Clock Synchronization in Ad-hocMicrophone Arrays Using (Android) Smartphones

Microphone arrays facilitate the capture of spatially localized audio sources. Consequently, a desired audio source such as a talking person can be recorded while background noise and other unwanted audio sources are suppressed. This can be beneficial in many telecommunication scenarios such as teleconferencing. Traditional microphone arrays come in a fixed configuration which limits their flexibility of use. A better approach would be to set up an ad-hoc microphone array from different devices able to capture and transmit audio such as smartphones. Compared to the traditional microphone arrays where all the microphone digitization is driven by a central clock, each device in the ad-hoc microphone array has its own clock. Indeed, this issue is the key to the success of using ad-hoc microphone arrays.

The objective of this project is to design, implement and evaluate a procedure for clock synchronization on a set of Android phones. The procedure should include a protocol with a suitable means of communication between the different smartphones and a synchronization algorithm. The capturing of the data required for the synchronization (as part of the communication protocol) should be implemented as an Android app, while the processing that identifies the clock synchronization parameters may be performed offline in, for example, MATLAB.

Assignment

• Investigate different options for communication between devices and identify the most suitable for the purpose of clock synchronization.
• Implement a prototype of the synchronization protocol and algorithm. The for- mer as an Android app while the latter may be implemented in MATLAB.
• Evaluate the synchroinzation accuracy using both simulations and real data with suitable toy examples.

Contact

dr. Nikolay Gaubitch

Signal Processing Systems Group

Department of Microelectronics

Last modified: 2021-03-28