The performance of three wireless local-area network(WLAN) media access control(MAC) protocols is investigated and compared in the context of simulcast radioover-fiber-based distributed antenna systems(RoF-DASs) where...The performance of three wireless local-area network(WLAN) media access control(MAC) protocols is investigated and compared in the context of simulcast radioover-fiber-based distributed antenna systems(RoF-DASs) where multiple remote antenna units(RAUs) are connected to one access point(AP) with different-length fiber links.The three WLAN MAC protocols under investigation are distributed coordination function(DCF) in basic access mode,DCF in request/clear to send(RTS/CTS) exchange mode,and point coordination function(PCF).In the analysis,the inter-RAU hidden nodes problems and fiber-length difference effect are both taken into account.Results show that adaptive PCF mechanism has better throughput performances than the other two DCF modes,especially when the inserted fiber length is short.展开更多
The high-density population leads to crowded cities. The future city is envisaged to encompass a large-scale network with diverse applications and a massive number of interconnected heterogeneous wireless-enabled devi...The high-density population leads to crowded cities. The future city is envisaged to encompass a large-scale network with diverse applications and a massive number of interconnected heterogeneous wireless-enabled devices. Hence, green technology elements are crucial to design sustainable and future-proof network architectures. They are the solutions for spectrum scarcity, high latency, interference, energy efficiency, and scalability that occur in dense and heterogeneous wireless networks especially in the home area network （HAN）. Radio-over-fiber （ROF） is a technology candidate to provide a global view of HAN＇s activities that can be leveraged to allocate orthogonal channel communications for enabling wireless-enabled HAN devices transmission, with considering the clustered-frequency-reuse approach. Our proposed network architecture design is mainly focused on enhancing the network throughput and reducing the average network communications latency by proposing a data aggregation unit （DAU）. The performance shows that with the DAU, the average network communications latency reduces significantly while the network throughput is enhanced, compared with the existing ROF architecture without the DAU.展开更多
Millimeter-wave radio-over-fiber techno- logy demonstrates the potential for providing wireless broad-band service in the next generation wireless communication system.Optical generation of millimeter-wave signal is o...Millimeter-wave radio-over-fiber techno- logy demonstrates the potential for providing wireless broad-band service in the next generation wireless communication system.Optical generation of millimeter-wave signal is one of the most important technologies of millimeter-wave radio-over-fiber system.The virtues and shortcomings of some ways of optical generation of millimeter-wave signal are discussed.Then optical millimeter-wave signal transmission perfor- mance is described.Finally,an overview of the millimeter-wave radio-over-fiber system is given.It is suggested that the millimeter-wave radio-over-fiber technology should be paid more attention,especially for modulators for optical generation of millimeter-wave signal and radio-over-fiber system.展开更多
A novel scheme of optical modulation in 40 GHz radio-over fiber （RoF） system is proposed. It generates optical QPSK/16QAM signals in a serial-parallel structure of Mach-Zehnder modulators （MZMs）. The millimeter-wa...A novel scheme of optical modulation in 40 GHz radio-over fiber （RoF） system is proposed. It generates optical QPSK/16QAM signals in a serial-parallel structure of Mach-Zehnder modulators （MZMs）. The millimeter-wave is obtained with optical frequency multiplication （OFM）. Furthermore, modulation on optical-wave is transferred onto millimeter-wave. It can be used to increase transmission capacity of millimeter-wave RoF systems.展开更多
We experimentally built a W-band photonics-aided millimeter-wave radio-over-fiber transmission system and demonstrated the delivery of up to 8192-ary quadrature amplitude modulation[QAM] signal.Discrete multitone sign...We experimentally built a W-band photonics-aided millimeter-wave radio-over-fiber transmission system and demonstrated the delivery of up to 8192-ary quadrature amplitude modulation[QAM] signal.Discrete multitone signals are converted into 1-bit data streams through delta-sigma modulation and then modulated onto a 76.2 GHz carrier.An envelope detector is used at the receiver side for direct detection.The results prove that our proposed system can support 2048QAM and 8192QAM transmission while meeting the hard decision forward error correction threshold of 3.8×10^(-3)and the soft decision forward error correction threshold of 4.2×10^(-2),respectively.We believe this cost-effective scheme is a promising candidate for future high-order QAM millimeter-wave downlink transmission.展开更多
