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Session W3 Toward 4G Networks

Session W3 Toward 4G Networks. Ramachandran Ramjee, Ph.D. ramjee@bell-labs.com http://www.bell-labs.com/~ramjee. cdma2000 1X (1.25 MHz). cdma2000 3X (5 MHz). Wide-Area Wireless Standards Evolution. 1G. 2G. “2.5G”. 3G/ IMT-2000 Capable. Existing Spectrum New Spectrum. Analog

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Session W3 Toward 4G Networks

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  1. Session W3Toward 4G Networks Ramachandran Ramjee, Ph.D. ramjee@bell-labs.com http://www.bell-labs.com/~ramjee

  2. cdma2000 1X (1.25 MHz) cdma2000 3X (5 MHz) Wide-Area Wireless Standards Evolution 1G 2G “2.5G” 3G/ IMT-2000 Capable Existing Spectrum New Spectrum Analog AMPS IS-95-A/ cdmaOne IS-95-B/ cdmaOne 1XEV DO: HDR (1.25 MHz) IS-136 TDMA 136 HS EDGE TACS GSM GPRS EDGE GSM WCDMA HSCSD IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  3. Other wireless standards • 802.11/802.11b - 2-11 Mbps - uses 2.4GHz spectrum • 802.11a - 54 Mbps - Orthogonal Frequency Division Multiplexing (OFDM) • HiperLan2 - 50Mbps - local-area networks - uses 5GHz spectrum • Bluetooth - 720 kbps - very limited range using 2.4GHz spectrum • ARDIS - 19.2 Kbps - IBM/Motorola - slotted CSMA • MOBITEX - 9.6 Kbps - RAM mobile-slotted CSMA • CDPD - 19.2 Kbps - DSMA/CD using AMPS • Metricom - Frequency Hopped SS - 28.8 Kbps, 128 kbps upgrade - uses the ISM 900 Mhz band • iDEN - 20kbps - uses Mobile IP, supports WAP • DECT/CT2 - cordless, low-mobility - 32kbps - FDMA/TDMA • PHS - cordless system for microcell/indoor use, Japan - 128 Kbps - TDMA • iMode - 9.6 Kbps - packet data service, currently uses PDC • WAP - Wireless Application Protocol - currently circuit-switched data IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  4. Observations • The ‘G’ in #G stands for Generation and typically refers to the generation of wide-area wireless network’s air interface • While the 4G air interface has not been standardized yet, a plethora of wireless standards are prevalent and will continue to co-exist • Dominant among these are CDMA2000, WCDMA, and 802.11-based systems • Today, each of these air interfaces has its own network architecture standards though the network provides similar functionality of mobility and location management • A unified network architecture based on IP that provides a common mobility and location management mechanism can serve as the 4G network of the future while different air interfaces simply plug into this network IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  5. Outline • Motivation • IP Mobility • Macro-mobility: Mobile IP • Micro-mobility: HAWAII • IP Paging • HA/FA paging • Domain paging • Interworking of Wireless LANs with 3G Networks IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  6. Motivation: Why IP? • Migration of wireless access networks to IP allows • Support for anticipated growth of the wireless Internet access • merging of services for wireline and wireless networks • merging of wireless voice and data networks • Reduced product and operational costs of IP infrastructure • availability of “commodity” hardware, software, and services • increased efficiency of packet-based networks for combining voice and data IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  7. Industry Directions for Wireless Networking • Cellular Telecom Approach • Efforts to define wireless data networking standard (General Packet Radio Service/GPRS, UMTS) begin before full impact of Internet explosion is felt • Internet-Based Approach • Use Internet standards for networking and mobility with extensions to inter-operate and support cellular air interfaces (e.g., GPRS, CDMA) 1st UMTS customers GPRS/UMTS standards begin FPLMTS standards begin 1998 1994 1992 1990 1995 2002 3M Internet Users 153M Internet Users IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  8. Clash of models • Telecom/cellular model Approach: Extend current wireless circuit-based infrastructure to support wireless internet data • Flexibility at the cost of complexity and efficiency (e.g. X.25 support in GPRS, PPP support in CDMA) • Rich functionality through experience (e.g., paging, micro-mobility) • Internet model Approach: Extend current internet data-based infrastructure to support wireless