighbor Cell’s BSM ID 0 ~ 63 -
BSC ID Neighbor Cell’s BSC ID 0 ~ 1 -
DPSS ID Neighbor Cell’s DPSS ID 0 ~ 7 -
BTS ID Neighbor Cell’s BTS ID 0 ~ 2047 -
Sector ID Neighbor Cell’s Sector ID 0 ~ 7 -
Band Class Neighbor Cell’s Band Class bc0, bc1, bc2, bc3, bc4, bc5,
bc6, bc7, bc8, bc9, bc10,
bc11, bc12, bc13, bc14,
bc15, bc16, bc17
-
ARFCN Neighbor Cell’s ARFCN 0 ~ 2047 -
PN Offset Neighbor Cell’s PN Offset
(CDMA2000’s PCI)
0 ~ 511 -
Is Remove Allowed Whether or not delete the
neighbor cell
TRUE or FALSE TRUE
Is Handover
Allowed
neighbor cell
TRUE of FALSE TRUE

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Handover Event Configuration – Event A3 (1/3)
Event A3 : Use for Intra LTE Handover and SON ANR
- A3PurposeInraLteHandover
- A3PurposeReportStrongestCells
- Unit: dBm
- Actual value: PLD value * 0.5
- RSRP or RSRQ
- sameAsTriggerQuantity or both
Change EUTRA A3 Criteria information
CLI Command

58/73
Cell Num Cell number in base station 0~5 N/A
Purpose The purpose of Event A3 usage 0:
A3PurposeIntraLteHandov
er
1: A3ReportStrongestCells
2: A3PurposeSpare_1
3: A3PurposeSpare_2
N/A
Active State The status of Event A3 0: Inactive
1: Active
Active
A3 Offset RSRP threshold value using the
condition of EUTRA
measurement report triggering
for Event A3 .
(unit: dBm)
-30 ~ 30 4
A3 Report On
Leave
Whether or not to report in
case of Event A3 leaving
condition
TRUE or FALSE FALSE
Hysteresis The entry/leave condition on
Event triggered reporting.
(unit: dB)
0 ~ 30 0

59/73
Time To Trigger The sufficient time in
specific criteria when
UE try to trigger the
measurement report
. (unit: ms)
ms0, ms40, ms64, ms80, ms100,
ms128, ms160, ms256, ms320,
ms480, ms512, ms640, ms1024,
ms1280, ms2560, ms5120
ms480
Trigger Quantity The quantity
information used for
evaluating the
triggering condition
for Events.
RSRP or RSRQ RSRP
Report Quantity The quantity
information including
Measurement Report
Message.
SamsAsTriggerQuantity or Both SameAsTriggerQuantity
Max Report Cell The maximum number
of cell including
Measurement report
on UE.
1 ~ 8 8
Report Interval The interval
information between
Periodical reports.
(unit: ms)
ms120, ms240, ms480, ms640,
ms1024, ms2048, ms5120,
ms10240, min1, min6, min12,
min30, min60,
ms240
Report Amount The number of
messages on
Measurement report.
r1, r2, r4, r8, r16, r32, r64, infinity r8

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Handover Event Configuration – Event B2 (1/4)
Event B2 : Usage for Inter RAT(CDMA2000 1xRTT) Handover
CLI Command
Change CDMA2000 1xRTT B2 Criteria Information

61/73
Event B2 : Usage for Inter RAT(CDMA2000 HRPD) Handover
CLI Command
Change CDMA2000 HRPD B2 Criteria Information

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Cell Num Cell number in base station 0~5 N/A
Purpose The purpose of Event B2 Usage 0: B2PurposeInterRatHandover
1: B2PurposeSpare_1
3: B2PurposeSpare_2
N/A
Active State The status of Event B2 0: Inactive
1: Active
Active
B2 Threshold1 (RSRP) RSRP threshold value using the
condition of EUTRA
for Event B2 .
0 ~ 97 70
B2 Threshold1 (RSRQ) RSRP threshold value using the
condition of EUTRA
for Event B2.
0 ~ 34 10
B2 Threshold2 CDMA
2000
The threshold value using the
condition of CDMA2000 HRPD
for Event B2.
0 ~ 63 20
Hysteresis The entry/leave condition on
Event triggered reporting.
(unit: dB)
0 ~ 30 0

