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PERFORMANCE ANALYSIS OF RADIO OVER FIBER BASED
ON IEEE 802.11a
SITI IDANI AZURIATI BINTI ABDUL AZIZ
UNIVERSITI TEKNOLOGI MALAYSIA
PERFORMANCE ANALYSIS OF RADIO OVER FIBER BASED
ON IEEE 802.11a
SITI IDANI AZURIATI BINTI ABDUL AZIZ
A project report submitted in partial fulfilment of the
requirements for the award of the degree of
Master of Engineering (Electrical – Electronics & Telecommunications)
Faculty of Electrical Engineering
Universiti Teknologi Malaysia
APRIL 2011
iii
To my beloved husband
iv
ACKNOWLEDGEMENT
In preparing this thesis, I was in contact with many people, researchers,
academicians, and practitioners. They have contributed towards my understanding
and thoughts. In particular, I wish to express my sincere appreciation to my main
thesis supervisor, Assoc Professor Dr. Razali Ngah, for encouragement, guidance,
critics and friendship. I am also very thankful to a Phd student, Teguh Prakoso for his
guidance, advices and motivation. Without their continued support and interest, this
thesis would not have been the same as presented here.
I am also indebted to my husband, Mohd Saiful Mahdzir for funding my
Master study. My sincere appreciation also extends to all my colleagues and others
who have provided assistance at various occasions. Their views and tips are useful
indeed. Unfortunately, it is not possible to list all of them in this limited space. I am
grateful to all my family members.
v
ABSTRACT
In future wireless communication system, the essential for increased capacity
per unit area leads to higher operating frequencies and smaller radio cells. To reduce
the system installation and maintenance cost of such system, it is very important to
make the Remote Access Point (RAP) or Base Station (BS) as simple as possible.
This may be achieved by consolidating signal processing functions at central station
(CS). This is the reason why Radio over Fiber (RoF) is introduced. RoF technology
entails the use of optical fiber transmission link to distribute Radio frequency (RF)
signals from a CS to BS. The purpose of this project is to analyze the performance of
a RoF system based on IEEE 802.11a standard by experiment. The idea of
employing IEEE 802.11a standard is due to several advantages: the low cost of
equipment, its operation in the unlicensed spectrum and its higher data rates.
However, original IEEE 802.11a standard is designed for service range of less than
1km. So, it cannot provide a high speed link for long distance. Fortunately, this
problem is more on the Medium Access Control (MAC) layer only. By modifying
the parameter in the MAC layer, it is possible to overcome the problem. A RoF
system design is proposed in this project by using one of the modified protocols. The
results show that the performance of the proposed system is excellent for more than
5km of service range. Previous study has been shown that the standard IEEE 802.11a
MAC protocol working procedure is feasible for point to point links of up to 2.7 km
only when IEEE 802.11a technology is used. Combining the results, it is concluded
that a RoF system based on IEEE 802.11a with higher speed and longer distance is
achievable.
