Japan Railway & Transport Review No. 50 (p6-p15)
Feature: IC CARDS Development of Suica Autonomous Decentralized IC Card Ticket System Akio Shiibashi |
Introduction |
Japan faces major changes to its social environment, such
as a declining birth rate and aging population as well as
globalization. Where once it was sufficient to provide safe
and punctual transport, the railway business now faces
changes with demands for diverse and high-quality services
in areas such as safety, amenity, and convenience. One
important system supporting railway management is the
automatic fare collection (AFC) system. The Suica IC card
ticket AFC system introduced by East Japan Railway
Company (JR East) in November 2001 uses the Autonomous
Decentralized Architecture to prevent possible problems
spreading through the entire system. This resulted in the
ability to provide continuous high-quality services thanks to
the system’s expandability and reliability. Many new services
have been provided since the system’s introduction with
few major failures. This article explains the JR East Suica
development background and details, technologies, and
operation status since introduction.
Furthermore, it covers the management of technology
(MOT) strategy for Suica, which has become deeply
embedded in Japan’s social infrastructure.
IC card interoperability with Suica started in the greater
Tokyo area on 18 March 2007 with the PASMO IC card ticket
issued jointly by 100 railway, bus, and other companies.
Interoperability has made travelling around the Tokyo area
dramatically more convenient as exemplified by the issue
of 1 million PASMO cards in just 4 days. However, more
than just transportation was stimulated by Suica PASMO
interoperability and use of cards as e-money has surged.
Due to the characteristics of modern railway transport,
any system of fare collection at ticket gates requires continuity
of service throughout the operations area based on highspeed
processing and high reliability. As a result, the Suica
system uses an Autonomous Decentralized Architecture, but
the technical development required a tremendous amount of
labour and time.
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Characteristics of Railway Ticket Systems |
Railway services must continue every day without a break,
so stable system operation is a key requirement. In these
conditions, reliable high-speed processing is the first
indispensable function. A feature of Japanese urban railways
is the tremendous surge of commuters in the morning and
evening rush. At these times, about 24 million transactions
occur at ticket gates every day, so the gate processing speed
must be able to handle these passenger flows. The second
indispensable function is high reliability, because a ticket has
monetary value.
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Suica Development Concept |
Instantly replacing all magnetic tickets with IC cards as part
of efforts to introduce contactless railway tickets would have
been impossible. Therefore, it was important to define the
most appropriate specifications, assuming current magnetic
tickets would continue in use for some time.
The development concept took into account the following
points as conditions for introducing a contactless IC card
ticket system.
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Processing with IC Card Ticket System |
Card processing differs between magnetic and contactless IC card ticket gates in several ways. Processing at magnetic ticket gates is completed in about 0.7 s in four steps: reading data, evaluating ticket validity, writing required data, and confirming data. In contrast, processing at contactless IC card gates, involves confirming the card presence in the signal field and authenticating the card for processing. Then reading, evaluating, writing, and reconfirming data are performed. Field-testing showed that the fastest users put their cards in the reader/writer (R/W) signal field only for about 0.2 s. Considering the gate processing time of about 0.1 s, the processing time between the card and R/W must be less than 0.1 s so the passenger does not have to pause while passing through the gate (Figure 1). As a result, development focused on achieving high-speed processing between the IC card and ticket gate R/W. |
Figure 1: Comparison of Automatic Fare Collection Gate (Magnetic and IC Card) Processing Times |
Details |
JR East started examining use of contactless IC cards as a next-generation system to replace magnetic ticket systems in 1987, immediately after the company was established. IC cards can be contact or contactless, but because processing would have to be done at a ticket gate while the passenger was moving through, the contactless type was thought to be best. At the time, there were three makers of contactless IC cards; two used medium-frequency radio waves and one used quasi-microwaves; all required built-in batteries. Repeated improvements to the cards and testing of standalone functions, made it hard to determine the merits of one card over the others but the two medium-frequency cards required addition of an emitter circuit to generate the data transfer signal. While this function could be added to gates reading/writing quasi-microwave cards, the focus shifted to battery-equipped IC cards using quasi-microwaves, which also seemed more practical in terms of processing speed, price, and other factors. By 1993, development had reached the field test stage in actual stations and tests in 1994, 1995, and 1997 verified aspects such as reliability, gate processing capacity, and ease of use (Figure 2). The field tests were conducted at stations by JR East employees. Communications speeds and card application were varied during the course of 30,000 to 170,000 tests in each set. The third test set achieved the same performance as the existing magnetic system. An important change was made after the third-stage testing. Due to the thickness and longevity issue of the batteries, Suica became battery-free; its power is now provided via electromagnetic induction. |
