The Scalability of WiFi for Mobile Embedded Sensor Interfaces

In this work we test the performance of multiple ESP32microcontrollers used as WiFi sensor interfaces in the context of real-time interactive systems. The number of devices from 1 to 13, and individual sending rates from 50 to 2300 messages per second are tested to provide examples of various network load situations that may resemble a performance configuration. The overall end-to-end latency and bandwidth are measured as the basic performance metrics of interest. The results show that a maximum message rate of 2300 Hz is possible on a 2.4 GHz network for a single embedded device and decreases as the number of devices are added. During testing it was possible to have up to 7 devices transmitting at 100 Hz while attaining less than 10 ms latency, but performance degrades with increasing sending rates and number of devices. Performance can also vary significantly from day to day depending on network usage in a crowded environment.