Initial Distance Estimation and Signal Detection for Diffusive Mobile Molecular Communication

Mobile Two-Way Molecular Communication via Diffusion Using Amplify-and-Forward and Analog Network Coding

Mobile molecular communication via diffusion (MCvD) has attracted lots of attentions due to its time-varying channels. In this paper, we investigate a mobile two-way MCvD model, which consists of two mobile source nanomachines and a mobile relay nanomachine. The amplify-and-forward (AF) relaying and analog network coding (ANC) are utilized to implement the exchange of information between two source nanomachines in this model. To explore the performance of the mobile two-way MCvD system, we first adopt the depleted molecule shift keying (D-MoSK) modulation, and then the mathematical expressions of symbol error probability (SEP) and mutual information are derived by using AF and ANC scheme on the basis of maximum a posteriori (MAP) probability detection. Finally, we present the numerical and simulation results. Compared with the AF-No-ANC scheme which is without use of ANC scheme, the scheme of combining AF and ANC can significantly improve the performance of SEP and mutual information. Moreover, the D-MoSK modulation outperforms the molecule shift keying (MoSK) modulation for this mobile two-way MCvD system. In addition, we propose the evaluation and discussion about the impacts of several important parameters on the performance of this system. These results can be used to design mobile two-way MCvD system with lower SEP and higher mutual information.

Clock Synchronization for Mobile Molecular Communication Systems

Molecular communication (MC) is a promising paradigm, which conveys messages at the nano- or micro- scale for information exchange by using molecules or particles as signal carriers. Clock synchronization between transmitters and receivers in MC systems plays an important role in information exchange and nanodevices' collaboration. The current research about the synchronization mainly focuses on fixed MC systems. However, the movements of transmitters and receivers commonly exist in MC systems. In this paper, two clock synchronization schemes, the least square method and the peak time method, are proposed to estimate the clock offset between a mobile transmitter and a mobile receiver in mobile MC systems. The synthesis time of information molecules is also taken into consideration in the proposed schemes, and by using different types of molecules, the influence of the synthesis time of molecules can be solved. The effects of the movement of receiver on the received signal are discussed. The performance of the proposed schemes is evaluated by simulations and discussed.

dMole: A Novel Transreceiver for Mobile Molecular Communication Using Robust Differential Detection Techniques

This paper proposes two differential detection techniques for signal detection in mobile molecular communication (MMC) for targeted drug delivery (TDD) application. In MMC, a nano-transmitter and a nano-receiver are considered to be in Brownian motion in an extracellular fluid medium. Transmitter uses calcium molecules to communicate with the receiver. Detection is performed using concentration difference based detector (CDD) at the receiver which calculates the maximum absolute concentration difference of the received signal within the same bit interval to detect the bit. This improves the bit error rate (BER) performance in MMC. The performance is further enhanced using manchester coded transmission with differential detection (MCD). In MCD, Bit-1 is coded by the symbol [1 0] and Bit-0 is coded by the symbol [0 1] and the difference between peaks of signals received in consecutive bit duration is taken to detect the bit. Simulation results prove that the MCD technique is 3 dB less sensitive to inter symbol interference (ISI) than the CDD technique. The detection threshold is selected using maximum a posteriori probability (MAP) rule. The performance of these detectors is compared with other existing detection techniques. Results reveal that BER performance of the CDD and MCD better by at least 3 dB and 6 dB, respectively. The proposed CDD and MCD techniques perform better in different bit-sequence length, various initial distance and different bit duration than other existing techniques.