Sevia Mahdaliza Idrus

Optical wireless communications : IR for wireless connectivity

INTRODUCTION Technology Overview System Configurations Evolution of Infrared Communication Systems The Optical Wireless Channel Design Fundamentals Power Budget Considerations Summary and Conclusions ATMOSPHERIC TRANSMISSION LIMITATIONS Introduction to Atmospheric Propagation Important Definitions Atmospheric Transmission Effect of Rain, Fog, and Mist Scintillation Summary and Conclusions DATA TRANSMISSION LIMITATIONS AND EYE SAFETY Data Transmission Limitations Eye Safety Extended vs. Collimated Sources Holographic Diffusers LEDs vs. LDs Special Considerations for Outdoor Systems Summary and Conclusions FUNDAMENTALS OF OPTICAL CONCENTRATION Overview of Optical Concentration Geometrical Optics and Ray Tracing Optical Path Length and Fermats Principle The Etendue or Lagrange Invariant The Edge Ray Principle Concentration Ratio Summary and Conclusions OPTICAL CONCENTRATORS Overview of Optical Concentrators Wireless IR Receiver Requirements Optical Filters Optical Concentrators DTIRC Characteristics Comparison of Concentrators Practical Issues Other Shapes of DTIRCs Summary and Conclusions OPTICAL WIRELESS TRANSMITTER DESIGN Introduction to Optical Wireless Transmitter Design Transmitter Design Considerations Optical Source Characteristics Types of Optical Modulation Driver Circuit Design Concepts Current Steering Output Circuit Back Termination Circuit Predriver Data Retiming Automatic Power Control Transmitters Linearization Techniques OPTICAL WIRELESS RECEIVER DESIGN Receiver Design Considerations Photodetection in Reverse-biased Diodes Choosing the Photodetector Receiver Noise Consideration Bit Error Rate and Sensitivity Bandwidth Signal Amplification Techniques Receiver Main Amplifier (RMA) Transceiver Circuit Implementation Technologies: Hybrid and Monolithic Integration Summary and Conclusions MODULATION, CODING, AND MULTIPLE ACCESS Introduction to Modulation and Multiple Access Techniques Modulation Modulation Techniques Comparison Modulation Schemes in The Presence of Noise Modulation Schemes in the Presence of Multipath Distortion Multiple Access Techniques Summary and Conclusions IrDA PROTOCOLS Wireless Protocol Standards The Infrared Data Association IrDA Standard Overview The Physical Layer Protocol Framer/Driver IrLAP IrLMP Information Access Service and Protocol Tiny Transport Protocol Session and Application Layer Protocols Summary and Conclusions WIRELESS IR NETWORKING Introduction to Wireless IR Networking Network Architecture Optical Wireless Network Specifications The Ad Hoc Network Quality of Service (QoS) Future Infrared Networking REFERENCES

IEEE 802.15.3c WPAN Standard Using Millimeter Optical Soliton Pulse Generated by a Panda Ring Resonator

A system of microring resonators (MRRs) connected to an optical modified add/drop filter system known as a Panda ring resonator is presented. The optical soliton pulse of 60 GHz frequency band can be generated and used for Wireless Personal Area Network (WPAN) applications such as IEEE 802.15.3c. The system uses chaotic signals generated by a Gaussian laser pulse propagating within a nonlinear MRRs system. The chaotic signals can be generated via a series of microring resonators, where the filtering process is performed via the Panda ring resonator system wherein ultrashort single and multiple optical soliton pulses of 60 GHz are generated and seen at the through and drop ports, respectively. The IEEE 802.15.3c standard operates at the 60 GHz frequency band, and it is applicable for a short distance optical communication such as indoor systems, where the higher transmission data rate can be performed using a high frequency band of the output optical soliton pulses. The single and multi-soliton pulses could be generated and converted to logic codes, where the bandwidths of these pulses are 5 and 20 MHz, respectively. Thus, these types of signals can be used in optical indoor systems and transmission link using appropriate components such as transmitter, fiber optics, amplifier, and receiver.

