Spatial Nanomechanical Communications Based on State Transitions

In this paper, we present a novel framework of a nanomechanical communication (NMC) system where nanomechanical (NM) systems can communicate using mechanical movements to encode and transfer information between a transmitter (TX) nanomachine and a receiver (RX) nanomachine. First, some unique features of the envisioned NMC system have been presented in contrast to traditional communications systems. It is demonstrated that the encoding of distinct repeatable movements or motions is the key to information transfer in an NMC system. Using a state transition framework, we identify rest states (RSs) and motional degrees of freedom (MDoF) as the two essential concepts that determine the transmission rate of an NMC system in the spatial domain in two different modes, namely, synchronous and asynchronous transmissions. While the synchronous transmission is found to achieve much higher transmission rate compared to the asynchronous transmission in the noise-free case, the asynchronous mode is less restrictive and may have wider applicability. A stochastic model is considered to incorporate the influence of thermal noise in the system. A closed-form expression of the symbol error rate (SER) and its bounds have been derived for a particular symbol of a synchronous sliding motion NMC system with MDoF = 2. Numerical results show a promising SER performance in support of developing an NMC system model for nanoscale communications networks.

I. Introduction

The ability to transfer information at the nanoscale can revolutionize the fields of nanotechnology, medicine, and the Internet of Things (IoT). In general, it can lead to many new sensing and monitoring technologies in the future. In recent years, nanoscale communication systems have become an important area of research, which has the potential to realize communication among nanomachines [1], [3], [4]. A nanomachine is a tiny machine of the size of nanoscale to microscale dimensions that has at least one dimension of up to 100 nm, where 1 nm equals one billion-th of a meter, i.e., 10⁻⁹m. When size of machines goes down to nanoscale dimension, the properties of material change. Individual nanomachines are extremely limited in terms of their functionalities and capabilities. As a result, there is a significant level of difficulty in scaling down the traditional macroscale communication systems to work at nanoscale dimensions. Moreover, in some instances, these machines are envisioned to be autonomous, distributed and self-organizing.