Duobinary RF envelope detection in coherent optical millimeter-wave systems (original) (raw)
2012
We propose a millimeter-wave (MMW) coherent radio-over-fiber (RoF) transmission system for application to an access network with a direct broadband last-mile wireless connection to an optical fiber network. The coherent RoF system comprises an optical twotone RoF signal generator with an advanced modulation format for high-throughput transmission and employs a digital-signal-processing-aided coherent detection technique for MMW radio, which is a technique similar to that of optical digital coherent detection. As proof of concept, a 20-GBd quadrature phase-shift keying RoF transmission over 20 km of optical fiber before a radio transmission over 20 m of air is demonstrated. The results of the radio transmissions using Cassegrain-type antenna pairs with a gain of 50 dBi are consistent with theoretical estimations; this suggests the possibility of developing a midrange transmission system using a high-power MMW amplifier.
A Full-Duplex Optical Millimeter Waves (60-100 GHz) Radio-over-Fiber System
2020 12th International Symposium on Communication Systems, Networks and Digital Signal Processing (CSNDSP)
In this paper, we propose and simulate the most compact full-duplex optical millimeter wave radioover-fiber (mmW-RoF) system employing binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) with error-free transmission over 10, 25 and 50 km of single mode fibers (SMF) in up-link (UL) and down-link (DL). We evaluate the EVM values for DL and UL are < 24% for BPSK and QPSK over the 10, 25 and 50 km of SMF. Keywords-full-duplex optical millimeter wave radio-overfiber(Optical mmW-RoF); dual parallel Mach-Zehnder modulator (DP-MZM
Journal of Lightwave Technology, 2000
In this paper, we propose a novel and cost effective system for optical millimeter-wave (mm-wave) generation and transmission of downstream data based on a gain switched laser (GSL). The GSL produces an optical comb spectrum that can be appropriately filtered to generate two optical sidebands spaced by more than 4 times the repetition rate of the GSL. These sidebands are modulated by baseband data and then transmitted via optical fiber to the remote antenna unit (RAU). At the RAU, the two sidebands are heterodyned using a photodetector to generate the electrical modulated mm-wave signal, before demodulation using self mixing. We demonstrate the distribution of 1.25 Gbit/s data OOK modulated onto a 60 GHz carrier, similar to that used in the IEEE 802.15.3c draft standard, over fiber lengths up to 62 km.
Optically envelope detected QAM and QPSK RF modulated signals in hybrid wireless-fiber systems
Microwave and Optical Technology Letters, 2009
We experimentally demonstrate optical envelope detection of 40 Mbaud 16-QAM and QPSK RF modulated signals. The proposed system employs an electro-absorption modulator performing the function of an optical halfwave rectifier. In this experiment, the QAM and QPSK signals are frequency down converted from a 1.6 GHz carrier frequency to an IF at 500 MHz, requiring no high frequency local oscillator and mixer at the remote base station. This result proves the feasibility of optical envelope detection for complex modulation formats of RF signals for hybrid wireless-fiber transmission links. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 864–866, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24182
Journal of Lightwave Technology, 2000
We have proposed and experimentally demonstrated three different optical front-ends to implement in wavelengthdivision-multiplexing (WDM) radio-over-fiber (ROF) networks to minimize the cost of the ROF system. When the number of WDM channels is small, such as smaller than four channels, the simplest front-end to generate WDM optical millimeter (mm)-wave signals is to use only broadband direct-modulation laser (DML) for each WDM channel. In this case, the expensive external modulator can be removed. However, when the number of WDM channels is large, such as larger than four, the frond-end to generate WDM optical mm-wave signals can be realized by using an external modulator to upconvert simultaneously all channels after the WDM channel signals are multiplexed. In this way, the cost of the expensive external modulator will be shared by all channels. For seamless integration of WDM signals that come from the existing backbone with ROF system, a broadband external modulator can be used to upconvert WDM signals.
