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WLAN field trial in high speed moving environment

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					May 2009                                                                                                                   doc.: IEEE 802.11-09/0111r2


        Broadband V2I Access for High Speed Transportation
                                                                           Date: 2009-5-12
Authors:
Name                                  Company                              Address                                       Phone                            email
Hitoshi MORIOKA ROOT Inc.                                                  2-1-22-307 Momochihama, +81-92-832-3391                                        hmorioka@root-hq.com
                                                                           Sawara-ku, Fukuoka
                                                                           814-0001 JAPAN
Hiroshi MANO                          ROOT Inc.                            8F TOC2 Bldg. 7-21-11   +81-3-5719-7631                                        hmano@root-hq.com
                                                                           Nishi-Gotanda, Shinagawa-
                                                                           ku, Tokyo 141-0031 JAPAN




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Submission                                                                                  Slide 1                                               Hitoshi MORIOKA, ROOT Inc.
May 2009                                          doc.: IEEE 802.11-09/0111r2


                                  Abstract
 • We talk about WLAN broadband access for high speed
   transportation.
       –     Motivation
       –     Market
       –     Applications
       –     Why Wi-Fi?
       –     Why standardization is needed?
       –     Requirement
              • Handover Latency Case Study
       – Comparison with Existing IEEE802.11 Standards
       – Straw Poll


Submission                              Slide 2           Hitoshi MORIOKA, ROOT Inc.
May 2009                                   doc.: IEEE 802.11-09/0111r2


                            Motivation

 • Many high speed trains (>200km/h) are already in operation in
   Europe and Asia.
 • Developments of 10,000km of express railway tracks are estimated
   in next 20 years in the world.
 • Train operators want broadband network between rail-side and
   train for such as train survey, passenger service and so on.
 • And they want to operate the network by their own.



                      Wi-Fi will meet their needs.
             (Equipments cost, Operation cost, Bandwidth…)

Submission                       Slide 3           Hitoshi MORIOKA, ROOT Inc.
May 2009                                                                     doc.: IEEE 802.11-09/0111r2


                                                   Markets
 •    Train (Railway Transportation)                            Existing High Speed Train (> 300km/h)
 •    Total extension of railway is approximately
      1,350,000km in the world.                                       Name           Country           Max. Speed
       –     North America: 278,000km                           Shanghai
       –     EU:                             236,000km                            China              430km/h
                                                                Transrapid
       –     Russia:                         128,000km
       –     East Asia:                      110,000km          Beijing-Tianjin
                                                                                  China              350km/h
       –     Central/South America:          110,000km          HSCL
                                                                TGV               France             320km/h
 •    Existing high speed train
                     (> 200km/h operation)                      ICE               Germany            320km/h
       –     22 systems in operation in 15 countries.           Shinkansen        Japan              300km/h
 •    Expected new high speed train                             AVE               Spain              300km/h
       –     10,000km in next 20 years.                         Eurostar          EU                 300km
       –     In US, President Obama unveiled his plan to
             develop new high speed passenger railway.          Thalys            EU                 300km/h
                                                                Treni Eurostar
 •    Of cause, not only high speed train but also                                Italy              300km/h
      ordinary train can use this technology.                   Italia
                                                                Taiwan HSR        Taiwan             300km/h
                                                                KTX               Korea              300km/h

Submission                                                 Slide 4                        Hitoshi MORIOKA, ROOT Inc.
May 2009                                           doc.: IEEE 802.11-09/0111r2


                       Expected Applications
                                                                     Internet
 •    Hot-spot service for passengers.
 •    Passenger information services.
 •    Cabin monitoring.
 •    Backbone for femtocell.
       –     Subway
       –     Tunnel




Submission                               Slide 5           Hitoshi MORIOKA, ROOT Inc.
May 2009                                              doc.: IEEE 802.11-09/0111r2


             Backbone for Hot-spot Service
• Passengers can access to the Internet
  while traveling at low price and high speed.

