Showing papers by "Hung-Chang Chien published in 2010"

Cost-Effective Optical Millimeter Technologies and Field Demonstrations for Very High Throughput Wireless-Over-Fiber Access Systems

Abstract: The broadband penetration and continuing growth of Internet traffic among residential and business customers are driving the migration of today's end user's network access from cable to optical fiber and superbroadband wireless systems The integration of optical and wireless systems operating at much higher carrier frequencies in the millimeter-wave (mm-wave) range is considered to be one of the most promising solutions for increasing the existing capacity and mobility, as well as decreasing the costs in next-generation optical access networks. In this paper, several key enabling technologies for very high throughput wireless-over-fiber networks are reviewed, including photonic mm-wave generation based on external modulation or nonlinear effects, spectrum-efficient multicarrier orthogonal frequency-division multiplexing and single-carrier multilevel signal modulation. We also demonstrated some applications in wireless-over-fiber trials using these enabling techniques. The results show that the integrated systems are practical solutions to offer very high throughput wireless to end users in optically enabled wireless access networks.

Multi-service multi-carrier broadband MIMO distributed antenna systems for in-building optical wireless access

Abstract: A novel broad spectrum band-shifting technique is experimentally demonstrated to simultaneously transmit broadband (500MHz to 3 GHz) multi-service, multi-carrier MIMO signals for in-building radio-over-fiber based wireless distributed antenna systems. The proposed scheme uses fewer local oscillators and does not require any service-specific narrowband band pass filters, thus upgrading of existing non-MIMO services to MIMO services or adding new MIMO services would be easier and cost-effective.

Multi-Band Transport Technologies for In-Building Host-Neutral Wireless Over Fiber Access Systems

Abstract: We present two key system technologies on the two ends of RF spectrum to support optical-wireless access using radio-over-fiber (RoF) based distributed antenna system (DAS) for in-building environments The proposed technologies can enable protocol-independent, multi-carrier broadband connectivity to the end users' devices deployed in the in-door facilities by supporting existing and emerging wireless services with lower radio frequency carrier (from 500 MHz up to 3 GHz) as well as future-proof very high throughput (VHT) gigabit wireless services using 60 GHz mm-wave band For low frequency wireless services, a broad spectrum band-shifting technique is experimentally demonstrated to simultaneously transmit multi-service multiple input multiple output (MIMO) radio signals over in-building active DAS This approach facilitates easy upgrading of existing non-MIMO services to MIMO services or adding future MIMO services in a simple and cost-effective way For wireless-VHT service, for the first time to our knowledge, we demonstrate simultaneous all-optical up-conversion of multiple, separate gigabit wireless services at 60 GHz and 64 GHz mm-wave band using one single lightwave transmitter This scheme can be used to achieve seamless convergence of very high throughput wireless personal area network (VHT-WPAN) with more conventional low frequency distributed antenna based optical-wireless access system

Optical Millimeter-Wave Generation and Transmission Without Carrier Suppression for Single- and Multi-Band Wireless Over Fiber Applications

Abstract: A new optical millimeter-wave generation scheme to double the beating frequency without suppressing the carrier by taking advantages of the out-of-phase property between sidebands of a phase-modulated optical carrier is proposed for the first time. Theoretical analysis shows that the generated 60 GHz optical millimeter-wave (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. The doubled frequency is continuously tunable from 60 to 90 GHz within 100 GHz filter bandwidth with RF power variation of less than 2 dB. In addition, simultaneously generating and transmitting multi-band signal: millimeter-wave band, microwave band, and baseband leveraging the same concept is also proposed. Error-free transmission of 2.5 Gb/s wireless baseband signals carried by the generated 60 GHz mm-wave is successfully demonstrated in both single- and multi-band network environments over a combined optical fiber and wireless distance with a proper equivalent isotropically radiated power of about 20 dBm for in-building access. Moreover, dispersion effect on the generated frequency-doubled optical mm-wave is analyzed by experimentally comparing the link performance of both single mode fiber (SMF-28) and dispersion-shifted fiber cases. It is concluded that for single-band service delivery, the proposed scheme is immune to the interference from the dispersion-induced, redundant 1st harmonics; however, to deliver multi-band services, launching lightwave at zero-dispersion wavelength over SMF-28 is highly recommended to mitigate inter-band interference.

A novel radio-over-fiber system using the xy-MIMO wireless technique for enhanced radio spectral efficiency

Abstract: By combining two different system technologies of optical polarization division multiplexing and wireless multiple-input, multiple-output spatial multiplexing, we have successfully demonstrated 2-Gb/s or 5-Gb/s wireless signal transmission over a 60-GHz wireless channel with a doubled spectral efficiency.

Next-generation E-health communication infrastructure using converged super-broadband optical and wireless access system

Abstract: Delivering affordable high-quality E-health care services requires effective telecommunication and multimedia technologies in conjunction with medical expertise. In this paper, we propose and demonstrate a telecommunication and networking architecture for implementing next generation Telemedicine and Telehealth systems. Our integrated optical-wireless based network provides super broadband, ultra low-latency connectivity for voice, video, image and data across various telemedicine modalities to facilitate real-time and near real-time communication of remote health care information.

Experimental analyses and optimization of equalization techniques for 60-GHz OFDM radio-over-fiber system

Abstract: We experimentally investigated transmission performance of 16QAM-OFDM signal over 25-km fiber and 5-m air distance using 60GHz ROF technology. It is the first time that the details of optimal equalization technique for 60GHz OFDM-ROF systems are presented.

On Frequency-Doubled Optical Millimeter-Wave Generation Technique Without Carrier Suppression for In-Building Wireless Over Fiber Applications

Abstract: 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.

