A MOBILE ELECTRONIC TOLL COLLECTION
Chin E. Lin*, Chih-Ching Li, Shuei-Mu Lin
Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan, Taiwan 701
Ling-Yan Bi, Li-Xin Xu
School of e-Business, South China University of Technology, Guangzhou, China 510006
Keywords: Mobile e-commerce (Me-commerce), Mobile and Radio Communication, Electronic Toll Collection (ETC),
e-Transaction.
Abstract: When mobile communication has been vastly used, its particular characteristic is appreciated for the idea of
mobile e-commerce (Me-commerce) in any electronic toll collection (ETC) applications. This paper
establishes a new method of ETC using mobile cell phones integrating mobile communication with radio
frequency (RF) communication adopting microprocessor control. A simple ETC system architecture and
protocol for transactions among vehicles to toll stations to complete payment is presented. The proposed
ETC contains e-transaction mechanism in hardware and software. A software flow through Internet is
developed to link from toll station roadside units to car units. A car unit for vehicle, a pair of roadside
units, and an e-Center are established. Data flow and interaction protocol are created. The proposed ETC
system can be applied to toll different systems on freeways, bridges, parking lots for un-manned operation.
The proposed system is designed with hardware circuit using microprocessors to match with software
system. The preliminary test results on system performance verifies as a good solution for ETC
applications. Some feasibility analysis is made with test support. The function capability for
Me-commerce is also demonstrated.
1 INTRODUCTION
Mobile communication has become a livelihood
technology to be widely adopted. Back to 2002,
the mobile communication users have already
overwhelmed the vehicle users in most developing
and developed countries. While e-commerce is
introduced to elevate daily commercial interactions
from the conventional concept, mobile e-commerce
(Me-commerce) is another trend to be considered
and a more popular topic in wider discussion.
Me-commerce is defined as a commerce trade by
mobile stations (Mueller-Veerese, 2000) (Tarasewich
et al., 2000). Mobile stations include wireless phone,
wireless handheld computer, laptop, personal
message pager device and personal digital assistants
(PDA) (Christoffer, 2001) (B. V. Education, 2000).
Me-commerce presents the function of personal
mobility, operational flexibility, and interactive
capability. Due to the high population of mobile
communication users, Me-commerce is a rising
demands to the public in the next decade.
Focusing on the development of Intelligent
Transportation Systems (ITS), road information
acquisition and data processing to road users are the
most important role of study. In China, road
construction and personal vehicle are two vast
expansions in the world. Toll collection is mostly
adopted to share the investments. How to carry out
efficient toll collection is most concerned.
Technologies on all different demands are studied
and designed to fit the requirements. Among them,
unmanned toll collection is one of the urgent
problems to solve in many places. Methods for toll
collection have been developed since 1980’s
including microwave system, optical system and
recent RFID system. Some technologies are quite
mature in real world implementation.
Since mobile communication has been accepted
as a popular livelihood handy device around the
world and in China, its mobility characteristics are
merited for extensive personal use. Especially in
China, most personal vehicle users (or around 99.9%)
use mobile phones. The combination of mobile
communication with toll collection is a useful idea to
toll center, road users, and system providers to
become a new added value application.
For toll collection, the e-transaction needs to be
134
E. Lin C., Li C., Lin S., Bi L. and Xu L. (2006).
A MOBILE ELECTRONIC TOLL COLLECTION.
In Proceedings of the International Conference on e-Business, pages 134-142
DOI: 10.5220/0001424601340142
Copyright
c
 SciTePress

established in conjunction with finance corporations
or banks. A survey shows that different countries
providers different strategies in offering the
e-transactions under Me-commerce system. In
China, bank system accepts e-transaction through
mobile system providers. However in Taiwan, the
bad debts or irrecoverable credits from mobile bills
are huge burden to them. However, the finance
corporations or banks, who issue credit cards, would
appreciate the new Me-commerce based on the
contracts. Under such circumstances,
Me-commerce for ETC using the proposed
mechanism will become viable. An Internet
linkage e-interaction system should be created in the
proposed ETC system.
