ABSTRACT
This chapter focuses on synchronization in molecular communication-based nanonetworks (MCNs). For MCNs, synchronization purpose is two-fold. First synchronization provides timing and carrier phase recovery for detecting incoming symbols successfully. Second, the limitations posed by the size and power of the nanomachines call for synchronization in the form of coordination among the nodes, thereby enhancing their operations. Any biological system, wherein a source of excitation, a restorative process, and a delay element exist, with appropriate system parameters that lead to a cyclic behavior can be regarded as a biological oscillator. The goal of maximum likelihood estimation is to estimate the clock skew and clock offset and use that information to update the local clocks, thereby achieving timing synchronization. The level of accuracy may differ from application to application, depending on the timing precision requirements constrained by the complexity that the nanomachines can handle. It, therefore, creates a caveat necessitating application-oriented synchronization techniques.