                                                                   Web            Mail
                                                                  Servers        Servers
                                                 Roadside
                                                 AP

               WLAN AP         Train                                        Internet
                               STA



                                                            LAN                     Misc.
                                                                                   Servers
                                                                      Web
                                                                     Servers


Submission                             Slide 6                Hitoshi MORIOKA, ROOT Inc.
May 2009                                             doc.: IEEE 802.11-09/0111r2


                  Backbone for Femtocell
• Passengers can use their celluler phone
  even in a tunnel or underground.

                                                                    Cellular Phone
                                                                       Network
                                                Roadside
                                                AP

               Femtocell      Train                                    Internet
                              STA



                                                           LAN

                                                                        Cellular Phone
                                                                           Network


Submission                            Slide 7                Hitoshi MORIOKA, ROOT Inc.
May 2009                                             doc.: IEEE 802.11-09/0111r2


             Passenger Information Services
• Passengers can get information such as
  news, travel information, advertisement
  in real time.
                                                                  Info.
                                                                 Servers
                                                Roadside
                                                AP

                              Train                                        Internet
                              STA

                   News
                   Advertisement
                   Travel Info…                            LAN

                                                                             Info.
                                                                            Servers


Submission                            Slide 8                Hitoshi MORIOKA, ROOT Inc.
May 2009                                             doc.: IEEE 802.11-09/0111r2


                       Cabin Monitoring
• Train operators can monitor the cabin.




                                                Roadside
                                                AP

                              Train                                    Internet
                              STA



                                                           LAN




Submission                            Slide 9                Hitoshi MORIOKA, ROOT Inc.
May 2009                                                doc.: IEEE 802.11-09/0111r2


                             Why Wi-Fi?
   • Wi-Fi can be easily operated by train/railway operators.
   • It means the networks are under their control, not rely on others.
   • And Wi-Fi has world-wide interoperability on frequency use.

             Standards       Bandwidth            Equipment Cost        Operation Cost
                         14.4Mbps
 3G, 3.5G                (Downlink)                 Very High                High
                         11.5Mbps (Uplink)
                         100Mbps (Downlink)
 LTE                                                Very High                High
                         50Mbps (Uplink)

 WiMAX (IEEE802.16e)     21Mbps                       High                   Low

                         100Mbps
 IEEE802.11                                            Low                   Low
                         (11n MAC)



Submission                             Slide 10                    Hitoshi MORIOKA, ROOT Inc.
May 2009                              doc.: IEEE 802.11-09/0111r2


             Why standardization is needed?

 • Multiple vendor and long term support is needed for
   sustainable operation.
 • A train may run across multiple railway network. So
   inter-/intra-national interoperability is needed.
 • According to these reasons, international
   standardization is needed.




Submission                 Slide 11           Hitoshi MORIOKA, ROOT Inc.
May 2009                                                 doc.: IEEE 802.11-09/0111r2


                                Requirements

 • Target Speed
       –     TGV plans 360km/h operation.
       –     TransRapid in Shanghai is operated in 430km/h.
       –     JR-Maglev records 581km/h and JR plans to start service in 2025.
       –     500km/h is enough?
 • Scalability
       – Many trains are running on a railway simultaneously.
       – Railway networks are vast. So a train may run across many
         communication networks.
       – Inter-network handover is required.
 • Security
       – Security is very important because private information will flow on
         networks.
       – For example, a train survey application will transfer a video which
         includes a passenger’s face.

Submission                                 Slide 12               Hitoshi MORIOKA, ROOT Inc.
May 2009                                                      doc.: IEEE 802.11-09/0111r2


                          Inter-Network Use


                                      Network A



             Network B                 Network C                         Network D


      AP        AP       AP      AP           AP         AP        AP         AP         AP

                     Inter-Network Handover          Inter-Network Handover


                 IEEE802.11r does not support inter-network handover.

Submission                                Slide 13                      Hitoshi MORIOKA, ROOT Inc.
May 2009                                            doc.: IEEE 802.11-09/0111r2


             Inter-network Handover Latency

 1. Discover a new AP.
       •     Latency can be reduced by 11k or multiple radio interfaces.
 2. Association with new AP.
    (includes authentication/key exchange…)
       •     11i authentication is NOT fast.
       •     It needs many packet exchanges.
 3. Network layer setup.




