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CDMA-LTE Handoff

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					1
    Interoperability with Next-Generation
    OFDM-Based Mobile Broadband
    Solutions In IP Networks
    Chuck Bradshaw
    bradshaw@nortel.com
    May 13, 2008



    BUSINESS MADE SIMPLE


2                         Nortel Confidential Information
Introduction
• Areas to considered for Inter-technology
  Interworking and Handoff:
   • Radio Capability of the Hybrid terminal
   • Core Network Architecture
   • Handoff Control: Network or Terminal
   • Intersystem functionalities: Loose and Tight Coupling
   • Service continuity across network boundaries
   • Ability to make measurements in target system
• Delivering IP-based Capabilities in the Network
   • What are they?
   • Why does an operator need them?
   • When will they become reality?
   • How do they work?




3
Radio Capability of Hybrid Terminals



                           Increasing terminal complexity/cost/interference
                           Reducing HO solution complexity




       Dual Radio:         Single Radio: Dual            Single Radio:
     Dual Rx/ Dual Tx       Radio Rx/ Single           Single Radio Rx /
                                Radio Tx               Single Radio Tx

    Reducing terminal complexity/cost/interference
    Increasing HO solution complexity



OFDM-CDMA Interworking Optimized with Single Radio
4Terminals, Also Allowing Dual Rx / Dual Tx Devices
Core Network Architecture

• The Interworking architecture must cover:
     •   Mobility
     •   Authentication / Security
     •   Policy and Charging
     •   Fixed / Mobile convergence
• Current agreed architectures for OFDM-CDMA Interworking
     • HRPD-LTE: based on 3GPP Evolved Packet Core (EPC) (agreed in
       3GPP and 3GPP2)
     • HRPD-UMB: based on 3GPP2 Converged Access Core (CAN)
     • WiMAX-HRPD: based on “commonalities” between 3GPP2 & WiMAX
       NWG




     Common Reference Architecture to Accommodate Performance
5   Requirements and Deployment Models for all Technology Pairings
Supporting an Access Aware Network
                        CDMA MSC
         BSC


                A1
                  A2                                                     Add LTE as Overlay:      Trials 3Q08
                       Media Gateway              PSTN
BTS                                                                      • Separate IP’s, No Network Interaction
                      S102
         RNC                     PDSN
                                 HSGW
                                                                         Add Mobile IP:            trials 1Q09
                  A10/A11
                                         MIP
                                               Home Agent                • Provides network mobility for non-real-
                                                                           time applications & common services
BTS


                                                         Pi
                                                                         Add Seamless Mobility: Trials 3Q09
               S101          S2 / SX-u
                                                                         • Optimizes network mobility for real-
                                                                           time applications & services
                                                    IP Core & Services
                                                         Network
           S1                      SGi
eNodeB                                                                   Add HO to 1xRTT Voice: Trials 3Q09
                  MME                                                    • Extends coverage of LTE VoIP by
                 P/S-GW                                                    adding seamless mobility to 1xRTT




Move to an All-IP, Simpler, Flatter, Cost Effective Network
6
 3GPP Evolved Packet Core
 (Example of Roaming Arch in TS 23.402)
                                              HSS
                                                                                                       SWx
                                                                               Rx
                                                                   hPCRF                      Operator’s IP
                                                              Gx                                 Services
                                S6a
                                                                                          (e.g. IMS, PSS etc.)
                                                                               SGi
                                                     PDN                                                          3GPP AAA
           HPLMN                                    Gateway                                                         Server
                                                                                    S6b

                                                                         S9
                                                      S2b                                                        SWd
                                      S8
                                                                   vPCRF


              3GPP    Serving
             Access   Gateway     Gxc
                                                                   Gxb
                                                                                                                 3GPP AAA
                                                                                                                   Proxy

                                        S2a                                                             SWm
                                                                    ePDG
           VPLMN


           Non-3GPP
           Networks                           Gxa                        SWn

                                 Trusted                                       Non-trusted
HRPD and WiMAX                  Non-3GPP
                                 Access
                                                                               Non-3GPP
                                                                                 Access                SWa
are considered                                                                                                     STa


Trusted Non-3GPP
Access
 7
Handoff Control
Network or Terminal Triggering

• Network Triggered:
    • Target selection (in the network) may be enhanced with
      additional parameters to finely tune the handoff criteria.
    • Network can be tuned to trigger handoff based on highly
      granular information (e.g. aggressive handoff regiment
      depending on deployment circumstances)
• Mobile Triggered:
    • The mobile makes the HO decision, potentially with
      assistance from the network.
      • Network push
      • Network receives measurement information.
    • The degree of network assistance (i.e. what information is
      provided) will determine the performance of the handoff


