A vibration-based multi-user concurrent communication system with commercial devices

Multi-user concurrent communication has become an increasingly important issue in mobile computing. Emerging vibration-based communication provides a new multi-to-single (M2S) data communication model for face-to-face tasks as opposed to most existing device-to-device (D2D) communication technologies. However, the transmission of multiple concurrent vibration signals often results in a highly coupled received signal, which makes it very difficult to reconstruct the source signals. This paper proposes ViCom, a vibration-based communication system that performs parallel decoding to achieve M2S transmission between mobile devices. The core of ViCom is a Decomposition Transformation Diagonal Algorithm (DTDA) that decomposes the received signal and constructs an estimated set of source signals, which are first decoupled by an autocorrelation function and then diagonalized to further improve the signal reconstruction accuracy. We implement ViCom using vibration motors and accelerometers embedded in existing smart phones and wearable devices, and evaluate its performance over different distances through disparate transmission media. Experimental results show that ViCom achieves effective data transmission of eight users with an accuracy of 98.6% and exhibits a superior overall performance over existing methods.