For most methods for e-commerce and
Me-commerce, there are demands of matching
hardware and software to meet the system
requirements for user identification, function
recognition, interaction authentication, data storage
and processing. A complete system design should
include software and hardware solutions to realize
the proposed system concept.
For personal mobility, any kind of wireless
communication can be considered. Radio
frequency communication has been used for several
decades. VHF data link (VDL) is developed as an
important media for long range data communication.
Its system infrastructure, operation and maintenance
are tedious and expensive engineering work but poor
coverage from ground users. Wireless
communication based on 802.11, blue tooth, RF and
others may be capable for excellent performance for
high data rate, but are limited in transmission range.
The wireless technologies are known as 100 meters
or less. The extension of communication coverage
requires a complete plan of networking, such as
mobile base stations. For consideration of limit
distance short message interaction, wireless
communication can be adopted. Another problem
might be considered on the population of users.
The frequency division multiple access (FDMA)
technology has its defect to occupy frequency
channel by each user. The time division multiple
access (TDMA) and code division multiple access
(CDMA) overcome these defects to use frames and
slots for each packet data. All users will not
occupy certain frequency channels, and will share
the quality of service in use. Mobile
communications, of the second generation (2G) of
Global System of Mobile communication (GSM),
the 2.5 G of General Packet Radio Service (GPRS),
the 3 G of wide band communication, and beyond
3G (B3G) of higher performance system, are
introduced (Jorg, 2001) (Joachim, 2001). Base
stations for wider coverage of excellent
infrastructure investment have been well furnished in
most developing and developed countries (Gunnar,
1998). The adoption of any mobile communication
service will be a correct choice in the future
development. Beyond wide range coverage, short
distance data exchange using wireless
communication can be considered as integration into
a new system design.
This paper proposes a feasible solution of ETC
using mobile communication infrastructure to
achieve toll collection as part of Me-commerce. The
proposed ETC protocol is organized by GSM, RF
module, microprocessor (AT89C52) and the related
hardware for circuit design and implementation.
The proposed ETC contains car unit (CU) and road
side units (RSU) to exchange the toll message
between vehicle and toll center. A toll protocol is
studied and established to fast complete a toll
transaction within driving through period. By
on-campus test, the proposed ETC is verified with
feasibility in GSM framework (Jorg, 2001) (Joachim,
2001) (Gunnar, 1998).
In this paper, system installation is designed
and fabricated out in the laboratory with complete
on-campus experiment. Technologies such as Car
Unit (CU) and Road Side Unit (RSU) using
microprocessor to exchange message between RF
transceivers are involved. The communication
means of RF and GSM in hierarchical structure is
organized to link a transaction and authentication
process with software implementation.
2 SYSTEM FRAMEWORK
In this paper, we propose a new ETC system design
using mobile communication for freeway and
parking lot application. The proposed ETC system
configuration is shown in Figures 1, 2 and 3 for
different applications as solutions for freeway
entrance gate control, toll station control and parking
lot control. In the proposed ETC system, there are
key components to develop, such as the Roadside
Transmitter (RS-TX), the Roadside Receiver
(RS-RX) and the Car Unit (CU). In the proposed
ETC system design, both systemic hardware as well
as Me-commerce software is discussed in details.
The CU includes a group of the identical electronic
transceivers as RS-TX and RS-RX, termed
functionally as CU-TX and CU-RX, respectively,
using a microprocessor for digital signal processing.
It is a device on the vehicle. The functions of
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Figure 1: Architecture of ETC System for freeway entrance gate control.
Figure 2: Architecture of ETC System for freeway toll station control.