vi
ABSTRAK
Dalam sistem komunikasi tanpa wayar masa hadapan, keperluan untuk
menambahkan kapasiti per unit kawasan membawa kepada frekuensi operasi yang
lebih tinggi dan sel radio yang lebih kecil. Untuk mengurangkan kos pemasangan
dan penyelenggaraan sistem, adalah penting untuk stesen tapak (BS) menjadi
seringkas yang boleh. Ini dapat dicapai dengan menjalankan semua fungsi
pemprosesan isyarat di stesen pusat (CS). Oleh sebab inilah, radio atas gentian (RoF)
diperkenalkan. Teknologi RoF melibatkan penggunaan talian penghantaran gentian
optik untuk menyebarkan isyarat frekuensi radio (RF) dari CS ke BS. Projek ini
bertujuan untuk menganalisa perlaksanaan system RoF berdasarkan piawai IEEE
802.11a secara eksperimen. Idea menggunakan piawaian IEEE 802.11a adalah
kerana beberapa kelebihan: kos peralatan yang rendah, beroperasi pada spektrum
tanpa lesen dan kadar penghantaran data yang lebih tinggi. Walau bagaimanapun,
pada mulanya piawaian IEEE 802.11a direkabentuk untuk jarak operasi kurang dari
1km. Oleh itu, ia tidak boleh melakukan penghantaran untuk jarak yang jauh. Tetapi,
masalah ini hanyalah pada lapisan kawalan akses media (MAC). Dengan mengubah
parameter dalam lapisan MAC, masalah ini mungkin boleh diatasi. Satu rekabentuk
sistem RoF dicadangkan dalam projek ini dengan menggunakan salah satu protokol
yang telah diubahsuai. Keputusan menunjukkan perlaksanaan sistem yang
dicadangkan adalah cemerlang sehingga melebihi jarak 5km. Kajian sebelum ini
telah menunjukkan prosedur kerja IEEE 802.11a boleh melakukan penghantaran
isyarat titik ke titik sehingga 2.7km. Bila semua keputusan diambilkira, dapatlah
disimpulkan bahawa sistem RoF menggunakan IEEE 802.11a dengan kelajuan yang
lebih tinggi dan jarak yang lebih jauh dapat dicapai.
vii
TABLE OF CONTENTS
CHAPTER TITLE PAGE
DECLARATION
DEDICATION
ACKNOWLEDGEMENTS
ABSTRACT
ABSTRAK
TABLE OF CONTENTS
LIST OF TABLES
LIST OF FIGURES
LIST OF ABBREVIATIONS
LIST OF SYMBOLS
LIST OF APPENDICES
ii
iii
iv
v
vi
vii
xi
xii
xiv
xvi
xvii
1 INTRODUCTION
1.1 Project Background
1.2 Problem Statement
1.3 Objective
1.4 Scopes
1.5 Project Report outline
1
1
2
4
4
4
2 RADIO OVER FIBER TECHNOLOGY
2.1 Introduction
2.2 Radio over Fiber
2.3 Benefits of RoF Technology
6
6
6
8
viii
2.3.1 Low Attenuation Loss
2.3.2 Large Bandwidth
2.3.3 Immunity to Radio Frequency interference
2.3.4 Easy Installation and Maintenance
2.4 Limitation in RoF technology
2.5 Applications of RoF Technology
2.6 Optical Transmission Link
2.6.1 Optical Fiber
2.6.2 Optical Transmitters
2.6.3 Optical Receivers
2.7 RoF Analog optical Links
2.7.1 Basic Radio Signal Generation Methods
2.7.2 RoF Link Configurations
9
9
10
10
10
11
12
12
13
13
14
15
16
3 IEEE 802.11 WLAN STANDARDS
3.1 Introduction
3.2 WLAN Standards
3.2.1 IEEE 802.11-1997 (802.11 Legacies)
3.2.2 IEEE 802.11a
3.2.3 IEEE 802.11b
3.2.4 IEEE 802.11g
3.2.5 IEEE 802.11-2007
3.3 RoF Based WLAN Requirement
3.4 The Advantages of Using IEEE 802.11 standard
3.5 Feasibility of Applying RoF into WLAN
3.6 IEEE 802.11 Radio Design
3.7 IEEE 802.11 MAC Protocol
3.7.1 The PCF Protocol
3.7.2 The DCF Protocol
3.8 Current and Past Researches
3.8.1 Analysis of IEEE 802.11 RoF Home Network
3.8.2 Propagation delay Influence in IEEE 802.11
20
20
21
22
23
24
24
25
25
27
28
29
30
31
32
34
34
35
ix
3.8.3 A High Gain Photonic Antenna for High Speed
3.8.4 Performance Impairments in SMF RoF System
36
37
4 RESEARCH METHODOLOGY
4.1 Introduction
4.2 Methodology
4.3 Proposed System
4.3.1 Nstreme2 Protocol
4.4 Components of Radio over Fiber for Experiments
4.4.1 Routerboard
4.4.2 WLAN Cards
4.4.3 PSI-1601 Microwave Photonic Links
4.4.4 Fiber Farm
4.4.5 Antenna
4.4.6 Connectors
38
38
38
39
40
41
41
42
45
47
48
50
5 RESULTS AND ANALYSIS
5.1 Introduction
5.2 Mikrotik Routerboard Set-up
5.2.1 Point-to-point Links Connection
5.2.2 Nstreme2 Application
5.3 Experiments
5.3.1 Experiment 1: Testing the Equipments used
5.3.1.1 Experiment 1(a): Power and frequency
5.3.1.2 Experiment 2(b): Power from PSI-1601
5.3.2 Experiment2: Performance Analysis of Nstreme2
5.3.3 Experiment3: Performance Analysis of RoF Link
51
51
51
52
55
59
59
59
60
63
69
x
6 CONCLUSION AND FUTURE WORK
6.1 Conclusion
6.2 Future Work
75
75
76
REFERENCES
Appendices A-E
78
81-86
xi
LIST OF TABLES
TABLE NO.
