The all-around presence of wireless communication links combined with functions that support mobility will make a roaming person-bound communication network possible in the near future. This idea of a personal network, in which a user has his own communication
environment available everywhere. The overall aim of this research project was to simulate the transmission wireless and baseband RF signals via fibre for a long distance in high quality, consuming a low-power budget. Therefore, this thesis demonstrated a green radio communication network and the advantage of transmitting signals via fibre rather than via air. The contributions of this research work were described in the follows:Firstly, a comparison of the power consumption in WiMAX via air and fibre is presented. As shown in the simulation results, the power budget for the transmission of 64 QAM WiMAX IEEE 802.16-2005 via air for a distance of 5km lies at -189.67 dB, whereas for the transmission via RoF for a distance of 140km, the power consumption ranges at 65dB. Through the deployment of a triple symmetrical compensator technique, consisting of SMF, DCF and FBG, the transmission distance of the 54 Mbps WiMAX signal can be increased to 410km without increasing the power budget of 65dB. An amendment of the triple compensator technique to SMF, DCF and CFBG allows a 120Mbps WiMAX signal transmission with a clear RF spectrum of 3.5 GHz and constellation diagram over a fibre length of 792km using a power budget of 192dB. Secondly, the thesis demonstrates a simulation setup for the deployment of more than one wireless system, namely 64 QAM WiMAX IEEE 802.16-2005 and LTE, for a data bit rate of 1Gbps via Wavelength Division Multiplexing (WDM) RoF over a transmission distance of 1800km. The RoF system includes two triple symmetrical compensator techniques - DCF, SMF, and CFBG - to obtain a large bandwidth, power budget of 393.6dB and a high signal quality for the long transmission distance. Finally, the thesis proposed a high data bit rate and energy efficient simulation architecture, applying a passive optical component for a transmission span up to 600km. AGigabit Optical Passive Network (GPON) based on RoF downlink 2.5 Gbps and uplink 1.25Gbps is employed to carry LTE and WiMAX, also 18 digital channels by utilising Coarse Wavelength Division Multiplexing (CWDM). The setup achieved high data speed, a lowpower budget of 151.2dB,and an increased service length of up to 600km.
Table of Contents
1. Introduction
1.1 Wireless Access Network
1.2 Research Motivation
1.3 Green Radio Communication
1.4 Fibre Optic Access Network
1.4.1 Radio over Fibre (RoF)
1.4.2 Challenges and Problems in RoF
1.5 Research Objective and Contributions
1.5.1 RoF base SMF, DCF, FBG and CFBG
1.5.2 WDM-RoF
1.5.3 GPON/CWDM-RoF
1.6 Thesis Structure
2. Literature Review - Fundamental Concept of Fibre Optic Technology
2.1 Introduction
2.2 Propagation of Light
2.2.1 Refraction of Light Waves
2.2.2 Nonlinear Schrödinger Equation (NLS)
2.3 Optical Fibre
2.3.1 Multi Mode Fibre (MMF)
2.3.2 Single Mode Fibre (SMF)
2.4 Fibre Attenuation
2.4.1 Low Water Peak
2.4.2 Rayleigh Scattering
2.5 Dispersion
2.5.1 Intermodal or Modal Dispersion
2.5.2 Intra-modal or Chromatic Dispersion
2.5.2.1 Material Dispersion
2.5.2.2 Wave-guide Dispersion
2.6 Dispersion Compensating Modules (DCM)
