doc.: ieee 802.11-11/1032r0 submission july 2011 jia-ru li, lilee systemsslide 1 ptc radio and...
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doc.: IEEE 802.11-11/1032r0
Submission
July 2011
Jia-Ru Li, Lilee Systems Slide 1
PTC Radio and System Architecture
Date: 2011-07-14
Authors:
Name Affiliations Address Phone Email
Jia-Ru Li Lilee Systems 2905 Stender Way, #78Santa Clara, CA, 95054
408-988-8672x128
doc.: IEEE 802.11-11/1032r0
Submission
July 2011
Slide 2
Abstract
Jia-Ru Li, Lilee Systems
• Mandate : United States President George Bush signed the railway safety bill [1] into law on October 16, 2008 after the collision of a Metrolink passenger train and a Union Pacific freight train in Los Angeles, California, resulted in the deaths of 25 and injuries to more than 135. The bill mandates the implementation of Positive Train Control (PTC) [2].
• Equipment : PTC involves four components – Equipment deployed on the locomotive
– Equipment deployed at trackside houses
– Equipment deployed at the control center
– A bi-directional wireless data link
• Deadline : The United States Congress set a
deadline of Dec 31, 2015 for the implementation of PTC technology.• Estimated 20,000 locomotives and 100,000 miles of track would need to be
equipped with PTC [7]
doc.: IEEE 802.11-11/1032r0
Submission
Wayside segment
July 2011
Slide 3
System Architecture
Jia-Ru Li, Lilee Systems
Back office Server
Back office Server
Dispatch System
Dispatch System
Office segment
Locomotive segment
Communicationsegment
doc.: IEEE 802.11-11/1032r0
Submission
July 2011
Slide 4
System Architecture (4 Segments)
• Central Traffic Segment:– Dispatching service, central monitoring, back office servers
• Locomotive Segment:– On-board train control computer, braking curve, movement authority
• Wayside Segment:– Track switches, railroad crossing, signals
• Communication Segment:– Mission critical radio that requires a standards committee to select
“best of the breed” technology and a common air interface
– IEEE LMSC has track records in creating standards for millions of devices to interoperate. (Bluetooth, WIFI, WIMAX, etc)
Jia-Ru Li, Lilee Systems
doc.: IEEE 802.11-11/1032r0
Submission
Comm for Office/Locomotive/Wayside
July 2011
Slide 5
Back Office Server Temp Speed RestrictionBack Office Server Temp Speed Restriction
Network Mgmt ServiceDatabase MaintenanceNetwork Mgmt ServiceDatabase Maintenance
RouterRouterMetroEtherMetroEther
Dispatcher
OfficeField
BSBS BSBS
BSBS
BSBS BSBS
BSBS
fiber
Jia-Ru Li, Lilee Systems
doc.: IEEE 802.11-11/1032r0
Submission
Real World Validation in Rain & Fog
July 2011
Slide 6 Jia-Ru Li, Lilee Systems
Mobile (3 watt)
19.2 miles
10 miles
19.2 miles
Mobile (10 watt)
Both uses 3 dbi Omni Antenna(5ft), cable 15 ft
10 miles
Base station
doc.: IEEE 802.11-11/1032r0
Submission
July 2011
Slide 7
PTC Radio Interface Requirement
• Supports various modulation (ex: GMSK, QPSK ….)