3.1
3.2
3.3
4.1
4.2
4.3
4.4
4.5
4.6
5.1
5.2
5.3
TITLE
Evolution of WLAN standards
802.11 networks standards
Main Parameters of the OFDM
RB433 Specifications
R52 Specifications
WLM54AG 6B-SuperAG Specifications
Specification of PS-1601 Microwave Photonic Links
Technical specifications for fiber farm
Technical specifications for panel antenna
Experimental Result for 100m distance (P16 to P04)
Experimental Result for 1km distance (P16 to Institut
Ibnu Sina)
Experimental Result for Experiment 3
PAGE
21
22
27
42
44
45
46
48
49
67
67
68
xii
LIST OF FIGURES
FIGURE NO.
1.1
2.1
2.2
2.3
2.4
3.1
3.2
3.3
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
5.1
TITLE
Components of a narrowband wireless access network
The concept of radio over fiber system
Optical transmission link
Intensity-modulation direct-detection (IMDD) analogue
optical link.
Representative RoF link configurations (a) EOM, RF
modulated signal (b) EOM, IF modulated signal (d) direct
modulation
Timing diagram of a IEEE 802.11 successful
transmission
The PCF of the 802.11 MAC protocol
The DCF of the 802.11 MAC protocol
Flowchart of the experiment process
Proposed system for broadband internet backhaul link
based on WLAN and RoF technology
Mikrotik routerboard
R52 wireless card used in one station
WLM54AG 6B-SuperAG
PSI-1601 Microwave photonic links
Fiber farm
Panel antenna
SMA connector, FC/APC cable and power splitter
Links connection
PAGE
3
8
12
16
19
29
31
32
39
40
42
43
43
46
47
49
50
52
xiii
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
5.11
5.12
5.13
5.14
5.15
5.16
5.17
5.18
5.19
5.20
5.21
5.22
5.23
5.24
5.25
5.26
5.27
5.28
5.29
Access point configuration result
IP address for access point
Station (client) configuration result
IP address for station (client)
Ping from access point to station
Nstreme2 link connection
First WLAN card, second WLAN card and Nstreme2
interface setting
Enabling Nstreme2
Assigning IP address and creating the bridge
First WLAN card, second WLAN card and Nstreme2
interface setting
Enabling Nstreme2
Assigning IP address and creating the bridge
Experimental setup for testing the radio card
Experimental setup for testing the RoF link
Experiment 2 (b)
Result from portable spectrum analyzer
Spectrum analyzer with lower noise level
Experimental setup for Nstreme2
Experimental setup for point to point (P2P)
Communication from P04 to P16
Station at Institut Ibnu Sina
Station at P16
Communication between P16 to Institut Ibnu Sina
Planned experimental setup for experiment 3
Actual experimental setup for experiment 3
Different lengths of fiber used in experiment 3
Fiber farm used to demonstrate the fiber length
Graph speed versus fiber length
53
53
54
54
55
55
56
56
57
57
58
58
60
61
61
62
62
63
63
64
64
65
65
69
70
70
71
73
xiv
LIST OF ABBREVIATIONS
RAP - Remote Access Point
BS - Base Station
CS - Central Station
RS - Remote Station
RoF - Radio over Fiber
MU - Mobile Unit
WTU - Wireless Terminal Unit
BB - Base Band
IF - Intermediate Frequency
RF - Radio Frequency
DCF - Distributed Coordination Function
MAC - Medium Access Control
2G - Second Generation
3G - Third generation
CDMA - Code Division Multiple Access
GPRS - General Packet Radio Service
xv
WLAN - Wireless Local Area Network
SMF - Single Mode Fiber
EMI - Electromagnetic Interference
NF - Noise Figure
DR - Dynamic Range
