FINAL YEAR PROJECT I REPORT
(Radio over Fiber Technology)
Project Advisor
(Muhammad Saadi)
Submitted by
(Syed Shahzaib Raza - 071020165)
(Osama Zaid - 071020149)
Department of Electrical Engineering
School of Science and Technology
University of Management and Technology
(Radio over Fiber Technology)
Project Report submitted to the
Department of Electrical Engineering, University of Management and Technology
in partial fulfillment of the requirements for the degree of
Bachelor of Science
in
Electrical Engineering
(Syed Shahzaib Raza - 071020165)
(Osama Zaid - 071020149)
(August 9, 2011)
Abstract
The demand of mobile communications in the modern world is increasing
day by day. It has been noticed that subscribers for the mobile communication
technologies are growing rapidly. The data transfer rate should be maximum for
uninterruptable communication. The radio over fiber technology offers much
more data transfer rate as compared to other technologies. This project is
research based on the simulation of WCDMA communication using Radio over
Fiber technology. Next generation mobile communication will require high
bandwidth for communication. 3G and 4G mobile communications are now being
offered by the Telecommunication Industries. The mm-wave in atmosphere gets
attenuated and the signal is sometimes lost. However, the upcoming technologies
will be using the optical fiber communication system along with wireless
communication for the high speed data transfer. This combination will increase
the capacity for the cellular base stations to change dynamically and meet the
traffic requirements. The Radio over Fiber (RoF) technology is the one which will
fulfill the requirements. This technology is actually the integration of optical fiber
and mm-wave transmission system. In this project a simulation of WCDMA using
Radio over Fiber Technology will be made so that the Bit Error Rate could
measured and the performance of this technology will also be calculated.
i
Table of contents
List of figures ii
List of tables iii
List of abbreviations iv
Chapter I Introduction to Project
1 Introduction 1
2 Objective 3
3 Methodology 5
Chapter II Radio over Fiber
1 Radio over Fiber Technology 6
2 Radio over Fiber Systems 8
3 Advantages of RoF Systems 8
4 Benefits of RoF for Mobile Communication 9
5 Applications of RoF Technology 9
Chapter III Wideband Code Division Multiple Access (WCDMA)
1 Introduction 10
2 Specifications of WCDMA 10
3 Operating Modes of WCDMA 11
Chapter IV Simulations
1 Creating a Sine Wave 14
2 Creating a High Frequency Wave 14
ii
3 Sine Functions 15
4 Creating Various Pulses 15
5 Amplitude Modulation 16
6 Frequency Modulation and Demodulation 16
7 Gaussian Distribution Function 17
8 AWGN to Signal 17
9 PSK Modulation and Demodulation 18
Chapter V References 19
iii
List of figures Figure 1 Radio over Fiber Technology Figure 2 BPSK Modulation Scheme Figure 3 QPSK Modulation Scheme Figure 4 WCDMA using RoF Figure 5 Methodology Figure 6 Radio over Fiber System Figure 7 Frequency Division Duplex Figure 8 Time Division Duplex
iv
List of tables Table 1 Parameters of WCDMA
v
List of abbreviations
3GPP Third Generation Partnership Project
AWGN Additive White Gaussian Noise
BER Bit Error Rate
BPSK Binary Phase Shift Keying
BS Base Stations
DWDM Dense Wavelength Division Multiplex
EDFA Erbium Doped Fiber Amplifier
FDD Frequency Division Duplex
GMSK Gaussian Minimum Shift Keying
GSM Global System for Mobile Communications
IF Intermediate Frequencies
IMDD Intensity Modulated Direct Detection
IMT-2000 International Mobile Telephony
ITS Intelligent Transport Systems
ITU International Telecommunication Union
IVC Inter-Vehicle Communication
LAN Local Area Network
MSC Mobile Switching Center
MVDS Multipoint Video Distribution Services
OFDM Orthogonal Frequency Division Multiplexing
PSK Phase Shift Keying
QAM Quadrature Amplitude Modulation
QoS Quality of Service
QPSK Quadrature Phase Shift Keying
RAP/RAU Radio Access Point/Radio Access Unit
RF Radio Frequency
RFI Radio Frequency Interference
RoF Radio over Fiber
RS Remote Station
RVC Road-to-Vehicle Communication
TDD Time Division Duplex
TDMA Time Division Multiple Access
UMTS Universal Mobile Telecommunication Systems
UTRA Universal Terrestrial Radio Access
WBMCS Wireless Broadband Mobile Communication
Systems
WCDMA Wideband Code Division Multiple Access
1
Chapter I. Introduction to Project
1 Introduction
Radio over Fiber (RoF) technology is now being used in many different
countries because of its low cost implementation and high data transfer rate
which it offers. RoF systems cover wide areas of deployment for enhanced cellular
coverage for its capacity and benefits. These networks include broadband
communication networks, satellite communication networks, wireless access
networks, IPTV and many more. These networks need high bandwidth for the
transmission. The RoF technology offers these benefits for the future networks as
it offers high bandwidth, low attenuation and cost. The RoF technology is basically
the integration of wireless and optical communication systems. This uses the
optical links to transfer the radio signals from the base stations (BSs) to multiple
radio access points (RAPs). The basic point of this technology is high speed data
transmission using optical fiber links which reduce the complexity of transmission
system, as is only requires the optical conversions and modulations. This will
provide the great advantage to wireless systems for the increasing capacity of
users and the improvement of quality of service (QoS) without acquiring a new
radio spectrum. This is basically the analog transmission system whereas the
optical fiber includes the digital communication system.