• Supports Forward Error Correction (FEC)
• Supports different channel spacing, different carrier
• Supports link layer fragmentation
• Supports
– QoS (11e)
– Link Layer Security (11i)
• Supports higher mobility speed than conventional WIFI
• Supports 64 time slot/sec (optional to support 128 slots/sec)
• Supports priority-based association (Hi/Lo contention slots)
• Supports Asymmetric uplink/downlink speeds
Jia-Ru Li, Lilee Systems
– Handover (Pre-auth)
– Link measurement (11k)
doc.: IEEE 802.11-11/1032r0
Submission
PHY using GMSK
Jia-Ru Li, Lilee SystemsSlide 8
July 2011
doc.: IEEE 802.11-11/1032r0
Submission
PHY using QPSK
Jia-Ru Li, Lilee SystemsSlide 9
July 2011
doc.: IEEE 802.11-11/1032r0
Submission
Low MAC protocol (CSMA/TDMA hybrid)
July 2011
Slide 10 Jia-Ru Li, Lilee Systems
# show basestation ptc station_tablestation slot type tx/rx self cast CRC error time to expired (ms)========================================================================================= beacon 00-00 0 T 1 1 0 never 01 01-01 3 T 1 0 0 47258 02 02-02 3 T 1 0 0 57852 …… 30 30-30 3 T 1 0 0 48584 brdcst 31-31 3 T 1 1 0 never Reg-Hi 32-32 3 R 1 0 0 never 01 33-33 3 R 1 0 0 41474 02 34-34 3 R 1 0 0 53135 …… 28 60-60 3 R 1 0 0 48179 29 61-61 3 R 1 0 0 56440 30 62-62 3 R 1 0 0 52599 Reg-Lo 63-63 3 R 1 0 0 never=========================================================================================
TransAir mode
contention slotBeacon data slot
1 second
2 3 4 5 6 7 8 9
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16 1 2 3 4 5 6 7 8 9
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16 1
16 2 3 4 5 6 7 8 9
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15 1 2 3 4 5 6 7 8 9
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16 1
16 slots 16 slots 16 slots 16 slots
doc.: IEEE 802.11-11/1032r0
Submission
High MAC protocol
• High MAC support – Beacon
– Probe request/response
– Association/Authentication
– Hand off request/response
– Action Frame
– Support MIB & PICS
– Station table
• Based on Std 802.11-2007
July 2011
Slide 11 Jia-Ru Li, Lilee Systems
CRC-16 implementation
Association State Machine
doc.: IEEE 802.11-11/1032r0
Submission
July 2011
Slide 12
Link Level Fragmentation
Jia-Ru Li, Lilee Systems
# ping -s 1500 10.3.10.1 PING 10.3.10.1 (10.3.10.1) 1500(1528) bytes of data. 1508 bytes from 10.3.10.1: seq=0 ttl=255 time=26728 ms1508 bytes from 10.3.10.1: seq=1 ttl=255 time=26152 ms1508 bytes from 10.3.10.1: seq=2 ttl=255 time=26024 ms1508 bytes from 10.3.10.1: seq=3 ttl=255 time=26772 ms1508 bytes from 10.3.10.1: seq=4 ttl=255 time=26966 ms1508 bytes from 10.3.10.1: seq=5 ttl=255 time=26724 ms1508 bytes from 10.3.10.1: seq=6 ttl=255 time=26952 ms1508 bytes from 10.3.10.1: seq=7 ttl=255 time=26956 ms1508 bytes from 10.3.10.1: seq=8 ttl=255 time=26238 ms1508 bytes from 10.3.10.1: seq=9 ttl=255 time=26384 ms1508 bytes from 10.3.10.1: seq=10 ttl=255 time=26466 ms
# ping –s 56 10.3.10.1 PING 10.3.10.1 (10.3.10.1) 56(84) bytes of data. 64 bytes from 10.3.10.1: seq=0 ttl=255 time=420 ms64 bytes from 10.3.10.1: seq=1 ttl=255 time=435 ms64 bytes from 10.3.10.1: seq=2 ttl=255 time=492 ms64 bytes from 10.3.10.1: seq=3 ttl=255 time=539 ms64 bytes from 10.3.10.1: seq=4 ttl=255 time=535 ms64 bytes from 10.3.10.1: seq=5 ttl=255 time=404 ms64 bytes from 10.3.10.1: seq=6 ttl=255 time=494 ms64 bytes from 10.3.10.1: seq=7 ttl=255 time=496 ms64 bytes from 10.3.10.1: seq=8 ttl=255 time=516 ms64 bytes from 10.3.10.1: seq=9 ttl=255 time=528 ms64 bytes from 10.3.10.1: seq=10 ttl=255 time=542 ms
1500 byte = 13 fragment takes 27s for round trip
56 byte = 1 fragment takes 500 ms for round trip
PayloadSession crcIP/TCP
1500 bytes (or bigger)
doc.: IEEE 802.11-11/1032r0
Submission
July 2011
Slide 13
Standards based Security – 802.1x (11i)
Jia-Ru Li, Lilee Systems
doc.: IEEE 802.11-11/1032r0
Submission
Standardization Drives Volume
• History tells us the 2nd hump comes from standardization
• It helps the customer to gain confidence in a given technology and willing to invest engineering resources
• Standardization helps other industries to adopt the same technology and drive more usage cases
• It usually happens 2-3 years after initial usage
July 2011
Slide 14 Jia-Ru Li, Lilee Systems
doc.: IEEE 802.11-11/1032r0
