Volterra series

About: Volterra series is a research topic. Over the lifetime, 2731 publications have been published within this topic receiving 46199 citations.

Enhanced Performance of a High-Speed WDM CAP64 VLC System Employing Volterra Series-Based Nonlinear Equalizer

Abstract: The light-emitting diode nonlinearity in visible light communication (VLC) systems is considered to be a major problem that deteriorates system performance. In this paper, we experimentally demonstrate a high-speed WDM CAP64 VLC system employing a Volterra series-based nonlinear equalizer to mitigate the nonlinear effect. A modified cascaded multimodulus algorithm (M-CMMA) is utilized to calculate the error function and update the weights of the nonlinear equalizer without using training symbols. An aggregate data rate of 4.5 Gb/s is successfully achieved over 2-m indoor free-space transmission with a bit error rate (BER) below the 7% forward error correction limit of 3.8 × 10 -3 . With the Volterra nonlinear equalizer, the Q factor of the VLC system is 1. 6 dB better than that without using the nonlinear equalizer, and the transmission distance is also increased by about 110 cm at the BER of 3.8 × 10 -3 . To the best of our knowledge, this is the first time that the Volterra nonlinear equalizer is utilized for high-speed carrierless amplitude and phase (CAP) modulation-based VLC systems.

Volterra and Wiener Equalizers for Short-Reach 100G PAM-4 Applications

Abstract: Unlike ultralong coherent optical systems that seriously suffer from fiber nonlinearities, short-reach noncoherent systems such as data center interconnections, which utilize small, cheap, and low-bandwidth components, are sensitive to nonlinearities that are mainly produced by devices responsible for electrical signal amplification, modulation, and demodulation. One of the most promising schemes for these applications is the four-level pulse amplitude modulation format combined with intensity modulation and direct detection; however, it can be significantly degraded by linear and nonlinear intersymbol interference. Linear and nonlinear signal degradation can efficiently be handled by different types of equalizers. In many cases, the straightforward linear equalizer cannot lower the error rate at the acceptable level. Therefore, much stronger equalizers based on nonlinear models such as the Volterra series are proposed. Volterra filter that can also be orthogonalized by the Wiener model is well described in the existing literature, and, in this paper, we investigate the most critical points related to high-speed Volterra filter design and implementation. Several experiments are carried out in order to indicate filter requirements/complexity, acquisition, and stability. We also provide a simple guidance for filter complexity reduction and useful hints for channel acquisition.

A Highly Linear Low-Noise Amplifier

Abstract: A low-noise amplifier (LNA) that achieves high third-order input intercept point (IIP3) at RF frequencies using a nonlinearity cancellation technique is proposed. The circuit tackles the problem of the effect of the second-order nonlinearity on IIP3 at RF frequencies. The circuit functionality is analyzed using Volterra series. The linear LNA was designed and fabricated in a TSMC 0.35-mum CMOS process. An IIP3 of +21 dBm was achieved with a gain of 11.5 dB, noise figure of 2.95 dB, and a power consumption of 9 mA at 2.5 V

Analysis of Non-Gaussian Surge Response of Tension Leg Platforms Under Wind Loads

Abstract: The nonlinearity in the wind loading expression for a complaint offshore structure, e.g., a tension leg platform (TLP), results in response statistics that deviate from the Gaussian distribution. This paper focuses on the statistical analysis of the response of these structures to random wind loads. The analysis presented here involves a nonlinear system with memory. As an improvement over the commonly used linearization approach, an equivalent statistical quadratization method is presented. The higher-order response cumulants are based on Volterra series. A direct integration scheme and Kac-Siegert technique is utilized to evaluate the response cumulants. Based on the first four cumulants, the response probability density function, crossing rates, and peak value distribution are derived. The results provide a good comparison with simulation. A nonlinear wind gust loading factor based on the derived extreme value distribution of nonlinear wind effects is formulated.

A novel envelope-termination load-pull method for ACPR optimization of RF/microwave power amplifiers

Abstract: A novel load-pull method for envelope-termination characterization is presented. The method enables the source and load envelope terminations to be easily evaluated to further optimize the linearity/efficiency tradeoff of RF/microwave power transistors used in digital wireless communication systems with time-varying envelopes. Results are presented for a 53 mm low-voltage LDMOS transistor at 850 MHz. It is shown that the optimal envelope termination may in general be complex, in contrast to the commonly held belief that the envelope-termination must be approximately zero. A simplified Volterra series analysis is used to qualitatively explain how the envelope termination impacts linearity.