Broadband IT Korea © ETRI, 2010 Confidential 1 APCC 2010 Impact of Reading System Information in Inbound Handover to LTE Femtocell 2010. 11. 03(Wednesday)

Broadband IT Ko-rea © ETRI, 2010 Confi-

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APCC 2010

Impact of Reading System Infor-mation in Inbound Handover to

LTE Femtocell

2010. 11. 03(Wednesday)

ETRI

Hyungdeug Bae([email protected])


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Overview of Inbound Han-dover


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Femtocell Access Mode

Open access mode Operate as normal eNB

Closed access mode (CSG mode) CSG cell has CSG Id (Closed Subscriber Group Identity) Users belonging to its CSG Id are allowed to connect to

CSG Cell

Hybrid access mode Limited resources are available to non-member UEs,

while the rests are operated in CSG manner


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Access Control in 3GPP

Initial access control at UE & final access control at CN

UE needs to measure MIB & SIB1 for access con-trol

Frame loss from source cell during SI measure-ment of target CSG cell


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SI Frames in LTE

MIB and SIB1 MIBs are scheduled with 40msec and repeated with

10msec SIB1 are scheduled with 80msec and repeated with

40msec on even FSN.

< MIB and SIB1 in MAC frame >


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Simulation Models


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Simulation Scenario

OPNET simulator (modified)Based on 3GPP Recommended models [4]Urban HeNB deployment

10 single-floor houses per femtocell block Simulated with eNB-to-Femtocell block distance 100m,

200m and 300m Femtocells are deployed evenly at 5 houses of femtocell

block & at the center of a house UE is outside a house & 1 meter from the nearest homes


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Other Assumptions

Macro eNB

Parameter Assumption

Inter-site distance 1700mNumber sites 1 cellsCarrier frequency 2000 MHzSignal bandwidth 10MHzTotal BS TX power 46dBmPenetration Loss 10dBeNB Antenna gain 14dB

Parameter AssumptionHeNB Frequency Channel Same frequency and same bandwidth

as macro cell

HeNB House Dimensions 10m x10mHeNB position House centerMin separation UE to HeNB 10mTx power of HeNB 20 dBmHeNB antenna gain 5 dBiPenetration loss of wall inside apartment

0.7 x R

Exterior wall penetration loss 10dB

Home eNB

Propagation


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Measurement Approaches

No-gap No gap assignment Assuming UE know the timing of MAC frame by monitor-

ing P-SCH UE can choose MIB sub-frame at the exact time Once UE know the timing of MAC frames and FSN, it can

calculate the exact timing of SIB1 sub-frames

Large-gap One large-gap assigned from serving cell UE measures MIB & SIB1 on the measurement gap indi-

cated by eNBUE can’t receive frames of serving cells during the gap


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Measurement Approaches

Small-gap First small gap assigned from serving cell for MIB mea-

surement UE report the FSN & timing of frames to serving cell Small gaps for SIB1 measurement are allocated at the ex-

act time


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Simulation Results & Analysis


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Gross Acquisition Time Distribution

Change rapidly when UE location are below 180m away from eNB The distance between UE and eNB has impact on SI measurement in

this area Converge to constant time over 180m

About 4ms for No-gap, 9ms for small-gap & 22ms for large-gap


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MIB & SIB1 Acquisition Time

MIB acquisition time No-gap shows better performance than small-gap In no-gap UE utilizes the timing of MIB sub-frame whereas in small-gap

it doesn’t SIB1 acquisition time

Same for No-gap & small-gap They utilizes the timing of SIB1 sub-frame


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Service Interruption Time

MIB/SIB1 Measurement UE begin to measure MIB/SIB1 at the time when MIB/SIB1 sub-frames

arrive Reducing frame loss


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MIB Measurement eNB allocate measurement-gap without knowing about timing UE begin to measure MIB on the measurement gap indicated by eNB In worst cases, 14ms for MIB measurement

SIB1 Measurement eNB allocate measurement gap at the time when SIB1 sub-frames ar-

rive UE can measure SIB1 on the shortest time


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MIB/SIB1 Measurement eNB allocate measurement-gap without knowing about timing In worst cases, 27ms for MIB/SIB1 measurement


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Conclusions

No-gap approach It utilizes the timing of both MIB & SIB1 Thanks to that, it shows best performance over others

Small-gap approach It utilizes only the timing of SIB1 sub-frame Because of that, it shows less performance than no-gap

approach In addition, it requires frequent gap assignment and

causes signaling overhead between eNB and UELarge-gap approach

It shows worst performance Tips for reducing service interruption time

Make use of the timing of target Home eNB


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References

[1] 3GPP TS 36.300, “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Overall descrip-tion; Stage 2,” Rel. 9, v9.2.0, Dec. 2009.

[2] 3GPP TS 23.401, “General Packet Radio Service (GPRS) enhancements for E-UTRAN access,” Rel. 9, v9.2.0, Dec. 2009.

[3] 3GPP TS 36.331, ‘E-UTRA RRC Protocol Specifications,’ Rel. 9, v9.2.0, Dec. 2009.

[4] R4-092042, “Simulation assumptions and parameters for FDD HeNB RF re-quirements,” 3GPP TSG-RAN WG 4, San Francisco, USA, May 2009.


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Thank you! and Q/A

Documents

Broadband IT Korea © ETRI, 2010 Confidential 1 APCC 2010 Impact of Reading System Information in Inbound Handover to LTE Femtocell 2010. 11. 03(Wednesday)