2.6.1 Dispersion Compensating Fibre (DCF)
2.6.2 Fibre Bragg Grating (FBG)
2.6.3 Chirped Fibre Bragg Gratings (CFBG)
2.7 Radio over Fibre in Communication Networks
2.7.1 Direct Modulation
2.7.2 External Modulator
2.8 Applications in RoF Networks
2.8.1 RF over Fibre (Remote RoF)
2.8.2 Orthogonal Frequency-Division Multiplexing (OFDM)
2.8.3 Wavelength Division Multiplexing (WDM)
2.8.4 Dense Wavelength Division Multiplexing (DWDM)
2.8.5 Coarse Wavelength Division Multiplexing (CWDM)
2.9 Chapter Summary
3. 64-QAM WiMAX Signals Distributed via RoF Applying Different Compensators
3.1 Overview
3.2 Introduction
3.3 Methodology
3.4 Setups and Simulations of Green Radio Solutions for the Deployment of WiMAX
3.4.1 WiMAX-Tx via Air
3.4.1.1 Simulation Results and Discussion
3.4.2 WiMAX via RoF-SMF
3.4.2.1 Simulation Results and Discussion
3.4.3 WiMAX via RoF (SMF-DCF)
3.4.3.1 Simulation Results and Discussion
3.4.4 WiMAX via RoF (SMF-DCF-FBG)
3.4.4.1 Simulation Results and Discussion
3.4.5 Extended Mobile WiMAX Signal Transmission over RoF via Triple Symmetrical Dispersion System SMF, DCF and CFBG
3.4.5.1 Related Work
3.4.5.2 Theory and Analyses
3.4.5.3 WiMAX via RoF (SMF-DCF-CFBG)
3.4.5.4 Simulation Results and Discussion
3.5 Chapter Summary
4. LTE and WiMAX Signal Transmission via WDM-RoF for a Length of 1800km
4.1 Overview
4.2 Introduction
4.3 Related Work
4.4 Theory and Analyses
4.5 System Description and Simulation
4.6 Simulation Results and Discussion
4.7 Chapter Summary
5. Efficient Transmission of WiMAX, LTE and CWDM Channels via GPON-RoF
5.1 Overview
5.2 Introduction
5.3 Related Work
5.4 Passive Optical Network (PON) Technologies
5.4.1 APON / BPON
5.4.2 Ethernet Passive Optical Network (EPON)
5.4.3 Gigabit Passive Optical Network (GPON)
5.5 Simulation Design of GPON-CWDM via RoF and Discussion
5.5.1 GPON-CWDM via RoF for fibre length of 210km
5.5.2 SMF, DCF, and CFBG Extended GPON Network for Fibre length 600km
5.6 Simulation Results and Discussion
5.6.1 GPON/CWDM Based RoF for a SMF length of 210km
5.6.2 RoF Based GPON - CWDM System for Transmission of LTE/WiMAX/ Baseband over 600km
5.7 Chapter Summary
6. Conclusion and Future Work
6.1 Conclusion
6.1.1 Performance of WiMAX Signals Distributed via RoF Applying Symmetrical Compensators
6.1.2 Performance of LTE and WiMAX Signal transmission via WDM-RoF for a length of 1800km
6.1.3 Performance of WiMAX, LTE and CWDM Channels via GPON-RoF
6.2 Future Work
6.2.1 WiMAX- Femtocell via RoF
6.2.2 Sleep Mode in the RoF System
Objectives and Topics
The primary objective of this research is to develop energy-efficient "green" radio communication networks by leveraging Radio-over-Fibre (RoF) technology. The research addresses the challenges of high power consumption and signal degradation in long-distance wireless transmissions by proposing and simulating architectures that integrate WiMAX, LTE, and baseband signals over fibre optic infrastructure using various dispersion compensation techniques.
- Power efficiency in wireless and fibre-based access networks.
- Mitigation of chromatic dispersion using SMF, DCF, FBG, and CFBG techniques.
- Integration of multiple wireless systems (WiMAX and LTE) via WDM and RoF.
- Implementation of high-capacity GPON-CWDM architectures.
- Simulation-based validation using OptiSystem software.
