Femto Activities in 3GPP2 TSG-C

1. Femto Activities in 3GPP2 TSG-C TBD TBD

2. Status • cdma2000 1x air interface signaling enhancement for Femto is part of cdma2000 1x air interface revision E specification • Start: Q1 2008 • Baseline: Q1 2009 • Expected Publication: Q2 2009 • cdma2000 HRPD air interface signaling enhancement for Femto is on-going as part of cdma2000 HRPD air interface revision C specification • May reuse some enhancements from 1x • Expected Publication in Q4 2009

3. Challenges with the Current Practice While femtocell deployment is possible without any enhancements to the air interface, the following challenges are addressed more efficiently with the enhancements in 1x Revision E • No prioritization of femtocell over macrocell • Need to be able to distinguish femto pilot vs macro pilot • Open / signaling association models increase number of idle handoffs and registrations • Impact on MS standby time • Frequent registrations can lead to page loss and increase the signaling load • MS may not select HRPD femtocell following the 1x femtocell selection • Select HRPD femtocell following 1x femtocell selection • Manual search is slow and inconvenient • Support fast and user friendly manual search by providing human-readable ID • Macro  Femto handover encounters PN ambiguity problem • Support seamless connected handovers

4. Introduction to 1x Signaling Enhancements • In order to more efficiently support Femto AP operations for cdma2000 1x, the following signaling messages are introduced • Access Point Pilot Information Allow the femto access point (FAP) and/or basestation to broadcast the band/channels/PN offsets of femto access points deployed in the geographical region • Access Point Identification Allow a FAP to advertise to the MS a unique identifier and other information about the FAP that assist system selection and handoff • Handoff Supplementary Information During handoff to target FAP, allow the MS to report information that disambiguate the target FAP

5. 1. Access Point Pilot Information Message (APPIM) • APPIM is broadcasted by FAPs and/or macro network • Broadcast from FAPs allows the macro network to remain unchanged • APPIM includes femtocell deployment information • Band, frequencies, and PN offsets allocated for the femtocell deployment • Scope of allocation in the macro network, e.g., SID/NID that information would be valid • MS can cache the information upto LIFETIME limit specified • To optimize overhead when this message is advertised on macro paging channel, the message can be sent with low duty cycle and MS can go to sleep mode before receiving this message • Benefits • Helps MS distinguish between macrocells and femtocells, e.g., MS may want to only idle handoff to FAP in the home area • MS would not need to be pre-provisioned with such scan information especially when in roaming conditions • Offers flexibility in allocation of frequencies and PN offsets for femtocell deployment • Speeds up manual / exploratory scans to discover nearby femtocells

6. 2.1 Access Point Identification Message (APIDM) • Contents • SID, NID, and unique access point identifier • Supported association model (i.e., open/restricted/signaling-only) • MSC_ID, CELL_ID (for assisting hand-in to FAP) • Associated HRPD band class and channel • Location Information LAT, LONG, ALT, and horizontal and vertical uncertainty • Broadcasted by FAP at high frequency schedule • Benefits • Quick identification of FAP with synergy to Enhanced System Selection (ESS) • Association model information helps MS avoid registration on unknown femtocells with signaling/restricted association • Reporting MSC ID and Cell ID information identifies target FAP in macro  femto handoff • HRPD information enables selection of FAP for HRPD following 1X selection

7. 2.2 Access Point Identification Text Message (APIDTM) • Contents • Variable length text identification of the FAP (similar to WIFI SSID) • International encoding supported • Broadcasted by femtocell on only normal channel at low frequency schedule • Benefits • Enable user friendly manual scans to discover and identify nearby femtocells

8. 3. Handoff Supplementary Information Notification / Solicit • The notification message includes mapping between PN Offset and <CELL_ID, MSC_ID> of APs that the MS considers to handoff to • Purpose is to disambiguate target FAP during handoff • Same PN may be used by several FAPs under the same macro network • CELL_ID and MSC_ID are used in Handoff Required message from macro basestation to MSC identically to handoff in macro network • The MS retrieves the <CELL_ID, MSC_ID> information from Access Point Identification message • This message can be sent along with Pilot Measurement report • The BS may request the information using the Handoff Supplementary Information Solicit message

9. 4. IS-41<CELL_ID> MSC MFIF Macro BSPN = a 3. A1-Handoff Required<MSC_ID, CELL_ID> 5. MFIF contactsFemto AP2 for handoff 1. APIDM (MSC_ID, CELL_ID) 2. PSMM+ HSIN<MSC_ID, CELL_ID> Femto AP1PN = b Femto AP2PN = b Active Call Hand-in Example • Under the same macro BS, it is likely that the same PN will be assigned to many Femto APs • Macro BS needs to be able to resolve target MSC_ID and CELL_ID for the PN that has ambiguity • Femto AP is configured with unique MSC_ID and CELL_ID. This information is advertised in the APID message. The MS includes this info with the PSMM. The remaining standard handoff process will route the call to the MFIF (based on MSC_ID) and correct femto AP (based on CELL_ID) with no modification to A1 and IS-41 interfaces