1. Southern Coastal Optical Cable Engineering Project. The cable was completed and put into operation in 1992, and has a total length of 2,800km, starting from Nanjing in the north, via Shanghai, Hangzhou, Fuzhou, Xia...1. Southern Coastal Optical Cable Engineering Project. The cable was completed and put into operation in 1992, and has a total length of 2,800km, starting from Nanjing in the north, via Shanghai, Hangzhou, Fuzhou, Xiamen, Huizhou, leading to Guangzhou in the south, covering Jiangsu, Shanghai, Zhejiang, Fujian and Guangdong. The whole line has展开更多
Rising sea levels and climate change are reshaping coastal landscapes,exacerbating erosion,and increasing flood frequency,posing serious threats to the ecological balance,economic growth,and the livelihoods of coastal...Rising sea levels and climate change are reshaping coastal landscapes,exacerbating erosion,and increasing flood frequency,posing serious threats to the ecological balance,economic growth,and the livelihoods of coastal city residents[1].This necessitates advanced monitoring to mitigate climate impacts and strengthen coastal resilience.While geophysical methods for first-order coastal properties monitoring have gained traction in academia[2,3],traditional monitoring techniques are limited by sparse and unevenly distributed observation stations,failing to meet the needs for detailed regional monitoring.Moreover,the complex social and cultural environments of coastal cities challenge sustained and intensive monitoring efforts.展开更多
MIMO technique can provide higher information throughput and transmission reliability for the PLC system.However,the MIMO-PLC system based on three-conductor cable has a high correlation among its sub-channels.Spatial...MIMO technique can provide higher information throughput and transmission reliability for the PLC system.However,the MIMO-PLC system based on three-conductor cable has a high correlation among its sub-channels.Spatial multiplexing technology will be affected by the spatial correlation between MIMO-PLC sub-channels.To reduce the system bit error rate caused by MIMO-PLC correlation among sub-channels,this paper proposed a phase rotation precoding scheme for the 2×2 closed-loop MIMO-PLC system.According to the channel transfer function of high correlation MIMO-PLC system,the phase rotation precoding matrix F is calculated,and the transmission signal matrix S is modulated with the F,the code distance at the receiving point with smallest code distance is increased by phase rotation.Simulation results show that the scheme can effectively reduce the bit error rate of the 2×2 MIMO-PLC system based on ML detection,and significantly improve the system performance.展开更多
The scientific monitoring and reliable telecommunications(SMART)initiative,led by a joint task force including ITU,aims to integrate electronic sensors into undersea telecommunications cables for real-time and high-se...The scientific monitoring and reliable telecommunications(SMART)initiative,led by a joint task force including ITU,aims to integrate electronic sensors into undersea telecommunications cables for real-time and high-sensitivity subsea monitoring.The current integrated sensing and communication(ISAC)solution to the SMART application still relies on wavelength band multiplexing of sensing information via Ethernet switches,leading to optical communication bandwidth waste.To achieve the dense and low-interference ISAC for SMART network applications,we demonstrate the co-transmissions of coherent optical digital subcarrier modulation(DSCM)communication signals and temperature sensing information in the SMART system.Besides the co-transmission capability,the special design of the sensing transmission format is made to enable the compatible DSP with DSCM communications,which shares the same wavelength channel.Moreover,due to the different physical locations of the in-line sensing joints to the communication transceivers in the SMART system,it is hard to align the wavelength of the communication laser and the sensing one,which cannot ensure the precise allocation of sensing information into the frequency blanks of DSCM communication signals.To deal with these two issues,the sensing information at inline joints is proposed to be modulated in the manner of optical single-sideband(SSB)modulation and frequency modulation(FM),and then the precise allocation into the frequency blanks of DSCM communication signals can be realized,along with the full compatibility to demodulate the sensed temperature using the traditional frequency offset estimation in coherent DSP.Experiments on a two-span repeatered single-mode fiber link validate the integration of 20 GBaud optical DP-QAM16 transmissions and real-time temperature sensing at a sensing joint.Advanced communications are enabled by implementing space-time coding on DSCM communication signals,with 0.2 dB Q factor improvement.As for the sensing functionality,the temperature sensing resolution at 0.0625°C,which reaches the limitation of the employed electronic thermometer DS18B20,has been obtained by using the communication-compatible DSP.We believe the proposed ISAC scheme along with the corresponding DSP flowchart makes sense for monitoring the subsea via the advanced SMART cables.展开更多
文摘1. Southern Coastal Optical Cable Engineering Project. The cable was completed and put into operation in 1992, and has a total length of 2,800km, starting from Nanjing in the north, via Shanghai, Hangzhou, Fuzhou, Xiamen, Huizhou, leading to Guangzhou in the south, covering Jiangsu, Shanghai, Zhejiang, Fujian and Guangdong. The whole line has
基金supported by scientific grants from Zhejiang University(2023QZJH07)。
文摘Rising sea levels and climate change are reshaping coastal landscapes,exacerbating erosion,and increasing flood frequency,posing serious threats to the ecological balance,economic growth,and the livelihoods of coastal city residents[1].This necessitates advanced monitoring to mitigate climate impacts and strengthen coastal resilience.While geophysical methods for first-order coastal properties monitoring have gained traction in academia[2,3],traditional monitoring techniques are limited by sparse and unevenly distributed observation stations,failing to meet the needs for detailed regional monitoring.Moreover,the complex social and cultural environments of coastal cities challenge sustained and intensive monitoring efforts.
