QAM
Quadrature Amplitude Modulation (QAM) encodes data by varying both the amplitude and phase of a carrier signal. Higher-order QAM (256-QAM, 1024-QAM, 4096-QAM) packs more bits per symbol but requires a cleaner signal-to-noise ratio. 5G uses up to 256-QAM; 6G research targets 4096-QAM and beyond for maximum spectral efficiency.
Related terms explained
Orthogonal Frequency Division Multiplexing (OFDM) is the modulation scheme used in 4G LTE and 5G NR. It splits a wideband signal into many narrow orthogonal subcarriers, making it resilient to multipath interference
Spectrum sharing allows multiple operators or technologies to dynamically use the same frequency bands instead of relying on exclusive licensed allocations. Approaches include CBRS (Citizens Broadband Radio Service), dynamic spectrum access (DSA), and database-driven coordination