internet data • Simplicity using IP (support other protocols, e.g. X.25, through tunneling if necessary) • Missing functionality (e.g., paging, micro-mobility) IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  9. SGSN MD Internet SGSN Emerging Mobile Packet Networks: GPRS and UMTS Tunneled packets using GTP Regular routing GGSN Radio Access Networks Host Intranet • Compatible with cellular telecom networks • may be deployed leveraging existing infrastructure • requires separate advances from the Internet • Specialized nodes manage mobility and forward packets • requires no changes to fixed hosts or intermediate routers • results in tunneling and triangular routing • special failure recovery mechanisms needed • Inter-SGSN handoffs always managed by GGSN • high update overhead • slow handoffs IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  10. FA FA Emerging Mobile Packet Networks: CDMA2000 and 802.11 (Mobile IPv4) Tunneled packets using Mobile IP HA Regular routing Radio Access Networks MD Host Internet • Compatible with regular IP networks and hosts • most Internet advances apply • Specialized agents manage mobility and forward packets • requires no changes to fixed hosts or routers • results in tunneling and triangular routing • special failure recovery mechanisms needed • Handoffs always managed by Home Agent • high update overhead • slow handoffs IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  11. Trends Trends • Local and Wide-area wireless data networks • high and low mobility users • IP functionality in access network elements including base stations • homogeneous IP-based access network • Diverse applications • quality of service support necessary • Mobility has to be processed locally IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  12. Micro-mobility: Design Goals • Scalability • process updates locally • Limit disruption • forward packets if necessary • Efficiency • avoid tunneling where possible • Quality of Service (QoS) support • local restoration of reservations • Reliability • leverage fault detection mechanisms in routing protocols • Transparency • minimal impact at the mobile host IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  13. Hierarchy and unique address • Hierarchy through domains • Mobile-IP for movement between domains • HAWAII Path Setup for movement within domain • Users retain their unique IP address while moving within a domain • Home address could be dynamically assigned • Co-located care-of address used in foreign domain • Unique and unchanging address limits updates to Home Agent and simplifies QoS support in the network IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  14. Domain Router R R R R R R R R R R R R HAWAII: Enhanced Mobile IP Internet Domain Router MD Local mobility Local mobility Mobile IP • Distributed control: Reliability and scalability • host-based routing entries in routers on path to mobile • Localized mobility management: Fast handoffs • updates only reach routers affected by movement • Minimized or Eliminated Tunneling: Efficient routing • dynamic, public address assignment to mobile devices IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  15. Domain Root Router 2 Domain Root Router 1 Internet 1 1 2 R R 4 2 4 3 3 1.1.1.100-> port 3, 239.0.0.1 3 4 1.1.1.100->port 4, 239.0.0.1 1 5 1 2 5 1 5 R 4 2 R R 4 4 3 3 2 3 2 BS1 BS2 BS3 BS4 1.1.1.100->wireless, 239.0.0.1 1 5 MY IP: 1.1.1.100 BS IP:1.1.1.5 Mobile IP HAWAII Power-up IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  16. Design Principle III:Soft-state Soft-State • Host-based routing entries maintained as soft-state • Base-stations and mobile hosts periodically refresh the soft-state • HAWAII leverages routing protocol failure detection and recovery mechanisms to recover from failures • Recovery from link/router failures IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  17. Internet 1 1 2 5 5 R 2 R 4 4 3 3 Mobile IP HAWAII Failure Recovery Domain Root Router 2 Domain Root Router 1 1 1 1.1.1.100-> port 4, 239.0.0.1 2 R R 4 2 4 3 3 3 1.1.1.100->port 3, 239.0.0.1 5 1 4 R 3 2 2 BS1 BS2 BS3 BS4 1.1.1.100->wireless, 239.0.0.1 1 MY IP: 1.1.1.100 BS IP:1.1.1.5 IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  18. Path Setup Schemes • Host-based routing within the domain • Path setup schemes selectively