Wideband Code Division Multiple Access (WCDMA) technology usually
called third generation wireless communication system is now being used all over
the world. This system needs microcells and picocells for high speed data
transmission and high bandwidth in order to provide services. The system
comprises of multimedia communication which includes high definition videos
and pictures, internet and audio communication. This supports the high data
transmission rate up to 384 kbps for wide area coverage and 2 Mbps for local
coverage. The data modulation consists of digital modulation for uplink and
downlink. This air interface mature technology provides various business
2
opportunities for the telecommunication operators, service providers and
manufacturers. In WCDMA communication system, FDD is commonly used for
macro and microcells and TDD is normally used for picocells. The specifications of
this technology were created by 3GPP (Third Generation Partnership Project)
which is the joint standardization project of Europe, Korea, Japan, China and USA.
In 3GPP, WCDMA is called UTRA (Universal Terrestrial Radio Access) FDD and TDD.
3G was named as IMT2000 (International Mobile Telephony-2000) by the ITU
(International Telecommunication Union). The larger bandwidth of WCDMA gives
multipath diversity for BSs especially in microcells. The advantages of utilizing RoF
technology for WCDMA communication system are very much important as it
provides the high bandwidth and data transfer rate and low attenuation loss
which fulfills the requirement for 3G systems.
Figure 1: Radio over Fiber Technology
3
2 Objective
The objective of this project is to simulate the WCDMA using RoF
technology on MATLAB for mobile communication systems. For the achievement
of this objective, various simulations have to be performed. There are different
simulations blocks that are to be developed. This will be consisting of the
different modulation, demodulation schemes, channels, communication system
which is to be used and various parameters that are to be used for the
transmission. This will help to reduce the system complexity from the BSs. The
technology will be used by modulation of laser by a RF signal and will be
transmitted on optical fiber channel. The configuration of RoF link will be the
interface of radio signals and optical signals which will contain the analog laser
transmitter and the photodiode receiver at the BSs. These optical fibers connect
the RAPs and Central Processing Units.
Figure 2: BPSK Modulation Scheme
4
Figure 3: QPSK Modulation Scheme
Figure 4: WCDMA using RoF
5
3 Methodology
Figure 5: Methodology
Start
Literature Study
Study of RoF Systems
Study of Mobile Communication
Systems
WCDMA Communication
SystemsStarting MATLAB
Performing Simulations
Setting the simulation Block
Comparing AWGN channel
using RoF
Performing Final Simulation
Observing BER
Final Report Submission
End
6
Chapter II. Radio over Fiber
In this chapter, further explanations regarding RoF technology are mentioned. The basic concept, systems, parameters, advantages and applications of RoF technology are discussed. Further it contains the information of RoF technology in mobile communication networks, implementations and advantages.
1 Radio over Fiber Technology
The 3G and future generation systems use the air interface methods using various channels and combination of cells for high traffic so that they could be changed dynamically to meet the requirements. The TDMA, CDMA and WCDMA mobile communication systems acquire the combination or groups of BSs for the implementation of technology to overcome the needs of traffic capacity. But these increase the complexity of the systems and may demand more BSs which will require high cost. User terminals vary in capabilities of transmission rates, cost, mobility and modulation levels. The increase in the complexity of BSs will require more BSs installation for the whole network deployment. The alternate way to decrease the complexity of BSs is to shift the complexity towards the central processing units. The RoF technology implies this alternate in which fiber optical links are used to distribute the radio signals from the CPUs to the RAPs. This needs the optoelectronic conversion of signals. In this technology the basic communication functions like modulation, coding and conversions are performed at CPUs. This results in the centralization of RAPs which allows the dynamic allocation of cells and high mobility management.
