1. Broadband IT Korea © ETRI, 2010 Confidential 1 APCC 2010 Impact of Reading System Information in Inbound Handover to LTE Femtocell 2010. 11. 03(Wednesday) ETRI Hyungdeug Bae(hdbae@etri.re.kr)

2. Broadband IT Korea © ETRI, 2010 Confidential 2 Overview of Inbound Handover

3. Broadband IT Korea © ETRI, 2010 Confidential 3 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

4. Broadband IT Korea © ETRI, 2010 Confidential 4 Access Control in 3GPP Initial access control at UE & final access control at CN UE needs to measure MIB & SIB1 for access control Frame loss from source cell during SI measurement of target CSG cell

5. Broadband IT Korea © ETRI, 2010 Confidential 5 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.

6. Broadband IT Korea © ETRI, 2010 Confidential 6 Simulation Models

7. Broadband IT Korea © ETRI, 2010 Confidential 7 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

8. Broadband IT Korea © ETRI, 2010 Confidential 8 Other Assumptions Macro eNB ParameterAssumption Inter-site distance1700m Number sites1 cells Carrier frequency2000 MHz Signal bandwidth10MHz Total BS TX power46dBm Penetration Loss10dB eNB Antenna gain14dB ParameterAssumption HeNB Frequency ChannelSame frequency and same bandwidth as macro cell HeNB House Dimensions10m x10m HeNB positionHouse center Min separation UE to HeNB10m Tx power of HeNB20 dBm HeNB antenna gain5 dBi Penetration loss of wall inside apartment 0.7 x R Exterior wall penetration loss10dB Home eNB Propagation

9. Broadband IT Korea © ETRI, 2010 Confidential 9 Measurement Approaches No-gap No gap assignment Assuming UE know the timing of MAC frame by monitoring 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 indicated by eNB UE cant receive frames of serving cells during the gap

10. Broadband IT Korea © ETRI, 2010 Confidential 10 Measurement Approaches Small-gap First small gap assigned from serving cell for MIB measurement UE report the FSN & timing of frames to serving cell Small gaps for SIB1 measurement are allocated at the exact time

11. Broadband IT Korea © ETRI, 2010 Confidential 11 Simulation Results & Analysis

12. Broadband IT Korea © ETRI, 2010 Confidential 12 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

13. Broadband IT Korea © ETRI, 2010 Confidential 13 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 doesnt SIB1 acquisition time Same for No-gap & small-gap They utilizes the timing of SIB1 sub-frame

14. Broadband IT Korea © ETRI, 2010 Confidential 14 Service Interruption Time MIB/SIB1 Measurement UE begin to measure MIB/SIB1 at the time when MIB/SIB1 sub-frames arrive Reducing frame loss

15. Broadband IT Korea © ETRI, 2010 Confidential 15 Service Interruption Time 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 arrive UE can measure SIB1 on the shortest time

16. Broadband IT Korea © ETRI, 2010 Confidential 16 Service Interruption Time MIB/SIB1 Measurement eNB allocate measurement-gap without knowing about timing In worst cases, 27ms for MIB/SIB1 measurement

17. Broadband IT Korea © ETRI, 2010 Confidential 17 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 UE Large-gap approach It shows worst performance Tips for reducing service interruption time Make use of the timing of target Home eNB

18. Broadband IT Korea © ETRI, 2010 Confidential 18 References [1] 3GPP TS 36.300, Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Overall description; 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 requirements, 3GPP TSG-RAN WG 4, San Francisco, USA, May 2009.

19. Broadband IT Korea © ETRI, 2010 Confidential 19 Thank you! and Q/A