smart parking management system based on rfid

Smart Parking Management System Based on

RFID

Weiwei Wang Beijing University of Posts and Telecommunications, Beijing, China

Email: [email protected]

Pengfei Ma Duke University, Durham, NC, America

Email: [email protected]

Abstract—This paper presents the design of a smart

parking managemnet system which consists of non-stop

automatic gate guard payment system and parking spot

detection system. We first briefly introduce RFID technique

and discuss its operating principles. Then we propose a

design for controlling and managing parking system using

RFID technique which is able to automatically calculate the

parking fee of vehicles and show the number of unoccupied

parking space in the screen at the entrance. Finally, we

simulated the anti-interference ability of Manchester coding

and decoding in this RFID system, the radio-frequency

interference circuit of RF tag and the transmission and

receiving module of the RF reader using the simulation

software Simulink.

Index Terms—RFID, parking management system, simulink

I INTRODUCTION

With the rapid development of society, the number of

various vehicles significantly increases. In some cities,

the existing parking management system cannot

efficiently operate thus raises congestion problem.

Moreover, drivers cannot be notified about the number of

parking spaces in the sparking lot before their entrance,

which exacerbate the congestion problem. To circumvent

this problem, we propose a smart parking management

system, which is composed of two aspects: automatic

collection of parking fee and detection of the number of

available parking spaces [1]. To enable the system to

efficiently operate, we employs radio frequency

identification technique (RFID).

As a wireless data transmission technique, RFID is

used in smart parking management system with multiple

advantages[2]: (1) at least 9 meters identification distance

and capability to identify static and high-speed mobile

objects at a speed of 100 km/h; (2) the capability to

identify multiple radio-frequency cards with different

serial numbers; (3) no electromagnetic pollution; (4) high

security and privacy; (5) easy to install and maintain.

The remainder of this paper is organized as follows.

First, in section 2, we describe RFID technique and its

Manuscript received February 25, 2013; revised July 18, 2013

principles. Next, in section 3, we present the structure of

smart parking management system and the results of

simulation in section 5, and conclude in section 6.

II RFID

Radio-frequency identification achieves non-contact

and bidirectional communications between the reader and

a radio-frequency card through using radio-frequency

electromagnetic fields. A RFID system consists of four

components: electronic tag, reader, computer

communication network and antenna.

As we can see from Fig. 1, to achieve automatic

identification and tracking, a tag is attached to the object.

When the object with the tag goes into the signal range

that the antenna covers, a wireless communication link is

built between the reader and the object. Then the tag

transmits the serial number and data stored in it to the

reader. Before the data is transmitted to the reader, it will

be encoded by the antenna. Upon receiving the signal, the

reader will demodulate it and then transmit the results to

background computer system, which handles the analysis

of data [3].

Figure 1. RFID structure and operating principle

III SYSTEM STRUCTURE

In this section, we describe how our smart parking

management system operates. The whole system consists

of non-stop automatic gate guard payment system and

parking spot detection system. When the vehicle enters

the parking lot, the payment system uses RFID reader to

collect the information via the RFID tag on the vehicle,

117©2013 Engineering and Technology Publishingdoi: 10.12720/ijoee.1.3.117-122

International Journal of Electrical Energy, Vol. 1, No. 3, September 2013

mailto:[email protected]

mailto:[email protected]

then send the information to control computer, storing

vehicle information, entrance time and picture into the

database. At the time the vehicle exits, relative

information is obtained via RFID tag and the parking

time is calculated and stores the picture again. Parking

spot detection system: each parking spot requires a RFID

tag and an ultrasonic probe, which serves to detect the

availability of the parking spot and the tag is responsible

for sending the status of parking spot and its sequence

number to control computer through RF network. The

backend control computer communicate with RF tag by

RF reader and update the database when tag information

is received.

Fig. 2 shows the structure of the hardware of parking

management system, two entrance channels are designed

and one for long term card holders who have RF tags

attached on their vehicles and another for temporary card

holders. The entrance and exit controller connect the

control computer and are responsible for managing the

camera, RFID reader and barrier. The RFID reader is

used to obtain both the vehicle information from the tag

on the vehicle and the parking spot status information.

Two cameras are installed at the entrance and exit, taking

pictures of the vehicles. Moreover, the control computer

sends the parking situation to the screens which are

installed both inside and outside the parking lot.