Fiber optics are the backbone networks of telecommunication as it provides low attenuation loss and high bandwidth. The optical links in RoF systems are analog and produce carrier signals which can be modulated with digital modulation schemes. In RoF system, light signal is modulated by a radio signal and transmitted over a fiber link. This modulation is analog because the radio signal is also analog in nature. This configuration between radio and optical signal consist of optical transmitter located at the CPU and the photodiode receiver which is located at RAP or BS. This reduction in complexity of BS can be found very economical which will increase the capacity of network and decrease the cost of data transmission. The commonly used wavelengths of light are 1300
7
nm or 1550 nm which have low attenuation loss as compared to other wavelengths and provides high bandwidth which can be up 50 THz. These integrated links are called IMDD (Intensity Modulated-Direct Detection) which involves PM and FM techniques.
Figure 6: Radio over Fiber System
8
2 Radio over Fiber Systems
The above mentioned picture shows the basic configuration of Radio over Fiber system. The system has low attenuation loss of signals and very high bandwidth of fiber optic channel. It fulfills the demand of high channel capacity and offers wide area for coverage. It also provides the economical solutions for the installation of BSs or whole network deployment. This system makes the group of cells that can changed dynamically and deliver high bandwidth to the subscribers. The radius of the zones can be reduced which will provide the effective use of radio frequencies. These systems are now being used widely for in-building networks, remote vehicles, office and wireless access points.
3 Advantages of RoF Systems
Low Signal Attenuation Loss
High Bandwidth
Reduced Power Consumption
Flexibility to systems
Economical Solutions for Installation
Immunity to Noise and Interference in Radio Signals
9
4 Benefits of RoF for Mobile Communication
The RoF systems provide dynamic channel allocation and adaptive antenna selection. Following are the benefits of mobile communication systems using RoF technology:
Wide area coverage
Dynamic radio resource management
Low power consumption for RAPs
Less multipath fading effects
Increased channel capacity and efficiency
Reduced handovers
Centralized processing
Low maintenance cost
High Bandwidth and data transfer rate
Support for future generation networks
Improved quality of signals
Low fiber attenuation loss
No electromagnetic interference
Multimedia broadband communication
5 Applications of RoF Technology
Cellular Networks
Satellite Communications
MVDS
Mobile Broadband Services
Wireless LANs
Vehicle Communication and Control
Next Generation Communication Systems
In-Building Networks
Multipoint Video Distribution Systems
Radio Access Points
10
Chapter III. Wideband Code Division Multiple Access
(WCDMA)
1 Introduction
The WCDMA air interface is the technology which is now providing its
services in different countries all over the world. This is also known as UMTS
which is the third generation wireless personal communication systems. The
WCDMA technology is more efficient than the previously used GSM system due to
its characteristics and wideband properties.
2 Specifications of WCDMA
The following table provides the information regarding WCDMA
technology, its characteristic, parameters and specifications:
Channel Bandwidth 5 MHz
Duplex mode FDD and TDD Modulation QPSK and BPSK
Chip Rate 3.84 Mbps Handover Soft and Inter frequency
Frame Length 10 ms
Channel Coding Convolution and Turbo codes Power Control Open and Fast closed loop (1.6 kHz) Table 1: Parameters of WCDMA
The bandwidth provided is about 5MHz. The length of frame is 10 ms
whereas each frame is divided into 15 slots which makes the chip rate of the
system to about 3.84 Mcps. The modulation symbols vary from 960k symbols per
second to 15 k symbols per second due to which the spreading factors range 256
– 4 for uplink and 512 – 4 for downlink. Orthogonal Variable Spreading Factor
(OVSF) codes of channelization are used for separating channels. Convolutional
11
and turbo channel coding is used. The data modulation is performed by QPSK for
downlink and BPSK for uplink.
Concluding the whole network architecture, WCDMA is deployed in UMTS.
This contains user equipment (UE) link with the BSs. These BSs are responsible for
modulation, conversion, error correction and transmission. The BSs can transmit
and receive signals from different cells and are controlled by Radio Network
Controller (RNC). RNC consists of various BSs and performs radio resource
management, call setup, location and QoS. The RNC is connected to PSTN and
Internet.
3 Operating modes of WCDMA
WCDMA consists of two modes of operation which provides it diversity.
Frequency Division Duplex (FDD) is used for the paired frequency band while Time
Division Duplex (TDD) performs operation for unpaired frequency bands available.
