Modulation in Molecular Communications: A Look on Methodologies

Nanonetworking is a recently proposed paradigm that aims to achieve collaboration between nanomachines to carry out complex tasks. Molecular communications has been the most vibrant area of research for nanonetworking, mostly because of its feasibility and existence of communication schemes similar to molecular communications in nature. In molecular communications, two nanomachines communicate with each other via propagation of molecules from the transmitter to the receiver nanomachines through the medium they reside in. How and where to encode the message, i.e. modulation, plays a key role in molecular communications since it greatly affects the communication performance at nanoscale. To this end, in this paper, we examine the landscape of modulation in molecular communications, categorize the modulation schemes in molecular communications by methodology and discuss how convenient they are in terms of synchronization requirements in a nanoscale environment and their biocompatibility for applications inside human body.