In this letter, we propose an Adaptive Modulation and Coding (AMC) scheme with relay protocols, such as Amplify-and-Forward (AF), Decode-and-Forward (DF) and De-Modulate-and-Forward (DMF). We perform simulations based on 3GPP Long Term Evolution-Advanced (LTE-A) parameters to compare the performance of an adaptive Modulation and Coding Scheme (MCS) using relay protocols of AF, DF, and DMF with non-adaptive MCS, with the same relay protocols. We analyze the performance of the proposed scheme and observe how the proposed AMC scheme with DMF performs at various Signal to Noise Ratio (SNR) regions. The simulation results have shown that the performance of the proposed AMC scheme with relay protocols of DMF is much better at lower and a higher SNR regions and also provides higher average throughput.

In this paper, an active control scheme is designed for the hybrid direct methanol fuel cell (DMFC) system to achieve the following three objectives simultaneously: (i) maximize the power produced by the DMFC stack in the stable operation as high loading (for avoiding the operation of DMFC in diffusion region), (ii) keep the power produced by the DMFC stack with the high efficiency as low loading, (iii) prevent the problem of methanol crossover at a very low load. Considering the characteristics of DMFC stack during actual operation, the states VP (t) and P (t) are utilized as the linguistic variables. Also considering the fuel efficiency of DMFC stack ηfuel as the linguistic variable, the active control scheme is designed to achieve the above multiple objectives. To clarify the reliability and stability of the proposed control scheme, an experiment is performed. Its results show that the proposed control scheme can achieve above multiple objectives efficiently.