CU-TX and CU-RX in the Car Unit will transmit
and receive message from the Roadside units. The
Roadside Transceiver (RS-TX) will transmit an
interrogation message to active the Car Unit to start
the GSM handset for ETC electronic transaction as a
part of Me-commerce. While the Toll Center
accepts the M-transaction, the GSM handset will
receive an approve code for the Car Unit. The Car
Unit will acknowledge to Roadside Unit at
appropriate instant of passing-by the Roadside
Receiver (RS-RX) to complete the
acknowledgement. The Roadside units are
connecting to the e-Center via wired or wireless
technology into Internet. GPRS onto Internet will
be a good means to adopt (Joachim, 2001).
In Figures 1 to 3, three different applications
will result in three different ways of Me-commerce
transaction. In this paper, GSM system handset is
generally considered as personal ID code to verify
the Me-commerce of ETC. We use Microsoft 2000,
VB 6.0 and Microsoft Access to simulate the
message exchange among CU, RS-TX and RS-RX
under different considerations.
In reality, we choose the hardware that is
suitable for conditions of this paper. The CU,
RS-RX and RS-TX architecture are shown in Fig. 4
in general configuration. Circuit parts may be
selected for either CU, RS-TX or RS-RX. We
choose AT89C52 to handle communication and
computation in the CU, RS-RX and RS-TX. The
HT-12E is encoding the signal data in CU-TX and
RS-TX for transmission. The HT-12D is decoding
the signal data in CU-RX and RS-RX. The HT-12E
and HT-12D have 8 address bits and 4 data bits to be
used. The RS-232 port is the communication
interface that is cell phone and AT89C52 (Carr,
1993). AT89C52 can command cell phone by
RS-232 port. In the hardware implementation, we
build the CU, RS-TX and RS-RX according to the
hardware designs as discussed previously (AT
Command Set of SIEMENS MC3.’5). ETC system
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hardware is installed and integrated for test as shown
below diagrams of Figures 5~7, correspondingly.
Evaluating from the circuit hardware, the
overall cost for road side units (RS-TX, RS-TX) and
card units (CU) are fairly cheap to implementation.
We will discuss the flow of experiment and test
and verify in the next section. The test circuit has
been completed and ready for tests. All circuits are
built in breadboards that make easy for changes and
modifications during tests.
Figure 3: Architecture of ETC System for parking lot.
Figure 4: Architecture of CU, RS-RX, RS-TX.
3 APPLICATION OF SYSTEM
From different ETC system configurations as shown
in Figures1~3, the ETC System for freeway entrance
gate control will be described in the following
section as shown in the Fig. 1.
3.1 Concept for Development
In Taiwan, the toll system will be converted from
toll station control into entrance gate control. In
China, gate entrance control is most adopted on most
freeways. In European countries, wither toll station
controls or gate entrance controls are applied.
Comparing the entrance gate control to toll station
control, the toll collection process might be
simplified the process and enhance efficiency. In
the proposed ETC, there is a Toll Collection
e-Center to be a server to accept toll payment
through Me-commerce system via mobile
communication in transmission control protocol in
addressed IP (TCP/IP) or point-to-point protocol
(PPP). The will process the authentication, charge,
and record in software and database.
Figure 5: Hardware circuit of CU.
Figure 6: Hardware circuit of RS-TX.
Figure 7: Hardware circuit of RS-RX.
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3.2 Definition of Basic Protocol
There are about sixty entrance gates of along the
freeways from north to south in Taiwan. Every
flow control gate includes two directions with
entrance and exit gates. We establish a set of
roadside unit at each direction of every entrance/exit
gate and assign code number for every entrance/exit
gate. The Roadside Transmitter, RS-TX0101 is
establishing in the entrance gate in the Fig. 1. The
0101 number code is an example of the entrance gate.
The meaning of the first bit is direction bound,
where 0 for the direction of northbound and 1 for the
direction of southbound. Gate numbering starts
from north to south. That means all southbound
vehicles will enter from smaller number of control
gates to larger number control gate to exit, and vice
versa. The second and third bits represent the
number of the flow control gate, where the tenth gate
from north is used as example. The least bit stands
for entrance or exit to this flow control gate, where 1
for entrance gate and 0 for exit gate.