The effects of optical losses oil a directly-modulated radio-over-fiber （RoF） system used for distributed antenna networks are determined. The results show that with a properly designed bidirectional amplifier, the ...The effects of optical losses oil a directly-modulated radio-over-fiber （RoF） system used for distributed antenna networks are determined. The results show that with a properly designed bidirectional amplifier, the RoF link can tolerate over 20 and 16 dB of optical losses for down- and up-links, respectively. Simulation results are also consistent with the experimental data. These findings can contribute to tile design of RoF distributed antenna systems with different topologies.展开更多
The principle of error vector magnitude （EVM） against modulator nonlinearity for vector modulation signal （VMS） transmission in radio-over-fiber （RoF） systems is theoretically and experimentally investigated. A ...The principle of error vector magnitude （EVM） against modulator nonlinearity for vector modulation signal （VMS） transmission in radio-over-fiber （RoF） systems is theoretically and experimentally investigated. A highly linear modulation scheme is proposed and demonstrated using a single-drive dual parallel Mach–Zehnder modulator （MZM）. This method improves EVM performance and enlarges the linear input dynamic range of the VMS transmission. An index of maximum allowable input power difference （MAIPD） that reflects the difference of upper input power limits between these two schemes is measured. An EVM limitation of 5% MAIPD has 5 dB. Both 16and 64-QAM results indicate that the proposed scheme supports VMS transmission better than the MZM one.展开更多
A radio-over-fiber(RoF) distributed antenna system(DAS) architecture is proposed, where millimeter wave(mm-wave) signals are transmitted to four different radio access units(RAUs) arranged in a ring topology.The propo...A radio-over-fiber(RoF) distributed antenna system(DAS) architecture is proposed, where millimeter wave(mm-wave) signals are transmitted to four different radio access units(RAUs) arranged in a ring topology.The proposed architecture transmits duplex data of 128 Mb/s to each RAU in both downlink(DL) and uplink(UL)directions. The radio frequency(RF) signals are transmitted by polarization multiplexing a multi-wavelength source.Millimeter-wave signals at a frequency of 25 GHz are generated at each RAU using remote heterodyne detection.The proposed architecture provides increased coverage while maintaining good bit error rate(BER) results.展开更多
A new radio-over-fiber system for use in hybrid fiber-wireless access networks is proposed and experimentally demonstrated,which is based on cascaded injection-locked Fabry-Perot laser diodes.It is verified that the p...A new radio-over-fiber system for use in hybrid fiber-wireless access networks is proposed and experimentally demonstrated,which is based on cascaded injection-locked Fabry-Perot laser diodes.It is verified that the proposed technique is able to achieve a good suppression ratio of an optical carrier suppressed(OCS) signal simultaneously through a programmable optical filter and by use of optical injection locking technique.A 60 GHz carrier with downlink baseband data has been generated and down converted to baseband signal in order to be characterized in our laboratory.展开更多
传统光载无线系统(radio over fiber,RoF)在光传输过程中容易受到非线性的影响,数字光载无线系统(digital radio over fiber,DRoF)可以通过射频信号数字化来实现较高的信号保真度。本文提出一种面向离散余弦变换(discrete cosine transf...传统光载无线系统(radio over fiber,RoF)在光传输过程中容易受到非线性的影响,数字光载无线系统(digital radio over fiber,DRoF)可以通过射频信号数字化来实现较高的信号保真度。本文提出一种面向离散余弦变换(discrete cosine transform,DCT)实时信号压缩DRoF的FPGA系统设计。实验结果表明,4-QAM、16-QAM和64-QAM的正交频分复用(orthogonal frequency division multiplexing,OFDM)信号在经过DCT信号压缩和信号量化后,其误差矢量幅度(error vector magnitude,EVM)性能均优于传统k均值聚变矢量量化方案,三种不同调制格式对应的EVM性能分别稳定在12.8%、5.7%和3.8%,均低于3GPP阈值,证明了该方案的可行性。展开更多
阐述光纤无线电(Radio over Fiber,RoF)技术的基本原理及其在广电领域应用的优势,深入剖析影响其长距离传输性能的因素,包括光纤损耗与色散、光电器件性能限制以及信号调制与复用方式等,并提出针对性的优化策略,涵盖光纤传输链路、光电...阐述光纤无线电(Radio over Fiber,RoF)技术的基本原理及其在广电领域应用的优势,深入剖析影响其长距离传输性能的因素,包括光纤损耗与色散、光电器件性能限制以及信号调制与复用方式等,并提出针对性的优化策略,涵盖光纤传输链路、光电器件以及先进信号处理技术等方面。通过这些研究,旨在提升广电系统RoF技术长距离传输的质量与可靠性,以适应广播电视业务不断发展的需求。展开更多
基金supported in part by National 973 Program(2012CB315705)NSFC Program(61302086,61271042,61107058, 61302016,and 61335002)+2 种基金Specialized Research Fund for the Doctoral Program of Higher Education(20130005120007)Program for New Century Excellent Talents in University(NCET-13-0682)Fundamental Research Funds for the Central Universities
文摘The performance of three wireless local-area network(WLAN) media access control(MAC) protocols is investigated and compared in the context of simulcast radioover-fiber-based distributed antenna systems(RoF-DASs) where multiple remote antenna units(RAUs) are connected to one access point(AP) with different-length fiber links.The three WLAN MAC protocols under investigation are distributed coordination function(DCF) in basic access mode,DCF in request/clear to send(RTS/CTS) exchange mode,and point coordination function(PCF).In the analysis,the inter-RAU hidden nodes problems and fiber-length difference effect are both taken into account.Results show that adaptive PCF mechanism has better throughput performances than the other two DCF modes,especially when the inserted fiber length is short.