Control Computer

Hub

Exit

Controller

Entrance

Controller

BarrierRFID

ReaderCamera Screen

Parking Spot

RFID tag 1

Parking Spot

RFID tag 2

Parking Spot

RFID tag n

Database

Figure 2. Structure of the parking management system

A. Entrance Design

Before the vehicle enters the parking lot, the drivers

are able to know the number of available parking spaces

in the parking lot through looking at the screen outside

the parking lot. For long term card holders, when the

vehicle enters the signal range, the reader automatically

reads the RF tag and checks the validation of the tag

through communications with the computer database.

Simultaneously, the camera will take photos of the

vehicle for records. If the tag is identified as valid, the

barrier will raise, allowing the vehicle to enter the

parking area. Otherwise, the driver will be notified the

card is invalid and the barrier keeps closing, suggesting

using the temporary entrance channel. In the first case,

the computer keeps records of entrance time, picture of

vehicle, tag serial number and vehicle plate number. For

temporary card holders, the driver obtains the temporary

parking card at the temporary entrance channel and the

barrier will raise, simultaneously, the entrance time,

picture of vehicle and plate number will be recorded.

Inside the parking lot, a LED screen is installed showing

the position of the available parking spaces.

B. Exit Design

Similarly, the validation of the tag on long term card

holders will be checked by the RF reader. If valid, the

barrier will raise and the vehicle leaves the parking area

without having to stop, and simultaneously parking fee

will be charged from the holder’s account; otherwise,

when the temporary card holder exits, the driver needs to

stop and return the temporary card and pay the parking

fee. In both cases, the exit time, picture of vehicle and

card number will be recorded into the computer and the

barrier returns to its original position. Fig. 3 shows the

flow chart of the entrance and exit design as follows.

Entrance

Reader

Logical

Judgement

Long term card/

Get temporary card

Take images

Save information

Open barrier

Vehicle passes

close barrier

valid

invalid

Reader

Long

Term

Take images &

Save information

Open barrier

Vehicle passes

close barrier

pay automaticly

Yes

Give back Card

And pay

No

Exit

Screen

（empty spot）

Screen

（parking situation）

Figure 3. Flow chart of entrance and exit design

C. Detection System Design

After initiation of detection system, the parking spot

availability flag is set to be zero. Then ultrasonic

transmitting and receiving circuit is used to detect

whether the parking spot is occupied, if so set the flag “1”

otherwise the flag remains “0”. Afterwards, the sequence

number of the tag, the availability flag and relative

information are encapsulated into a datagram, which will

be sent to the reader via the tag. Upon receiving the

datagram, the reader transmits the information to the

control computer which updates the database. Fig. 4

shows the flow chart of vehicle detector system.

118©2013 Engineering and Technology Publishing


System

Initialization

availability flag→0

Ultrasonic Vehicle

Detector

Empty？

availability flag→1

Send Status

Information

Reader

Control Computer

Database Update

N

Y

Ultrasonic Vehicle

Detector

Empty？ N

Yavailability flag→0

Figure 4. Flow chart of vehicle detector system

D. Software Structure

Smart Parking Management System

Non-stop Automatic Gate Guard Payment System

Parking Spot Detection System

Parking Information

Management Module

Service Interface Layer

Service Proxy

Database Implementation

Basic Information Management

Spot Status Management

Operation Log Management

Vehicle Information CollectionRFID Module

RFID Protocol Layer

Spot DetectionRFID Module

RFID Protocol Layer

LED DisplayModule

Function Library

RFIDMiddleware

RFIDMiddleware

LED Operation

Implementation

Screen Refresh

Screen Clear

RFID Reader Bottom-Driven

RFID Reader Bottom-Driven

LED Screen Bottom-Driven

Figure 5. System software function structure

The software structure consists of application layer,

service interface layer and bottom-driven layer and each

layer is composed of multiple software modules. As we

can see in Fig. 5, application layer is responsible for

communication with users, consisting of non-stop

automatic gate guard payment system and parking spot

detection system. These two systems use a parking

information management module to control the database

of the interface layer. Non-stop automatic gate guard

payment system obtains and stores the information of the

vehicle, including plate number, entrance time and

picture in the database through vehicle information

module. When the vehicle exits the parking lot,

corresponding information is obtained from the database

to calculate the parking time and parking fee,

simultaneously, relative information is stored in the

databse for later use when necessary. Parking spot

detection system is responsible for detecting the

occupation information of the parking lot and it uses

parking spot detection RFID module to collection the

status of all the parking spaces. The status information

will be sent to the parking information management

module which sends the number of available parking

spaces and the position of the available parking spot to

LED display module.

