Which QAM is currently used in telecommunications?

In telecommunications, 256-QAM (Quadrature Amplitude Modulation) is utilized as it allows for the transmission of a significant amount of data by encoding 8 bits per symbol. This advanced modulation technique is particularly effective in environments that support high bandwidth, making it ideal for cable television, broadband internet, and other high-speed data services. The increased number of states (256 distinct signal points) that can be represented enhances the effective data rate compared to lower-order QAM formats.

This capability facilitates more robust data transfer, especially in conditions of higher signal-to-noise ratios, enabling operators to optimize their bandwidth efficiency and deliver faster internet speeds and better-quality video streams. The choice of using 256-QAM instead of lower QAM variants, such as 64-QAM or 128-QAM, reflects the industry's move towards higher data rates to meet the growing demand for internet connectivity and multimedia content.