基金supported by the Ministry of Higher Education,Malaysia under Scholarship of Hadiah Latihan Persekutuan under Grant No.KPT.B.600-19/3-791206065445
文摘The high-density population leads to crowded cities. The future city is envisaged to encompass a large-scale network with diverse applications and a massive number of interconnected heterogeneous wireless-enabled devices. Hence, green technology elements are crucial to design sustainable and future-proof network architectures. They are the solutions for spectrum scarcity, high latency, interference, energy efficiency, and scalability that occur in dense and heterogeneous wireless networks especially in the home area network （HAN）. Radio-over-fiber （ROF） is a technology candidate to provide a global view of HAN＇s activities that can be leveraged to allocate orthogonal channel communications for enabling wireless-enabled HAN devices transmission, with considering the clustered-frequency-reuse approach. Our proposed network architecture design is mainly focused on enhancing the network throughput and reducing the average network communications latency by proposing a data aggregation unit （DAU）. The performance shows that with the DAU, the average network communications latency reduces significantly while the network throughput is enhanced, compared with the existing ROF architecture without the DAU.
文摘Millimeter-wave radio-over-fiber techno- logy demonstrates the potential for providing wireless broad-band service in the next generation wireless communication system.Optical generation of millimeter-wave signal is one of the most important technologies of millimeter-wave radio-over-fiber system.The virtues and shortcomings of some ways of optical generation of millimeter-wave signal are discussed.Then optical millimeter-wave signal transmission perfor- mance is described.Finally,an overview of the millimeter-wave radio-over-fiber system is given.It is suggested that the millimeter-wave radio-over-fiber technology should be paid more attention,especially for modulators for optical generation of millimeter-wave signal and radio-over-fiber system.
基金Project supported by the Shanghai Leading Academic Discipline Project (Grant No.S30108)the Science and Technology of Commission of Shanghai Municipality (Grant Nos.08DZ150010F, 10511500602)the National Natural Science Foundation of China (Grant No.60877053)
文摘A novel scheme of optical modulation in 40 GHz radio-over fiber （RoF） system is proposed. It generates optical QPSK/16QAM signals in a serial-parallel structure of Mach-Zehnder modulators （MZMs）. The millimeter-wave is obtained with optical frequency multiplication （OFM）. Furthermore, modulation on optical-wave is transferred onto millimeter-wave. It can be used to increase transmission capacity of millimeter-wave RoF systems.
基金partially supported by the National Key R&D Program of China(No.2018YFB1801703)the National Natural Science Foundation of China(Nos.62127802 and 61720106015)。
文摘We experimentally built a W-band photonics-aided millimeter-wave radio-over-fiber transmission system and demonstrated the delivery of up to 8192-ary quadrature amplitude modulation[QAM] signal.Discrete multitone signals are converted into 1-bit data streams through delta-sigma modulation and then modulated onto a 76.2 GHz carrier.An envelope detector is used at the receiver side for direct detection.The results prove that our proposed system can support 2048QAM and 8192QAM transmission while meeting the hard decision forward error correction threshold of 3.8×10^(-3)and the soft decision forward error correction threshold of 4.2×10^(-2),respectively.We believe this cost-effective scheme is a promising candidate for future high-order QAM millimeter-wave downlink transmission.
