Joint Parameter Optimization for Perpetual Nanonetworks and Maximum Network Capacity

One of the major bottlenecks in nanonetworks is the very limited energy that can be accessed by nanodevices. To achieve perpetual data transmission, it is required to investigate in-depth the relationship between energy harvesting and consumption, and the underlying constraints in nanonetworks. In this paper, the tradeoff between energy harvesting and consumption is analyzed by considering the peculiarities of THz communication. First, based on the TS-OOK scheme and constrained energy in nanodevices, the upper bound of the transmitted pulse amplitude is presented. Second, given the proposed mathematical expression of the signal-to-interference-noise ratio (SINR) in multi-user nanonetworks, the lower bound of pulse amplitude is presented to satisfy the required SINR threshold. Third, the minimum spreading factor is derived to guarantee the perpetual nanonetworks by considering the energy harvesting-consumption tradeoff. Finally, the maximization of network capacity is investigated by jointly optimizing the parameters of spreading factor, transmission distance, amplitude of the transmitted pulse, pulse probability, and node density for perpetual nanonetworks. The simulation results demonstrate short transmission distance and small spreading factor are recommended to improve the network capacity. Moreover, pulse probability, pulse amplitude, spreading factor, and node density are required to be comprehensively manipulated to achieve the maximum network capacity and perpetual communication.

I. Introduction

Nanotechnology is enabling the development of novel devices in the order of a few cubic micrometers in size, which can accomplish only very simple tasks [1], [2]. Due to the very limited abilities of individual nanodevice, communication among nanodevices will expand the potential applications of single nanodevice through collaboration. The resulting nanonetworks will be able to boost the range of applications of nanotechnology in biomedical, environmental and military fields, such as intra-body health monitoring systems, distributed air pollution control, and nanosensor networks [3]. Two main alternatives for communication in the nanoscale have been considered [1], named molecular communication [4]–[6] and electromagnetic communication [2]. In detail, molecular communication is defined as the transmission and reception of information encoded in molecules, while electromagnetic communication is defined as the transmission and reception of electromagnetic radiation from nanodevices using novel nanomaterials [1]. In this paper, we focus on electromagnetic communication among nanodevices.