The commercial launch of fifth-generation (5G) wireless cellular networks this year will pave the way for the widespread adoption of millimeter-wave (mm-wave) technology for spectrum access. To completely comprehend the real-world ramifications of offering several services across 6G networks at once, more investigation is required. 6G wireless technology offers improved capacity, latency, speed, and connection over 5G. It makes real-time communication, augmented reality, and the Internet of Things possible. Another objective is low latency, which ensures global coverage and environmental sustainability. In order to achieve high data throughput, 6G technology is experimenting with terahertz frequencies despite challenges such air attenuation and limited propagation ranges. In this work, we use mixed-carrier communication technology to investigate interference control and spectrum efficiency. Mixed-carrier systems are communication systems that transport data using numerous carriers at different frequencies. Numerous communication technologies frequently employ this technique to achieve a range of objectives, such as increased bandwidth efficiency, multiuser support, and improved performance under load. Data transfer is made quick, easy, and interference-free with the use of orthogonal frequency-division multiplexing (MCC) subcarriers. Lastly, several metrics are calculated and compared with the outcomes of lower-order QAM, including SNR, BER, optical power ratio, and interference analysis.