基金supported by the National "863" Program of China(No.2011AA010306)the National "973" Program of China(No.2012CB315705)+2 种基金the National Natural Science Foundation of China(Nos.61107058,61120106001,60932004,61001121,and 60837004)the Beijing Excellent Doctoral Thesis Project(No.YB20101001301)the Cooperation Project between Province and Ministries(No.2011A090200025)
文摘The effects of optical losses oil a directly-modulated radio-over-fiber （RoF） system used for distributed antenna networks are determined. The results show that with a properly designed bidirectional amplifier, the RoF link can tolerate over 20 and 16 dB of optical losses for down- and up-links, respectively. Simulation results are also consistent with the experimental data. These findings can contribute to tile design of RoF distributed antenna systems with different topologies.
基金supported by the National "973" Program of China (Nos. 2012CB315603 and 2012CB315604)the National Natural Science Foundation of China (Nos. 60736003, 61025004, and 61032005)+1 种基金the Ph.D. Program Foundation of the Ministry of Education of China (No. 20100002110039)the China Postdoctoral Science Foundation (No. 20110490426)
文摘The principle of error vector magnitude （EVM） against modulator nonlinearity for vector modulation signal （VMS） transmission in radio-over-fiber （RoF） systems is theoretically and experimentally investigated. A highly linear modulation scheme is proposed and demonstrated using a single-drive dual parallel Mach–Zehnder modulator （MZM）. This method improves EVM performance and enlarges the linear input dynamic range of the VMS transmission. An index of maximum allowable input power difference （MAIPD） that reflects the difference of upper input power limits between these two schemes is measured. An EVM limitation of 5% MAIPD has 5 dB. Both 16and 64-QAM results indicate that the proposed scheme supports VMS transmission better than the MZM one.
文摘A radio-over-fiber(RoF) distributed antenna system(DAS) architecture is proposed, where millimeter wave(mm-wave) signals are transmitted to four different radio access units(RAUs) arranged in a ring topology.The proposed architecture transmits duplex data of 128 Mb/s to each RAU in both downlink(DL) and uplink(UL)directions. The radio frequency(RF) signals are transmitted by polarization multiplexing a multi-wavelength source.Millimeter-wave signals at a frequency of 25 GHz are generated at each RAU using remote heterodyne detection.The proposed architecture provides increased coverage while maintaining good bit error rate(BER) results.
基金supported by the National Basic Research Program of China ("973" Project) (Grant No. 2012CB315701,2012CB315702)the National Hi-Tech Research and Development Program of China ("863" Project) (Grant No. 2011AA010303)the National Nature Science Foundation of China (Grant No. 60925019,61090393)
文摘A new radio-over-fiber system for use in hybrid fiber-wireless access networks is proposed and experimentally demonstrated,which is based on cascaded injection-locked Fabry-Perot laser diodes.It is verified that the proposed technique is able to achieve a good suppression ratio of an optical carrier suppressed(OCS) signal simultaneously through a programmable optical filter and by use of optical injection locking technique.A 60 GHz carrier with downlink baseband data has been generated and down converted to baseband signal in order to be characterized in our laboratory.
文摘传统光载无线系统(radio over fiber,RoF)在光传输过程中容易受到非线性的影响,数字光载无线系统(digital radio over fiber,DRoF)可以通过射频信号数字化来实现较高的信号保真度。本文提出一种面向离散余弦变换(discrete cosine transform,DCT)实时信号压缩DRoF的FPGA系统设计。实验结果表明,4-QAM、16-QAM和64-QAM的正交频分复用(orthogonal frequency division multiplexing,OFDM)信号在经过DCT信号压缩和信号量化后,其误差矢量幅度(error vector magnitude,EVM)性能均优于传统k均值聚变矢量量化方案,三种不同调制格式对应的EVM性能分别稳定在12.8%、5.7%和3.8%,均低于3GPP阈值,证明了该方案的可行性。
文摘阐述光纤无线电(Radio over Fiber,RoF)技术的基本原理及其在广电领域应用的优势,深入剖析影响其长距离传输性能的因素,包括光纤损耗与色散、光电器件性能限制以及信号调制与复用方式等,并提出针对性的优化策略,涵盖光纤传输链路、光电器件以及先进信号处理技术等方面。通过这些研究,旨在提升广电系统RoF技术长距离传输的质量与可靠性,以适应广播电视业务不断发展的需求。
