Experimental Demonstration and Performance Enhancement of 5G NR Multiband Radio over Fiber System Using Optimized Digital Predistortion

Abstract

This paper presents an experimental realization of multiband 5G new radio (NR) optical front haul (OFH) based radio over fiber (RoF) system using digital predistortion (DPD). A novel magnitude-selective affine (MSA) based DPD method is proposed for the complexity reduction and performance enhancement of RoF link followed by its comparison with the canonical piece wise linearization (CPWL), decomposed vector rotation method (DVR) and generalized memory polynomial (GMP) methods. Similarly, a detailed study is shown followed by the implementation proposal of novel neural network (NN) for DPD followed by its comparison with MSA, CPWL, DVR and GMP methods. In the experimental testbed, 5G NR standard at 20 GHz with 50 MHz bandwidth and flexible-waveform signal at 3 GHz with 20 MHz bandwidth is used to cover enhanced mobile broad band and small cells scenarios. A dual drive Mach Zehnder Modulator having two distinct radio frequency signals modulates a 1310 nm optical carrier using distributed feedback laser for 22 km of standard single mode fiber. The experimental results are presented in terms of adjacent channel power ratio (ACPR), error vector magnitude (EVM), number of estimated coefficients and multiplications. The study aims to identify those novel methods such as MSA DPD are a good candidate to deploy in real time scenarios for DPD in comparison to NN based DPD which have a slightly better performance as compared to the proposed MSA method but has a higher complexity levels. Both, proposed methods, MSA and NN are meeting the 3GPP Release 17 requirements.

SARS-CoV-2 Detection Using Optical Fiber Based Sensor Method

“…The testing technique involves the following steps: I specimen collection; (ii) clinical specimen packaging (storage) and transportation; (iii) (good) communication with the laboratory and giving the necessary information; (iv) laboratory testing; (v) reporting the results [25].…”

“…The time it takes to get the results can be as long as two or three days [25]. Only 66 to 80% of it is sensitive [23].…”

Practical Demonstration of 5G NR Transport Over-Fiber System with Convolutional Neural Network

“…With major developments in the fifth generation known as 5G and beyond 5G, the centralization of radio access network (RAN) has been established due to the ever increasing rate of base stations (BS) [1], which decreases capital expenditure by simplifying network management [2]. An optical fronthaul (OFH/FH) simply connects the base band units (BBU) to remote radio heads (RRH) to facilitate C-RAN (see Figure 1).…”

“…An optical fronthaul (OFH/FH) simply connects the base band units (BBU) to remote radio heads (RRH) to facilitate C-RAN (see Figure 1). Due to unlimited benefits and increase in wireless link reach for all kinds of applications such as short to long link applications, microwave photonics-based solutions such as Radio over Fiber (RoF) have a higher significance connecting the BBUs with RRUs [1,2] with 5G in the operational stage in most parts of the world [1,2].…”

“…Various RoF variants have been proposed in recent years, including Analog Radio over Fiber (A-RoF) [1][2][3][4][5], Digital transport over Fiber (D-RoF) [6][7][8][9], Sigma Delta transport/Radio over Fiber (SD-RoF) [10][11][12], and others (see Figure 2). A-RoF links are, to some extent, the simplest and most cost-effective option; nonetheless, they suffer from nonlinearities generated from signal impairments and components such as laser modules, fiber, and photodiodes.…”