In principle, since the northbound vehicles will
not leave the freeway at any southbound gates,
therefore, vehicles register from Gate 0101 should
possibly leave from Gate 0080, which means 0
northbound, at Gate 08, to 0 exit, by the four digit
assignment. Another example, the southbound
vehicle enters at Gate 1101 may possibly to exit at
Gate 1120. The toll charge will count the traveling
distance between the entrance and thee exit. The
former example northbound from 10 to 08, while the
other southbound from 10 to 12. Fare basis can be
determined from the Freeway Bureau in future
realization.
In the proposed ETC concept, there will be a
large number of installations for roadside units, and
the car units. Cost for each unit will be concerned,
as will the overall operation system.
3.3 Example of Freeway
Entrance/Exit Gate Control
The proposed ETC system is organizing procedures
in software to match with the hardware
implementation for tests. The procedures have
entrance to freeway and Exit from Freeway as shown
in Fig. 1. The roadside units are installed on the
entrance or exit ramps.
Figure 8: Procedures of entrance to freeway.
Figure 9: Procedures of exit from Freeway.
A. Entrance to Freeway
Fig.8 shows the procedure of vehicle from entrance
gate onto freeway with the following steps.
(1) Step 1: The RS-TX0101 is operating on an
interrogation mode to transmit a set code of
0101 and e-Center phone number at the
entrance gate to the vehicles enter freeway.
The RS-TX should be located near the
intersection of thee local way and the
entrance access road with an antenna to
focus on small areas. The “0101” is
designated as the address code of this
particular entrance gate. When the
vehicle enters the freeway entrance access,
the CU will receive the 0101 code and the
designated e-Center phone number from
CU-RX. The LED display on CU will
turn from orange to red. Note, each
entrance or exit gates will be assigned with
different phone numbers to link with the
e-Center. The gate code 1010 will direct
to its database assignment.
(2) Step 2: When the CU receives the 0101 code
and e-Center phone number (0910773868)
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from RS-TX0101, the CU will activate the
GSM cell phone to dial up to register a toll
collection.
(3) Step 3: The Toll Collection e-Center is
always on-line to receive a call. When
the mobile phone is connected, the
e-Center will immediately aware of the cell
phone number by on-call display
(0919101976), the CU will send the
RS-TX0101 code to the e-Center. The
e-Center will store the registration data into
database. Then the e-Center will bounce
back an approval code (APC) 0072 to the
CU. The entrance gate code 0101 and the
approved code 0072 are memory into
microprocessor AT89C52. This is the
simple procedure of entrance registration.
Approval code is a sequential number
generating from each gate control
processor for 4 digits. Approval code
may possibly overlap within one day,
however the marking time is different to
identify.
(4) Step 4: The CU will send out the approval
code on interrogation mode to RS-RX to
acknowledge. The front panel will have
red display turn to green for any visual
inspection. The vehicle entrance to
freeway is successful. The CU will write
the data into memory as shown in Table 1.
(5) Step 5: The vehicle will proceed on freeway
and the green LED will vanish to switch to
orange. The data of 20 bytes to record
date (ddmmyy), time (hhmmss), entrance
gate code 0101 and approval code 0027
will be stored in the memory. The
e-Center will write this data into 1010
database memory as shown in Table 2.
Each database is assigned with is gate code.
This reduces the database memory size and
makes easy to search while the vehicle is
existing from another gate.
B. Exit from Freeway
Fig.9 shows the procedures of vehicle to exit from
freeway with the following steps.
(1) Step one: When the vehicle approaches the
exit lane the freeway, the CU will receive
the interrogation 0030 code and a new
e-Center phone number from RS-TX0030
near the exit. The orange LED on CU
will turn to red.
(2) Step two: The CU activate the cell phone to
connect to the new e-Center phone number
(0910773877), and send code 0101 to
specify where the vehicle enters.
