SUMMARY TSG-S Hosted 3GPP2 Femto Cell Workshop OCTOBER 2007 Hyatt Harborside Boston 101 Harborside Drive, Boston, Massachusetts, USA Sponsored by Airvana Contact –Workshop Coordinator: Clif Barber (KDDI)

16 October Logistics Approximately 80 attendees representing 36 companies (attendance list is attached). Contributions: ftp://ftp.3gpp2.org/TSGS/Working/_2007/ Femto_Cell_Workshop-Boston/ Agenda Discussion Summaries are attached. Agenda:

16 October High Level Summary of Issues There is a strong interest in Femto Cell standardization in the 3GPP2 community. Basic Femto Cell service should be achieved using legacy MS devices and existing system operator networks to the greatest extent possible. The most important issues for standardization of Femto Cell operations are: –The decision on the appropriate network architecture and related protocols for integration into cdma2000 networks. –The decisions on system selection. Other concerns are: –Understanding RF interference issues (femto-femto, femto-macro) –Addressing femto-macro synchronization issues Options have been proposed for OAM&P protocols. DSL Forum and others have their own recommendations Development of supporting radio interface standards for future, femto aware MS devices, can enhance the cdma2000 Femto Cell functionality and performance. This radio interface standardization can proceed independently of the development of the network architecture since there are no “hooks” in the architecture that are required for the radio interface. Requirements development (S.R0126-0) is proceeding in TSG-S but functionality phasing is still TBD. –Release for TSG reviewNovember 2007 –PublicationMarch/April 2008

16 October High Level Summary of Issues (2) Architecture issues recommended for consideration: –Architecture decisions: Distribution of functionality –PDSN functions –Service support functions –PDIF functions –Convergence Server (CSRV) functions Phased approach to IMS MAP/SIP Interworking Impact of Common IMS Initiative? –Minimize protocol enhancements to support legacy handsets and existing services. –Consider gateway to femto cells to support an IPsec/IKE communication link with the femto cells and to protect the core network from the public Internet. –System selection will require coordination between Core Network and Radio Interface.

16 October High Level Summary of Issues (3) Radio interface issues that have been identified: –Interference management (femto-femto, femto-macro) –Understanding femto cell system selection –Handoff operations (macro-femto, then femto-femto in a later phase) –A review needs to be conducted regarding the applicability of BS MPS for femto cells. Changes may be needed or a new specification developed specifically for femto cells. –Power limits and other power control issues. –C.S0016 OTASP/OTAPA may be enhanced for system selection –Air interface parameters (objects) for femto cell OAM&P. –Mechanisms to enhance timing/location for femto cells.

16 October Agenda 1. General Overview OBJECTIVE: Home BS which is connected by a wireless broadband link in conjunction with an operator of licensed spectrum. BENEFITS: –USER In-home quality of service Supports use of MS as primary phone Battery life enhancements Cost benefits? –OPERATOR Economic expansion of network capacity Targets high phone usage in home environments SERVICES AND PERFORMANCE: –Support cdma2000 1x, HRPD, and UMB in all variations –Supports all existing Legacy MS services –Supports all existing All IP services –Support all services with same quality levels and setup times as the macro network

16 October General Overview (2) Envisioned challenges –Use standard MS Devices for all cdma2000 technologies –Re-use existing system operator network –Self-configuring Femto Cells – PLUG N PLAY. –Scalability –System Timing Synchronization –Location Determination –RF Interference (femto-femto, femto-macro) –System Selection –Access Control –Handoff –Security including secure tunnel over wireline link –QoS, Policy, and Accounting –Integration of SIP/IMS-based Femto Cell Networks –Management Framework

16 October Agenda 2. High Level Requirements Synchronization: Alternatives to GPS –Macro (if within coverage) –Internet for “isolated” femto System Selection –Femto subscriber must find its femto cell –Legacy mobiles must be supported Access Control: Multiple use models must be supported, e.g: –Open access –Access limited to subscriber of that femto –… and points in-between –Move to macro, e.g. if fixed broadband connection QoS inadequate Mobility –Comprehensive set of handoff desirable –Time to market overrides non-essential handoffs until later release (e.g. femto-femto) Deployment Scenarios: One or both –Dedicated carrier frequency –Reuse - macro on same carrier

16 October Agenda 2. High Level Requirements (2) Services –CS Voice on cdma2000-1x initially; keep in mind migration to VoIP –Other widely deployed services –BCMCS Performance: Comparable with macro Location: Explore/use options –Termination point of fixed broadband line –Location derived off the macro system (if within coverage) –Use macro system for mobile location Evolution: Allow for phased development –Initial support for legacy mobiles –Future support for femto-aware mobiles –Time to market should override initial feature set creep –Later releases can address more advanced features OAM&P: Plug & Play –Configuration of radio parameters such as neighbor list, Pilot PN offset, power level, other radio resources –Operator control over service initiation/continuation

16 October Agenda 2. High Level Requirements (3) Security –Femto authentication by core? –Core authentication by femto? –Security threats specific to femto

16 October Agenda 3. Radio Interference Issues Femto Cell Association Open access –All MS can use femto cell Restricted access –Only specific MS can use femto cell –Family, friends, visitors Signaling access –MS can receive signaling (may be limited) from femto 911 issues –Restricted assocation –Position –Backhaul failures Emergency broadcast issues