IV SIMULATION

As the main components of our smart parking

management system are RF tag and RF reader, we

implement and simulate the following four parts: (1)

design and simulation of the radio-frequency interface

circuit of the RF tag; (2) design of the transmission

circuit of the RF reader with working frequency 915MHz

under ISO 18000-6 Type B protocol; (3) design and

simulation of the receiving circuit of RF reader; (4)

simulation of the anti-interference ability of Manchester

coding and decoding that the system employs.

A. RF Interface Circuit Simulation of RF Interface

Circuit

The ISO 18000-6 Type B[4] protocol regulates that the

system adopts ASK modulation, the modulation depth is

11% or 99% and bit rate is 10 kb/s or 40 kb/s. The

radio-frequency interface circuit consists of four circuits:

sine-wave carrier modulation circuit, DC power supply

generation circuit, envelope generation and detection

circuit and reset signal generation circuit.

To obtain sine-wave modulation circuit, we use a sine

wave as the carrier wave and multiply it by digital signal

and then adapt the gain of the digital signal via adding a

constant if necessary. DC power supply generation circuit

is achieved by obtaining the absolute value of the signal

and then putting the signal into a low pass filter.

Envelope generation circuit consists of a nonlinear device

that is realized by absolute value and a low pass filter that

is simulated by a transfer function [5]. Detection circuit

consists of a narrow-band filter and a voltage decision

unit, narrow-band filter is simulated by a transfer function

and voltage decision unit is simulated by a comparator.

Envelope generation circuit and detection circuit together

form the envelope modulation circuit thus can recover the

digital signal. Reset signal is obtained by using a voltage

comparator and when the supply voltage rises up to a

value that is able to support the operation of RF tag, the

reset signal keeps this value to ensure steady operation of

the circuit. We have implemented simulation of the four

parts above and obtained ideal results. Here we present

the result of the integrated circuit consisting of the four

parts we have described as in Fig. 6.



Figure 6. RF interface circuit

B. Simulation of RFID Reader Transmission and

Receiving Circuit

Figure 7. Type B protocol transmission module

We have simulated the time-domain characteristics of

the 915MHz RFID reader. ISO 18000-6 Type B reader

transmission interface consists of Manchester encoding,

ASK modulation (modulation depth 11% or 99%), and

power amplification [6]. In the simulation, we use

demodulation in order to precisely the change of the data

flow. We conduct tests for both 11% and 99%

modulation depth and here we present the test results for

modulation depth 99%. As we can see in Fig. 7, pulse

generator is used to generate raw data or command and a

XNOR operation is conducted between the raw data and

second frequency multiplication signal to realize

Manchester encoding. Then the baseband signal is

modulated by the ASK modulation and power is

amplified to achieve the transmission signal. When

demodulation, transmission signal and carrier signal is

processed by a down converter and low pass filter thus

achieving the demodulation signal. Finally, the encoding

signal is obtained by shaping the signal, putting the

demodulation signal into a voltage comparator.

Figure 8. Simulation waveform of the transmission module under Simulink (99%)

The simulation result of the waveform is shown in Fig.

8; we can see that transmission signal is obtained by

Manchester encoding, modulation and power

amplification. The signal can be recovered by passing a

low pass filter, demodulation and shaping [7]. Thus, the

design of transmission signal module can produce

desirable result.

As in Fig. 9, to simulate the receiving circuit, we use

Butterworth fourth-order low pass filter, the transfer

function of which is

)/()(

)( 0csS

SB

ASA

(1)

where )(SB is Butterworth polynomial.



432 613.2414.3613.21)( SSSSSB (2)

In simulation, we set Hzc 100 .

Figure 9. Receiving module

From the simulation waveform in Fig. 10, we can see

that the signal is encoded by FM0 and modulated, then is

transmitted to the received. At the receiver, we can obtain

FM0 baseband signal by low pass filter demodulation.

The source signal is finally obtained by FM0 encoding

and demodulation.

C. Simulation of Anti-inference Ability of Manchester

Coding

RFID adopts Manchester coding to encode

transmission data. According to Manchester coding, if the

original signal is 1, Manchester code is 10 and if the

original signal is 0, Manchester code is 01. Thus, we can

implement Manchester coding by a XNOR operation

between the original data and a rectangle wave with the

frequency equal to double the original frequency.

Reversely, Manchester decoding is implemented by a

XNOR operation between the data and a rectangle wave

with the frequency equal to half of the original wave

frequency. The Manchester coding and decoding circuit

is then obtained by connecting the coding module to the

decoding module.

