Equalisation and performance of diffusive molecular communication systems with binary molecular-shift keying modulation

This study investigates the equalisation techniques for the diffusive molecular communication (DMC) systems with binary molecular-shift keying (BMoSK) modulation, referred to as the BMoSK-DMC systems, in order to mitigate the effect of inter-symbol interference (ISI). The authors first show that in terms of receiving equalisation, a BMoSK-DMC system is in fact equivalent to a conventional binary phase-shift keying modulated radio communication system encountering ISI. Hence, a wealth of equalisation techniques developed with the conventional radio communication systems may be introduced for equalisation of BMoSK-DMC signals. However, considering the limited capability of molecular transceivers on computation and storage, in this study, the authors investigate only the linear equalisers (LEQ) in the principles of matched-filtering, zero-forcing (ZF) and minimum mean-square error (MMSE). They characterise the effects of the different aspects related to DMC signalling and propagation on the achievable performance of the BMoSK-DMC systems with these LEQ. Their studies and performance results demonstrate that both the ZF- and MMSE-LEQ are capable of efficiently suppressing the ISI and attaining promising performance, while still have low-complexity to facilitate implementation.