Network Controlled Handoff Optimizes Access Network Interworking
8
Inter-system Functionalities

                             • Little or no inter-system functionalities
    Loose coupling               • UE-centric L3 mobility based on (P)MIP
    a) “Break Before Make”   • Resources are released in the source system prior to
                               Handover execution
                                 • Service break is significant


                             • Resources in target system are obtained prior to HO
    b) “Dual-radio MBB”        execution directly over target radio interface -
                               “seamless mobility”
                                 • Requires dual radio capability, simultaneous
                                   transmit.
                             • Requires inter-system functionalities
                                 • Network-controlled; L3 mobility based on
                                   (P)MIP (S101)
    Tight coupling           • Ability to configure and report measurements of the
                               target system
    “Make Before Break”      • Inter-system interface for establishing resources in
    “Network-controlled”       target system prior to HO execution
                             • Possibility of data forwarding
                             • Suitable for single radio devices, but also
9
                               applicable to dual radio devices
Requirements for Mobility and HO

• The connected systems…
     • Shall support terminals with single radio and dual radio
       solutions.
     • Shall support voice service continuity between access
       networks.
     • Shall support bidirectional service continuity between access
       networks to enable both best effort and real-time applications.
     • Shall minimize impact on service quality, e.g. Quality of
       Service (QoS), reduce interruption times.
     • Should minimize the coupling between access networks (e.g.
       by using transparent signaling through the source system)
       allowing independent protocol evolution in each access.
     • Shall be based on the principles of network controlled radio
       access mobility.

10
Principles for Optimised Handovers

     • Inspired from the A21 interface defined for HRPD=>1xRTT voice
       call continuity
     • Terminal interacts directly with target system (LTE or HRPD) to
       perform handover preparation
     • Source system provides “tunnelling” capability (S101) for terminal to
       interact with target system
     • In the LTE=>HRPD direction there are two distinct steps
       • 1) Pre-registration: when conditions are such that a handover to HRPD
         may be required, the source system provides the UE with sufficient
         information to perform pre-registration with the target HRPD access and
         core network, over the S101 tunnelling interface
       • 2) HO execution: if conditions subsequently warrant that a handover
         should occur, the handover signalling will also be performed over the
         S101 tunnelling interface, whereas data forwarding takes place on S103
     • Similar logic applies in the HRPD=>LTE direction
       • Pre-registration also triggers the HO execution


11
Voice Continuity with the Legacy CS Domain:
OFDM to CS HO
• EPC/LTE is Packet Switched (PS) only system
• Voice continuity between LTE and 1xRTT Circuit Switched
  (CS) domain requires a transformation of a VoIP (on IMS) call
  into CS session and vice versa
• Requirement is that there should be minimum impact on the
  CS domain
• The solution to the problem falls in the Voice Call Continuity
  (VCC) with “single radio hybrid terminal” category
     • VCC = Voice Call Continuity between CS domain and PS via
       IMS
     • Because of the similarities with 3GPP2 VCC and 3GPP Rel-7
       VCC, the problem is referred to as Single Radio VCC
     • Single Radio VCC for LTE-1xRTT is specified in 3GPP TS
12
       23.216
SR-VCC Architecture for 1xRTT CS

          1xCS
         SRVCC     1xRTT CS     A1              1xRTT
           UE                                             ANSI-41
                     Access                      MSC
                                      A1                  (ISUP)        VCC
                                                                         AS
                                     1xCS IWS
                                                                        3GPP2
                              S102                                       IMS
                                       MME
                         S1-MME                 S11
           1xCS
                                             Serving/PDN       SGi
          SRVCC    E-UTRAN
            UE                                   GW
                     (LTE)
                                     S1-U


                                                      Tunnelled 1xRTT messages


• Based on the A21 solution in 3GPP2 A.S0008-C
   • While attached to EUTRAN, the UE initiates tunnelled
     establishment of the CS access leg (via Uu - S1-MME – S102 – A1)
   • After handover to 1xRTT, the LTE access behaves as if the UE has
     went out of coverage i.e. it performs the S1 release procedure and
     considers the UE to be in IDLE state
• 3GPP mostly specifies the transport of A21 messages over S102
13
Planning for Success


