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Abstract In this paper, we propose a low-overhead equalization algorithm used in the intensity modulation direct detection (IMDD) system with offset-quadrature amplitude modulation orthogonal frequency division multiplexing (OQAM-OFDM) modulation. By utilizing the complex interference approximation (IA) structure and the comb pilot-based frequency domain intra-symbol averaging and intra-subcarrier linear interpolation (CFAL) method, the OQAM-OFDM signal's intrinsic imaginary non-orthogonal distortions can be mitigated and the low overhead of channel estimation with high estimation accuracy can be achieved. The experiment and numerical simulation are constructed to evaluate the proposed IA-CFAL algorithm from the aspects of bit error rate (BER) performance, mean square error (MSE), dispersion tolerance, time jitter tolerance and complexity. Comparison with the previous algorithms are made to prove its robustness to transmission impairments with low training overhead. Highlights • Low pilot overhead. • Simultaneously Estimating Channel and Mitigating Intrinsic imaginary interference. • High estimation accuracy. • Complex interference approximation (IA) structure. • The comb pilot-based frequency domain intra-symbol intra-subcarrier linear interpolation. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we present an integral imaging microscopy, which can achieve continuous depth extraction. The multiple stereo matching algorithm is optimized with data point interpolation and calculation range correction, which can improve the computing efficiency and accuracy. A water suspension of silica-embedded magnetic particles in light-trap environment is used as a specimen. The elementary image array is obtained through sequentially imaging the specimen by the objective lens and microlens array, which contains continuous depth information that can give the optical tweezers a feedback for precise 3-D manipulation. Experimental and calculated results show the feasibility of our method. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we present a newfound in the two-dimensional Visible Light Communication (VLC) system, i.e., additional modulation orders are generated in the receiver. Meanwhile, an algorithm named High/Low order Bit Interleaving (HLBI) is proposed in a formulated VLC Multiple-Input-Single-Output (MISO) model, which aims to decrease part of these orders. A data rate of 1.24Gbit/s is achieved in 1.3 m indoor Line-Of-Sight (LOS) scenario with the Bit Error Rate (BER) is under 3.8 × 10−3. Since the algorithm also aids STBC decoding, the Q factor can be improved to 1.92dB. [ABSTRACT FROM AUTHOR]

In this paper, we propose a blind Volterra series based nonlinear equalization (VNLE) with low complexity for the nonlinear distortion mitigation in short reach optical carrierless amplitude and phase (CAP) modulation system. The principle of the blind VNLE is presented and the performance of its blind adaptive algorithms including the modified cascaded multi-mode algorithm (MCMMA) and direct detection LMS (DD-LMS) are investigated experimentally. Compared to the conventional VNLE using training symbols before demodulation, it is performed after matched filtering and downsampling, so shorter memory length is required but similar performance improvement is observed. About 1 dB improvement is observed at BER of 3.8×10 −3 for 40 Gb/s CAP32 signal over 40 km standard single mode fiber. [ABSTRACT FROM AUTHOR]

A frequency offset estimation (FOE) algorithm based on fast Fourier transform (FFT) of the signal's argument is investigated, which does not require removing the modulated data phase. In this paper, we analyze the flaw of the argument-FFT algorithm and propose a combined FOE algorithm, in which the absolute of frequency offset (FO) is accurately calculated by argument-FFT algorithm with a relatively large number of samples and the sign of FO is determined by FFT-based interpolation discrete Fourier transformation (DFT) algorithm with a relatively small number of samples. Compared with the previous algorithms based on argument-FFT, the proposed one has low complexity and can still effectively work with a relatively less number of samples. [ABSTRACT FROM AUTHOR]