An approach of Bluetooth performance evaluation in an Android automotive setting

Abstract

In recent years cars are becoming more and more connected and it has become commonplace to connect one’s phone to the car interface, allowing streaming of music, making calls and sending messages. The primary technology used for connection is Bluetooth, a short-ranged wireless communication technology that has been around since 1999 and improved and expanded upon ever since. It is of vital importance to evaluate the performance of Bluetooth in an in-car system to make sure the connection establishment and communication flow is without hindrance and to assess the Bluetooth functionality whenever there is a new software update within the infotainment system. In this thesis we investigate ways to develop a test for Bluetooth performance in an Android in-car infotainment system. To simulate a scenario of a person entering their car, a test is designed to measure relevant Bluetooth profiles, the time it takes for the phone book to get downloaded to the in-car system, and the total time for the entire auto connection process to finish. The software of the test is developed in the source code of the infotainment unit to allow for evaluation in a lab environment as well as in cars. The test is run on two different phone models, to show how an comparison could be made with the test method, repeatedly in a lab to produce 10000 measurements. The results given are consistent measurements in a lab environment and potential for implementation in the real world with further improvements. The results from the test can be used to evaluate differences in connection times for various cars and phone models, or to continuously monitor the connection performance in a single setup.

Popular Abstract

The car industry is in a constant state of improvement. In recent times there has been a surge to electrify the whole industry and with it new vehicles become more technologically advanced. The mobile phone is closely linked to this scenario, as its connection to the car allow users to navigate roads, stream music and make calls and messages from the car interface. The connection between car and phone is typically facilitated via Bluetooth communication. A reliable and quick connection is vital for the user experience of any car owner. As with any product development, testing is the first step in ensuring the result is satisfactory. This thesis takes a look into several ways of developing a test to enable performance evaluation of the Bluetooth connection in a car-to-phone system. The test was chosen to focus on relevance to the user experience and thus measuring the time it takes for establishing a connection. There are many different parameters and methods one could use when developing a test for Bluetooth performance, and this thesis look into a number of them and assess their strengths and weaknesses. The final approach chosen for the design of the test developed was to measure connection times in the upper application layer. More specifically, the test measures the automatic connection of phones, previously paired with the car’s infotainment unit. During this automatic connection process several Bluetooth profiles are connected, which allow functions such as streaming music, making calls and sending messages. The test measures the connection time for each profile separately and stores it locally on the infotainment unit. The phone book, containing contacts and call history, is downloaded to the infotainment unit for each auto-connection process, and was thus chosen to be measured as well. A total time from the start of connection until the whole process is finished is also measured. The test software is integrated into the main source code of the infotainment unit, which allows test to be run both in labs as well as in cars. The measurements in this thesis were collected in a lab environment, using an external infotainment unit, with the intention of future testing being easily integrated in cars out in the real world later on. Two different test phones were used to show how a comparison with the test could look like, each with phone books containing 100 contacts. Connection time for the Bluetooth profiles were measured 10000 times and the phone book download times were measured 4000 times. Due to difficulties in automating a test for the total time, it was measured manually 20 times for each phone as a way of proving the feasibility of the method. All in all, the test works reliably in a lab environment and should in theory work in cars, although this is yet to be attempted. With slight improvements it can be used to collect data from customer cars and development vehicles as well. The data collected from the test can be used for statistical analysis of the overall Bluetooth connection performance which can be useful for testing the performance of different phone models and monitoring the potential performance change from software updates.

• author: Barvesten, Adam and Olde, Ola
• supervisor: Christian Nyberg
• organization: Department of Electrical and Information Technology
• alternative title: En metod för utvärdering av Bluetooth-prestanda i Android Automotive
• course: EITM01 20212
• year: 2022
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Android Automotive, Car, Bluetooth, Bluetooth Performance, Infotainment, In-car system, Android, Automotive, PBAP, MAP, A2DP, AVRCP, Phone Book, Connection times, Bluetooth Profiles
• report number: LU/LTH-EIT 2022-875
• language: English
• id: 9091749
• date added to LUP: 2022-06-22 16:42:56
• date last changed: 2022-06-22 16:42:56