In wireless sensor networks, the traditional multi-relay incremental cooperative relaying (MIR) scheme could improve the system throughput over the fading channel enormously by exploiting multiple relay nodes to retra...In wireless sensor networks, the traditional multi-relay incremental cooperative relaying (MIR) scheme could improve the system throughput over the fading channel enormously by exploiting multiple relay nodes to retransmit the copy of the source packet to the destination in turn, but increase the energy consumption and transmission delay. In order to mitigating the energy consumption and transmission delay, this paper proposes a new cooperative relaying scheme termed as incremental-selective relaying with best-relay selection (ISR), which selects the best relay node from the candidate relays to retransmit the packet to the destination only when the direct transmission between the source and the destination is not successful. Expressions of normalized throughput, normalized delay and energy efficiency for the ISR and MIR systems are derived respectively and their performances are compared through simulations. The results show that normalized throughput, normalized delay and energy efficiency for the ISR system all outperform the corresponding performances of the MIR system. Especially, there are different the optimal number of relays which can maximize the energy efficiency of system.展开更多
We report on a power-scalable sub-100-fs laser in the 2-μm spectral range using a Tm;-doped‘mixed’(Lu,Sc);O;sesquioxide ceramic as an active medium.Pulses as short as 58 fs at 2076 nm with an average output power o...We report on a power-scalable sub-100-fs laser in the 2-μm spectral range using a Tm;-doped‘mixed’(Lu,Sc);O;sesquioxide ceramic as an active medium.Pulses as short as 58 fs at 2076 nm with an average output power of 114 mW at a pulse repetition rate of approximately 82.9 MHz are generated by employing single-walled carbon nanotubes as a saturable absorber.A higher average power of 350 m W at 2075 nm is obtained at the expense of the pulse duration(65 fs).A maximum average power of 486 mW is achieved for a pulse duration of 98 fs and an optical conversion efficiency of 22.3%,representing the highest value ever reported from sub-100-fs mode-locked Tm lasers.展开更多
文摘In wireless sensor networks, the traditional multi-relay incremental cooperative relaying (MIR) scheme could improve the system throughput over the fading channel enormously by exploiting multiple relay nodes to retransmit the copy of the source packet to the destination in turn, but increase the energy consumption and transmission delay. In order to mitigating the energy consumption and transmission delay, this paper proposes a new cooperative relaying scheme termed as incremental-selective relaying with best-relay selection (ISR), which selects the best relay node from the candidate relays to retransmit the packet to the destination only when the direct transmission between the source and the destination is not successful. Expressions of normalized throughput, normalized delay and energy efficiency for the ISR and MIR systems are derived respectively and their performances are compared through simulations. The results show that normalized throughput, normalized delay and energy efficiency for the ISR system all outperform the corresponding performances of the MIR system. Especially, there are different the optimal number of relays which can maximize the energy efficiency of system.
基金partly supported by the National Natural Science Foundation of China(NSFC)(52032009,61975208,62075090,51761135115,61575199,61850410533,and 52072351)Deutsche Forschungsgemeinschaft(PE 607/14-1)+6 种基金Sino-German Scientist Cooperation and Exchanges Mobility Program(M-0040)Natural Science Foundation of Jiangsu Province(BK20190104)National Research Foundation of Korea(2020R1A4A2002828)CAS Key Laboratory of Optoelectronic Materials Chemistry and Physics,FJIRSM CAS(2008DP173016)Foundation of the President of China Academy of Engineering Physics(YZJJLX2018005)State Key Laboratory of Crystal Materials(SKLCM),SDU(KF2001)financial support from the Alexander von Humboldt Foundation through a Humboldt fellowship。
文摘We report on a power-scalable sub-100-fs laser in the 2-μm spectral range using a Tm;-doped‘mixed’(Lu,Sc);O;sesquioxide ceramic as an active medium.Pulses as short as 58 fs at 2076 nm with an average output power of 114 mW at a pulse repetition rate of approximately 82.9 MHz are generated by employing single-walled carbon nanotubes as a saturable absorber.A higher average power of 350 m W at 2075 nm is obtained at the expense of the pulse duration(65 fs).A maximum average power of 486 mW is achieved for a pulse duration of 98 fs and an optical conversion efficiency of 22.3%,representing the highest value ever reported from sub-100-fs mode-locked Tm lasers.