update local routers as users move • Path setup schemes customized based on user, application, or wireless network characteristics • Micro-mobility handled locally with limited disruption to user traffic IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  19. Domain Root Router 2 Domain Root Router 1 Internet 1 1 2 R R 4 2 4 3 3 1.1.1.100-> port 3, 239.0.0.1 1.1.1.100->port 3 (4), 239.0.0.1 5 1 1 1 2 5 5 4 2 R R R 4 4 3 2 3 3 4 2 3 BS1 BS2 BS3 BS4 1.1.1.100->wireless, 239.0.0.1 1.1.1.100->port 1(wireless), 239.0.0.1 1 5 MY IP: 1.1.1.100 BS IP:1.1.1.2 Mobile IP HAWAII Micro-Mobility IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  20. Internet 1 1 2 5 5 2 R R 4 4 3 3 BS1 Mobile IP HAWAII Macro-Mobility Domain Root Router 2 Domain Root Router 1 Mobile IP Home Agent: 1.1.1.100-> 1.1.2.200 1 1 2 R R 4 2 4 3 3 1.1.2.200-> port 3, 239.0.0.1 3 5 4 1.1.2.200->port 2, 239.0.0.1 6 5 1 4 R 3 2 2 BS2 BS3 BS4 1.1.2.200->wireless, 239.0.0.2 1 7 MY IP: 1.1.1.100 BS IP:1.1.2.1 COA IP:1.1.2.200 IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  21. Simulation Topology IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  22. Performance: Audio and Video IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  23. Performance: TCP • TCP - Web transfers in Mobile IP: Interaction between Tunneling and TCP Path MTU discovery results in 1 round trip wasted for each object. • TCP - File transfers: 5-15% improvement over Mobile IP IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  24. Router 1 BS-20 BS20 BS1 BS1 Update Rates Network Model Domain Router • 39 users/sq. miles • users moves at 112 Km/hr. • base stations cover 7 Km2 ... Router 7 ... Mobile IP Updates at Home Agent: 2 L B r L B rn MIP = B D + B D T p 16 M • Varies linearly with # of base stations <<1, local mobility Hawaii Updates at Domain Router: M-IP 2 rn L B gr L B H = + B D B D T p 16 • Varies O(BD1/2) M 2 BD r L L B R Hawaii rn B + B D D + 16YTR p aggregation IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  25. Performance: Update Rates • Scalability at the Domain Root Router • Number of entries: entries are from a given domain’s IP subnet -> perfect hashing for route lookup. • Number of updates: updates for Mobile IP varies linearlywith the number of base stations in domain whereas in HAWAII, updates vary with the square root of number of base stations in domain. • Based on FreeBSD implementation, for a typical network configuration, update ratio of Mobile IP to HAWAII is 3:1 and CPU utilization ratio is 9:1. IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  26. Standardization: IETF SeaMoby Working Group • Draft-seamoby-ietf-mm-problem-01.txt identifies the goals for a new IETF micro-mobility protocol: • Mobility without changing routable IP address • Use Mobile IP for inter-domain mobility • Use Mobile IP for signaling from the mobile host • IP version neutral • Optimized routing • Plug & Play • Inter-technology/heterogeneous mobility support • Inter-operate with existing QoS protocols • HAWAII appears an excellent fit! • Work is in IRTF now. IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  27. Changes from Mobile IP (rfc2002) • Previous Foreign Agent Notification Extension (Route Optimization draft) • NAI extension (NAI draft) • Mobile challenge-response extension (Challenge Response draft) • NAI in foreign agent advertisements to detect domain changes (Private addresses draft) • Register with foreign agent while using co-located addresses • Allow split Mobile-IP registrations at the foreign agent (regionalized tunnel draft) IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  28. HAWAII: Benefits Summary • Scalability through reduced updates as micro-mobility transparent to home agents • Limited disruption of traffic as Path Setup Schemes are optimized for the environment • Efficiencythrough reduced data packet header overhead as no tunneling in a (large) home/power-up domain • Ease of QoS support: unique address • Reliability through soft-state • Transparency to hosts that use Mobile IP • Integration with existing wireless infrastructure IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  29. Outline • Motivation • IP Mobility • Macro-mobility: Mobile IP • Micro-mobility: HAWAII • IP Paging • HA/FA paging • Domain paging • Interworking of Wireless LANs with 3G Networks IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  30. What is Paging? Mobile Host State Diagram • “Idle” mobile hosts update network less frequently than “active” mobile hosts • Network has only approximate location information for idle mobile hosts • Network determines the exact location by paging to deliver packets IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  31. IP Paging Outline • Motivation • IP Paging Architectures • Performance • IETF Standardization (SeaMoby Working Group) • Summary IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  32. Radio Access Networks SGSN MD Internet SGSN Paging in wireless networks (1): GPRS, UMTS Tunneled packets using GTP Regular routing GGSN Host Intranet • Paging for voice initiated differently (MSC) from data (SGSN) • may be deployed leveraging existing infrastructure • requires separate mechanisms • Specialized nodes, protocols (BSSGP) manage paging • requires no changes to intermediate routers • separate advances from other paging protocols • special failure recovery mechanisms needed IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  33. FA Radio Access Networks FA Paging in wireless networks (2): CDMA2000, Mobile IP Tunneled packets using Mobile IP HA Regular routing MD Host Internet • Paging for voice initiated differently (MSC) from data (RAN/MSC) • may be deployed leveraging existing infrastructure • requires separate mechanisms • No paging in Mobile IP • Specialized nodes, protocols (IS2001) manage paging • requires no changes to fixed hosts or routers • separate advances from other paging protocols • special failure recovery mechanisms needed IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  34. Why IP paging? As wireless access networks migrate to IP, IP paging allows • common infrastructure to support different wireless technologies • seamless merging of LAN/WAN • avoids duplication of paging protocols, resulting in cost savings • deployment of sophisticated paging algorithms • leverages the support of multicast, if available • user-customized paging areas IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  35. IP Paging Goals • Efficiency limit updates from mobile host when idle to conserve battery power • Scalability push paging initiation closer to base station • Reliability allow paging initiation to occur at any router/base station (no single point of failure) • Flexibility allow for fixed, hierarchical, or user-defined paging areas IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  36. Home Agent R R R Internet Domain Paging Area Foreign Agent Foreign Agent Foreign Agent Mobile IP Paging Area IP Paging Architectures HA initiates page • Uniform mobility management • wireless LANs, outdoor Old FA initiates page Any router initiates page • 3 Options: • Home Agent Paging • Home agent buffers packets and initiates page to all Foreign Agents • Can be controlled by corporate network • Does not scale • Foreign Agent Paging • Last active Foreign agent buffers packets and initiate paging • Distributes load • Domain Paging • Fully distributed, very scaleable and reliable IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  37. Home Agent (HA) Paging • Centralized at HA • Simple implementation • Issues/concerns • Inefficient signaling: long delays if HA far from mobile host • Scalability at HA • Multicast-based addressing of paging area needs global visibility, scalability of paging areas IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  38. Foreign Agent (FA) Paging • Initiated at previously attached FA • Distributed among different foreign agents in paging area • Simple implementation • Efficient: paging restricted to local domain • Issues/concerns • Reliability when previous FA crashes • Requires FA deployment IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  39. Domain Paging • Initiated at any node (router/base station) in path from mobile to root router • Completely distributed among different nodes in domain • Highly scalable, reliable to node failures • Efficient: paging restricted to local domain • Issues/concerns • implementation complexity • router support IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  40. Router operation Routing Paging entry entry State Operation YES YES Active Regular Forwarding YES NO Active No paging support NO NO Null Forward