Channel Capacity Analysis of a Comprehensive Absorbing Receiver for Molecular Communication via Diffusion

As a promising communication paradigm, Molecular Communication (MC) has been developing for more than ten years. During this period, with the continually development and mature of molecular channel, more and more factors from the actual molecular environment are taken into account to model the molecular channel more precisely. Due to the fact that chemical reactions are common and crucial in molecular communication environment, this paper investigates the impacts of various reaction rates on the channel modeling and channel capacity of MC. First, a detailed molecular system model is presented with a first-order degradation reaction in the channel and a second-order reversible reaction at the receiver side. Because of the Inter-Symbol Interference (ISI) induced by the stochastic nature of molecule motions, we propose an approximation method with low complexity to describe the received molecule signal with an arbitrary length of ISI. Based on the noisy molecular signal, closed-form expressions for probabilities of detection and false alarm are derived. The performance of channel capacity is evaluated concentrating on different circumstances with decoupled reaction rates and two prevalent modulation techniques (BCSK and MoSK) are implemented to ensure the accuracy and scientific of the conclusion. Numerical results show that the channel capacity could be enhanced significantly by selecting proper messenger molecules with desirable reaction rates in specific molecular channel.