# BDCOA: Wavefront Aberration Compensation Using Improved Swarm Intelligence for FSO Communication
###### Abstract
The summarization of related works is provided along with the advantages and limitations in Table 1.  
The limitations found from the existing studies are as follows: failure to concentrate on WA correction, higher BER, inadequate coupling efficiency, and inappropriate searching for control signals. The solution provided by the proposed research is specified in the subsequent text. The Brownian motion and Directional mutation scheme-based Coati Optimization Algorithm, namely BDCOA, is proposed to discover the optimum control signal value for DM in SLAO to minimize the WA. The issue of local optimum is avoided, while the search space efficiency is enhanced by integrating the Brownian motion and directional mutation in BDCOA. This enhanced searching process helps find optimum control signals. Hence, the optimization of dynamic control signals in DM using BDCOA also improves the coupling efficiency. Further, the compensation of WA is used to enhance optical signal concentration and minimize BER. \begin{table}
\begin{tabular}{c c c c} \hline
**Author** & **Methodology** & **Advantages** & **Limitations** \\ \hline \multirow{4}{*}{[PERSON] et al. [22]} & An uplink and downlink communication system was developed by using AO correction in the transmitter and MRC diversity approach in the receiver. & The performance of BER was minimized based on the AO correction and MRC receiver. & Signal distortion was caused during communication because of the failure in performing phase compensation. \\ \hline \multirow{2}{*}{[PERSON] et al. [23]} & The convergence in the fiber coupling of FSO was enhanced by using the AS-SFCD. & The incorporation of Staged SFCD was used to enhance the local convergence in FSO. & Reduction of WA was required to be done based on the selection of optimum control signal. \\ \hline \multirow{4}{*}{[PERSON] et al. [24]} & The performance of data broadcasting in FSO was examined with different modulation approaches such as MPS, BPK, OOK and M-QAM in transmitters and APD in receivers. & The M-PSK was designed for maximizing the data rate to enhance the transmission quality and BER. \\ \hline \multirow{2}{*}{[PERSON] et al. [25]} & The correction of wavefront was achieved by integrating the Adam from deep learning and AdamSFCD in FSO. & A precise depiction of WA was obtained by utilizing the Zernike polynomial modes. & In communication phase, the signal distortion occurred due to processing of DM with an inappropriate control signal in SLAO. \\ \hline \multirow{2}{*}{[PERSON] and [PERSON] [26]} & An adaptive threshold for Z-OKO decision was developed according to the self-joint tone to obtain the CSI of FSO. & The power of CSI signal was enhanced by assigning the optimum weight factors to achieve ATD. & In this work, there was a probability of signal to distortion occurrence when the WA compensates not done in FSO. \\ \hline \multirow{2}{*}{[PERSON] et al. [27]} & A hybrid approach of SA with SFCD was developed to perform error correction. & The integration of SAA and SFCD reduced the probability of local optimization, supporting the reliability in correction. & Phase compensation was required to be done for further minimizing the errors in communication. \\ \hline \multirow{2}{*}{[PERSON] et al. [28]} & The AMFSCD was presented for improving the correction of WA. & The integration of global and local gradient in AMFSCD was used to effectively adjust the search gradient and obtain an optimal value for WA correction. & Corrections in FSO were unstable due to hard max recognition. \\ \hline \multirow{2}{*}{[PERSON] and [PERSON] [29]} & The WA correction in SLAO system was developed by using OBAFS. & The control parameters selection was utilized to compensate the WA which improved FSO performances. & However, the selection of appropriate control signals was required to be obtained for additionally minimizing the error performances. \\ \hline \end{tabular}
\end{table} 
Table 1: Literature review.