Analysis of Adaptive M-Ary QAM Modems for High Data Rate Transmission in Software-Defined Radio

The requirement for high data rate transmission in software-defined radio (SDR) systems has necessitated the employment of adaptive M-ary quadrature amplitude modulation schemes. This work focuses on the design and optimization of an adaptive M-ary QAM modem for achieving maximum spectral efficiency and transmission reliability in dynamic wireless channels. Fixed-Modulation schemes are not efficient in following the dynamic channel conditions and hence provide suboptimal performance. An adaptive modulation scheme that varies the modulation order adaptively according to real-time channel conditions is employed in the proposed modem for achieving maximum throughput with guaranteed error performance. With the combination of machine learning-based signal processing and channel estimation schemes, the system optimizes the choice of M-ary QAM levels for achieving maximum data rates with minimal bit error rate (BER). An adaptive modem design is implemented and tested on an SDR platform and is found to be effective in improving the link quality and the usage of resources. Experiments reveal significant improvement in transmission efficiency, resistance to fading, and overall adaptability of the system compared to fixed-modulation schemes. Apart from this, the work also studies challenges in practical implementations like synchronization, computational complexity, and hardware limitations and provides insight into practical SDR deployment for future wireless communication systems. The work makes contributions towards the design of SDR-based adaptive modulation schemes for future wireless systems with increased resilience and efficiency.