Analysis of Molecular Nano Communication Channels with Relays

A nanomachine is a device whose components are in nanoscale, and can perform only simple tasks. However, nanomachines can cooperate with each other and form up a nanonetwork to achieve more complex tasks. Free diffusion based molecular communication is one of the information transport methods that are employed among these nanomachines. In contrast with the traditional communication techniques where electromagnetic waves are employed as information carriers for the communications, here the molecules are used as information carriers. As a general scenario, a sender nanomachine encodes the information into the information molecules and then releases them in a fluidic medium. These information molecules propagate in the medium according to Fick’s laws of diffusion, and then are received by the receiver nanomachine where their information will be decoded. The main disadvantage of using free diffusion is the fact that the number of information molecules that can reach to the destination falls down drastically as the distance between the sender and receiver nanomachines increases. In this thesis, a repeater nanomachine (i.e., relay node) is introduced to the scenario discussed above, which is positioned between the sender and receiver nanomachines, and its responsibility is to get the weakened molecular signal sent by the sender, and repeat it by releasing the same molecular signal in the medium. According to the numerical analysis and the results, employing a relay node can increase the signal strength and increase the number of molecules that can reach to the receiver, while the total number of molecules available for communication is held constant.