\begin{tikzpicture}
	\tikzstyle{myPoint}=[draw=black, fill=DARCblue, radius=0.03];
	\tikzstyle{complexNumber}=[draw=DARCgray, fill=white, minimum width=25, minimum height=0.2, rounded corners=1, font=\tiny, inner sep=1];

	\def\deltaX{0.2}
	\def\deltaY{0.1}
	
	\begin{axis}[
		axis lines=center, width=3in, height=3in, scale only axis,
		yticklabel={}, ytick={},
		xticklabel={}, xtick distance=5*360, xmajorgrids, xtick style={color=DARCblue},
		scaled ticks=false,
		clip=false,
		xlabel={$I$},xlabel style={anchor=north},
		ylabel={$Q$}, ylabel style={anchor=east},
		title=8QAM,
		xmin=-1.3, xmax=1.3, ymin=-1.3, ymax=1.3, axis line style={-Triangle}
	]			
		
		\addplot [ draw=DARCgray, domain=-1:1, samples=500 ] { sqrt(1-x*x)}; % oberer Halbkreis r=1
		\addplot [ draw=DARCgray, domain=-1:1, samples=500 ] {-sqrt(1-x*x)}; % unterer Halbkreis r=1
		
		\addplot [ draw=DARCgray, domain=-0.5:0.5, samples=500 ] { sqrt(0.25-x*x)}; % oberer Halbkreis r=0,5
		\addplot [ draw=DARCgray, domain=-0.5:0.5, samples=500 ] {-sqrt(0.25-x*x)}; % unterer Halbkreis r=0,5
		
		\draw[myPoint] ( 1,  0) circle;
		\node [complexNumber] at (axis cs:  1+\deltaX, 0+\deltaY) {1 | 0°};
		
		\draw[myPoint] ( 0,  1) circle;
		\node [complexNumber] at (axis cs:  0+\deltaX, 1+\deltaY) {1 | 90°};
		
		\draw[myPoint] (-1,  0) circle;
		\node [complexNumber] at (axis cs:  -1-\deltaX, 0+\deltaY) {1 | 180°};
		
		\draw[myPoint] ( 0, -1) circle;
		\node [complexNumber] at (axis cs:  0+\deltaX, -1-\deltaY) {1 | 270°};
		
		\draw[myPoint] (  0.35355339059,  0.35355339059) circle;
		\node [complexNumber] at (axis cs:  0.35355339059+\deltaX, 0.35355339059+\deltaY) {0,5 | 45°};
		
		\draw[myPoint] ( -0.35355339059,  0.35355339059) circle;
		\node [complexNumber] at (axis cs:  -0.35355339059-\deltaX, 0.35355339059+\deltaY) {0,5 | 45°};
		
		\draw[myPoint] ( -0.35355339059, -0.35355339059) circle;
		\node [complexNumber] at (axis cs:  -0.35355339059-\deltaX, -0.35355339059-\deltaY) {0,5 | 45°};
		
		\draw[myPoint] (  0.35355339059, -0.35355339059) circle;
		\node [complexNumber] at (axis cs:  0.35355339059+\deltaX, -0.35355339059-\deltaY) {0,5 | 45°};

	\end{axis}
		
\end{tikzpicture}