Submission                             Slide 14              Hitoshi MORIOKA, ROOT Inc.
May 2009                                        doc.: IEEE 802.11-09/0111r2


                     MAC Requirements

 • Fast Association
       – Train must handover during passing overlap zone for seamless
         handover.
       – Handover latency impacts distance between APs. (= cost)
       – Low handover latency is needed.


         Old AP                                      New AP




                                Overlap Zone



Submission                          Slide 15             Hitoshi MORIOKA, ROOT Inc.
May 2009                                                doc.: IEEE 802.11-09/0111r2


                                    Case Study
 • Assumption
       – Maximum speed: 500km/h = 140m/s
       – Cell Radius: 200m
       – Route Length: 1,000km
Case 1:       Handover Latency = 100ms
              Minimum Overlap Zone length= 14m
              Distance between adjacent APs = 386m
              Number of APs = 2,591

     Old AP                                                       New AP




                            200m              14m
                                                          200m
                                             386m

Submission                                   Slide 16            Hitoshi MORIOKA, ROOT Inc.
May 2009                                            doc.: IEEE 802.11-09/0111r2


                           Case Study (cont.)
Case 2:      Handover Latency >1.43s
             Minimum Overlap Zone distance > 200m




 Old AP                             New AP                         New AP




                          200m




STA must begin new handover process before completing old handover process.


Submission                               Slide 17           Hitoshi MORIOKA, ROOT Inc.
May 2009                                                        doc.: IEEE 802.11-09/0111r2

                   Protocol Sequence of
             IEEE802.11+IEEE802.1x(EAP-MD5)
• At least 6 roundtrip packet exchanges STA                            AP                     RADIUS
  between STA and AP, and 2 roundtrip             Beacon                                      Server
  packet exchanges between AP and
                                                  Probe Request
  RADIUS server are needed.                      Probe Response
• EAP-TLS, EAP-TTLS, etc. needs more          Authentication Request
  packet exchanges.                           Authentication Reply
                                               Association Request
                                                Association Accept
                                                  EAPOL-Start
                                               EAP-Request/Identity
     It increases handover latency            EAP-Response/Identity
                                                                            RADIUS-Access-Request
                                          EAP-Request/Credentials           RADIUS-Access-Challenge
                                          EAP-Response/Credentials
                                                                            RADIUS-Access-Request
                                                  EAP-Success               RADIUS-Access-Accept




Submission                                Slide 18                             Hitoshi MORIOKA, ROOT Inc.
May 2009                                            doc.: IEEE 802.11-09/0111r2

       Comparison with Existing IEEE802.11
                   Standards
                            Inter-Network                     Fast Roaming
 Standards                                Security
                            Use                               (Handover)

 IEEE802.11/a/b/g/n

 +IEEE802.11i

 +IEEE802.11r

 We need

 Approaches
       a.    Fast authentication/key exchange.
       b.    Inter-network fast roaming.

Submission                               Slide 19           Hitoshi MORIOKA, ROOT Inc.
May 2009                             doc.: IEEE 802.11-09/0111r2


                PHY Compatibility

 • Existing PHY can be used in high speed environment.
   (08/1020r1)
 • So existing WLAN chipset can be used with some
   firmware and/or driver modification.




                    LOW COST


Submission                Slide 20           Hitoshi MORIOKA, ROOT Inc.
May 2009                        doc.: IEEE 802.11-09/0111r2


             Questions & Comments




Submission           Slide 21           Hitoshi MORIOKA, ROOT Inc.
May 2009                              doc.: IEEE 802.11-09/0111r2


                      Straw Poll

 • “A Study Group to develop a PAR and 5C for High-
   speed Broadband Access for 802.11 should be created”

     Yes:
     No:
     Don’t Know, Need More Discussion:
     Don’t Care:




Submission                 Slide 22           Hitoshi MORIOKA, ROOT Inc.

				
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