Research On Reliable Transmission Of The Diffusive Molecular Communication Model

The diffusive molecular communication model is a promising paradigm of nanoscale communication,which communicates through the diffusion of molecules as the carrier of information in the biological environment.Considering the stochastic behavior of the molecules in a biological environment and the inter-symbol interference of the molecules released by transmitter nanomachine to the current time slot from all the previous time slots,molecular communication system easily suffers from high unreliability and long delay.Furthermore,link interference exists in multipath molecular communication network.Therefore,how to improve the transmission reliability of the diffusive molecular communication model is one of the challenges of current research on molecular communication model.The major work of this dissertation is as follows:1.According to the diffusion characteristic of molecular motion,using probability density function of delay for one dimensional Brownian motion of molecules to model the transmission channel.We obtain the mathematical expressions of reliability and delay in the scenarios of single link as well as the multihop.The retransmission mechanism is used to ensure the reliable transmission of information for the failed link.Then,the simulation results show that different parameters including the number of molecules emitted in each time slot,diffusion coefficient in biological environment and the distance between transmitter nanomachine and receiver nanomachine have impacts on the reliability and delay.Finally,compared to the virus-based molecular communication model and the model without considering the inter-symbol interference,in the same scenario,the delay is greatly reduced by the diffusive molecular communication model under the same reliability.2.Considering a multicast molecular communication network consisting of one transmitter nanomachine,two receiver nanomachines,and four nanomachines acting as relays,two different relay schemes are used the same type and different types of molecules in each hop to transmit information to ensure the reliability of the multicast molecular communication.First,we propose the method for adjusting the decision threshold as an effective mechanism to mitigate interference when transmitting the same type of molecules between parallel relay nanomachines.Then,mathematical expressions for the average bit error rate of the multicast molecular communication network for both relay schemes are derived.Finally,the simulation results show that different parameters including decision threshold,the number of molecules emitted in each time slot,the distance between transmitter nanomachine and receiver nanomachine,the number of samples,bit interval duration and diffusion coefficient have impacts on the average bit error rate of the multicast molecular communication network.