An experiment of dual-LTE MPTCP with In-Car Voice Assistant

The use of voice assistants in vehicles has been increasing drastically in recent years. Most of the current in-car assistants send voice commands to their cloud server to recognize the speech, process the requests, and return responses. Given that the Vehicle-to-Infrastructure connection quality is sufficient, the response times should be negligible, so that users and their assistants can keep a seamless conversation. The vast majority of current in-car systems are using LTE to connect to the Internet, even though not every LTE provider offers good coverage, especially on highways. In this paper, we investigate the use of multiple LTE providers to enhance connection availability and robustness. To combine multiple LTE interfaces into a single connection, we use MPTCP – a TCP extension that enables multi-path transmission. This work evaluates the voice response latency of MPTCP with two well-known schedulers (Lowest-RTT-first and Redundant) and compares them to single LTE configurations in three setups: emulated network, stationary, and in-car mobile measurements.