                       Device and
                  Application Ecosystem


             1x       DO      WiMAX       LTE


                      Ethernet and
                   Optical Connectivity

                      Common Core
                       Architecture

                   Design, Engineering,
                    Operations hosting



14      Bridging Today’s Networks with Tomorrow
What Can IP do for Operators?
                           END USERS
     Demand Convenience, Simplicity and Freedom of choice



Consumer                           Unified Billing

                               Consistent & Ubiquitous
                                                         Communication
                                 Integrated Services
                  Any Access


           Home
                                                           Multimedia
           Road                     Simple to use
                                                         Entertainment
           Work                 Reduction of devices
                                                          Information
                                   Personalization
Employee
                                Easy administration


                            OPERATORS
            Need to be the provider of integrated services
15
Benefits of Migration to IP


     OPEX savings                              Transport Efficiency
     • Recurring OPEX costs 30% to 50%         • TDM inherently inefficient:
       lower than with E1/T1 Leased Lines         • Symmetrically provisioned links
     • Converging mobile flows onto single        • Channels reserved even when idle
       cost-effective transport architecture   • Packet transport enabling superior
                                                 link utilization and bandwidth
                                                 recovery


     Transport Flexibility &                   Future-proof evolution
       Scalability                             • Multi-generation 2G/3G/4G flows
     • Highly scalable packet network vs         convergence onto single unified IP
       “rigid” TDM networks                      network
     • Flexibility to deploy IP and TDM        • Evolution to IP-centric networks for
       concurrently in the network               convergence and new applications
     • Operational simplicity (Connection-
       less IP & Quick to scale)



16
   Momentum from the Wireless Data
   Waves

                               Wave 1 - Initial Wireless Data Service
                                 • Voice & Text Driven – Low Volume
                                 • Billing via legacy Circuit – Limited controls
        Voice Devices




                               Wave 2 – Wireless Data Service of Value
                                 • Data rate acceptable – Traffic Approaches Voice
                                 • Data Plans, Wireline explodes - Content Billing
  Special Devices / PC Cards     • Carrier class Intelligent Packet Core Required


                               Wave 3 – Mass Market Mobile Broadband
                                 • Consumer Devices, Multi-Access, Traffic >Voice
                                 • Multi-nodes / Person, Flat Rate, Special Rate
Consumer & Special Devices
                                 • Carrier Class, COTS, Scalable, & QOS



   DO Rev A is creating the Mass Market Mobile Broadband
   17
 Improve Operator Efficiency
                                      Presence         WAP        Presence
                                        for IM                     for PTT


          MMS         PTT
                                           IM                          PTT                   A S
                Multiple devices                                                   Email     p i
                Multiple clients                                                             p l
                                                   Call Server                                 o
  Chat/IM
 Presence                                                                                      s


                                                      MMSC          GLMS
                                          GLMS
                       Email                                       for PTT
PMO         WAP                           for IM


FMO                                                        IM          WAP

          PTx                                                                      MMSC
  Chat           Dwnld
                                   CSCF
  IM              Video
                                                Presence        GLMS
                                                                                     Email

      Single device
        SIP client
                                                                             PTT
                                                   Application Servers
Single network, common elements, enablers, & applications
 18
  Via Multi-Function Core Solutions
                      Region 1                                         Market 3
                      Market 1                                         (Remote
                                                                      Coverage)
                                                                        Packet Transport Saving
                         MSC                                              > Leverage LD bypass
                        Server
                                                                          > Improved Voice quality
                                  MGW BSC              MGW BSC              and increased transport
                                                                            savings: keep native
   SIP/SIP-T
                                                                            vocoder (TrFO & RTO)

          Packet                  PDSN
       Data Network                FA
                                     PDSN
                                    HA & FA
                                                                          Cover Remote Areas
Other Softswitches,
CSCF, App Servers                                                        > Keep Traffic local
                          MSC
                         Server               EVRC                       > Central office
                                                                           consolidation
                      Region 2
                                                       MGW
                                  MGW BSCCommon IP Network BSC
                      Market 2
Bridge Application Domains
 > SIP/SIP-T support:
 Packetization between                                     Market 4
              W-/W+
 regions and gi                                            (Remote
 > SIP to ISUP conversion:                                Coverage)
 MGCF role for MMD
 & WLAN/CDMA convergence
  19
Packetizing Voice Delivers Crystal
Clear CDMA Calls