FDD mode consists of symmetric data transmission as it has 5MHz carrier
frequencies for uplink and downlink which are separately used. These two bands
transmit data separately from BS to Mobile Switching Center (MSC) and the other
from MSC to BS. Thus, the information can be simultaneously exchanged in both
directions. The FDD principle of operation can be viewed in the following figure:
12
Figure 7: Frequency Division Duplex
In TDD principle only one band of 5MHz is available which is shared by both
uplink and downlink in time separate mode. The information in uplink and
downlink is alternated as the TDD is being used for unpaired spectrum. The
bandwidths shared can also be altered between uplink and downlink, but the
bandwidth of downlink is usually greater than the bandwidth of uplink. This
sharing makes TDD mode more efficient. The following figure shows the TDD
principle:
13
Figure 8: Time Division Duplex
14
Chapter IV. Simulations
1. Creating a Sine Wave
2. Creating High Frequency wave
15
3. Sine Functions
4. Creating Various Pulses
16
5. Amplitude Modulation
6. Frequency Modulation and Demodulation
17
7. Gaussian Distribution Function
8. Add White Gaussian Noise to Signal
18
9. Phase Shift Keying (PSK Modulation and Demodulation)
19
Chapter V. References
“Over Fiber Technologies For Mobile Communication Network. 1st edition”
Hamed Al-Raweshidy and Shozo Komaki Radio. Universal Personal
Communication, Norwood, MA: Artech House Publishers. 2002.
“WCDMA for UMTS-Radio Access For Third Generation Mobile Communication” Harri Holma and Antti Toskala. John Wiley & Sons,Ltd. 2001
“Capacity Improvement in the Downlink of WCDMA with Radio over Fibre Access Network” Nazem Khashjori and H.S. Al-Raweshidy. University of Kent, UK.
“WCDMA-Based Radio over Fibre System Performance with Multiple-User Interference in Multiple Service Transmission” H.S. Al-Raweshidy and S.O. Ampem-Darko. University of Kent, UK. March 2001.
“System Level Performance of WCDMA With Radio Over Fibre Access Network” Nazem Khashjori and H.S. Al-Raweshidy. University of Kent, UK.
“Radio over Fiber Technology for Braodband Wireless Communication Systems” Anthony Ng’oma.
“Simulation of WCDMA Radio over Fiber Technology” S.H. Binti Mohd Razali. Universiti Teknologi Malaysia. April 2007.
“Radio Access Point Design for Radio over Fiber Technology” M. M. Mohammoud Hadow. Universiti Tecknologi Malaysia. April 2008.
“Front-End Design of Low Power Radio Access Points for Radio over Fiber Technology” A.S. Mohammed Al-Ahmadi. Universiti Teknologi Malaysia. May 2007.
“Design of a Radio-over-Fiber System for Wireless LANs” Anthony Ng’oma, (MTD. Report, Eindhoven University of Technology, Eindhoven, 2002).
“A Radio over Fiber based Wireless Access Network Architecture for Rural Areas” Hong Bong Kim and Adam Wolisz. (In Proc. of 14th IST Mobile and Wireless Communication Summit, Dresden, Germany. June 2005).
“A Radio over Fiber Network Architecture for Road Vehicle Communication Systems” Hong Bong Kim, Marc Emmelmann, Berthold Rathke, and Adam Wolisz. (In Proc. of IEEE Vehicular Technology Conference, 2005 Spring)
“Radio over Fiber Technology for the Next Generation” Hamed Al-Raweshidy.
20
“Radio over Fiber- An optical Technique for Wireless Access” Xavier Fernando. Ryerson Communication Lab, Toronto, Canada. October 2009
“Radio over Fiber Technology for Wireless Access” D.Opati, GSDC Croatia.
“Radio over Fiber for Picocellular Network Architectures” Michael Sauer, Andrey Kobyakov and Anthony Ng’Oma Science and Technology, Corning.
