Herein,an attention-grabbing and up-to-date review related to major multiplexing techniques is presented which in-cludes wavelength division multiplexing(WDM),polarization division multiplexing(PDM),space division mul...Herein,an attention-grabbing and up-to-date review related to major multiplexing techniques is presented which in-cludes wavelength division multiplexing(WDM),polarization division multiplexing(PDM),space division multiplexing(SDM),mode division multiplexing(MDM)and orbital angular momentum multiplexing(OAMM).Multiplexing is a mech-anism by which multiple signals are combined into a shared channel used to showcase the maximum capacity of the op-tical links.However,it is critical to develop hybrid multiplexing methods to allow enhanced channel numbers.In this re-view,we have also included hybrid multiplexing techniques such as WDM-PDM,WDM-MDM and PDM-MDM.It is prob-able to attain N×M channels by utilizing N wavelengths and M guided-modes by simply utilizing hybrid WDM-MDM(de)multiplexers.To the best of our knowledge,this review paper is one of its kind which has highlighted the most prom-inent and recent signs of progress in multiplexing techniques in one place.展开更多
In the context of next-generation optical access networks beyond 10 G, for high SE and flexible dynamic bandwidth allocation (DBA), the scheme of hybrid 64/16/4QAM-OFDM signal for downlink transmission and hybrid 16/8...In the context of next-generation optical access networks beyond 10 G, for high SE and flexible dynamic bandwidth allocation (DBA), the scheme of hybrid 64/16/4QAM-OFDM signal for downlink transmission and hybrid 16/8/QPSK-OFDM signal for uplink transmission is successfully proposed and experimentally presented in a full-duplex PON based on OFDM system. Here, for the uplink, in order to unit management of the optical line terminal (OLT) and reduce cost, the optical source functioned as the optical subcarrier at optical network units (ONUs) is from OLT in the central station. Moreover, there is an external cavity laser (ECL) with center frequency of 193.2 THz not only employed as optical modulated signal but also acted as LO signal. Our simulation results show that bit error ratio (BER) under hardware detection forward error correction has been successfully gained after 20 km of SSMF transmission. It is observed that the receiver sensitivity of multilevel PSK (M-PSK) is obviously larger than that of the M-QAM in this measurement scheme.展开更多
Reliability-based hybrid automatic repeat request(HARQ)(RB-HARQ)is a recently developedform of incremental-redundancy ARQ.It achieves good performance whereas large retransmission requestpackets should be fed back.In ...Reliability-based hybrid automatic repeat request(HARQ)(RB-HARQ)is a recently developedform of incremental-redundancy ARQ.It achieves good performance whereas large retransmission requestpackets should be fed back.In this paper,in order to reduce the number of the fed back bits,we pro-pose a HARQ scheme applied in time duplex division orthogonal frequency division multiplexing(TDD-OFDM)system over the slow fading channel which is named channel-based HARQ(CB-HARQ).Be-cause one bit which meets deep fading is always with small value of log likelihood ratio(LLR)during theprocess of decoding of LDPC code,the bits transmitted on the carrier with deep fading are retransmitted.At the receiver,the decoder will compute the locations of retransmission bits according to the channelfading values which are gotten by utilizing the feature of channel symmetry in TDD mode.So the indicesof retransmission bits are avoided to be transmitted.Simulation results show that this method achievesbetter BER performance and requires much smaller request packets in feedback link.展开更多
近几年来,由于低损耗单模光纤技术的进步,光网络已经被用来满足各种应用的需求。波分复用(WDM)技术被认为能更有效地利用巨大的光纤带宽。IP over WDM技术是网络发展的一个重要方向。本文提出了一种新型混合模型网络结构,并进行了模拟...近几年来,由于低损耗单模光纤技术的进步,光网络已经被用来满足各种应用的需求。波分复用(WDM)技术被认为能更有效地利用巨大的光纤带宽。IP over WDM技术是网络发展的一个重要方向。本文提出了一种新型混合模型网络结构,并进行了模拟仿真研究,结果表明此技术是可行的。展开更多
基金financially supported by the Russian Foundation for Basic Research(grant No.18-29-20045)for WDM,MDM and hybrid WDM-MDM,WDM-PDM sectionsthe Russian Science Foundation(grant No.21-79-20075)for PDM,OAMM and hybrid PDM-MDM sectionsthe Ministry of Science and Higher Education of the Russian Federation under the FSRC"Crystallography and Photonics"of the Russian Academy of Sciences(the state task No.007-GZ/Ch3363/26)for comparative analysis.
文摘Herein,an attention-grabbing and up-to-date review related to major multiplexing techniques is presented which in-cludes wavelength division multiplexing(WDM),polarization division multiplexing(PDM),space division multiplexing(SDM),mode division multiplexing(MDM)and orbital angular momentum multiplexing(OAMM).Multiplexing is a mech-anism by which multiple signals are combined into a shared channel used to showcase the maximum capacity of the op-tical links.However,it is critical to develop hybrid multiplexing methods to allow enhanced channel numbers.In this re-view,we have also included hybrid multiplexing techniques such as WDM-PDM,WDM-MDM and PDM-MDM.It is prob-able to attain N×M channels by utilizing N wavelengths and M guided-modes by simply utilizing hybrid WDM-MDM(de)multiplexers.To the best of our knowledge,this review paper is one of its kind which has highlighted the most prom-inent and recent signs of progress in multiplexing techniques in one place.
文摘In the context of next-generation optical access networks beyond 10 G, for high SE and flexible dynamic bandwidth allocation (DBA), the scheme of hybrid 64/16/4QAM-OFDM signal for downlink transmission and hybrid 16/8/QPSK-OFDM signal for uplink transmission is successfully proposed and experimentally presented in a full-duplex PON based on OFDM system. Here, for the uplink, in order to unit management of the optical line terminal (OLT) and reduce cost, the optical source functioned as the optical subcarrier at optical network units (ONUs) is from OLT in the central station. Moreover, there is an external cavity laser (ECL) with center frequency of 193.2 THz not only employed as optical modulated signal but also acted as LO signal. Our simulation results show that bit error ratio (BER) under hardware detection forward error correction has been successfully gained after 20 km of SSMF transmission. It is observed that the receiver sensitivity of multilevel PSK (M-PSK) is obviously larger than that of the M-QAM in this measurement scheme.
基金the National High Technology Research and Development Programme of China(No.2003AA12331004)
文摘Reliability-based hybrid automatic repeat request(HARQ)(RB-HARQ)is a recently developedform of incremental-redundancy ARQ.It achieves good performance whereas large retransmission requestpackets should be fed back.In this paper,in order to reduce the number of the fed back bits,we pro-pose a HARQ scheme applied in time duplex division orthogonal frequency division multiplexing(TDD-OFDM)system over the slow fading channel which is named channel-based HARQ(CB-HARQ).Be-cause one bit which meets deep fading is always with small value of log likelihood ratio(LLR)during theprocess of decoding of LDPC code,the bits transmitted on the carrier with deep fading are retransmitted.At the receiver,the decoder will compute the locations of retransmission bits according to the channelfading values which are gotten by utilizing the feature of channel symmetry in TDD mode.So the indicesof retransmission bits are avoided to be transmitted.Simulation results show that this method achievesbetter BER performance and requires much smaller request packets in feedback link.