RIN - Relative Intensity Noise
OFDM - Orthogonal Frequency Division Multiplexing
BER - Bit Error Rate
AM - Amplitude Modulation
FM - Frequency Modulation
PM - Phase Modulation
ASK - Amplitude Shift Keying
FSK - Frequency Shift Keying
PSK - Phase Shift Keying
OOK - On-off Keying
BB - Baseband
PD - Photodiode
IMDD - Intensity Modulation Direct Detection
PSTN - Public Switched Telephone Network
LD - Laser Diode
EOM - External Optical Modulator
MH - Mobile Host
SDRAM - Synchronous Dynamic Random Access Memory
DDR - Double Data Rate
CPU - Central Processing Unit
xvi
LIST OF SYMBOLS
km - Kilometer
µs - Microsecond
nm - Nanometer
mm - Milimeter
G - Giga
H - Hertz
T - Tera
dB/km - Decibels per Kilometer
xvii
LIST OF APPENDICES
APPENDIX
A
B
C
D
E
TITLE
Nstreme2 Group Settings
Experiment 2 (P16 to P04) details result
Experiment 2 (P16 to Ibnu Sina) details
result
Experiment 3 details result
Data sheets
PAGE
81
82
83
84
85
86
1
CHAPTER 1
INTRODUCTION
1.1 Project Background
In cellular networks, the current trends now are to reduce cell size to
accommodate more users and to operate in the microwave/millimeter wave
frequency bands to avoid spectral congestion in lower frequency bands. This requires
a large number of base stations (BS) to cover a service area. The base station also
must be cost effective to make it success in market. This requirement has led to the
development of system where functions such as signal routing or processing,
handover and frequency allocation are carried out at a central control station (CS),
rather than at the BS. An interesting way for connecting a CS with BSs in such a
radio network is through an optical fiber network, since fiber has low loss, immunity
to EMI and broad bandwidth. The radio signals from CS are transmitted over optical
fiber and will be radiated by remote antennas. The cost is reduced since the BS or
Remote Station (RS) needs to perform only simple functions, and it is in small size.
Besides that, the resources provided by the CS can be shared among many antenna
BSs. This technique of modulating the radio frequency (RF) subcarrier onto an
optical carrier for distribution over a fiber network is known as radio over fiber
(RoF) technology [1].
2
Interest in RoF network has been gaining increasing popularity for RF
distribution networks. This project examines the link transmission quality and
performance characteristics of RoF between the CS and RS by experiment. The
signal used in this project is 5GHz signal compliant to IEEE 802.11a standard.
Signal strength, speed and throughput of the experimental link are presented as a
performance indicator to show the effectiveness of RoF signal distribution. A
proposed system of RoF based on IEEE 802.11a is used for this purpose.
1.2 Problem Statement
Figure 1.1 illustrates the configuration of narrowband wireless access systems
(e.g. GSM). The central office handles call processing and switching, while the Base
Stations (BS) act as the radio interfaces for the Mobile Units (MU) or Wireless
Terminal Units (WTU). The BSs may be linked to the central station (CS) through
either analogue microwave links or digital fiber optic links. Once the baseband
signals are received at the BS, they are processed and modulated onto the appropriate
carrier. The radius covered by the signal from the BS is the cell radius.