(3) Step three: The e-Center receives CU with
user’s phone (by on-call display) and the
entrance gate 0101. The software will
start trace onto 0101 database to find and
match the vehicle using cell phone number
0919101976. The e-Center approves the
toll collection from e-transaction and reply
with a new approval code (APC) 0988 to
the CU.
(4) Step four: The CU gets the new approval
code 0988 from its cell phone and memory
at the microprocessor AT89C52. The new
approval code 0988 will be interrogated
from CU-TX during exit to the roadside
unit RS-RX0300.
(5) Step five: The RS-RX 0030 receives the
interrogation 0988 and acknowledges to
CU to turn on its LED from red to green.
The vehicle will proceed to leave onto
local highway, the data of 20 bytes to
record date (ddmmyy), time (hhmmss), exit
gate code 0030 and approval code 0988
will be stored in the memory. The CU
memory is a read only memory (EEROM)
by a auto-write process and a manual-clear
process. A USB interface is used in the
CU to exchange memory data from
external devices, such as PDA or USB
memory, to send out the record. The CU
memory of 512 kB will maintain at least
6400 travel data. Table 1 shows the
memory at car unit to memorize all travel
data at 512 kB memory size.
(6) Step six: When the vehicle finishes the
e-transaction, the e-Center will shift the
memory data to the ETC Billing System to
create a charge list to the bank. The ETC
billing software will calculate the toll
charge according to the traveling distance
and fare. The fare is dependent if
discount may apply.
Table 1: Memory at CU microprocessor for this test.
Memory at Vehicle 0919010976
Gate Code Date Time
0101 0072 020604 134648
0030 0988 020604 151341
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Figure 10: Display of 0919101976 at entrance gate 0101
processor.
3.4 e-Center Authentication
We establish a virtual e-Center to handle each
entrance gate and exit gate. A Tabletop PC is used
to simulate the e-Center. On the campus, we built a
simulation drive way to set up Entrance gate 0101
and exit gate 0030 using roadside units RS-TX and
RS-RX and Fig. 6 and Fig. 7. Two car units CU
are built for two vehicles of 0919010976 and
0958890720. The Fig. 10 shows the display of two
vehicles at the entrance gate 0101 and exit gate 0030
in e-Centers. In our simulation, the e-Center is
connection to each gate unit by two GPRS phones
(0910773868, 0910773877) through Internet as an
wireless interconnection. We connect the e–Center
to collect the CU phone number calling from the
vehicle. The e-Center sends the AT+CLIP=1 of
AT command for cell phone to enable the function to
read the on-call display to identify the sender phone
number 0919101976 and 0958890720. The CU
phone number will be transmitted into the database
built by VB 6.0 programs as Fig. 10. The CU cell
phone may hang up at receiving the approval code
0072.
The ETC system will collect data from
entrance 0101 and exit 0030 at e-Center to each
relative database. Table 2 shows the designated
database for Gate 0101 and Gate 0030 at e-Centers.
Each phone number stands for a vehicle with a set of
record to travel on the freeway. The ETC billing
system can pick the first one on Gate 0101 and the
first one on Gate 0030 to calculate the travel distance
and charge. By the same way for vehicle user
0958890720, the charge can be calculated. The
mechanism to adopt gate code as the database can
reduce the overall size of the memory that search for
a vehicle data appears will prompt. While the
vehicle exits the freeway, the data on Table 2 will be
moved to the Billing database at the e-Center. The
memory data on each gate database are only very
small part of vehicles running on the freeway.
Table 2: Database at e-Center for Gate 0101 and Gate
0030.
