A Synchronization-assisted Photolysis Scheme to Mitigate ISI in Diffusion-based Molecular Communication

Bio-inspired Molecular Communication (MC) is a promising communication paradigm benefiting from the advance in bio-nanotechnology. Due to diffusion motion’s slow and stochastic nature, inter-symbol interference (ISI), resulting from previous symbols’ residual information molecules, inevitably occurs in diffusion-based MC. As one of the challenges in diffusion-based MC, ISI impacts signal detection significantly. This paper proposes a synchronization-assisted photolysis scheme to mitigate ISI and improve the bit error rate (BER) performance. Inspired by on-off keying (OOK) modulation, the proposed modulation implements a switch of molecules and light alternatively. The light emitted is triggered by a synchronization signal, and the photolysis reactions could reduce the redundant molecules. We establish a hybrid channel model of diffusion and photolysis-reaction and derive the relevant channel impulse response (CIR) expression. Through the maximum posterior estimation scheme the optimal decision threshold is obtained and the BER performance of the proposed scheme is analysed in terms of different time intervals of the system. Numerical simulations show that the proposed method can eliminate ISI effectively.