All the MU/WTU within the cell, share the radio frequency spectrum. In
general, low carrier frequencies offer low bandwidth. Low-frequency RF signals
allow for larger cells, due to the longer reach of the radio waves. The larger cells
enable high mobility, but lead to poor spectrum efficiency, since the spectrum is
shared by all MUs/WTUs operating within the cell. Therefore, for broadband
wireless communication systems to offer the needed high capacity, it appears
inevitable to increase the carrier frequencies and to reduce cell sizes [2].
The need for increased capacity per unit area leads to higher operating
frequencies (above 6GHz) and smaller radio cells. To reduce the system installation
and maintenance costs of such system, it is imperative to make the remote access
point (RAP) as simple as possible. This may be achieved by consolidating signal
3
processing functions at a centralized headend or central station. Because of this, RoF
technology is introduced and IEEE 802.11a is a very attractive standard due to
several advantages.
Figure 1.1: Components of a narrowband wireless access network [8]
However, in RoF systems, the longer the fiber length the higher the delay
imposed to the system. For example, using 1km of fiber introduces approximately
5µs of delay to each packet that passes through. This extra propagation delay poses a
challenge to the system design since this delay exceeds the 1µs propagation delay
boundary defined in the IEEE 802.11 standard where only wireless propagation is
assumed [6]. As a result, the performance of the distributed coordination function
(DCF) of the medium access control (MAC) layer may degrade significantly or even
break down entirely. It is noted that network fails long before physical layer
limitations due to the timeout values defined within the MAC protocol.
4
1.3 Objective
The objective of this project is to analyze the performance of RoF system by
experiment. A proposed system of RoF is used for this purpose. The performance
parameter such as signal strength, speed and throughput is measured by experiment.
The measurement of the performance parameter is analyzed.
1.4 Scopes
In order to achieve the objective of this project, there are following scopes
will be covered:
(i) To study and understand the concept of RoF system.
(ii) This project will focus on set up and analyze the performance of RoF system.
(iii) The equipments that will be used for the experiment are recognized.
(iv) The analysis will be carried out by experiment.
1.5 Project Report Outline
The project report consists of six chapters which include Introduction; RoF
Technology; IEEE 802.11 WLAN Protocol; Research Methodology; Results and
Analysis, and finally Conclusion and Future Works.
For Chapter Two, RoF technology, will explain about the introduction of
RoF, its advantage, its application and its optical transmission link.
5
In Chapter Three, IEEE 802.11 WLAN standards will cover about the
characteristics of IEEE 802.11 standards, the IEEE 802.11 MAC protocol and the
feasibility of applying RoF into WLAN standard. Besides that, this chapter also
shows brief explanation about current and past researches regarding the issue on this
project.
Chapter Four is explained about the research methodology. While Chapter
Five shows the result and analysis of this project. And lastly, the conclusion and
future work are stated in Chapter Six.
78
REFERENCES
1. K. Lee, “Radio over Fiber for Beyond 3G,” 2005 IEEE International Topical
Meeting on Microwave Photonics, 2005, pp. 9-10
2. M. J. Cryan, M. Dragas, J. Kung, V. Jain, F. Fornetti, T. Houle, R. Varazza,
and M. Hill, “A 2.4-GHz wireless-over-fiber transceiver using photonic
active integrated antennas (PhAIAs),” Microwave and Optical Technology
Letters, vol. 48, pp. 233-237, 2006
3. T. Prakoso, R.Ngah, T. A. Rahman, Z. Ghassembloy, “A High Gain Active
Photonic Antenna for high speed Backhaul Link: A System Analysis”, 17th
International Conference on Telecommunications (ICT2010), 4-7 April 2010,
Doha Qatar.
4. A. Cerquira, D.C Valente e Silva. “Performance Analysis of a Radio over
Fiber System based on IEEE 802.15.4 standard in a real optical network”,
Mikrowave and Optical Technology Letters, Vol. 51, August 2009.
