# Application Layer Coding for IoT: Benefits, Limitations, and Implementation Aspects

## TL;DR

This paper analyzes application layer fountain coding in IoT networks, demonstrating its benefits and limitations in recovering lost packets amid high interference and strict duty cycles, supported by theoretical analysis and simulations.

## Contribution

It provides a detailed analysis of fountain coding for IoT, highlighting the impact of redundancy on latency and decoding complexity, and identifying limits of redundancy benefits.

## Key findings

- Redundancy improves packet recovery up to a certain point.
- Latency and decoding complexity increase with packet loss rate.
- There is a limit to the benefits of adding more redundancy.

## Abstract

One of the key technologies for future IoT/M2M systems are low power wide area networks, which are designed to support a massive number of low-end devices often in the unlicensed shared spectrum using random access protocols. However these usually operate without centralised control and since Automatic Repeat request and acknowledgement mechanisms are not very effective due to the strict duty cycles limits and high interference in the shared bands, many packets are lost from collisions. In this paper we analyse a recently proposed application layer coding scheme, which aims to recover lost packets by introducing redundancy in the form of a fountain code. We show how latency and decoding complexity is affected by the packet loss rate but also prove that there is a limit to what can be achieved by introducing more redundancy. The analysis is backed up by simulation results.