• Deliver high quality voice service while reducing operating
  costs
     • Improved Voice:
       • Reduction of end to end delay => better speech perception
       • Better Voice Quality = Higher MOS score
       • Higher MOS score reduces subscriber churn
     • Reduced Opex:
       • Reduces transport costs as native CDMA-encoded voice
         transported more efficiently in the Packet networks than legacy
         TDM
       • EVRC Voice transported over IP in 8k payload versus 64k TDM
         payload across network


20     Improve Voice Quality, Lower Operations Costs
      How TrFO/RTO Enable Crystal Clear Calls
               Legend
                   Signaling - Circuit                                            ANSI-41
                                                                                   Over
                  Signaling - Packet                                                                HLR
                                                                                   SS7

                  Bearer - Circuit                                                 SS7 Network
                  Bearer - Packet                              SGW
                                                                                                             ISUP over
                                                                                               SGW                     SS7
                  BTS – EBSC Interface
                  EVRC Voice Path               MSC                                                 MSC
                                                              ANSI-41 Over
                 TDM Voice Path                                 M3UA


                                                                                                                                  DM
                                                                                                                                /T
                                                                                                                               M
                       A1 Interface                                                                                          PC
                                                                        SIP-T                                                                          Phone
       BSC
                                                                                                                               A1 Interface
                                                      H.248                                 H.248
                                                                                                                                                  BSC




                                                                     IP Network

                                     EVRC                                                                          EVRC
                                      RTP                                                                           RTP
                                             Media Gateway                                   Media Gateway
                                      UDP                                                                           UDP
                                       IP                                                                            IP
                                       L2                             EVRC                                           L2
                                       L1                              RTP                                           L1
                                                                       UDP
Base Station                                                                                                                                    Base Station
       Base Station
                                                                        IP
              Base Station                                              L2
                                                                                                                                        Base Station
                                                                        L1                                                       Base Station

      21
                              Mobile Phone                                                                         Mobile Phone
   CDMA Provides Better Support For
   Low-latency Applications
                                                                     Round Trip Time
        Push-to-Talk
        High Quality



                                               EV-DO rev A                  ~45 ms

                                                  HSUPA                   80 – 100 ms
                                                                                        Source: Qualcomm

                                        Call set-up time and signaling for EV-DO rev A
                                        have been optimized to provide high-quality PTT
        EV-DO Rev A delivers much lower latency to support much better quality of experience in PTT
  EV-DO Rev A Mobile VoIP provides superior end-user experience and results in fewer dropped calls
                                                       Source: Qualcomm
                         Handoff Interruption




                                                                                         Video Telephony
Mobile VoIP
                       Inter-cell   Inter-sector
EV-DO rev A            ~23 ms          ~13 ms
                                     Slightly lower
  HSUPA                ~100 ms       than inter-cell

        New features to deliver acceptable QoS on UMTS
        VoIP calls not available until UMTS Rel 8!



 Rev A applications provide high penetration & lower churn
   22
How Do You Want To Provide Service?
 FMC Service Types
                                                           Access personal agent features
                                                           Access personal agent features
                                                          • • GUI on mobile for routes, IM, presence
                                                               GUI on mobile for routes, IM, presence
                 Packet Cellular                          • • “Mobile Assistant” (F, M)
                                                               “Mobile Assistant” (F, M)
     Mobile
                                                           Access fixed telephony services
                                                           Access fixed telephony services
                                                          • • Turn the mobile into aaenterprise extension
                                                               Turn the mobile into enterprise extension
                 Circuit Cellular                         • • “Mobile Extension” (M)
                                                               “Mobile Extension” (M)

                                                               WiFi/cellular on one device
                                                               WiFi/cellular on one device
                                                          • • Reduced call costs on WiFi
                                                               Reduced call costs on WiFi
                                                          • • “Converged Mobility” (F, M)
                                                               “Converged Mobility” (F, M)
                      WiFi                                • • “Voice Call Continuity” (M)
                                                               “Voice Call Continuity” (M)

                                                             Cellular/PC call convergence
                                                             Cellular/PC call convergence
                                                          • • Voice on mobile with multimedia PC GUI
                                                               Voice on mobile with multimedia PC GUI
                                                          • • “Mobile Converged Desktop” (M)
                                                               “Mobile Converged Desktop” (M)
                PC