16 October Agenda 3. Radio Interference Issues (2) Some Basics Femto Cell Identity –Use NID –Use BASE_ID –Use (SID, NID, REG_ZONE) Same or Separate Carriers –Same carrier as macro cell –Separate carrier –Femto cells can be on a set of carriers 1x and DO typically take two carriers

16 October Agenda 3. Radio Interference Issues (3) Femto Cell Selection for Legacy Mobiles Two classes –Those that can update PRL –Those that cannot make PRL changes Use PRL –Include femto cell in PRL –May cause MS to search frequently for femto cell –Mechanisms to construct PRLs need to be developed Use GNLM –As long as neighbor is 3 dB stronger, the MS will choose –May limit the range of femto-cells –May require additional use of restricted assocation mechanisms Use Beacon –May impact other mobiles; additional network interference –May needs to be on multiple frequencies –Adds complexity to femto cell –May require additional use of restricted assocation mechanisms Registration, filter, redirect (SRDM) –Mobile will periodically check for femto; battery life issues Global Service Redirection Message (GSRM)

16 October Agenda 3. Radio Interference Issues (4) Possible Modifications to Enhance System Selection Two basic extreme approaches –Select first, reject –Select right Use position location to indicate to MS when to search Use user zones on Forward Link –Already in standards –User Zone Identification Message (UZIM) –Private Neighbor List Message (PNLM) –Limited number of user zones Use PRL enhancements, such as PUZL in IS-683/C.S0016) –Allows PRL (PUZL) for femto cells to be separated from existing lists –Black lists –Add range/masks for NIDs and BASE_IDs –Would need to be done for DO –May want to reexamine whether another mechanism is preferable Mechanisms to update lists

16 October Agenda 3. Radio Interference Issues (5) Interference Issues Co-channel Macro-Femto deployment –MS using femto cell on same frequency as macro cell Femtocell deployment on a carrier adjacent to a macro-cell carrier –Adjacent channel rejection In dense femto cell deployments inter-femto outage scenarios must be addressed –More than just dense; any close coupling between femto cells Modeling of interference between femto cells

16 October Agenda 3. Radio Interference Issues (6) RF Issues Frequency interference and planning –Is a frequency reuse used over a set of frequencies PN offset allocation –Is a small number used? Otherwise need to expand GNLM size significatly (there is a size limit) –Reuse pattern –Ambiguity at the macro cell level Femto cell transmit power –Power classes Femto cell emissions and other RF specifications MS using femto cell can cause interference to macro cells or other femto cells How to limit MS output power –Limit data rate when possible –Introduce limit for MS output power –Possibly have MS report output power to femto cell Reduce minimum size of PN search window Reverse Link silence periods –Synchronized or unsynchronized Other Smart femto cells –Learn environment

16 October Agenda 4. Architecture Decision Points Network Architecture –Architecture Layers 1x/circuit 1x/HRPD packet HRPD IMS/SIP –Architecture Decisions Distribution of functionality –PDSN functions –PDIF functions –CSRV Server –Service support functions Phased Approach to support legacy vs IMS –Issues Scalability Tunneling Security Mutual Authentication Qos Accounting Mobility

16 October Agenda 4. Architecture Decision Points (2) Femto Services –Must support existing circuit/data services Profile services Emergency services Operator services – LNP, OTA, regulatory –Support existing terminals –Minimize impact to existing Network Infrastructure –IMS Services Basic Voice Service (circuit/VoIP) Emergency Services Supplementary Services Short Message Service IMS Centralized Services –MAP/SIP interworking –Impact of Common IMS Initiative?

16 October Agenda 4. Architecture Decision Points (3) Mobility –Reuse existing standards as much as possible –Need to support both hand-in and hand-out All combinations of 1X/HRPD and femto/macro Need to define a phased approach – which combinations are supported in which phase –System Selection is key to successful mobility –Roaming How do family/friends attach to the femto? –MAP/SIP interworking for mobility may be separable from interworking for service support

16 October Agenda 5: Standardization Work Plan In order to stage the work efficiently: focus on Architecture up front –Stage 1: stabilizing (see S00-FEMTO , slide 2) –Stage 1.5 (architecture): progressing, with identification of options and selections –Stage 2 and 3: issues to be explored in parallel to aid in complexity/tradeoff analysis of architecture selection! Immediate Next Steps: –Focus on a joint session planned for November TSG meeting –TSG-S & TSG-X leadership to determine details & announce via 3GPP2 exploders: Perhaps co-hosted by TSG-X ERA WG and TSG-S Architecture WG Note: issues related to other groups under discussion: –TSG-S Security WG (CAVE/AKA Authentication considerations) –TSG-S OA&M (tunneling of OA&M objects) –TSG-A –TSG-C Summary: –Work plans are set by TSGs More information across TSGs assists in anticipating issues early in development cycles –November cross-TSG session is next step towards the goal of a service that will deliver to the market –NOTE: clear input from the carrier community will help to identify the market we target for our work

16 October Thank You! For more information, please visit Thank You very much to Airvana for their sponsorship of this workshop!