Acoustic data transmission for embedded software platforms: an empirical study

Abstract

As microcontrollers become increasingly powerful at a lower cost, they continue to expand to new fields of applications, in particular those under the process of a digital transformation. These systems are often packed with a broad array of complementary subsystems, that can be selectively enabled to further facilitate their integration in larger designs. Due to this immense malleability, they often enable creative problem-solving approaches that not only serve to improve the product’s overall functionality, but may also help to drive down costs even further. This thesis is based on the design and implementation of an embedded software modem system, consisting of a non hardware-native communication interface. The interface is based on the transmission of audio signals and can thus be often implemented with little to no additional hardware costs by utilizing the preexisting functionality of the platform’s features. Under the constraints of the limited computational capabilities of embedded processors, the system works as an efficient communication layer that can be easily integrated into broader software systems concurrently running on these devices. In contrast with signal propagation of wired interfaces, the wireless transmission of acoustic signals brings forth a new set of challenges, which are tackled using sensible strategies based on well-established telecommunication’s theory. Nevertheless, the design approach is largely platform independent, with configurable performance parameters that can be adapted to the available computational resources and system specifications. The proposed architecture is based on the OFDM signalling scheme with QAM-16 carrier modulation and the implementation results show that the system can reliably support up to 32kb/s message transmission speeds for an average interface setup.