Optimization of Multi-Band DFT-Spread DMT System for Polymer Optical Fiber Communications

Abstract--Recently, polymer optical fiber (POF) became a popular solution for the indoor communications. In this paper, a multi-band discrete-Fourier-transform spread (MB-DFT-S) discrete multi-tone (DMT) system is proposed to study and optimize in terms of POF communications. A joint optimization of used subcarrier number, used bandwidth and multi-band number is investigated. The transmission of MB-DFT-S DMT over 50 m POF link is implemented. Both theoretical and experimental results demonstrate that optimized MB-DFT-S DMT system outperforms the original DMT and DFT-S DMT systems, which means that it is a promising technique for future POF transmission systems

On Bit-loading for Discrete Multi-tone Transmission over Short Range POF Systems

International audienceA novel bit-loading approach is proposed for the discrete multi-tone (DMT) transmission over short range polymer optical fiber (POF) systems. First of all, from the extract signal-to-noise ratio (SNR) table of quadrature amplitude modulation (QAM) for different desired bit error rates (BER), a new linear approximation (LA) expression is introduced to implement bit-loading for DMT systems. Then, based on water-filling concept, the performance bounds and optimal power allocations for the classical and the proposed bit-loading algorithms in Gaussian low-pass channel models are derived. Consequently, introducing the measured channel parameters of step-index (SI)-POF channels with different transmission distances, the theoretical performance bounds are computed and the practical transmission rates are simulated. Simulation results show that the proposed LA expression based bit-loading achieves higher transmission rate than classical modulation gap based bit-loading. Both algorithms use sub-optimal Chow algorithm with constant power allocation and iterative process. Finally, real DMT transmissions over SI-POFs are implemented in order to verify the proposed method. The LA expression based bit-loading outperforms the modulation gap based bit-loading in DMT transmission systems over different transmission distances. Moreover, experimental results show that the longer fiber length, the higher performance gain with LA expression based bit-loading. In the comparisons, for a 50 m SI-POF transmission, the transmission rate in DMT system with LA expression based bit-loading is improved by 5 % with the same experimental setups for a given BER at 1e-3 and by 10% for a 100 m length

Optimized Discrete Multitone Communication Over Polymer Optical Fiber

International audienceIn this paper, we propose an overall optimization of discrete multitone (DMT) transmissions over polymer optical fiber (POF). The optimization is carried out from both a theoretical and experimental approach. At first, the parameters of the POF channel characteristics, resonant cavity light emitting diode (RC-LED) dynamic nonlinearity performance and analog-to-digital converter effective number of bits (ENOB), in our digital storage oscilloscope are measured. From the measured results, we investigate the channel capacity of a 50 m step-index POF system. Then the optimal DMT bandwidth is theoretically derived. We also optimize the system with different experimental setups. The optimal cyclic prefix length and RC-LED optimal working current are given. The ENOB can be improved by oversampling and averaging. The optimal oversampling factor is discussed. Furthermore, a joint DMT clipping and subcarrier number optimization is synthetically investigated. Based on the proposed approaches, an optimized DMT gigabit transmission over a real 50 m POF channel employing low-cost components is presented. Finally, a methodology for the practical design of the DMT transmission over POF is concluded

Optimum Configuration for Discrete Multi-tone Transmission over Polymer Optical Fiber

High bit rate transmission over polymer optical fiber (POF) attracts great interests recently. This paper investigates the discrete multi-tone (DMT) transmission over 50-meter step-index POF (SI-POF) based on an experimental system. The system adopts a digital storage oscilloscope (DSO) and processes the data off-line, which is the most common solution in the POF researches. We first study the problem of effective number of bits (ENOB) in the DSO's analog-to-digital converter (ADC). Then we investigate the optimum configuration of the DMT transmission in terms of subcarrier number selection, clipping and ADC quantization effect mitigation. The proposed method of selecting optimum configuration can be easily applied to any other DMT over POF systems

1.5 Gbps PN-ZP-DMT Transmission System for 1-mm Core Diameter SI-POF with RC-LED

A novel PN-ZP-DMT transmission scheme without requiring dedicated pilots for channel estimation is proposed. Hardware experiments on 50 m SI-POF with RC-LED show that the proposed scheme achieves a transmission rate of 1.5 Gbps with low cost off the shelf components

Radio frequency fingerprint identification for Internet of Things: A survey

Radio frequency fingerprint (RFF) identification is a promising technique for identifying Internet of Things (IoT) devices. This paper presents a comprehensive survey on RFF identification, which covers various aspects ranging from related definitions to details of each stage in the identification process, namely signal preprocessing, RFF feature extraction, further processing, and RFF identification. Specifically, three main steps of preprocessing are summarized, including carrier frequency offset estimation, noise elimination, and channel cancellation. Besides, three kinds of RFFs are categorized, comprising I/Q signal-based, parameter-based, and transformation-based features. Meanwhile, feature fusion and feature dimension reduction are elaborated as two main further processing methods. Furthermore, a novel framework is established from the perspective of closed set and open set problems, and the related state-of-the-art methodologies are investigated, including approaches based on traditional machine learning, deep learning, and generative models. Additionally, we highlight the challenges faced by RFF identification and point out future research trends in this field