SIMULATION OF WCDMA RADIO OVER FIBER TECHNOLOGY SITI HARLIZA BINTI MOHD RAZALI

Transcription

1 iii SIMULATION OF WCDMA RADIO OVER FIBER TECHNOLOGY SITI HARLIZA BINTI MOHD RAZALI A project report submitted in partial fulfillment of the Requirements for an award of the degree of Master of Engineering (Electrical-Electronics and Telecommunication) Faculty of Electrical Engineering Universiti Teknologi Malaysia APRIL 2007

2 v Dedicated to my loving husband & family, ABG HAKIM & MAMA, ANGAH, NINI, AISHAH and my adorable baby HAZIQ.

3 vi ACKNOWLEDGEMENT Alhamdulillah, I am greatly indebted to ALLAH SWT on His blessing for making this study successfully. I would like to express my gratitude to honorable Dr. Razali Bin Ngah, my supervisor, for his guidance, support and encouragement throughout my study. I am also thank you to my colleagues for providing an enjoyable study environment at UTM. Finally, I would like to thank my husband and my mum, angah, nini and aishah for their full support and patience. For my baby, I hope to make up for all the lost time that we have not spent together.

4 vii ABSTRACT The demand for broadband services has driven research on millimetre wave frequency band communications for wireless access network due to its spectrum availability, and compact size of radio frequency devices. However, the mm-wave signals suffer from severe loss along the transmission as well as atmospheric attenuation. In other words, upcoming wireless networks will use a combination of airinterface methods in different channels and in different cells that can be changed dynamically to meet variations in traffic conditions. One of the solution to overcome these problem is by using low-attenuation, electromagnetic interference-free optical fiber. Radio over Fiber (RoF) is integration of optical fiber for radio signal transmission within network infrastructures that is considered to be cost-effective, practical and relatively flexible system configuration for long-haul transport of millimetric frequency band wireless signals. This project is about to simulate WCDMA Radio Over Fiber using Matlab Simulink. By doing so, the efficiency can be measured by the performance of BER (Bit Error Rate). The finding of this project is the WCDMA RoF is suite with 3G and 4G application along with increasing users every year whole the world. The conclusion is the simulation of WCDMA RoF was success developed throughout objective.

5 viii ABSTRAK Permintaan yang semakin tinggi dalam perkhidmatan jalur lebar telah membuka ruang para penyelidik untuk mengkaji dan menyelidik dalam bidang komunikasi jalur frekuensi gelombang milimeter untuk rangkaian penyampai tanpa wayar yang bergantung pada ketersediaan spektrum dan saiz kompak sesuatu alat radio frekuensi itu. Walau bagaimanapun, isyarat gelombang milimeter ini terancam kepada gangguan sepanjang proses penghantarannya seperti gangguan atmosfera. Dengan kata lain, perkembangan rangkaian tanpa wayar menggunakan kombinasi kaedah ruang hubungkait udara dalam saluran yang berlainan dan sel-sel yang berlainan yang boleh berubah secara dinamik untuk variasi penyesuaian dalam kondisi bebanan. Antara jalan penyelesaian untuk mengatasi masalah tersebut ialah menggunakan pengecilan yang rendah, gentian optik bebas gangguan elektromagnetik. Isyarat radio menggunakan gentian diintegrasikan dari gentian optik untuk penghantaran isyarat radio dalam rangkaian infrastruktur yang mempertimbangkan kos-efektif, praktikal dan sistem konfigurasi fleksibel secara relatif untuk penghantaran jarak jauh isyarat jalur frekuensi tanpa wayar. Projek ini berkisar dengan simulasi WCDMA isyarat radio dalam gentian menggunakan perisian Matlab Simulink. Dengan itu, keberkesanannya boleh diukur melalui kadar kesalahan bit (BER) yang diperolehi dari simulasi tersebut. Projek ini menemukan penggunaan WCDMA isyarat radio dalam gentian ini sangat sesuai digunakan bagi pembangunan sistem 3G dan 4G dengan pertambahan pengguna setiap tahun di seluruh dunia. Kesimpulannya, simulasi ini berjaya dibangunkan mengikut objektif projek.