IEEE Photonics Technology Letters, 2000
In this letter, a novel technique for direct conversion of an optical baseband quadrature phase-shift keying (QPSK) signal to a millimeter-wave wireless signal and subsequent signal demodulation is reported. Optical heterodyne mixing of the optical baseband QPSK signal with a free-running unmodulated laser for the wireless signal generation is employed. To correct for the phase and frequency offset originating from the heterodyne mixing of the two free-running lasers, wireless signal demodulation based on optical coherent detection in combination with baseband digital signal processing is implemented. As a proof of concept, 5-Gb/s amplitude-shift keying and up to a 16-Gb/s QPSK wireless signal in the band of 75-110 GHz was generated and successfully demodulated. All-photonic millimeter-wave wireless signal generation and digital coherent detection at baud-rate are employed without complex optical phase-locked loop.
IEEE Transactions on Microwave Theory and Techniques, 2006
In this paper, we propose a novel millimeter-waveband radio-over-fiber (RoF) system with a dense wavelengthdivision multiplexing (DWDM) bus architecture. Two lasers with a small wavelength difference, phase locked and polarization aligned, are allocated at a central station (CS) for connecting the CS and each base station (BS), one laser for transmitting and the other for detection (the remote local oscillator). For the conceptual illustration, we consider a DWDM RoF system with a channel spacing of 12.5 GHz and RF of 30-GHz millimeter-wave band. In the downlink system, a single-sideband (SSB) subcarrier is used with low RF imposed on an optical carrier at the CS, and an millimeter-wave-band RF signal is obtained at each BS using direct photodetection by the SSB subcarrier beat with the remote oscillator. In the uplink system, the received millimeter-wave-band RF signal at each BS is imposed on the two optical carriers simultaneously, one optical carrier with the closest SSB subcarrier is optically filtered out and fed into in the uplink transmission fiber without frequency interleaving; the electrical signal with a low IF can be photodetected directly at the CS. Such an RoF system has simple, cost-effective, and maintenance-reduced BSs, and is immune to laser phase noise in principle. Index Terms-Access networks, millimeter-wave communications, optical fiber communications, radio-over-fiber (RoF), subcarrier modulation, wavelength-division multiplexing. I. INTRODUCTION I N ORDER to provide broad-band service in local wireless access networks, exploring where the RF can be allocated with a large amount of bandwidth to implement broad-band services has been explored across the world [1]. Due to the limited availability of the RF bands, the fourth generation of wireless access systems would be moved to millimeter-wave band. However, cost-effective technology and systems have to be developed to deliver the millimeter-wave-band signals. The hybrid radio-over-fiber (RoF) system has been studied for many years as a promising technique for providing wireless broad-band service [2]-[24]. The advantage of the RoF system is that complicated signal processing can be localized at the central station Manuscript
IEEE Photonics Technology Letters, 2000
We proposed and experimentally demonstrated a novel scheme to generate an optical millimeter-wave and realized wavelength reuse for uplink connection in a radio-over-fiber system. We employed an optical interleaver to separate the spectrum of the double-sideband signals generated by a single-arm intensity external modulator. The separated first-order sideband modes were used to generate optical millimeter-wave with double RF frequency, while the separated optical carrier was reused for uplink connection.
2012
A simplified millimeter-wave (mm-wave) radio-over-fiber (RoF) system employing a combination of optical heterodyning in signal generation and radio frequency (RF) self-homodyning in data recovery process is proposed and demonstrated. Three variants of the system are considered in which two independent uncorrelated lasers with a frequency offset equal to the desired mm-wave carrier frequency are used to generate the transmitted signal. Uncorrelated phase noise in the resulting mm-wave signal after photodetection was overcome by using RF self-homodyning in the data recovery process. Theoretical analyses followed by experimental results and simulated characterizations confirm the system's performance.
