Electric vehicles communicating with WebSockets: Measurements and estimations

In this work we study alternative ways to handle the communication between electric vehicles (EVs) and different services. Our main interest is on use cases where the servers need to know the status of the EVs for e.g. intelligent management of the EV fleet. We assume that communication would take place with the regular cellular technologies and would use WebSocket technology, often related to HTML5. We implement an Android application, which emulates EV status, and a node.js server to collect EV status data. We use these to measure how accurate and frequent data the services needing EV status information would be able to receive, how different sampling and encoding techniques influence the amount of data, and how much load different vehicle densities would create to the communication infrastructure. We compare secure communication with Web-Sockets with regular TCP and with HTTP. We also investigate the pros and cons of different cellular technologies (GSM, 3G, LTE) from communication volume, latency, and energy spending point of view, and propose a set of suggestions to consider when deciding how to implement EV to infrastructure communication.