High-Order QAM/APSK Receiver Design with Blind CFO Estimator of CORDIC-Based High-Order Power Pre-Processor for LEO Satellite Communications
Juinn‐Horng Deng, Pavan Vatal Shankar Prasad, Yuan-Pei Wang, Min-Sion Yang, T. N. Vyas Kaushik, P. R. Siva Prasanna · 2023
Low-Earth orbit (LEO) satellite communications are the research topics of 6G communication. High-order QAM/APSK communication transceiver design is the core research technology. Moreover, it pays more attention to overcoming the high-speed Doppler frequency offset problem of LEO. The blind frequency offset estimation technique is a popular solution. To achieve the blind estimator, the pre-processor of the high-order power operation is proposed to remove the coexisting high-order QAM/APSK signals. Therefore, the pre-processed received signal reserves the pure frequency offset signals, which can be used for a phase-locked loop (PLL) to estimate the frequency offset. In this paper, we will propose the overall frequency/time/channel synchronization and demodulation schemes for the high-order QAM/APSK system. Besides, the pre-processing operation of high-order power, i.e., the 16th-order power operation used for 32QAM, is the key technology of hardware realization. The hybrid coordinate rotation digital computer (CORDIC) techniques are proposed to jointly complete the high-order power operations. Finally, the software-defined radio (SDR) platform confirms that the proposed transceiver with the hardware realization exhibits the excellent performance.