# Modelling the Memory of Turbulence-Induced Beam Wander

## TL;DR

This paper introduces a novel memory model for turbulence-induced beam wander in FSO communication, accurately simulating deep fading and enabling improved error correction and system reliability.

## Contribution

A new memory model for beam wander that accurately captures time-dependent intensity fluctuations and deep fading in FSO systems.

## Key findings

- Model accurately simulates deep fading events.
- Enhances the development of error correction coding.
- Improves reliability of FSO communication systems.

## Abstract

One of the major challenges for long range, high speed Free-Space Optical (FSO) communication is turbulence induced beam wander. Beam wander causes fluctuations in the received intensity as well as crosstalk in mode division multiplexed systems. Existing models for beam wander make use of probability distributions and long term averages and are not able to accurately model time-dependent intensity fluctuations such as deep fading, where the received intensity is too low to maintain reliable communication for an extended period of time. In this work we present an elegant new memory model which models the behaviour of beam wander induced intensity fluctuations with the unique capability to accurately simulate deep fading. This is invaluable for the development of optimised error correction coding and digital signal processing in order to improve the throughput and reliability of FSO systems.