The carrier-free phase-retrieval(CF-PR)receiver can reconstruct the optical field information only from two de-correlated intensity measurements without the involvement of a continuous-wave optical carrier.Here,we pro...The carrier-free phase-retrieval(CF-PR)receiver can reconstruct the optical field information only from two de-correlated intensity measurements without the involvement of a continuous-wave optical carrier.Here,we propose a digital subcarrier multiplexing(DSM)-enabled CF-PR receiver with hardware-efficient and modulation format-transparent merits.By numerically retrieving the optical field information of 56 GBaud DSM signals with QPSK/16QAM/32QAM modulation after 80-km standard single-mode fiber(SSMF)transmission,we identify that the DSM enabled CF-PR receiver is beneficial in reducing the implementation complexity of the CF-PR process,in comparison with the traditional single-carrier counterpart,because the lower symbol rate of each subcarrier is helpful in reducing the implementation complexity of multiple chromatic dispersion compensations and emulations during the PR iteration.Moreover,the DSM-enabled CF-PR receiver is verified to be robust toward various transmission imperfections,including transmitter-side laser linewidth and its wavelength drift,receiver-side time skew,and amplitude imbalance between two intensity tributaries.Finally,the superiority of the DSM-enabled CF-PR receiver is experimentally verified by recovering the optical field information of 25 GBaud 16QAM signals,after 40-km SSMF transmission for the first time.Thus,the DSM-enabled CF-PR receiver is promising for high-capacity photonic interconnection with direct detection.展开更多
In this paper, the problem of channel estimation for superposition coded modulation-orthogonal frequency division multiplexing (SCM-OFDM) systems over frequency selective channels is investigated. Assuming that the pa...In this paper, the problem of channel estimation for superposition coded modulation-orthogonal frequency division multiplexing (SCM-OFDM) systems over frequency selective channels is investigated. Assuming that the path delays are known, a new channel estimator based on modified Kalman filter algorithms is introduced for the estimation of the multipath Rayleigh channel complex gains (CG). In the simulation, the mean square error (MSE) and bit-error-rate (BER) performances are given to verify the effectiveness of the Kalman estimation algorithms for SCM-OFDM systems.展开更多
In this paper, a blockwise adaptive subcarrier allocation algorithm for multiuser Orthogonal Frequency Division Multiplexing (OFDM) system is introduced. Assuming the knowledge of channel information for all users, th...In this paper, a blockwise adaptive subcarrier allocation algorithm for multiuser Orthogonal Frequency Division Multiplexing (OFDM) system is introduced. Assuming the knowledge of channel information for all users, the algorithm minimizes the total transmit power while satisfying the total power and users' rate constraints. The result of simulation shows that the proposed algorithm reduces the average bit Signal-to-Noise Ratio (SNR) by approximately 4 dB compared with OFDM-Frequency Division Multiple Access (OFDM-FDMA), and supports more users in a multiuser Rayleigh fading channel. As assigning subcarriers in block, the computational complexity of the algorithm is much lower than that of the derivation of "water-filling" algorithm.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB2900702)the National Natural Science Foundation of China(Grant No.U21A20506)the Guangdong Introducing Innovative and Entrepreneurial Teams of“The Pearl River Talent Recruitment Program”(Grant No.2021ZT09X044).
文摘The carrier-free phase-retrieval(CF-PR)receiver can reconstruct the optical field information only from two de-correlated intensity measurements without the involvement of a continuous-wave optical carrier.Here,we propose a digital subcarrier multiplexing(DSM)-enabled CF-PR receiver with hardware-efficient and modulation format-transparent merits.By numerically retrieving the optical field information of 56 GBaud DSM signals with QPSK/16QAM/32QAM modulation after 80-km standard single-mode fiber(SSMF)transmission,we identify that the DSM enabled CF-PR receiver is beneficial in reducing the implementation complexity of the CF-PR process,in comparison with the traditional single-carrier counterpart,because the lower symbol rate of each subcarrier is helpful in reducing the implementation complexity of multiple chromatic dispersion compensations and emulations during the PR iteration.Moreover,the DSM-enabled CF-PR receiver is verified to be robust toward various transmission imperfections,including transmitter-side laser linewidth and its wavelength drift,receiver-side time skew,and amplitude imbalance between two intensity tributaries.Finally,the superiority of the DSM-enabled CF-PR receiver is experimentally verified by recovering the optical field information of 25 GBaud 16QAM signals,after 40-km SSMF transmission for the first time.Thus,the DSM-enabled CF-PR receiver is promising for high-capacity photonic interconnection with direct detection.
文摘In this paper, the problem of channel estimation for superposition coded modulation-orthogonal frequency division multiplexing (SCM-OFDM) systems over frequency selective channels is investigated. Assuming that the path delays are known, a new channel estimator based on modified Kalman filter algorithms is introduced for the estimation of the multipath Rayleigh channel complex gains (CG). In the simulation, the mean square error (MSE) and bit-error-rate (BER) performances are given to verify the effectiveness of the Kalman estimation algorithms for SCM-OFDM systems.
基金Supported by the National 863 High-Tech Program of China (No.2001AA121031)the National Natural Science Foundation of China (GG065760242003)
文摘In this paper, a blockwise adaptive subcarrier allocation algorithm for multiuser Orthogonal Frequency Division Multiplexing (OFDM) system is introduced. Assuming the knowledge of channel information for all users, the algorithm minimizes the total transmit power while satisfying the total power and users' rate constraints. The result of simulation shows that the proposed algorithm reduces the average bit Signal-to-Noise Ratio (SNR) by approximately 4 dB compared with OFDM-Frequency Division Multiple Access (OFDM-FDMA), and supports more users in a multiuser Rayleigh fading channel. As assigning subcarriers in block, the computational complexity of the algorithm is much lower than that of the derivation of "water-filling" algorithm.