63/73
Time To Trigger The sufficient time in
specific criteria when UE try
to trigger the measurement
report. (unit: ms)
ms0, ms40, ms64, ms80,
ms100, ms128, ms160,
ms256, ms320, ms480,
ms512, ms640, ms1024,
ms1280, ms2560, ms5120
ms80
Max Report Cell The maximum number of
cell including Measurement
report on UE.
1 ~ 8 1
Report Interval The interval information
between Periodical reports.
(unit: ms)
ms120, ms240, ms480,
ms640, ms1024, ms2048,
ms5120, ms10240, min1,
min6, min12, min30, min60,
ms240
Report Amount The number of messages
on Measurement report.
r1, r2, r4, r8, r16, r32, r64,
infinity
r1
Trigger Quantity
EUTRA
The quantity information
used for evaluating the
condition of EUTRA event
triggering.
RSRP or RSRQ RSRP

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Periodic Report Configuration – Periodic (1/4)
Periodic Report : Usage for ICIC, SON ANR.
CLI Command
Change EUTRA Periodic Criteria Information

65/73
Periodic Report : Usage for interworking CDMA2000 1xRTT in the future.
Change CDMA2000 1xRTT Periodic Criteria Information
CLI Command

66/73
Periodic Report: Usage for interworking CDMA2000 HRPD in the future.
CLI Command
Change CDMA2000 HRPD Periodic Criteria Information

67/73
Purpose The purpose of
configuration on
Periodic measurement
reporting.
PeriodicalPurposeReportStrongestCells
PeriodicalPurposeReportStrongestCellsForSON
PeriodicalPurposeReportCGI
N/A
Active State The operation status of
Periodic report.
0: Inactive
1: Active
Inactive
Trigger Quantity
(EUTRA Only)
The quantity
information for
evaluating the
triggering condition for
event.
RSRP or RSRQ RSRP
Report Quantity
(EUTRA Only)
The quantity
information including
Measurement report
message.
SamsAsTriggerQuantity or Both SameAsTrigg
erQuantity
Max Report Cell The maximum number
of cell including
Measurement report on
UE.
1 ~ 8 1
Report Interval The interval information
between Periodical
reports. (unit: ms)
ms120, ms240, ms480, ms640, ms1024,
ms2048, ms5120, ms10240, min1, min6, min12,
min30, min60,
ms240
Report Amount The number of
messages on
Measurement report.
r1, r2, r4, r8, r16, r32, r64, infinity r1

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Handover Related Timers (1/2)
X2, S1 Protocol Timers
TX2RELOCprep, TX2RELOCoverall, TS1RELOCprep, TS1RELOCoverall
CLI Command
Change timer operation Information

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Handover Related Timers (2/2)
S1_PATH_SWITCH Target eNB sends Path Switch Request message to MME for
S1 handover.
The timer should be set when Target eNB is waiting Path
Switch Request Acknowledge message from MME.
0 ~ 65535 (ms) 3000
S1 HANDOVER
PREPARATION
Source eNB sends Handover Request message to target
eNB for S1 handover.
The timer should be set when Source eNB is waiting
Handover Request Acknowledge message from Target eNB.
0 ~ 65535 (ms) 5000
S1 RELOC
OVERALL
After the preparation procedure for S1 Handover, the timer
should be set when Source eNB is waiting UE Context
Release Command message from MME.
0 ~ 65535 (ms) 5000
S1 HANDOVER
CANCEL
Source eNB sends Handover Cancel message to MME for
S1 handover.
Handover Cancel Acknowledge message from MME.
0 ~ 65535 (ms) 5000
X2 HANDOVER
PREPARATION
Source eNB sends Handover Request message to target
eNB for X2 handover.
Handover Request Acknowledge message from Target eNB.
0 ~ 65535 (ms) 5000
X2 RELOC
OVERALL
After the preparation procedure for X2 Handover, the timer
should be set when Source eNB is waiting UE Context
Release message from target eNB.
0 ~ 65535 (ms) 5000
X2 STORE UE
CONTEXT
After X2 Handover, the MRO timer is working on target
eNB. If target eNB receives RLF indication message while
this timer is working on Target eNB, MRO statistic function
is executed.
0 ~ 65535 (ms) 10000

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Handover Restriction
Configuration

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eNB-controlled Handover Restriction (1/2)
NO_HO
If this option parameter is set to ‘TRUE’, It is not handover to the
designated eNB.
Set IP version 6 format for specific neighbor eNB IP address.
CLI Command

72/73
eNB-controlled Handover Restriction (2/2)
IS_HOALLOWED
If this option parameter is set to ‘FALSE’, It is not handover to the
designated cell.
CLI Command
Change E-UTRA cell’s information which is located at surrounding base station.

LTE Call Processing and Handover

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