Example 6.2
Draw the constellation diagrams for square 16-QAM.
If the maximum vector length in a square 16-QAM
constellation is 100V rms, determine the long-term average power that would be delivered
into a 50-ohm antenna load if each point in the constellation has an equal probability of
transmission.
Solution

With reference to one quadrant of the 16-QAM
constellation, the average power developed by each of the vectors A, B, C, D is as follows:

The maximum vector length,

Therefore the average power for all symbol states is:
Average power = 10a2 / R = 111 W