An optical Amplitude and Pulse Position Modulation(APPM) mapping scheme for strong turbulent atmospheric channel is proposed to optimize Bit Error Rate(BER) performance.In this scheme,a nonequidifferent amplitude seri...An optical Amplitude and Pulse Position Modulation(APPM) mapping scheme for strong turbulent atmospheric channel is proposed to optimize Bit Error Rate(BER) performance.In this scheme,a nonequidifferent amplitude series is designed based on quantitative BER analysis of the specific A×M APPM demapping procedures containing time slot selection and amplitude decision in selected time slot,which are different from traditional ones.Simulation results of 4×4,4×8 and 4×16 APPM show 4,3.4 and 6.9 d B SNR gain against traditional APPM scheme respectively.Thus significant BER performance improvement is achieved which helps to enhance reliability of freespace optical communication systems.展开更多
A novel trellis coded-4×8 overlapping amplitude and pulse position modulation(TC-4×8AOPPM) scheme is proposed to enhance bit error rate(BER) performance of free-space optical communication(FSO) system. In ad...A novel trellis coded-4×8 overlapping amplitude and pulse position modulation(TC-4×8AOPPM) scheme is proposed to enhance bit error rate(BER) performance of free-space optical communication(FSO) system. In addition, an uncoded AOPPM referential scheme is also designed. The schemes manage to decrease BER by designing gamma-gamma(GG) channel applicable decoding and demodulation methods. Simulation results of 8, 16 and 64-state TC-4×8AOPPM show 2.5-3.3 dB SNR gain against traditional TC-4×8AOPPM scheme respectively. Thus significant BER performance improvement is achieved and the reliability of the FSO system is also enhanced.展开更多
We investigate the decoy state quantum key distribution via the atmosphere channels. We consider the efficient decoy state method with one-signal state and two-decoy states. Our results show that the decoy state metho...We investigate the decoy state quantum key distribution via the atmosphere channels. We consider the efficient decoy state method with one-signal state and two-decoy states. Our results show that the decoy state method works even in the channels with fluctuating transmittance. Nevertheless, the key generation rate will be dra-matically decreased by atmosphere turbulence, which sheds more light on the characterization of atmosphere turbulence in realistic free-space based quantum key distributions.展开更多
We investigate the continuous variable quomtum teleportation in atmosphere channels. The beam-wandering mode/is employed to analyze the teleportation of the unknown single-mode coherent state. Two methods, one is dete...We investigate the continuous variable quomtum teleportation in atmosphere channels. The beam-wandering mode/is employed to analyze the teleportation of the unknown single-mode coherent state. Two methods, one is deterministic by increasing the aperture size of the detecting device and one is probabilistic by entanglement distillation, are proposed to improve the teleportation fidelity in the presence of atmosphere noises.展开更多
In free-space optical(FSO) communications, the performance of the communication systems is severely degraded by atmospheric turbulence. Channel coding and diversity techniques are commonly used to combat channel fadin...In free-space optical(FSO) communications, the performance of the communication systems is severely degraded by atmospheric turbulence. Channel coding and diversity techniques are commonly used to combat channel fading induced by atmospheric turbulence. In this paper, we present the generalized block Markov superposition transmission(GBMST) of repetition codes to improve time diversity. In the GBMST scheme, information sub-blocks are transmitted in the block Markov superposition manner, with possibly different transmission memories. Based on analyzing an equivalent system, a lower bound on the bit-error-rate(BER) of the proposed scheme is presented. Simulation results demonstrate that, under a wide range of turbulence conditions, the proposed scheme improves diversity gain with only a slight reduction of transmission rate. In particular, with encoding memory sequence(0, 0, 8) and transmission rate 1/3, a diversity order of eleven is achieved under moderate turbulence conditions. Numerical results also show that, the GBMST systems with appropriate settings can approach the derived lower bound, implying that full diversity is achievable.展开更多
基金financial supports from National High Technology 863 Program of China(No.2012AA011304)National International Technology Cooperation(No.2012DFG12110)+5 种基金National NSFC(No.61275158/61201151/61275074)Beijing Nova Program( No.Z141101001814048)Beijing Excellent Ph.D.Thesis Guidance Foundation(No.20121001302)the Universities Ph.D.Special Research Funds(No.20120005110003)the Fundamental Research Funds for the Central Universities with No.2014RC0203Fund of State Key Laboratory of IPOC(BUPT)
文摘An optical Amplitude and Pulse Position Modulation(APPM) mapping scheme for strong turbulent atmospheric channel is proposed to optimize Bit Error Rate(BER) performance.In this scheme,a nonequidifferent amplitude series is designed based on quantitative BER analysis of the specific A×M APPM demapping procedures containing time slot selection and amplitude decision in selected time slot,which are different from traditional ones.Simulation results of 4×4,4×8 and 4×16 APPM show 4,3.4 and 6.9 d B SNR gain against traditional APPM scheme respectively.Thus significant BER performance improvement is achieved which helps to enhance reliability of freespace optical communication systems.