Demonstration of simultaneous all-optical up-conversion of Gigabit wireless services at 60-GHz and 64-GHz in converged optical wireless system carried by single wavelength lightwave

Abstract: All-optical simultaneous up-conversion of multiple, separate 1-Gb/s wireless services at 60GHz and 64GHz mm-wave band carried by one single lightwave for in-building radio-over-fiber based optical wireless access system is proposed and experimentally demonstrated.

Link performance improved 16QAM-OFDM 60-GHz Radio-over-Fiber system employing convolutional codes

Abstract: We demonstrated the first transmission of 750-Mb/s 16QAM-OFDM signal over 1-km SMF-28 and 6-m air-link with 60-GHz ROF technology. The system improvement and low-power efficiency of RF transmitter are studied based on the convolutional code.

QPSK-OFDM radio over polymer optical fiber for broadband in-building 60GHz wireless access

Abstract: 500Mb/s Quadrature Phase-Shift Keying (QPSK)-Orthogonal Frequency Division Multiplexing (OFDM) signals on 60-GHz mm-wave are experimentally demonstrated over 100-m graded-index polymer optical fiber with less than 1 dB power penalty at BER =10-4.

Millimeter wave wireless communication system

Abstract: A wireless communication system adapted to transmit data between two locations, for example between a plurality of processors and memory. Digitally coded millimeter waves can be used to transfer data between antenna arrays. A global optical clock can provide network coherence, frequency self-tracking, and a local oscillator signal for data digital symbol coding/decoding and symbol up-down conversion to/from the millimeter wavelength carrier.

Millimeter-wave main memory-to-processor data bus

Abstract: The mainstreaming of chip multiprocessor (CMP) architectures exact a profound impact on valuable resources, for example, L3 cache capacity, off-chip bandwidth and on-board main memory capacity. Even with latency-hiding software strategies, in a memory-starved system, a processor can remain idle for several decades of clock cycles and performance will degrade [1]. Two hardware solutions are being developed for opening the memory bottleneck; (1) Stack bare SRAM die memory, with multiplexer-demultiplexer, using through-silicon vias and place the SRAM stacks around the multi-core processor at the multi-chip carrier level [2] to increase L3 capacity and, in addition, also stack dynamic random access memory (DRAM) dies on board to increase main memory capacity needed for numerically intensive and storage intensive computations.

Arbitrary-frequency optical millimeter-wave generation for radio over fiber systems

Abstract: The arbitrary-frequency optical microwave or millimeter (mm)-wave signals, ranging from 25 to 325 -GHz with 25-GHz spacing, can be simultaneously generated based on the generation technology of multi-wavelength laser source followed by a wavelength selected switch (WSS). These multi-wavelength signals are realized by cascading a phase modulator (PM) and a Mach-Zehnder intensity modulator. This technology is capable of generating 11 multi-wavelengths from single CW lightwave with less than 2-dB maximum power difference. One reconfigurable WSS with one input and four output ports is employed to select multiple optical mm-wave signals with a minimal frequency spacing of 25 GHz.

Spectrally Efficient 60-GHz xy-MIMO Data Transport over a Radio-Over-Fiber System for Gigabit Wireless Local Area Networks

Abstract: A radio-over-fiber system can provide a robust backbone network for the deployment of multi-gigabit wireless local area networks. By transmitting 2x2, MIMO signals over two polarizations in an optical fiber, we developed a new radio-over-fiber system to support MIMO-based wireless communications to improve the signal diversity or multiplexity. Two-Gb/s millimeter-wave signals were successfully transmitted through a 10-km optical fiber and a wireless channel with the equivalent spectral efficiency of 2bits/Hz using MIMO spatial multiplexing.

Converged broadband optical and wireless communication infrastructure for next-generation telehealth

Abstract: Emerging Telehealth and Telemedicine systems need to deliver affordable high-quality health care services by utilizing telecommunication and multimedia technologies in conjunction with medical expertise. In this paper, we propose and demonstrate a telecommunication and networking architecture for implementing next generation Telemedicine and Telehealth systems. Our integrated optical-wireless based network provides super broadband, ultra low-latency connectivity for voice, video, image and data across various telemedicine modalities to facilitate real-time and near real-time communication of remote health care information.

Multiband signals generation and transmission over fiber and air by a novel frequency-doubled, radio-over-fiber architecture without expensive carrier suppression filters

Abstract: We demonstrate a novel frequency-doubled wireless over fiber system to offer multiband services including baseband, 60-GHz millimeter-wave and 15-GHz microwave without carrier suppression. Multiband wireless signals are successfully transmitted through both fiber and air channels.

A novel carrier-eliminated optical millimeter-wave generation using a single over-driven phase modulator

Abstract: A carrier-eliminated 40-GHz optical mm-wave generated by over-driving a phase modulator is first proposed. Error-free transmission over 10-km SMF-28 and 3-m wireless is successfully demonstrated with a highly relaxed bandwidth requirement for sideband optical filtering.

Photonic generation and processing technologies for converged ultra-high throughput fiber-wireless systems

Abstract: We discuss the recent advances of key photonic generation and processing technologies toward high flexibility, integration, and spectrum efficiency for delivering ultra-high throughput wireless services over optical fiber systems for access and very-short-reach applications.

Spectrum-compressed, millimeter-wave wireless over fiber access system using duobinary line coding at 10-Gbps and beyond

Abstract: For the first time, a spectrum-compressed very-high-throughput wireless-over-fiber system leveraging duobinary signaling is proposed. Error-free transmission of a 10-Gbps duobinary signal at 60-GHz over 5-km SMF-28 and 6-ft free-space is successfully demonstrated without decoders/demodulators.