if default route exists, else discard NO YES Standby Paging: If (packet arrives from DRR or I am DRR) If (node is base station or no refresh from downlink port or queuesize < threshold) Initiate paging else Forward to port in paging entry Endif else Forward along default route Endif IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  41. Implementation • All three paging protocols implemented in FreeBSD • Paging protocol processing in user space, data forwarding in kernel space • Paging implementation does not affect fast path performance - use of virtual interfaces • Implementation used to measure processing load of different paging tasks - results to drive large scale simulation IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  42. Internet 1 1 2 5 5 2 R R 4 4 3 3 Paging Data HAWAII Paging Domain Root Router 2 Domain Root Router 1 1 1 2 R R 4 2 4 3 3 1.1.1.100-> port 3, 239.0.0.1 Buffer 1.1.1.100->port 3, 239.0.0.1 5 1 4 R 3 2 1 1 4 BS1 BS2 BS3 BS4 1.1.1.100->wireless, 239.0.0.1 2 3 2 MY IP: 1.1.1.100 BS IP:1.1.1.2 IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  43. Scalability (latency) • Simulation parameters • 36-90 zones per domain • paging area size = 6 • real, synthetic traces • processing times from implementation • HA paging needs 5 processors for comparable performance • FA paging scalable • Domain paging supports highest paging load IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  44. Scalability (updates) • Large Paging Area size results in fewer updates but increases latency due to higher paging processing load • In FA/HA paging, updates can occur due to movement or when user is paged and found at new location • In Domain paging, updates are only due to movement - results in least number of updates IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  45. FA FA FA FA R R R R R R R R IP Paging – Reliability Results Home Agent Domain Model Mobile IP Model Internet R DR/HA IP Paging Area IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  46. FA FA Domain Domain HA IP Paging – Reliability Results HA IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  47. Standardization: IETF SeaMoby Working Group • Draft-ietf-seamoby-paging-problem-statement-02.txt identifies need for IP paging (now RFC 3132) • Draft-ietf-seamoby-paging-requirements-02.txt identifies following requirements (now RFC 3154): • minimize impact on host’s power consumption • on receiving page, host must re-establish layer three link • efficient utilization of layer two, if available • support existing mobility protocols • flexible support for different paging areas • allow arbitrary mapping between paging areas, subnets • robust against failures, packet losses • FA, Domain paging suitable candidates! IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  48. Summary • IP-based wireless access networks - efficient, cost-effective • IP paging allows common infrastructure to support different wireless interfaces including CDMA, GPRS, wireless LAN etc. • Proposed three paging architectures: each has its applicability • HA paging useful in small networks with complete administrative control • FA paging simple, scalable, easily deployable • Domain paging scalable, flexible, reliable, most efficient • Future work • Standardization • Flexible and user-specific paging mechanisms IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  49. Outline • Motivation • IP Mobility • Macro-mobility: Mobile IP • Micro-mobility: HAWAII • IP Paging • HA/FA paging • Domain paging • Interworking of Wireless LANs with 3G Networks IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony

  50. Service Provider “Home” Network Core IP Network Radio Access Network Radio Access Network Radio Access Network Billing Billing Authentication Authentication Mobility Mobility Integrated Wireless Access Networks The next wave of Internet access will be through high-speed wireless packet access • Ubiquitous access to Internet and applications • Always-on high speed packet data access • Islands of multi-technology RF access networks connected to core IP network Service Provider “Home” Network Roaming Agreements Local Area Wireless Hotspot/Enterprise Wide Area Wireless IEEE NJ Coast Section seminar on Wireless LAN & IP Telephony 4G Wireless?

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