In this work,we proposed and experimentally demonstrated a novel probabilistic shaping(PS)64-ary quadrature amplitude modulation(QAM)orthogonal frequency division multiplexing(OFDM)with low-density parity-check(LDPC)-...In this work,we proposed and experimentally demonstrated a novel probabilistic shaping(PS)64-ary quadrature amplitude modulation(QAM)orthogonal frequency division multiplexing(OFDM)with low-density parity-check(LDPC)-coded modulation in a W-band radio-over-fiber(RoF)system using envelope detection.The proposed PS scheme has the advantages of no complex multiplication and division operations and low hardware implementation complexity.In our experiments,the two-stage bit weight distribution matching-based PS-64QAM OFDM signals with a rate of 28.13 Gb/s transmission over 4 m wireless+45-km standard single-mode fiber transmission can be achieved.The system performance is investigated under one LDPC code rate(3/4)and two PS parameter values(k=3 and 9).The experimental results show that the receiver power sensitivity and the system fiber nonlinear effect tolerance can be significantly improved compared with uniformly distributed OFDM signals.展开更多
An improved localization method consisting of ＂filtering-time delay estimationhyperbolic localization＂ is proposed. Combining the empirical mode decomposition（EMD）and time delay estimation method based on generali...An improved localization method consisting of ＂filtering-time delay estimationhyperbolic localization＂ is proposed. Combining the empirical mode decomposition（EMD）and time delay estimation method based on generalized average magnitude difference function,the original signals are decomposed into intrinsic mode function（IMF） components. The energy distribution criterion and spectrum consistency criterion are used to select the IMFs, which can represent the physical characteristics of the source signal. Several sets of signals are applied to estimate the time delay, and then a vector matching criterion is proposed to select the correct time delay estimation. Considering the hydrophones location, a shell model is established and projected to a plane according to the quadrant before the hyperbolic localization. Results of mooring and sailing tests show that the proposed method improves the localization accuracy,and reduces the error caused by time delay estimation.展开更多
For stroke-order free online multi-stroke charac- ter recognition, stroke-to-stroke correspondence search be- tween an input pattern and a reference pattern plays an im- portant role to deal with the stroke-order vari...For stroke-order free online multi-stroke charac- ter recognition, stroke-to-stroke correspondence search be- tween an input pattern and a reference pattern plays an im- portant role to deal with the stroke-order variation. Although various methods of stroke correspondence have been pro- posed, no comparative study for clarifying the relative su- periority of those methods has been done before. In this pa- per, we firstly review the approaches for solving the stroke- order variation problem. Then, five representative methods of stroke correspondence proposed by different groups, includ- ing cube search （CS）, bipartite weighted matching （BWM）, individual correspondence decision （ICD）, stable marriage （SM）, and deviation-expansion model （DE）, are experimen- tally compared, mainly in regard of recognition accuracy and efficiency. The experimental results on an online Kanji char- acter dataset, showed that 99.17%, 99.17%, 96.37%, 98.54%, and 96.59% were attained by CS, BWM, ICD, SM, and DE, respectively as their recognition rates. Extensive discussions are made on their relative superiorities and practicalities.展开更多
基金supported by the Natural Science Research Startup Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(No.NY223144)。
文摘In this work,we proposed and experimentally demonstrated a novel probabilistic shaping(PS)64-ary quadrature amplitude modulation(QAM)orthogonal frequency division multiplexing(OFDM)with low-density parity-check(LDPC)-coded modulation in a W-band radio-over-fiber(RoF)system using envelope detection.The proposed PS scheme has the advantages of no complex multiplication and division operations and low hardware implementation complexity.In our experiments,the two-stage bit weight distribution matching-based PS-64QAM OFDM signals with a rate of 28.13 Gb/s transmission over 4 m wireless+45-km standard single-mode fiber transmission can be achieved.The system performance is investigated under one LDPC code rate(3/4)and two PS parameter values(k=3 and 9).The experimental results show that the receiver power sensitivity and the system fiber nonlinear effect tolerance can be significantly improved compared with uniformly distributed OFDM signals.
基金supported by the National Natural Science Foundation of China(51209214)the Research Development Foundation of Naval University of Engineering(425517K031)
文摘An improved localization method consisting of ＂filtering-time delay estimationhyperbolic localization＂ is proposed. Combining the empirical mode decomposition（EMD）and time delay estimation method based on generalized average magnitude difference function,the original signals are decomposed into intrinsic mode function（IMF） components. The energy distribution criterion and spectrum consistency criterion are used to select the IMFs, which can represent the physical characteristics of the source signal. Several sets of signals are applied to estimate the time delay, and then a vector matching criterion is proposed to select the correct time delay estimation. Considering the hydrophones location, a shell model is established and projected to a plane according to the quadrant before the hyperbolic localization. Results of mooring and sailing tests show that the proposed method improves the localization accuracy,and reduces the error caused by time delay estimation.
文摘For stroke-order free online multi-stroke charac- ter recognition, stroke-to-stroke correspondence search be- tween an input pattern and a reference pattern plays an im- portant role to deal with the stroke-order variation. Although various methods of stroke correspondence have been pro- posed, no comparative study for clarifying the relative su- periority of those methods has been done before. In this pa- per, we firstly review the approaches for solving the stroke- order variation problem. Then, five representative methods of stroke correspondence proposed by different groups, includ- ing cube search （CS）, bipartite weighted matching （BWM）, individual correspondence decision （ICD）, stable marriage （SM）, and deviation-expansion model （DE）, are experimen- tally compared, mainly in regard of recognition accuracy and efficiency. The experimental results on an online Kanji char- acter dataset, showed that 99.17%, 99.17%, 96.37%, 98.54%, and 96.59% were attained by CS, BWM, ICD, SM, and DE, respectively as their recognition rates. Extensive discussions are made on their relative superiorities and practicalities.