基金supported by the National Natural Science Foundation of China (No.62001166)supported by the Natural Science Foundation of Hebei Province of China (E2019502186,F2019201362)supported by the Fundamental Research Funds for the Central Universities (2021MS073)。
文摘MIMO technique can provide higher information throughput and transmission reliability for the PLC system.However,the MIMO-PLC system based on three-conductor cable has a high correlation among its sub-channels.Spatial multiplexing technology will be affected by the spatial correlation between MIMO-PLC sub-channels.To reduce the system bit error rate caused by MIMO-PLC correlation among sub-channels,this paper proposed a phase rotation precoding scheme for the 2×2 closed-loop MIMO-PLC system.According to the channel transfer function of high correlation MIMO-PLC system,the phase rotation precoding matrix F is calculated,and the transmission signal matrix S is modulated with the F,the code distance at the receiving point with smallest code distance is increased by phase rotation.Simulation results show that the scheme can effectively reduce the bit error rate of the 2×2 MIMO-PLC system based on ML detection,and significantly improve the system performance.
基金National Natural Science Foundation of China(62475178)Yangtze River Delta Region Integration Project(2024CSJGG2600).
文摘The scientific monitoring and reliable telecommunications(SMART)initiative,led by a joint task force including ITU,aims to integrate electronic sensors into undersea telecommunications cables for real-time and high-sensitivity subsea monitoring.The current integrated sensing and communication(ISAC)solution to the SMART application still relies on wavelength band multiplexing of sensing information via Ethernet switches,leading to optical communication bandwidth waste.To achieve the dense and low-interference ISAC for SMART network applications,we demonstrate the co-transmissions of coherent optical digital subcarrier modulation(DSCM)communication signals and temperature sensing information in the SMART system.Besides the co-transmission capability,the special design of the sensing transmission format is made to enable the compatible DSP with DSCM communications,which shares the same wavelength channel.Moreover,due to the different physical locations of the in-line sensing joints to the communication transceivers in the SMART system,it is hard to align the wavelength of the communication laser and the sensing one,which cannot ensure the precise allocation of sensing information into the frequency blanks of DSCM communication signals.To deal with these two issues,the sensing information at inline joints is proposed to be modulated in the manner of optical single-sideband(SSB)modulation and frequency modulation(FM),and then the precise allocation into the frequency blanks of DSCM communication signals can be realized,along with the full compatibility to demodulate the sensed temperature using the traditional frequency offset estimation in coherent DSP.Experiments on a two-span repeatered single-mode fiber link validate the integration of 20 GBaud optical DP-QAM16 transmissions and real-time temperature sensing at a sensing joint.Advanced communications are enabled by implementing space-time coding on DSCM communication signals,with 0.2 dB Q factor improvement.As for the sensing functionality,the temperature sensing resolution at 0.0625°C,which reaches the limitation of the employed electronic thermometer DS18B20,has been obtained by using the communication-compatible DSP.We believe the proposed ISAC scheme along with the corresponding DSP flowchart makes sense for monitoring the subsea via the advanced SMART cables.