All-Optical OFDM Generation for IEEE802.11a Based on Soliton Carriers Using Microring Resonators

The optical carrier generation is the basic building block to implement all-optical orthogonal frequency-division multiplexing (OFDM) transmission. One method to optically generate single and multicarriers is to use the microring resonator (MRR). The MRRs can be used as filter devices, where generation of high-frequency (GHz) soliton signals as single and multicarriers can be performed using suitable system parameters. Here, the optical soliton in a nonlinear fiber MRR system is analyzed, using a modified add/drop system known as a Panda ring resonator connected to an add/drop system. In order to set up a transmission system, i.e., IEEE802.11a, first, 64 uniform optical carriers were generated and separated by a splitter and modulated; afterward, the spectra of the modulated optical subcarriers are overlapped, which results one optical OFDM channel band. The quadrature amplitude modulation (QAM) and 16-QAM are used for modulating the subcarriers. The generated OFDM signal is multiplexed with a single-carrier soliton and transmitted through the single-mode fiber (SMF). After photodetection, the radio frequency (RF) signal was propagated. On the receiver side, the RF signal was optically modulated and processed. The results show the generation of 64 multicarriers evenly spaced in the range from 54.09 to 55.01 GHz, where demodulation of these signals is performed, and the performance of the system is analyzed.

W-Band OFDM Transmission for Radio-Over-Fiber Link Using Solitonic Millimeter Wave Generated by MRR

A system comprises of a W-band (75-110 GHz) optical millimeter (mm)-wave generation using microring resonators (MRRs) and radio-over-fiber (RoF) link architectures is presented for multigigabit data rates demand. The MRRs are used to generate optical mm-wave soliton pulses for W-band applications. To achieve faster transmission speed wirelessly, higher spectral efficiency (SE) and better transmission performance, orthogonal frequency-division multiplexing (OFDM) is used. The results show that the MRRs support W-band optical soliton pulses, which can be used in an OFDM transmission/receiver system. Localized narrow bandwidth soliton pulses within frequencies of 92.2-93.2 GHz can be seen in the throughput port of the Panda system with respect to the full width at half maximum and free spectrum range of 3.5 and 184 MHz, respectively. The error vector magnitude of the system was measured and the viability of the solitonic OFDM-based system for RoF link over 25-Km fiber link and 2-m wireless link was confirmed. The data rate of the system with 16-quadrature amplitude modulation is measured as 43.6 Gb/s and with 10 GHz of bandwidth, the SE is obtained as 4.36 bit/s/Hz.

W-Band OFDM for Radio-over-Fiber Direct-Detection Link Enabled by Frequency Nonupling Optical Up-Conversion

A system involving W-band (75-110 GHz) optical millimeter (mm)-wave generation using the external optical modulator (EOM) in a radio-over-fiber (RoF) link is presented for satisfying the requirements for multi-gigabit-per-second data rates. A 90-GHz mm-wave signal was generated by a nonupling (nine times) increase in only a 10-GHz local oscillator by biasing the EOM at its zero level and choosing an appropriate modulation index. To achieve a fast transmission speed wirelessly, high spectral efficiency (SE), and better transmission performance, orthogonal frequency-division multiplexing (OFDM) is used. The bit error rate (BER) and error vector magnitude (EVM) of the system were measured for three different fiber lengths and for a wireless distance of 1-5 m. The results show that the system with the SE of ~4 (b/s)/Hz and 16-ary quadrature amplitude modulation (QAM) 40-GB/s OFDM signals can be received by the end user with BER less than 3.8 × 10-3 and EVM less than 25% over a 50-km optical fiber and 3-m wireless link.

Transmission of data with orthogonal frequency division multiplexing technique for communication networks using GHz frequency band soliton carrier

Microring resonators (MRRs) can be used to generate optical millimetre-wave solitons with a broadband frequency of 40-60 GHz. Non-linear light behaviours within MRRs, such as chaotic signals, can be used to generate logic codes (digital codes). The soliton signals can be multiplexed and modulated with the logic codes using an orthogonal frequency division multiplexing (OFDM) technique to transmit the data via a network system. OFDM uses overlapping subcarriers without causing inter-carrier interference. It provides both a high data rate and symbol duration using frequency division multiplexing over multiple subcarriers within one channel. The results show that MRRs support both single-carrier and multi-carrier optical soliton pulses, which can be used in an OFDM based on whether fast Fourier transform or discrete wavelet transform transmission/receiver system. Localised ultra-short soliton pulses within frequencies of 50 and 52 GHz can be seen at the throughput port of the panda system with respect to full-width at half-maximum (FWHM) and free spectrum range of 5 MHz and 2 GHz, respectively. The soliton pulses with FWHMs of 10 MHz could be generated at the drop port. Therefore, transmission of data information can be performed via a communication network using soliton pulse carriers and an OFDM technique.