基金supported in part by the National NSFC with No.61425022National High Technology 863 Program of China with No.2013AA013403+5 种基金National Basic Research Program of China with No.2010CB328300National NSFC(No.60932004,61275074,61275158,& 61201151)National International Technology Cooperation with No.2012DFG12110Universities Ph.D. Special Research Funds with No.20120005120007Beijing Excellent Ph.D. Thesis Guidance Foundation with No. 20121001302Open foundation of state key laboratory of optical communication technologies and networks(WRI)
文摘A novel trellis coded-4×8 overlapping amplitude and pulse position modulation(TC-4×8AOPPM) scheme is proposed to enhance bit error rate(BER) performance of free-space optical communication(FSO) system. In addition, an uncoded AOPPM referential scheme is also designed. The schemes manage to decrease BER by designing gamma-gamma(GG) channel applicable decoding and demodulation methods. Simulation results of 8, 16 and 64-state TC-4×8AOPPM show 2.5-3.3 dB SNR gain against traditional TC-4×8AOPPM scheme respectively. Thus significant BER performance improvement is achieved and the reliability of the FSO system is also enhanced.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11574400,U1304613,11204197,11204379 and 11074244the National Basic Research Program of China under Grant No 2011CBA00200the Doctor Foundation of the Ministry of Education of China under Grant No 20113402110059
文摘We investigate the decoy state quantum key distribution via the atmosphere channels. We consider the efficient decoy state method with one-signal state and two-decoy states. Our results show that the decoy state method works even in the channels with fluctuating transmittance. Nevertheless, the key generation rate will be dra-matically decreased by atmosphere turbulence, which sheds more light on the characterization of atmosphere turbulence in realistic free-space based quantum key distributions.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11574400,U1304613,11204197,11204379and 11074244
文摘We investigate the continuous variable quomtum teleportation in atmosphere channels. The beam-wandering mode/is employed to analyze the teleportation of the unknown single-mode coherent state. Two methods, one is deterministic by increasing the aperture size of the detecting device and one is probabilistic by entanglement distillation, are proposed to improve the teleportation fidelity in the presence of atmosphere noises.
基金partially supported by the Basic Research Project of Guangdong Provincial Natural Science Foundation (No.2016A030308008)the National Natural Science Foundation of China (No.91438101 and No.61501206)the National Basic Research Program of China (973 Program) (No.2012CB316100)
文摘In free-space optical(FSO) communications, the performance of the communication systems is severely degraded by atmospheric turbulence. Channel coding and diversity techniques are commonly used to combat channel fading induced by atmospheric turbulence. In this paper, we present the generalized block Markov superposition transmission(GBMST) of repetition codes to improve time diversity. In the GBMST scheme, information sub-blocks are transmitted in the block Markov superposition manner, with possibly different transmission memories. Based on analyzing an equivalent system, a lower bound on the bit-error-rate(BER) of the proposed scheme is presented. Simulation results demonstrate that, under a wide range of turbulence conditions, the proposed scheme improves diversity gain with only a slight reduction of transmission rate. In particular, with encoding memory sequence(0, 0, 8) and transmission rate 1/3, a diversity order of eleven is achieved under moderate turbulence conditions. Numerical results also show that, the GBMST systems with appropriate settings can approach the derived lower bound, implying that full diversity is achievable.
