A Novel Modulation Technique Using Modulated QAM Signals as Carriers for Lower Data Rate Transmission In IoT Era

This article introduces a novel technique to improve communication efficiency by modulating Quadrature Amplitude Modulation (QAM) signals with data from a lower data rate (LDR) source. By utilizing the power levels within the QAM constellation as a new modulation index, the approach facilitates the concurrent transmission of LDR data over the same communication channel. This method significantly enhances system capacity, enabling simultaneous data transmission from multiple devices. On the receiving end, the LDR user decodes the modulated signal based on two distinct power levels representing binary values. Meanwhile, for the receiver of the original signal, the LDR modulation is treated as a simple increase in power, which eliminates the need for separate decoding before retrieving the carrier signal's data. The probability of error analysis, covering QPSK, two-user NOMA, and the proposed modulation technique, demonstrates the outperforming performance of the introduced modulation technique. Implementation details of the transmitter and receiver are explored, and the simulation results indicate that this technique achieves performance levels comparable to traditional QAM and two-user NOMA systems. This innovative approach has the potential to revolutionize IoTs, making them more efficient and scalable for future demands.