Low Complex Receiver Design for Modified Inverse Source Coded Diffusion-Based Molecular Communication Systems

Diffusion Based Molecular Communication (DBMC) uses messenger molecules to transfer information between nanomachines. A major challenge for DBMC is Inter Symbol Interference (ISI), which is due to the diffusive nature of the molecular channel. By computing lower and upper bounds for the number of received molecules, in this letter we prove that ISI and Bit Error Rate (BER) of a DBMC system depend on a-priori probability of transmitted data. We derive the optimal value of the a-priori probability for which ISI and BER are minimized. A coding technique, called Modified Inverse Source Coding (MISC), is proposed to control the a-priori probability of the transmitted data. We also propose two low complexity receivers for MISC-DBMC. The first is a low complexity Reduced State Sequence Detector (RSSD) based on the Viterbi algorithm. The second is a computationally less intensive Decision Feedback based Maximum A-Posteriori (DF-MAP) threshold detector. Simulation results demonstrate that the DF-MAP receiver has a similar BER performance as that of the RSSD receiver in the ideal scenario, but practically it is limited by error propagation. Also, we show that the MISC-DBMC system using RSSD or DF-MAP receiver has better BER performance, increased range, and lower complexity compared to uncoded DBMC system.