The noise, caused by electromagnetic interference during the transmission of uplink signals in the balise, could result in a high demodulation error rate at the receiver. A variational mode decomposition method based on optimized parameters is designed to reduce the noise. This method decomposes the signal into several intrinsic mode function components. The sum of the center frequency bandwidth of each intrinsic mode function component is the smallest, which can extract useful frequency components. The Archimedean optimization algorithm is used to optimize the penalty factor and the number of decomposed modes in the variational mode decomposition. Simulation experiments have shown that the method is capable of determining the optimal key parameters. This capability allows it to effectively separate the useful signal from the interference signal. Furthermore, by employing signal reconstruction, the method is able to filter out the interference signal. The experimental results prove that within the signal-to-noise ratio range of 1–10 dB, the bit error rate is reduced by an average of 43% by demodulating the signal reconstructed by variational mode decomposition, compared to the unprocessed noisy signal.