Adaptive Amplitude-Phase Quantization in MIMO Quantize-Forward Relay System

Relay technology is essential for enhancing coverage and reliability in wireless communication systems. Among various relay algorithms, quantize–forward (QF) stands out for its balance between performance and complexity. However, existing QF methods, such as phase quantization and hybrid amplitude-phase quantization (APQ), face limitations in performance and high computational complexity. To address these issues, we propose an adaptive APQ (A-APQ) that selectively quantizes amplitudes, thereby reducing memory usage and computational burden at the relay and receiver, while preserving performance. Maximum likelihood detection analysis demonstrates that A-APQ achieves superior efficiency in multi-antenna relay systems compared to existing QF techniques.