Submission
ERTMS (European Rail Traffic Management System) http://en.wikipedia.org/wiki/European_Rail_Traffic_Management_System
• The two main components of ERTMS – ETCS (European Train Control System) - a standard for on-board
train control( http://en.wikipedia.org/wiki/European_Train_Control_System)
– GSM-R – GSM standard modified for railway operations
• Specification– Modulation is GMSK . FDD duplex
– TDMA frames with a period of 4.615 ms. Each TDMA frame is divided in 8 time-slots (577 µs each), carrying 148 bits
– Frequency Band• In Europe — 876 MHz — 880 MHz: data transmission (uplink)
— 921 MHz — 925 MHz: data reception (downlink)
• In China: a 4 MHz of the E-GSM band (900 MHz-GSM)
• In Australia, it is being implemented using 1800MHz band
July 2011
Slide 15 Jia-Ru Li, Lilee Systems
doc.: IEEE 802.11-11/1032r0
Submission
July 2011
Slide 16
Radio Interoperability Requirement[6]
• Interoperability is achieved through an open, peer reviewed process
– IEEE selects best of breed technology with cost maturity in mind
– IEEE provides long term spec maintenance & administration
• Interoperable mechanisms1) By single vendor – Limited competition. High risk and high cost
2) By closed industry consortium – Not enough radio experts or researchers
3) By open Industry consortium (eg. ERTMS[4]) – allow peer reviews
4) By standards body(eg. IEEE) – allow diff industry to share spec (rail & sensor)
5) By national body(ANSI, ITU) – allow countries to adopt as national standard
• Ultimate Goal: Interchangeability – allows end users to select different vendors’ products based on the same industry standards.
• Interchangeability supports free market responseJia-Ru Li, Lilee Systems
doc.: IEEE 802.11-11/1032r0
Submission
Why IEEE and LMSC?
• Rail related standards AREMA/AAR/ITC[5] (similar to ETCS) Radio related standard IEEE (similar to GSM-R)
• Reuse mature technology from IEEE LMSC WGs– Association, Beacon, Information Element, interface MIB
– Authentication, security (802.1x, 802.11i), 4-way handshake
– PICS (Protocol Implementation Conformance Statement proforma)
• Small modification to low MAC and PHY– CSMA+TDMA hybrid
– BPSK/QPSK with GMSK for backward compatibility
– Full duplex or half duplex
– TDD (similar to WIFI)
– Meets different FCC subpart rules
July 2011
Slide 17 Jia-Ru Li, Lilee Systems
doc.: IEEE 802.11-11/1032r0
Submission
Relationship with existing TG/WG
• S1G: Study Group Sub 1 GHz Operation– Study to determine if PTC requirement is already included in S1G
– If not, add PTC requirement into PAR and 5C
• TGaf : TV White Spaces– meet the legal requirements for channel access and coexistence in
the TV White Space
• TGae: Prioritize 802.11 management frames – Defines mechanisms for sending the PTC management frame
using existing mechanisms for medium access
• Decide if new SG/Adhoc group should be established to facilitate the Congressional mandate (RSIA’08)
July 2011
Slide 18 Jia-Ru Li, Lilee Systems
doc.: IEEE 802.11-11/1032r0
Submission
Straw Poll #1
• Do you think 0WNG should invite various industry experts in railroad and others (eg. sensor) to provide more information about requirements?
• Agree:
• Disagree:
• Abstain:
July 2011
Slide 19 Jia-Ru Li, Lilee Systems
doc.: IEEE 802.11-11/1032r0
Submission
Straw Poll #2
• Assuming the results of Straw Poll #1 are affirmative, do you agree that the IEEE 802.11 WG should form a study group to pursue this task?
• Agree:
• Disagree:
• Abstain:
July 2011
Slide 20 Jia-Ru Li, Lilee Systems
doc.: IEEE 802.11-11/1032r0
Submission
July 2011
Slide 21
References
1. RSIA’08 - Summary of the Rail Safety Improvement Act of 2008 http://www.fra.dot.gov/downloads/RSIA%20Overview%20031009.pdf
2. PTC - Positive train controlhttp://en.wikipedia.org/wiki/Positive_train_control
3. ACSES - Advanced Civil Speed Enforcement System http://en.wikipedia.org/wiki/ACSES
4. ERTMS - European Rail Traffic Management system http://en.wikipedia.org/wiki/European_Rail_Traffic_Management_System
5. ITC Draft Standards http://aar-x.arinc.net
6. Interoperable Positive Train Control http://www.billpetit.com/Papers/2009%20AREMA%20Conf/Petit_2009_AREMA_ICBS_Paper_V2.pdf
7. Signal and Train Controlhttp://www.fra.dot.gov/downloads/research/PTC_Technical.pdf
Jia-Ru Li, Lilee Systems