Terahertz-Excited Protein Conformation-Based Communication: Optimization and Signal Detection

Terahertz (THz) signalling, when tuned its frequency to the resonant frequency of target proteins, can induce conformational changes, which enables the design of interfaces for data exchange between external THz devices and intra-body protein-based molecular communication systems. Leveraging existing energy transfer models of the THz-excited protein resonance phenomenon, this work presents a THz-protein communication system, consisting of an inter-symbol interference (ISI)-free and an ISI-involved scenario. For ISI-free cases, we deduce the theoretical bit error rate (BER) and the optimal binary detection threshold. Then, a constrained BER optimization problem is created and solved to find optimal THz signalling variables, aiming at further improving the communication performance and mitigating the side-effects of THz signalling on undesired proteins. To address ISI contamination, we design a sequential maximizing a posteriori (MAP) signal detection scheme to recover the transmitted OOK sequences modulated onto the THz sinusoidal carrier. Numerical results show: (i) our constrained BER optimization provides optimal THz variables to simultaneously minimize BER and prevent THz side-effect on undesired proteins, and (ii) the designed sequential MAP scheme offers the best signal detection accuracy compared to other methods. This therefore, paves the way for the implementation of THz-protein communication systems to enable external to intra-body applications.