5. M.L. Yee, A. N. Oma, M. Sauer, “Performance Analysis of IEEE 802.16e
WIMAX Radio over Fiber Distributed Antenna System”, Microwave
Symposium Digest, 2009. MTT’09. IEEE MTT-S International
6. B. K Sabet, M. Mjeku, N. J Gomes, “Performance Impairments is Single
Mode Radio over Fiber Systems Due to MAC Constraints”, Journal of
Lightwave Technology, Vol. 26, Issue 15, pp. 2540-2548, 2008
7. B. K Hong, “Radio over Fiber based Network Architecture”, Master Thesis,
Berlin 2003.
8. N. O Anthony, “Radio over Fiber Technology for Broadband Wireless
Communication System”, PhD thesis, Zambia, 2005.
9. D. Novak, “Fiber Optics in Wireless Applications”, OFC 2004 Short Course
217, 2004.
10. D. Wake, “Radio over Fiber Systems for Mobile Applications in Radio over
Fiber Technologies for Mobile Communications Networks”, H. Al-
Raweshidy, and S. Komaki, ed. (Artech House, Inc, USA, 2002).
79
11. A. Powell, “Radio over Fiber Technology: Current Applications and Future
Potential in Mobile Networks – Advantages and Challenges for a Powerful
Technology in Radio over Fiber Technologies for Mobile Communications
Networks”, H. Al-Raweshidy, and S. Komaki, ed. (Artech House, Inc, USA,
2002).
12. LAN / MAN Standard Committee, “DRAFT Supplement to the IEEE
P802.11a/D7.0 Standard”, IEEE Standards Department, USA, 1999.
13. E. I. Ackerman and C. H. Cox, “RF Fiber-Optic Link Performance”, IEEE
Microwave, pp. 50.58, Dec. 2001.
14. H. Al-Raweshidy and S. Komaki, editors, “Radio over Fiber Technologies
for Mobile Communications Networks”, Norwood: Artech House, 2002.
15. W. David, N. Anthony, J.G. Nathan, “Radio over fiber Link Design for Next
Generation Wireless Systems”, Journal of Lightwave Technology, vol. 28,
issue 16, pp. 2456-2464, 2010.
16. S.P. Chul, Y.K. Yeo, L.C. Ong, “Demonstration of the GbE Service in the
Converged Radio over Fiber/Optical Networks”, Journal of Lightwave
Technology, Vol. 28, Issue 16, pp. 2307-2314,2010.
17. W. Xu, Z. Xiaoping, Z. Hanyi, “BER Performance Analysis of Radio over
Fiber System with Different Modulation Schemes”, Optical Transmission
Systems, Switching, and Subsystems VII. Edited by Chiaroni, Dominique.
Proceedings of the SPIE, Volume 7632, pp. 76321V-76321V-6 ,2009.
18. B. L. Dang and I. Niemegeers, “Analysis of IEEE 802.11 in Radio over Fiber
Home Networks,” Proceedings of the IEEE Conference on Local Computer
Networks 30th
Anniversary: IEEE Computer Society, 2005.
19. K.K. Leung, M. V. Clark, B. McNair, Z. Kostic, L. J. Cimini, and J. H
Winters, “Outdoor IEEE 802.11 Cellular Networks: Radio and MAC Design
and Their Performance,” IEEE Transactions on Vehicular Technology,
vol.56, pp.2673-2684, September 2007.
20. E. Lopez-Aguilera, J. Casademont, and J. Cotrina, “Propagation delay
influence in IEEE 802.11 outdoor networks,” Journal Wireless Networks,
Volume 16 Issue 4, May 2010
21. L. Kleinrock, Queueing Systems, Vol. 2: Computer Applications, Hoboken,
NJ: Wiley, 1976, p.398.
80
22. IEEE 802.11: Wireless LAN Medium Access Control (MAC) and Physical
Layer (PHY) Specifications. (2007 revision). IEEE-SA. 12 June 2007.