Acoustic Modems for Ubiquitous Computing
Cristina Videira Lopes and Pedro Q. Aguiar
The idea of Ubiquitous Computing (ubicomp) has been challenging the dominant desktop computing paradigm in many ways. In a world where several small computing devices communicate with each other and with humans in a context-aware manner, the need for short-range, localized communications emerges as a critical issue. Devices that are nearby must take advantage of the proximity, rather than overloading the links for long-distance communication. Short-range communication cannot be properly addressed by simply scaling down the existing communication networks. Efforts such as IrDA and Bluetooth attest to that. We argue that sound will also play an important role in this new computing world.
This article revisits acoustic modems in the context of ubicomp applications. In particular, it focuses on modems specifically designed for short-range, low bandwidth communications in air. The objectives of the article are three-fold. First, we identify a class of applications within the ubicomp paradigm that greatly benefit from such communication system, and identify human factors that the design of these modems must account for. Second, we show how standard modulation techniques can be used to produce communication systems that account for those human factors, i.e., in which the messages are musical and other familiar sounds. Finally, we demonstrate the feasibility of our aerial acoustic modems with illustrative examples.
This work lays out the ground work for an interdisciplinary collaboration seldom seen in the desktop world: one where communications engineers and sound artists will work together. The modems described here are only a hint of what can come next.
Appears in IEEE Pervasive Computing. Summer 2003.