Figure 10. Receiving circuit simulation waveform

Figure 11. Simulation model of anti-interference ability of Manchester Coding

TABLE I. SIMULATION RESULTS OF MANCHESTER ERROR DETECTION RATE

Coding Simulation times

Total errors

e

Detected errors

1e

Error Detection Rate

Omission Rate

1

Manchester coding 10000 848 796 93.9% 6.13%

We have conducted simulation of the anti-interference

ability of Manchester encoding in our system

environment. We use a signal source to generate a

random cluster of binary array, which represents the



command of the RF reader or the data transmitted by the

RF tag to the reader. Then Manchester coding technique

is used to encode the binary array and the result is

transmitted through binary symmetric channel. Before

decoding, the data is checked whether error exists in the

sequence. Then the anti-interference ability can be

examined by comparing the decoded wave to the original

wave. Fig. 11 shows the simulation model of

anti-interference ability of Manchester coding technique.

Since the size of the frame data is approximately several

to tens of bytes, we determine the length of each frame to

be 100 bytes in simulation. Moreover, we make the error

probability of the binary symmetric channel change

between 1% and 50% and repeat the simulation 1000

times. Then we compare the signal at the receiver end to

the original signal and record the number of detected

errors. According to the formula below, the error

detection rate can be computed by Eq. (3).

%1001 e

e (3)

where denotes the error detection rate, 1e and e

denote the number of detected errors and the number of

made-up errors respectively.

As we can see in Table I, the error detection rate is

93.9%, which indicates the ability to detect error is good.

Moreover, Manchester coding can satisfy RFID data

transmission for the following reasons. First, when the

vehicle enters the radio-frequency range, the RF reader

can read the signal continuously such that a small

amount of errors can be tolerated. Second, the absence of

clock circuit in RF tag requires RF tag to fetch clock

information from the signal transmitted from the reader.

The fetch of the clock information can be easily achieved

since each code element in Manchester coding has jumps

internally. Finally, most RFID tag has no power supply

itself, which requires the RF tag to extract energy from

the electromagnetic wave that RF reader emits. This

mechanism requires the code pattern to vary, which

Manchester coding can satisfy. Therefore, Manchester

coding scheme can be employed as the data transmission

encoding technique in RFID.

V CONCLUSION

This paper focuses on improving the inefficient

problem of current parking management system,

proposing a design of a smart parking management

system that can solve the congestion and unreasonable

parking charges problem，and also shows the number of

available parking spaces and the position of them for the

drivers. Moreover, this paper presents the simulation

results of several important components of the system.

The simulation result is also shown to have reference

value to some application systems based on RFID, which

enables this smart system to have broader use in practice.

REFERENCES

[1] H. T. Du, “The Parking management system based on RFID,” Computer Knowledge and Technology: Academic Exchange 6, pp.

1265-1266, 2008.

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no. 5, pp. 153-155, 2008. [3] Z. Q. You, K. S. Liu, et al. Radio Frequency Identification (RFID)

and Bar Code Technology, China Machine Press, 2007.

[4] Joint Technical Committee, ISO 18000-6 standard, May 2002. [5] Y. Sun and L. Wu, Simulink Communication Simulation

Development Handbook, 1 st ed, Beijing: National Defence

Industry Press, 2004. [6] J. Wei and S. C. H. Leung, “A simulation modeling and analysis

for RFID-enabled mixed-product loading strategy for outbound

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Weiwei Wang was born in Panjin city of Liaoning Province, China on the day of Jan 20th, 1989. In June

2011, Weiwei earned bachelor degree in Sichuan

University, Chengdu, China, majoring in communication engineering. She will earn her Master

of Science Degree in Beijing University of Posts and

Telecommunications in March 2014, majoring in communication and information system. Currently, she is a graduate student in Beijing

University of Posts and Telecommunications and an intern in China Telecom Group in Beijing. As the third author, she has another

published paper: Stadium Traversal Algorithm on Simulation Robot

Platform, which is included in IEEE index.

Pengfei Ma was born in Langfang city of Heibei

Province, China on the day of Dec 1st, 1988. In June

2011, Pengfei earned bachelor degree in Sichuan University, Chengdu, China, majoring in automation.

He earned Master of Science Degree in Duke

University, Durham, North Carolina, USA, majoring

in electrical and computer engineering. Currently, he is working as a

product manager in Lenovo Group in Beijing, China. As the first author,

he has another published paper: Stadium Traversal Algorithm on Simulation Robot Platform, which is included in IEEE index.

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