6 ix TABLE OF CONTENTS CHAPTER TITLE PAGE DECLARATION DEDICATION ACKNOWLEDGEMENT ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF ABBREVIATIONS iv v vi vii viii ix xiii xiv xvi 1 INTRODUCTION 1.1 Introduction Objective of Study Scope of Project Research Methodology Thesis Outline 7

7 x 2 RADIO OVER FIBER 2.1 Introduction What Is RoF? The Radio Over Fiber Technology Radio Over Fiber System Radio Over Fiber Concept Advantages Of Using RoF In Mobile Communication Networks Benefits of Radio over Fiber Systems Low Attenuation Loss Large Bandwidth Immunity to Radio Frequency Interference Easy Installation and Maintenance Reduced Power Consumption Operational Flexibility Millimeter Waves Advantages of mm-waves Disadvantages of mm-waves Radio System Functionalities Applications of Radio over Fiber Technology Cellular Networks Satellite Communications Video Distribution Systems Mobile Broadband Services Wireless LANs Vehicle Communication and Control Summary 26

8 xi 3 WIDEBAND CODE DIVISION MULTIPLE ACCESS (WCDMA) 3.1 Introduction RoF Using WCDMA Parameters Of WCDMA WCDMA Overview Direct-Sequence CDMA Wideband Synchronization Aspects Modes of Operation Basic WCDMA Transmission Technologies Characteristics Of WCDMA (Technical) Highly Efficient Frequency Usage Freedom From Frequency Administration Low Mobile Station Transmit Power Resources Used Independently in Uplink and Downlink The Wideband Properties Of WCDMA Allow Higher Efficiency In The Following Aspects Wide Range of Data Speeds Improved Multipath Resolution Statistical Multiplexing Effect Reduced Intermittent Reception Rate Summary 46

9 xii 4 SIMULATIONS 4.1 Introduction Simulations BPSK Modulation QPSK Modulation QPSK Modulation using RoF Results and Discussion BPSK vs QPSK RoF with different of Fiber Length Summary 60 5 CONCLUSION AND SUGGESTIONS 5.1 Conclusion Suggestion For Future Research 62 REFERENCES 64

10 xiii LIST OF TABLES TABLE TITLE PAGE 3.1 Parameter of WCDMA Comparison of 2G and 3G CDMA Systems 34

11 xiv LIST OF FIGURES FIGURE TITLE PAGE 1.1 Research methodology flow chart Typical layout of a bidirectional analog optical link using direct modulation of laser diodes Radio over Fiber Concept Optically fed remote antenna network for microcellular RoF systems The basic techniques of the Direct Sequence Spread Spectrum Principles of DS-CDMA Allocation of bandwidth in WCDMA in the time-frequency-code space Spreading and dispreading in DS-CDMA Constellation Diagram for BPSK Block simulink for BPSK Modulation Constellation Diagram for QPSK Block simulink for QPSK Modulation Block simulink for WCDMA using RoF Theoretical BER performance with AWGN channel BER performance with AWGN channel for BPSK BER performance with AWGN channel for QPSK Comparison BER of BPSK and QPSK Comparison BER of BPSK, QPSK and Theory 56

12 xv 4.11 BER performance for fiber length 0.2 km BER performance for fiber length 1 km BER performance for fiber length 48 km Comparison BER between 0.2 km, 1 km and 48 km 59

13 xvi LIST OF ABBREVIATIONS AWGN BER BPSK BS DWDM EDFA FDD GMSK GSM IF IMDD ITS IVC LAN MBS MS MVDS OFDM OTDM POF PSK QAM QPSK Additive White Gaussian Noise Bit Error Rate Binary Phase Shift Keying Base Stations Dense Wavelength Division Multiplex Erbium Doped Fiber Amplifier Frequency Division Duplex Gaussian Minimum Shift Keying Global System for Mobile Communications Intermediate Frequencies Intensity Modulation and Direct Detection Intelligent Transport Systems Inter-Vehicle Communication Local Area Network Mobile Broadband System Mobile Station Multipoint Video Distribution Services Orthogonal Frequency Division Multiplexing Optical Time Division Multiplexing Polymer Optical Fiber Phase Shift Keying Quadrature Amplitude Modulation Quadrature Phase Shift Keying

14 xvii RAP RF RFI RHD RIN RS ROF RVC SC SMF TDD UMTS UTRA WBMCS WCDMA Radio Access Point Radio Frequency Radio Frequency Interference Remote Heterodyning and Detection Relative Intensity Noise Remote Station Radio Over Fiber Road-to-Vehicle Communication Switching Centre Single Mode Fiber Time Division Duplex Universal Mobile Telecommunication Systems Universal Terrestrial Radio Access Wireless Broadband Mobile Communication Systems Wideband Code Division Multiple Access

15 CHAPTER 1 INTRODUCTION 1.1 Introduction Radio over Fiber (RoF) application has attracted much attention recently because of the increasing demand for capacity/coverage and the benefits it offers in terms of low-cost base station deployment in macrocellular system. RoF systems are now being used extensively for enhanced cellular coverage inside buildings such as office blocks, shopping malls and airport terminal. RoF is fundamentally an analog transmission system because it distributes the radio waveform, directly at the radio carrier frequency, from a central unit to a Radio Access Point (RAP). Note that although this transmission system is analog, the radio system itself may be digital such as GSM. Mainstream optical fiber technology is digital. Telecommunication networks use synchronous digital hierarchy transmission technology in their cores. Fiber-based data networks such as fiber distributed data interface and gigabit Ethernet all use digital transmission. Fiber transmission links to base stations in mobile communications systems are digital. Digital optical fiber transmission links are therefore ubiquitous in telecommunications and data communications, constituting a high volume market worth billions of dollars worldwide.