Database for Gate 0101
APC
code
User Date
(ddmmyy)
Time
(hhmmss)
0072 0919010976 020604 134648
0073 0932977345 020604 135052
0074 0929771991 020604 135321
0075 0958890720 020604 135701
Database for Gate 0030
APC User Date
(ddmmyy)
Time
(hhmmss)
0988 0919010976 020604 151341
0989 0933751685 020604 151522
0990 0915872561 020604 152233
0991 0958890720 020604 153400
The CU is offered by the credit card banks or
the system providers when the cell phone users apply
for ETC application. There is one possibility that
the vehicle driver uses different cell phone that is not
the one originally registered. An alternative may
be created from the EEROM to input the claimed
cell phones to be used. When the CU is connecting
to a cell phone, the EEROM will check the cell
phone. This is a necessary if payment
authentication. In this proposal, the ETC charge
will be placed onto the mobile phone bills.
4 TEST AND VERIFICATION
The proposed mobile ETC system has been
implemented in hardware and software for tests on
campus. There are some significant data being
collected from the tests.
(1) The RF transmission range for RS-TX,
RS-RX, CU is tested up to 50 meters for a
speed of 40 km/hour, which is the post
speed limit on the freeway ramps.
(2) The GSM connection time from receiving
the RS-TX interrogation is 5 to 12 seconds,
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with the most population falls at 7 seconds.
The normal travel distance for a vehicle at
the ramp is from 55 to 133 meters, or most
population at 77 meters. Typical ramp
distance is much longer than 300 meters.
(3) The CU processes the reply interrogation to
RS-RX takes 10 milli seconds, and then
writes the approval code and time into
EEROM.
(4) In our tests, the roadside units are
connecting with GPRS modules to link
with e-Center through Internet, that no
additional engineering work for wiring is
necessary.
(5) At the exit, when the vehicle connects to
Gate 0030 database, the search time from
0101 database takes only a few mili
seconds on 200 simulation data. The
traveling distance at the exit ramp is much
longer than the entrance. However, the
GSM connection time is still enough for
this process.
(6) The GSM charge for two connections is
calculated less than 6 seconds, which
means NT$ 1 for this travel using mobile
ETC. There can be discount plan to offer
attractive fare to the users, or the system
providers to absorb assign all gate control
phones in free charge. In Taiwan, 5%
discount is applied for mass users, or
typically from NT$ 2 for very short travel
to NT$ 20 for a long travel.
5 CONCLUSION
The proposed mobile electronic toll collection
system is verified from hardware fabrication and
implementation with a simulation test on campus.
The test data show that the proposed technique is
useful to create a new concept of mobile
e-commerce to enhance the mobile phone users.
From point of view of the freeway operators, the
banks or the system providers, the proposed mobile
ETC will reduce some labor work to shift to discount
plans. Considering the created technology in this
paper, the roadside units are much less than any
investments on ETC projects. The necessary car
unit (CU) is estimated for about NT$ 400 (or RMB$
100, US$ 15) that the ETC system can absorb this
cost for promotion. In the EEROM, the EEROM
memory of the registered user cell phone is a kind of
authentication. There is no necessary process to
identify the users at the e-Center.
Me-commerce is a rising technology that most
applications may be directed into possible
connection with mobile phones. As for today,
GSM, GPRS, 3G or even B3G technologies are still
expanding. However, GSM for voice is still the
most profitable system at all. There are some
defeats in GSM services such as minor chance of
congestion, some unavailable area, and significant
longer delay at SMS (short message service).
Taking the known defeats into account, the mobile
ETC is still most convenient system to develop.
Another problem will be the connection wire from
CU, RS-232, USB, or mini USB, to the cell phones.
Different specifications may vary to cause a little
difficulty. Standard port of mini USB in the cell
phones may be required in the future. In our tests,
the proposed mobile ETC system has acceptable
time delays with feasible database design. The
overall test efficiency is excellent. The system
stability is good that the RF frequency matches
easily. The reliability of mobile base station
transceiver (BTS) is good enough to offer ETC
service.
The same concept may be applied directly into
unmanned park lot system. This is a most sensitive
problem for the next 5 to 10 years in China, due to
her vast increase of personal vehicles. The low
investment with high reliability and stability
performance may lead its valuable application in
China.
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