UEP Concepts in Modulation and Coding

Figure 1

Hierarchical quadrature amplitude modulation (QAM): (a) 4/16/64-QAM and (b) 2/4/8-QAM.

(a) A 4-QAM (𝐿₀) is embedded in a 16-QAM (𝐿₁) which is embedded in a 64-QAM (𝐿₂)

(b) A BPSK (𝐿₀) is embedded in a 4-QAM (𝐿₁) which is embedded in a nonsquare 8-QAM (𝐿₂)