## 1 Introduction
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline
**Literature** & **Approach/Methods Used** & **Comments** \\ \hline
[13] & Nonlinear post-equalizers, such as a Volterra series-based equalizer and a neural network-based (NN) equalizer to combat signal degradation in a 28 GHz mm-wave A-RoF 10 km fiber link for OFDM 16-QAM, and 64-QAM. & - 28 GHz mm-wave frequency. \\ \hline
[14] & Artificial neural network nonlinear equalizer (ANN-NLE) for single-carrier 16-QAM and 64 QAM signal transmissions in the 60 GHz RoF transmission system of length 15 km. & - & Short reach and complex algorithm. \\ \hline
[16] & DSP unit in simulated software for 5 to 35 km direct and coherent detection 16-PSK, 16-QAM, and 64-QAM 100 Gbit/s data rate link at 28 GHz. & - & Simple technique. 28 GHz mm-wave frequency. \\ \hline
[17] & Use of the iterative block (IB) decision feedback equalization (DFE) method for an intensity modulation and direct-detection (IM/DD) based optical code division multiplexing (OCDM) system. & - & Effectively compensates for chromatic dispersion in an IM/DD-based system. Complex receiver structure for the IM/DD-OCDM system using costly hardware. \\ \hline
[18] & Adaptive activated artificial neural network nonlinear equalizer (ANN-NLE) to enhance BER performance. & - & Complex algorithm. \\ \hline
[19] & Convolutional neural network (CNN) and binary convolutional neural network (BCNN)-based decision schemes. & - & Complex algorithm. \\ \hline
[21] & Transmission of a single channel 112 Gb/s PAM-4 direct detection signal using the maximum likelihood sequence estimation (MLSE) algorithm. & - & Achieved the highest sensitivity for 112 Gb/s transmission. \\ \hline
[22] & Experimental generation, detection and transmission of a 112 Gb/s dual-polarization, single- and dual-carrier 16-QAM half-cycle Nyquist subcarrier modulation, over 4 km of SMF length for short-reach IM/DD systems using CMA and RDE algorithms for equalization & - & Not suitable for higher-order QAM. Costly receiver. \\ \hline
[23] & Experimental demonstration of 200 Gbps 32 Gbaud polarization-multiplexed carrier-based self-homodyne (PMC-SH) system using 16-QAM 10 km SSMF link. Offline equalization is executed by cascading RDE with a DFE. & - & Short reach and costly hardware used DFE. \\ \hline
[24] & 12.5 GBd 16-QAM analog processing-based coherent receiver built and simulated in 130 nm BiCMOS. RDE-based equalization and Costas loop-based carrier phase compensation are used in the receiver for a transmission over 10 km-long fiber. & - & Short reach and costly hardware used. \\ \hline
[28,29] & LMS, CMA, and AMF-based equalization in converged mm-wave A-RoF system at 60 GHz. & - & Not suitable for higher-order modulation formats. \\ \hline
[This Work] & **Converged OFDM-based mm-wave A-RoF system at 60 GHz with signal processing using DFE, MLD, and RDE algorithms.** & - & **Electronic dispersion Compensation for higher-order modulation formats.** \\ \hline \end{tabular}
\end{table} 
Table 1: Comments on the algorithms discussed in the literature review. The rest of the paper is organized as follows: Section 2 provides the details of the different equalization algorithms used. Section 3 briefly provides the simulation setup for a converged mm-wave A-RoF system at 60 GHz for testing the algorithms. Subsequently, Section 4 compares the DFE, MLD, and RDE algorithms with different modulation formats along the maximum fiber lengths achieved, while Section 5 provides details of the assessment of the proposed work against different well-known equalization algorithms. The relationship between RF input power and EVM for QPSK, 16-QAM, and 64-QAM modulation formats is considered in Section 6, and Section 7 presents the conclusions.