http://www.radio-electronics.com/info/rf-technology-design/quadrature-amplitude-modulation-qam/what-is-qam-tutorial.php

https://en.wikipedia.org/wiki/Quadrature_amplitude_modulation

http://www.slideshare.net/fiberoptics4sale/what-is-16-qam-modulation

http://www.researchinventy.com/papers/v1i9/E019023027.pdf

Communication book chapter 7  (page 298)

http://www.gaussianwaves.com/2012/10/constructing-a-rectangular-constellation-for-16-qam/ 

http://www.wikiwand.com/pl/Modulacja_QAM

http://www.mathworks.com/help/comm/ref/awgn.html

