Enhancing5Gmulti‐bandlong haul optical fronthaul links performance by magnitude‐selective affine digital predistortion method

Abstract

This paper presents a novel magnitude-selective affine (MSA) based digital predistortion (DPD) method for the performance investigation of multiband 5G new radio (NR) based analog radio over fiber link. The proposed MSA-DPD method is derived from the canonical piecewise linear (CPWL) based model by employing MSA functions, which can result in reduction of the number of multiplication operations and the model complexity. The 5G NR standard at 20 GHz with 50 MHz bandwidth and flexible-waveform signal at 3 GHz with 20 MHz bandwidth is used. A dual drive Mach Zehnder modulator having two distinct RF signals modulates a 1310 nm optical carrier using distributed feedback laser for 22 km of standard single mode fiber. The proposed MSA-DPD method is compared with the CPWL and generalized memory polynomial method. The experimental results are presented in terms of adjacent channel power ratio, error vector magnitude, number of estimated coefficients and multiplications suggesting that MSA-DPD method achieves a better performance as compared to CPWL and GMP models with much lesser complexity meeting the 3GPP Release 17 requirements.

Optimized MSA DPD method for improving 5G multiband optical fronthaul performance

“…In this context, we are discussing the fundamental modeling for DPD. The MSA function, which was previously suggested, can be presented in its efficient form as 10,13,14…”

“…10 Recently, we proposed the use of the magnitude-selective affine (MSA) method to mitigate the impairments in the RoF system. 10 This architecture provided good performance, but the complexity is still high (low as compared to CPWL) and may require more hardware resources compared to the other architectures. However, it can provide good performance and improve the overall performance of the RoF system.…”

“…Similarly, the memory polynomial (MP) is a simplified version of the GMP architecture, which uses a fixed polynomial model to represent the nonlinear behavior of the RoF system. This architecture can provide good performance but is less flexible than the GMP architecture 9,10 . Canonical piece‐wise linearization (CPWL) architecture can be used for DPD as a way to approximate the nonlinear transfer function of a radiofrequency (RF) for RoF systems.…”

“…This architecture has a good performance as compared to GMP or MP architectures. However, the complexity of the CPWL is very high and it makes the usage questionable 10 . Recently, we proposed the use of the magnitude‐selective affine (MSA) method to mitigate the impairments in the RoF system 10 .…”

“…However, the complexity of the CPWL is very high and it makes the usage questionable 10 . Recently, we proposed the use of the magnitude‐selective affine (MSA) method to mitigate the impairments in the RoF system 10 . This architecture provided good performance, but the complexity is still high (low as compared to CPWL) and may require more hardware resources compared to the other architectures.…”