                                                               Services on fixed & mobile
                                                               Services on fixed & mobile
                                                          • • Make/receive calls from any device
                                                               Make/receive calls from any device
              Fixed
                      F = applicable to fixed operator
                                                          • • Applicable to all solutions
                                                               Applicable to all solutions
                      M = applicable to mobile operator

23    FMC Provides Wide Range of Services to End-Users
Voice Call Continuity (VCC)
 Key Attributes                                           Solution Impact
                                          Carrier         Mobile (IN integration needed)
                                        Device/client   Dual-mode with client, or any mobile

End-user value                           Service-provider value
• Reduces calling costs                  • Differentiated dual-mode offer
    • Cheaper calls in WLAN                   • Advanced services beyond cellular
                                              • Tight integration with fixed devices
• Increased reachability with service
  integration across devices             • IMS standards compliant solution
    • Basic telephony                         • Extends SIP/IMS applications into the cellular
                                                network
    • Enhanced telephony
                                              • Allows applications servers to be added for
    • Multimedia                                incremental services
                                              • Future devices/client will align with IMS-VCC
• Call handling across access types             standard
  and devices
   • WLAN/cellular handover              • Supports new services on classic 2G
   • Switch calls between fixed and        device without client
      mobile devices                     • Can be enhanced with Mobile Assistant




Full Set of Features Supporting Multi-access, Multi-device
24
Testing with Qualcomm VCC Chipset


• Successful testing of Nortel solution & Qualcomm chipset
• Mobile Station Modem (MSM) chipset powering a test
  handset
• Nortel WMG 6000 with IMS network
• Capabilities
     • In-call handover using manual and automatic triggers
     • Authentication
     • Calls on cellular/WiFi         "The number of networks, devices and
                                  applications is exploding, and there is a pot of
     • Variety of error cases     gold — a very large pot of gold — awaiting the
                                            vendors who do the best job of allowing data
• Live cellular coverage                     and applications to seamlessly flow between
                                            them all. Qualcomm and Nortel have taken a
                                           step in the right direction." IT Business Edge,
                                                                Dec 2007

25
                                                VCC Application
                                                  VCC Application
VCC Network Overview                            • • Routes calls to correct domain
                                                     Routes calls to correct domain
                                                • • Anchors calls for handover
                                                     Anchors calls for handover
                                                • • SMS to IM interworking
                                                     SMS to IM interworking




                                                              Voice AS

                   Any IP
                                                          IMS
                                                                                Internet
                                                          Core


                                                      MGCF/
                 WiFi, Femto                          MGW
                                WMG 6000




                                                      Cellular                    PSTN
         1XRTT, VoIP over
                                                       Core
         DOrA, Wimax, LTE

       Access services          Seamless        Reuse         IMS          Connect
     from any device and       selection of    existing    multimedia       to any
       any access type           access          core       services       domain
                                 domain       elements



26   Seamlessly Service Across Multiple Access Types
 Designed to Go Beyond WiFi and
 Femto

 • IMS VCC plays a key role in 4G deployments
      • e.g. Seamless call handoff to 2G and 3G networks
      • e.g. LTE femtocells
 • Nortel is continuing to drive the IMS Centralized Services
   (ICS) standards
      • World’s first ICS prototype available now
 • Nortel is continuing to develop the VCC ecosystem




VCC Bridges Multiple Technologies, including WiFI, Femto,
 27                 WiMAX, and LTE
Services Intertwine and Drive More Traffic


                                                              Communities Of
      Voice & Video              Peer to Peer                 Communications
• Imbedded Natively        • 40% - 60% traffic is P2P      • Xbox Live - largest social
  Everywhere.                today and moving from           network in the living room (2.6
                             music to HD video.              million IM, text voice messages /day)
• Multi-Device gaming on
  horizon, incorporates    • Microsoft’s LiveStation and   • mobile.youtube.com . 4X
  wireless                   others targeting mobiles        cellphones than PCs – Just
                             with P2P                        do the math!




 28   Riding the Data Waves to Higher Revenue and Profits
29

				
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Description: 3G Long Term Evolution is the evolution of the project, began in Toronto in 2004 3GPP meeting. LTE is not 4G technology is widely misunderstood, but between 3G and 4G technology as a transition, is the global standard for 3.9G, 3G is to improve and enhance air access technology, using OFDM and MIMO for its wireless network evolution the only criterion. 20MHz of spectrum in the downlink bandwidth to deliver 326Mbit / s and uplink 86Mbit / s peak rate. Improve the performance of cell edge users, increase cell capacity and reducing system latency.