Figure 2: IC Card Ticket System R & D Figure 3: Touch-and-Go Style |
Stabilizing Processing between IC Card and Terminal |
The human eye cannot see the signal field between a gate and IC card, so each person ‘waves’ the IC card over the R/W in a slightly different way. Field tests showed that the average card residence time in the signal field was 0.52 s, while the shortest time was 0.2 s. At this point, the system could not be speeded up any further to achieve shorter processing times. As a result, a ‘touch-and-go’ style (Figure 3) was formulated to secure sufficient processing time by making the user move the card in a V-shaped arc and lightly touch the reader, reducing the read/write failure rate to the same level as the magnetic system (Table 1). |
Table 1: Results of Suica Field Tests |
Overview of Autonomous Decentralized IC Card Ticket System |
The IC card ticket processing relies on people moving the card over the R/W by hand, a process that is inherently variable and unstable. Furthermore, gate failure would instantly create chaos in a station. To overcome these risks and continue operating with failed equipment, the system was designed with an Autonomous Decentralized Architecture, featuring autonomous control and autonomous coordination. Ticket gates autonomously process IC cards at high speed and store data for fixed time periods without accessing the centre server. Likewise, the centre server stores data from terminals for fixed periods and performs data matching using Autonomous Data Consistency Technology to secure high reliability. As a result, even if some equipment fails, the overall system remains unaffected. Moreover, the centre acquires information on terminal operation and takes autonomous measures such as restarting and stopping to improve reliability. |
Merging Heterogeneous Aspects |
The railway business must assure the flow of large numbers of passengers and continuity of services from the first to last train everyday, non-stop, year-round. A large part of these operations is calculating fares and checking for ticket fraud. The following explains the specifics of the system configuration satisfying the above conditions. The system is composed of IC cards, terminals (automatic gates, etc.), station servers, and a centre server. Assuring the minimum operation even when equipment fails is essential to prevent chaos so the Autonomous Decentralized Architecture was adopted. Data are collected and processed by wireless communications between passengers’ IC cards and terminals (ticket gates). Smooth passenger flows are achieved by asynchronous online real-time processing in 0.2 s. At the same time, gates, ticket vending machines, and station servers are connected by local area network (LAN), and the station servers and centre server are connected by a wide area network (WAN). Collected data is processed across these networks. To assure high reliability for fare data, the information system uses database processing. A key feature is how to merge the different control/information systems, wired/wireless technologies, and LAN/WAN protocols to harmonize the conflicting needs for high-speed processing and high reliability. The system processes data by the second, hour, and day. It is described as a Heterogeneous Autonomous Decentralized IC card ticket system. |
Figure 4: Composition of Autonomous and Decentralized Data Processing Suica System |
Specific Suica Composition |
Figure 4 shows the specific composition of the JR East Suica
system. Suica cards are purchased at card vending machines
where stored fares can also be added. Automatic ticket gates
support both Suica cards and older magnetic tickets but JR
East has introduced simplified Suica gates supporting only
Suica (and PASMO) at some stations where the automatic
ticket gates were not installed.
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Figure 5: Suica and MOT Introduction Figure 6: Future Suica Development Strategy |
Suica Transformation into Social Infrastructure |
In the 7 years since Suica was introduced, there have been
few major problems.
Interoperability with PASMO IC cards of other transport companies as well as the start of Mobile Suica services incorporating Suica functions into mobile phones has expanded the system beyond JR East into a large-scale social infrastructure. Mobile Suica was introduced in January 2006, and currently has more than 1.2 million users. As a result, Suica has become indispensable to passengers in greater Tokyo. If railways are a primary social infrastructure, it is no exaggeration to say that Suica has become a secondary infrastructure and lifestyle foundation. As a result, stable operation of this giant is the most important future issue for JR East. However, the system size and its spread into all aspects of Tokyo’s society means that industry, government and other groups will be forced to cooperate in building sustainable frameworks. |
Figure 7: Transformation of Suica into Social Infrastructure Photo: Co-branded credit card with home appliance retailer |
Akio Shiibashi After graduating from the Department of Mechanical Engineering at Saitama University in 1976, Dr Shiibashi joined Japanese National Railways and became a JR East employee in 1987. He started R&D into IC card ticket systems in 1994, taking charge of the Suica System Promotion Project from 1998. He gained his doctorate in engineering from Tokyo Institute of Technology in 2006 and is a member of The Japan Society of Mechanical Engineers and the Institute of Electronics, Information and Communications Engineers. |