Performance Optimization by Nonparametric Histogram Estimation for Low Resolution in IMDD-OQAM-OFDM System

Abstract

In this paper, for the first time, we propose a nonparametric histogram estimation (NPHE) scheme for the nonuniform quantization in intensity modulated direct detection with filter bank multicarrier signal to improve system performance. By combining the NPHE scheme and the common nonlinear programming method, the distribution of offset quadrature amplitude modulation based optical orthogonal frequency division multiplexing (OQAM-OFDM) signal is accurately estimated and then it is used to achieve the optimal nonuniform quantization level. In this way, the low-level signal can achieve much more effective digitalizing bits, thereby significantly reducing the quantization noise. The numerical simulation and experiment with 10-Gb/s 16-order OQAM-OFDM signal over 20 km fiber are conducted to further verify the feasibility of our scheme. The results show that our scheme always outperforms the uniform quantization and Gaussian-like nonuniform schemes in terms of the signal to quantization noise ratio, error-vector-magnitudes, and bit error rate. Compared to the conventional method, our scheme also achieves received sensitivity improvement thereby improving the system power budget. So, it can support the low-bit resolution transmission in intensity modulated direct detection-based OQAM-OFDM system.

Volterra Expansion Based Intra Channel Nonlinear Effect Equalization Method for Optical OFDM/OQAM Systems

“…Then, SVEM equations in (21) could be further abbreviated as in (23). To obtain the solution of (23), VENE methods based on the use of specially designed pilot blocks will be analyzed in the following discussion.…”

“…Preamble blocks for performing VENE have been designed according to Fig.2. In order to simplify the generating of the pseudo pilots, we place nulls at the first, the third and the fifth preamble blocks, while the second and the fourth blocks are loaded with OQAM pilots so as to obtain the solution for (23).…”

“…Recently, numerous experimental demonstrations for optical OFDM/OQAM (O-OFDM/OQAM) have been reported [21][22][23][24][25]. Horlin proposed the concept of coherent optical OFDM/OQAM (CO-OFDM/OQAM) in [15].…”

Photonics-Assisted Millimeter-Wave Communication System Based on Low-Bit Gaussian Mixture Model Adaptive Vector Quantization

“…On the other hand, non-uniform quantization is another effective method to reduce the required number of quantization bits. To date, some non-uniform quantization schemes with low-bit resolution have been presented, achieving the improved quantization performance to some extent [9][10][11][12][13][14][15]. To be specific, these non-uniform quantization schemes mainly include the A-law quantization [9,10], Lloyd quantization [11], non-parametric histogram estimation (NPHE) [12], Gaussianlike estimation (GLE) [13,14] and other novel quantization schemes [15].…”

“…To date, some non-uniform quantization schemes with low-bit resolution have been presented, achieving the improved quantization performance to some extent [9][10][11][12][13][14][15]. To be specific, these non-uniform quantization schemes mainly include the A-law quantization [9,10], Lloyd quantization [11], non-parametric histogram estimation (NPHE) [12], Gaussianlike estimation (GLE) [13,14] and other novel quantization schemes [15]. Nevertheless, these above-mentioned quantization schemes either have the fixed quantization levels which cannot be adjusted adaptively according to the actual distribution of input signal, or need to extra estimation the probability density function (PDF) of the signal, which increases the complexity of the quantization operation.…”