16 2 Wideband Code Division Multiple Access (WCDMA), air interface can now is regarded as a mature technology ready to provide the basis for the third generation wireless personal communication systems, known as Universal Mobile Telecommunication Systems (UMTS). These systems will make extensive use of microcells and picocells in order to deliver high bandwidth services to customers. WCDMA also known as third generation systems. The systems are designed for multimedia communication can be enhanced with high quality images and video and access to information and services on public and private networks will be enhanced by the higher data rates and new flexible communication capabilities of third generation systems. This together with the continuing evolution of the second-generation systems will create new business opportunities for manufacturers, operators and the providers of content and applications using these networks. In the standardization forum, WCDMA technology has emerged as the most widely adopted third generation air interface. Its specification has been created in 3GPP (the 3 rd Generation Partnership Project), which is the joint standardization project of the standardization bodies from Europe, Japan, Korea, the USA and China. Within 3GPP, WCDMA is called UTRA (Universal Terrestrial Radio Access), FDD (Frequency Division Duplex) and TDD (Time Division Duplex). The name of WCDMA being used to cover both FDD and TDD operation. The benefit of using RoF for WCDMA distributed antenna systems is expected to be even more important, partly because of their higher frequency and bandwidth requirements. In this project, the simulation of WCDMA RoF using Matlab Simulink had successful developed. In this simulation, the fiber was represented by gain and 3 rd order

17 3 polynomial was represented laser diode. The complete simulink block successfully run and get BER performance to rate it. 1.2 Objective of Study Objective of this research is to simulate a WCDMA radio over fiber (RoF) for microcellular mobile communication systems using Matlab Simulink. To achieve this objective various simulink blocks are developed such as with AWGN Channel, polynomial as laser diode and gain is present fiber using MATLAB SIMULINK. From the research, main cause of using RoF is to shift the system complexity away from the remote base station antenna and toward centralized radio signal processing installation. In a RoF link, laser light is modulated by a radio signal and transported over an optical fiber medium. The laser modulation is analog since the radio-frequency carrier signal is an analog signal. The modulation may occur at the radio signal frequency or at some intermediate frequency if frequency conversion is utilized. The basic configuration of an analog fiber optic link consists of a bi-directional interface containing the analog laser transmitter and photodiode receiver located at a base station or remote antenna unit, paired with an analog laser transmitter and photodiode receiver located at a radio processing unit. One or more optical fibers connect the remote antenna unit to the central processing location.

18 4 1.3 Scope Of Project The works undertaken in this project are limited to the following aspects: i) Literature review. Reviews on the WCDMA using RoF technology by specific parameters of WCDMA. ii) Modeling and simulation of the WCDMA downlink system with RoF using suitable parameters for laser diode, fiber and photodiode. iii) Perform a simulation works by using a MATLAB/Simulink to observe BER. iv) Compare the performance of the normal AWGN channel and different length of fiber by setting different value of gain that present fiber.

19 5 1.4 Research Methodology The methodology of this research is shown in the flow chart in Figure 1.1 below:- Start Literature study Mastering in simulation tools Research on Radio over Fiber system Identify various parameters Setting strategy for evaluation Design Block Simulink Comparison between AWGN normal and AWGN using RoF Evaluate and verification BER using MATLAB End Figure 1.1 Research methodology flow chart

20 6 In the beginning, there are two tasks that need to be done simultaneously. Besides of doing literature review, exercises and tutorials need to be done for mastering the simulations tools and some preliminary simulations need to be carried out as well. Then, the problem of this research will be stressed with radio over fiber system that an alternative to increasing base station complexity is to move the complex portions of the network to a central processing location where the number of expensive signal processing elements can be reduced by greater sharing among users. Thus, identify various parameters and set the strategy for evaluation that can be used to develop the block simulink. After the preliminary research, the design of block simulink are developed and tested by several of parameters. Then, comparison between normal case and new case is done to get the result. All simulink is using MATLAB SIMULINK. Finally, the proposed block simulink will be evaluated with BER (bit error rate) to determine the performance.

21 7 1.5 Thesis Outline The thesis is structured as follows. The Chapter 1 discusses the general introduction of this project. Chapter 2 outlines the project background of this project, which is including the basic introduction of RoF (Radio over Fiber) and further knowledge about RoF and their characteristics. Chapter 3 outlines the literature review of this project that is introduce more to WCDMA technologies and characteristics. Chapter 4 contains simulation and result. The conclusion of the results and recommendation for future works will be presented in Chapter 5.