# Framework for channel access policies in IoT network

This tutorial demonstrate the use of the updated EPHYL framework.

IoT transmissions suffer from extensive collisions when an ALOHA-style transmission policy is used. The study of new decentralized channel access policies is promising to reduce energy consumption, latency and errors due to retransmission induced by such collisions. 
In this tutorial we use a modular and open-source slotted framework for multi-user access protocols developed in a GNU radio environment. Each node transmission to the base station is made in a shared slotted time-frame where a decentralized access policy determines which slot to use. Then, a modular and replaceable physical (PHY) layer is used to create the transmitted signal.