Simplified Coherent Receiver for Analogue Radio Transmission Over High Optical Budgets
Journal of Lightwave Technology, 2021
The bandwidth and latency demands driven by 5G wireless networks are putting a focus on analog radio-over-fiber techniques as a promising candidate for broadband optical fronthauling. In contrast to intensity modulation / direct detection systems, as they are commonly adopted for mobile fronthaul links due to their simplicity, we are exploring a migration option towards coherent radio-over-fiber transmission. A simplified coherent homodyne receiver based on an electroabsorption modulated laser is co-integrated at the die-level with a transimpedance amplifier and evaluated for analogue coherent radio-over-fiber transmission. This low-complexity homodyne receiver can unlock channel selectivity and high receiver sensitivity inherent to coherent detection, but without the need for digital signal processing. We will demonstrate a sensitivity that allows for an optical budget of 42 dB, and thus eases the fixed-mobile convergence in power-splitting fiber plants. We further show filterless radio signal reception in presence of modulated adjacent channels. Signal integrity is confirmed through transmission of orthogonally frequency multiplexed radio signals with 16-point quadrature amplitude modulated formats, with an error vector magnitude below the corresponding antenna limit.
Multi-channels radio-over-fiber system using direct detection method
8TH ENGINEERING AND 2ND INTERNATIONAL CONFERENCE FOR COLLEGE OF ENGINEERING – UNIVERSITY OF BAGHDAD: COEC8-2021 Proceedings
This paper investigates the performance of high data rate Radio-over-Fiber (RoF) system for multi-channels radio frequency (RF), 2.4 GHz, 5 GHz, 7.5 GHz and 10 GHz respectively. Each RF channel is phase modulated with a simple modulation scheme named Binary phase shift keying (BPSK) which has a high immunity against errors over long distance transmission. These four channels form four subcarriers that are combined together via a power combiner device. The combined output is externally modulated by a single optical laser beam at wavelength of 1550 nm via a dual Mach-Zehnder modulator (MZM). The optical signal is transmitted over a single mode optical fiber and detected by a single laser diode (LD) to transfer the optical signal to an electrical one. The output of the LD is divided into four identical signals and each signal is phase demodulated to retrieve the initial data. It is found that the RoF system is robust against noise, losses and attenuation over 50 Km optical fiber channel length. In addition, high quality factor Q and high height eye diagram are obtained, furthermore, the simplicity of using direct detection at the receiver side which decrease the complexity of the system and reduce the cost. The system is tested under Optisystem 7 software simulation.
Journal of Lightwave Technology, 2000
The performance of wireless signal generation and detection at millimeter-wave frequencies using baseband optical means is analyzed and experimentally demonstrated. Multigigabit wireless signal generation is achieved based on all-optical orthogonal frequency division multiplexing (OFDM) and photonic upconversion. The received wireless signal is optically modulated and detected using digital coherent detection. We present a theoretical model, ultimate performance limitations based on simulations as well as experimental validation of the proposed architecture. In order to demonstrate the RF scalability and bit-rate transparency of our proposed approach, we experimentally demonstrated generation and detection in the 60 GHz and 75-110 GHz band of an all-optical OFDM quadrature phase shift keying, with two and three subcarriers, for a total bit rate over 20 Gb/s. Index Terms-Coherent detection, high-speed wireless, optical heterodyning, optical orthogonal frequency division multiplexing (OFDM), radio-over-fiber.
Investigation of optical millimeter-wave and heterodyne techniques in radio-over-fibre systems
2011
Radio over Fibre (RoF) has been proposed as an alternative medium to extend the coverage of radio frequency (RF) millimetre wave (MMW). The main challenges are the fibre attenuation and chromatic dispersion which degrade the signal power and induces inter-symbol interference (ISI), respectively. Two electrical modulation schemes are employed in this paper, namely binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) at electrical bandwidth of 30 GHz. The proposed technique using optical continuous wave (CW) laser as the optical carrier to transmit BPSK and QPSK signals at 30 GHz. The performance of the proposed method than compared to optical MMW carrier at 60 GHz in order to carry 30 GHz BPSK and QPSK electrical signals. The results indicate the improvement in transmission distance of up to 20 km for both BPSK and QPSK modulation schemes at signal to noise ratio (SNR) of 11 dB and 16 dB respectively for bit error rate (BER) of 10 -5 in the proposed method. These results compared to 15 km and 10 km in case of optical MMW using BPSK and MMW QPSK systems at SNR of 18 dB and 26 dB to achieve the same BER value.