“GSM signal transmission through external modulated single Mode fiber link” Sathyanandan.S, Swaminathan.R, Lavanya.R, Piramasubramanian.S, Ganesh Madhan.M. ICOP 2009-International Conference on Optics and Photonics Chandigarh,India. Oct.-1 Nov.2009
21
Appendices 1. Sin Functions
>>A1=1;
>> A2=1.5;
>> y1=A1*sin(2*pi*f1*t);
>> y2=A2*sin(2*pi/f2*t);
>> plot(y1)
>> subplot 211
>> plot(t,y1)
>> xlabel('t in s')
>> ylabel('y in V')
>> subplot 212
>> plot(t,y2)
>> xlabel('t in s')
>> ylabel('y in V')
>> y2=A2*sin(2*pi*f2*t);
>> plot(t,y2)
>> xlabel('t in s')
>> ylabel('y in V')
>> title('Sin Function')
>> subplot 211
>> title('Sin Function')
>> axis([Tst,Te,-2,2])
>> subplot 212
>> axis([Tst,Te,-2,2])
2. Creating Various Pulses >> t=[-10:0.01:10];
>> m=cos(2*pi*t);
>> x=square(m);
>> y=rectpuls(m);
>> z=gauspuls(m);
>> subplot 411
>> plot(t,m)
>> subplot 412
>> plot(t,x)
>> subplot 413
>> plot(t,y)
>> subplot 414
22
>> plot(t,z)
>> subplot 411
>> axis([-1.5,1.5,-12,12])
>> axis([-12,12,-1.5,1.5])
>> title('Input Signal')
>> subplot 412
>> axis([-12,12,-1.5,1.5])
>> title('Square Pulses of Input Signal')
>> subplot 413
>> axis([-12,12,-1.5,1.5])
>> title('Rectangular Pulses of Input Signal')
>> title('Rectangular or (Binary) Pulses of Input Signal')
>> subplot 414
>> axis([-12,12,-1.5,1.5])
>> title('Gaussian Pulses of Input Signal')
3. Amplitude Modulation >>t=[-10:0.01:10];
>> s=cos(2*pi*t);
>> subplot 411
>> plot(s)
>> axis([-2,2,-5,5])
>> title('Input Signal')
>> axis([-5,5,-2,2])
>> plot(t,s)
>> axis([-5,5,-2,2])
>> title('Input Signal')
>> subplot 412
>>x=ammod(s,1,3,1);
>> plot(t,x)
>> axis([-5,5,-2,2])
>> title('Modulated Signal')
>> subplot 413
>>y=ammod(s,1,3,1,-1.75);
>> plot(t,y)
>> title('Modulated Signal with -1.75 carrier amplitude')
>> subplot 414
>> z=ammod(s,1,3,1,1.75);
>> plot(t,z)
>> title('Modulated Signal with +1.75 carrier amplitude')
23
4. Frequency Modulation >>t=[-10:0.01:10];
>> ws=2*pi;
>> s=cos(ws*t);
>> y=fmmod(s,3000,9000,50);
>> plot(t,y)
>> plot(t,s)
>> subplot 211
>> plot(t,s)
>> subplot 212
>> plot(t,y)
>> axis([-10,10,-2,2])
>> axis([-10,10,-1.5,1.5])
>> title('Frequency Modulated Signal')
>> subplot 311
>> plot(t,s)
>> axis([-10,10,-1.5,1.5])
>> title('Input Signal')
>> subplot 312
>> plot(t,y)
>> axis([-10,10,-1.5,1.5])
>> subplot 313
>> z=fmdemod(y,3000,9000,50);
>> plot(t,z)
>> axis([-10,10,-1.5,1.5])
>> title('Frequency Demodulated Signal')
>> subplot 312
>> title('Frequency Modulated Signal')
5. Gaussian Distribution
>>t=[-10:0.01:10];
>> ws=2*pi;
>> s=cos(ws*t);
>> y=fmmod(s,3000,9000,50);
>> plot(t,y)
>> plot(t,s)
>> subplot 211
24
>> plot(t,s)
>> subplot 212
>> plot(t,y)
>> axis([-10,10,-2,2])
>> axis([-10,10,-1.5,1.5])
>> title('Frequency Modulated Signal')
>> subplot 311
>> plot(t,s)
>> axis([-10,10,-1.5,1.5])
>> title('Input Signal')
>> subplot 312
>> plot(t,y)
>> axis([-10,10,-1.5,1.5])
>> subplot 313
>> z=fmdemod(y,3000,9000,50);
>> plot(t,z)
>> axis([-10,10,-1.5,1.5])
>> title('Frequency Demodulated Signal')
>> subplot 312
>> title('Frequency Modulated Signal')
6. AWGN
>> t=[-10:0.01:10];
>> m=cos(2*pi*t);
>> SNR=5;
>> x=awgn(m,SNR);
25
>> subplot 211
>> plot(t,m)
>> axis([-11,11,-1.5,1.5])
>> title('Orignal Signal')
>> subplot 212
>> plot(t,x)
>> axis([-11,11,-1.5,1.5])
>> title('AWGN Signal')
>> title('AWGN Signal with SNR=5')
7. PSK Modulation and Demodulation
>> l=1000;
>> M=16;
>> m=randint(l,1,M);
>> x=pskmod(m,M);
>> subplot 311
>> plot(m)
>> title('Orignal Signal')
>> subplot 312
>> plot(x)
>> title('PSK Modulated Signal')
>> subplot 313
>> y=pskdemod(x,M);
>> plot(y)
>> title('PSK Demodulated Signal')
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