A Novel Approach to ISI Mitigation in Diffusion-Based Molecular Communication: Optimizing Hybrid Symbol Time Interval

One of the major concerns in a Molecular Communication via Diffusion (MCvD) system is intersymbol interference (ISI), which arises due to the high memory component in the channel. In this paper, we have introduced a hybrid symbol time interval (HSTI) to combat the effect of ISI in the MCvD channel. We have shown that with a combination of two non-identical symbol time intervals (STIs), we can achieve an improved BER than that of the constant symbol time intervals (CSTIs) by reducing the ISI in the channel. The analytical expression for the optimum HSTI is derived for the MCvD channel and is validated by solving an optimization problem on the expected ISI over some convex constraints. The simulation results show that both the optimized receiver threshold and the optimized HSTI match the analytical result.