Receiver design and performance analysis for pulse position modulation technique in diffusion-based molecular communication

Abstract

Molecular Communication via Diffusion (MCvD) is one of the most prominent approaches to interconnect the nano-machines which can do some simple communication functions. In this paper, Pulse Position Modulation (PPM) is studied. We divide the received time step to four separated bins and recognized the distribution model of received molecules in each bin. As a benchmark, we derive Maximum Likelihood (ML) detector for comparison with other methods. Furthermore, we propose a technique called MAX detector in order to design the receiver for simplifying the symbol detection procedure. By changing the values of time step and distance between the transmitter and the receiver, we change the effect of Inter Symbol Interference (ISI). Further, we find the BER (BER) of MAX detector analytically. It is seen that two detection methods for PPM can achieve the same BER for some practical cases, while the MAX detector is simpler than ML detector. Compared to other methods such as type-based and concentration-based modulations, we find that at high rates, i.e., low Ts, the pulse position modulation works better and it has better performance in the intense ISI conditions.