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1.2 Research Motivation
The main challenge of wireless access networks is the vast amount of energy needed to power the base stations. A typical 3G base station needs 12.5 times more input power than it produces output RF power (500W input; 40W output), which adds up to an annual energy consumption of approximately 4.5MWh [5]. With 12,000 base stations building up a 3G mobile network, it consumes more than 50GWh a year. For example, Vodafone needs one million litres of diesel per day to operate its remote base stations worldwide [5]. The number of mobile subscribers is increasing continuously and at the same time the amount of energy consumption. The fact is that sending more data requires more RF energy. At the Mobile World Congress this year, a sale of worldwide 1.4 billion handsets in 2010 was announced, where the Chinese market had 842 million subscribers and presently only 15 per cent on 3G networks [5]. The global shift from 2G to 3G networks, with predicted 775 million handsets supporting 3G in 2011, takes part in the rising quantity of data and so the rising amount of energy needed to transfer the data [6]; 30 to 40 per cent of the total cost of a base station is caused by the power amplifier [6]. The RF cable, carrying the signal between the power amplifier and the antenna introduce some loss that also increases the transmission cost. Furthermore, the cables are expensive, afford strong mechanical support, due to their heaviness, and are regarded as one of the main causes for mechanical problems in base stations. Another challenge for broadband wireless systems is the Mobility Management to find the right balance between capacity and coverage. The wireless network needs to provide the device to reach inactive/active users everywhere in the network, which is described as roaming also, to maintain a persisting session free from interruption while the user is moving (handoff).
Summary of Chapters
Chapter 1: Provides the research background, identifies key challenges like high power consumption, and outlines the research objectives focused on green radio via RoF.
Chapter 2: Reviews the fundamental technical concepts, including light propagation, fibre types, dispersion, and various fibre components like DCF, FBG, and CFBG.
Chapter 3: Compares WiMAX transmission via air and RoF, proposing symmetrical dispersion compensation setups to extend transmission distances up to 792km.
Chapter 4: Examines the integration of LTE and WiMAX via WDM-RoF, achieving signal transmission over 1800km using a triple compensation technique.
Chapter 5: Focuses on the efficient transmission of WiMAX, LTE, and CWDM channels using GPON-RoF, demonstrating successful 600km signal transmission with a low-power budget.
Chapter 6: Concludes the thesis by summarizing the findings and suggesting future research areas, such as implementing femtocells and sleep-mode operations in RoF systems.
Keywords
Radio-over-Fibre, RoF, Green Radio, WiMAX, LTE, Chromatic Dispersion, Dispersion Compensating Fibre, DCF, Chirped Fibre Bragg Grating, CFBG, Wavelength Division Multiplexing, WDM, Passive Optical Network, PON, GPON
Frequently Asked Questions
What is the core focus of this research?
This work focuses on designing energy-efficient radio communication networks by using Radio-over-Fibre (RoF) technology to minimize power consumption in wireless base stations.
What are the key themes addressed in this thesis?
The research addresses signal transmission challenges in long-distance networks, specifically focusing on overcoming fibre attenuation and chromatic dispersion using various optical components.
What is the primary goal of the research?
The primary goal is to simulate and demonstrate high-quality signal transmission for WiMAX and LTE systems over extended fibre distances while maintaining a significantly low power budget.
Which scientific methods are applied?
The research relies on comprehensive simulation experiments using the professional software tool OptiSystem, which allows for the accurate modelling of complex fibre-optic network parameters.
What is the main subject of the main part of the thesis?
The main part covers the deployment of specific fibre-based setups to handle signal dispersion and power consumption, testing them with mobile broadband standards like WiMAX and LTE over distances ranging from several hundred to 1800km.
Which keywords define this work?
The work is defined by terms such as RoF, Green Radio, WiMAX, LTE, chromatic dispersion, fibre optics, and PON technologies.
How does the author address the problem of signal dispersion?
The author uses a "triple symmetrical compensator technique" utilizing a combination of Single Mode Fibre (SMF), Dispersion Compensating Fibre (DCF), and Chirped Fibre Bragg Gratings (CFBG) to cancel out dispersion effects.
What is the benefit of the GPON-CWDM architecture proposed in the final chapter?
The proposed architecture integrates 18 digital channels and wireless services over a single infrastructure, allowing for significant energy savings by utilizing coarse wavelength spacing, which eliminates the need for expensive, temperature-controlled lasers.
- Arbeit zitieren
- Dr. Mazin Al Noor (Autor:in), 2011, Green Radio Communication Networks Applying Radio-over-Fibre Technology for Wireless Access, München, GRIN Verlag, https://www.grin.com/document/196589
