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')