An overview of radio-over-fiber network technology

Current trends for future provision of broadband, interactive and multimedia services over wireless media in both mobile and fixed cellular networks are- 1) to reduce cell size to accommodate more users and 2) to operate in the microwave/millimeter wave (mm-wave) frequency bands to avoid spectral congestion in the lower frequency bands. The development of a cost-effective Base Station (BSs) is a key to be success in the market. Radio-over-fiber (RoF) technology is a promising solution for this requirement. This technique involves modulating the radio frequency (RF) subcarrier onto an optical carrier for distribution over a fiber network. Optical fibers are attractive for RoF systems due to the following characteristics: very high bandwidth, low loss, immune to EMI, light weight, small cross section, low cost, and high flexibility. Such an advantageous system will be presented throughout this paper including the backgrounds, architectures, benefits and limitations, and its milestone.

Review on system architectures for the millimeter-wave generation techniques for RoF communication link

Generation of millimeter-wave (mm-wave) signal for radio over fiber (RoF) currently being investigated and studied by many researchers due to the demand of the mm-wave band for future communication system mostly in wireless local area networks (WLANs) applications. RoF is a system where high microwave frequency signals are delivered through optical fiber between the central station (CS) and the base stations (BSs). The use of optical fiber for signal distribution in mm-wave radio communication systems has been widely investigated, since they provide high bandwidths and small cell sizes (picocell). They also offer the potential for the low cost infrastructure needed to develop broadband mobile services. This paper will explain the whole picture of RoF technology followed by RoF link configurations where radio frequency (RF) signal can be transmitted directly over fiber either at the RF or intermediate frequency (IF) signals. The review mainly focuses on the mm-wave generation techniques for radio over fiber including: optical heterodyning, external modulation, optical transceiver, and up- and down-conversion.

Modeling and performance study of inter-satellite optical wireless communication system

Optical communications systems have evolved from lengthy fibers to powerful wireless system. This has hence resulted in the use of optical wireless communication system in space communications. As the number of satellites orbiting Earth increase year by year, a network between the satellites provides a method for them to communicate with each other. This is important for satellites to send information to one another and also to relay the information from one satellite to another satellite and then to the ground stations. By using laser satellite communication, the satellites can be connected with data rates up to several Gbps. The paper will present the optical wireless communication (IsOWC) link performance focusing on data transfer between Low Earth Orbit satellites. The system performance including bit rates, input power, wavelength and distance on an inter-satellite link were analyzed.

Performance Analysis of the OFDM Scheme for Wireless over Fiber Communication Link

 Abstract—Radio over fiber (ROF) has been developed since 20 th century and has been used efficiently for the provision of untethered access to broadband wireless communications in a range of applications including last mile solutions, extension of existing radio coverage and capacity, and backhaul. RoF is the next generation communication systems that can utilize the high capacity of optical networks along with the mobility of wireless networks. Optical fiber has many advantages compared to conventional system with low attenuations and superior signal integrity found, it allow much longer intervals of signal transmission. It is not unusual for optical systems to go over 100 kilometers, emerging technologies promise even greater distances in the future. By incorporating OFDM along with RoF, the system can be used for both short distance as well as long-haul transmission at very high data rate. Large capacity RF signals as well as ultra-wide band wireless access is achieved. This paper investigates the performance and characteristics of Orthogonal Frequency Division Multiplexing (OFDM) as a modulation technique for a ROF. The project is about to modeling and simulates OFDM Radio Over Fiber scheme using latest commercial software called Optisystem. This is the pre-exquisite method that only uses standard components of optical telecommunications. As a result the model of this paper can be used with different wireless communication systems such as high data rate Wireless LANs, Fiber-To-Home (FTH), WiMax, and Digital Video Broadcasting (DVB) and it is supporting to the 4th generation cellular systems. The detail of the design in Optisystem and simulated results for the proposed model are shown and elaborate.