IEEE Photonics Technology Letters, 2000
A novel optical millimeter-wave (mm-wave) generation scheme based on double-sideband phase modulation (DSB-PM) to achieve frequency doubling without suppressing the carrier is proposed. Theoretical analysis shows that the generated 60-GHz optical mm-wave can tolerant 0.016-nm wavelength drifting with filter bandwidth ranging from 70 to 100 GHz to sustain first to second harmonic suppression ratio of 18 dB. In addition, error-free transmission of 60-GHz mm-wave at 2.5 Gb/s is experimentally demonstrated over a combined distance of 3-m wireless with 21-dBm equivalent isotropically radiated power, and 250-m fiber to best emulate an in-building network environment. Dispersion effect on the frequency-doubled PM optical mm-wave without carrier suppression is also analyzed and experimentally studied by comparing the link performance over single-mode fiber (SMF-28) and dispersion-shifted fiber (DSF), respectively.
IEEE Photonics Technology Letters, 2000
We designed and experimentally demonstrated an efficient photonic frequency-tripling technology for 60-GHz radio-over-fiber systems to simultaneously realize millimeter-wave (mm-wave), microwave, and baseband signal generation. The technique utilizes vestigial sideband filtering in combination with optical carrier suppression to generate novel alternate subcarrier modulation for high tolerance of fiber dispersion. Experimental verification of the proposed scheme is presented with generation and error-free transmission of 2.1-Gb/s data on the 63-GHz mm-wave and 21-GHz microwave carriers over 50-km single-mode fiber (SMF-28) without dispersion compensation. The power penalty for both signals is less than 1.0 dB.
Optical and millimeter-wave radio seamless MIMO transmission based on a radio over fiber technology
Optics Express, 2012
Multi-input multi-output (MIMO) transmission of two millimeter-wave radio signals seamlessly converted from polarizationdivision-multiplexed quadrature-phase-shift-keying optical signals is successfully demonstrated, where a radio access unit basically consisting of only optical-to-electrical converters and a radio receiver performs total signal equalization of both the optical and the radio paths and demodulation with digital signal processing (DSP). Orthogonally polarized optical components that are directly converted to two-channel radio components can be demultiplexed and demodulated with high-speed DSP as in optical digital coherent detection. 20-Gbaud optical and radio seamless MIMO transmission provides a total capacity of 74.4 Gb/s with a forward error correction overhead of 7%.
IEEE Photonics Technology Letters, 2007
We experimentally demonstrated a novel radio-overfiber scheme to simultaneously obtain independent wired and wireless signals by using only a single intensity modulator. The optical 40-or 60-GHz millimeter-wave (mm-wave) carriers are generated by means of subcarrier-multiplexing techniques to carry 2.5-Gb/s wireless signals while 10-Gb/s wired signals are imposed on the original optical carrier via regular intensity modulation. The signals with dual services are successfully transmitted over 20-km single-mode fiber (SMF-28) with less than 1.5-dB power penalty.
Phase-Insensitive RF Envelope Detection Allows Optical Heterodyning of MHz-Linewidth Signals
IEEE Photonics Technology Letters, 2000
We demonstrate the insensitivity of the envelope detection based mobile terminal to phase fluctuations of the RF signal. This property enables the generation of radio over fiber (RoF) signals heterodyning non-narrow linewidth laser signals and using direct modulation. We report the experimental generation of up to 2-Gb/s orthogonal frequency division multiplexing (OFDM) signals and their transmission over a 25-km long fiber span using direct modulation and DFB lasers with a combined linewidth of 2.1 MHz with a resulting BER below 10 −3 .