documentclass[10pt]{article}

usepackage{mathtools}
usepackage{tikz}
usetikzlibrary{arrows, positioning, shapes, matrix}

tikzset{>=stealth}

tikzset{%
    main/.style = {},
    wait/.style = {rectangle,minimum width=0.5cm, minimum height = 0.5cm},
}

begin{document}

newcommand{bx}[1]{|[box, label=#1]|}

begin{tikzpicture}
  matrix (m) [matrix of nodes,
  nodes = {node distance=10cm, anchor = center},
      continue/.style={draw, rectangle, anchor=center, node distance=10cm},
      box/.style={draw, node distance=10cm}]
  {
  BC & |[continue]| &  $phantom{neg}$ BC &   \
     & |[box]|BPM   &  $neg$ BC &  \
     &              &  $phantom{neg}$ MP & \
     & |[box]|BPM   &  &  \
  RC & |[continue]| &  $phantom{neg}$ RC &  \
     &              &  $         neg $ RC &  \
     &              &  &  \
     &              &  &  \
     & |[box]|RP    &  &  \
  PH & |[continue]| &  $phantom{neg}$ PH &  \
     &              &  $         neg $ PH &  \
  };

% S0 -> AO
draw[->] (m-1-1) -- (m-1-2);
draw[->] (m-1-1) -- (m-2-2);

draw[->] (m-5-1) -- (m-4-2);
draw[->] (m-5-1) -- (m-5-2);

draw[->] (m-10-1) -- (m-9-2);
draw[->] (m-10-1) -- (m-10-2);

% AO
path[->] (m-1-2.south) edge [bend left=90,looseness=1] (m-2-2.north);
path[->] (m-5-2.north) edge [bend left=90,looseness=1] (m-4-2.south);
path[->] (m-9-2.south) edge [bend left=90,looseness=1] (m-10-2.north);

% A0 -> S1
draw[->] (m-1-2) -- (m-1-3);
draw[->] (m-2-2) -- (m-2-3);
draw[->] (m-2-2) -- (m-3-3);

draw[->] (m-5-2) -- (m-5-3);
draw[->] (m-4-2) -- (m-6-3);
draw[->] (m-4-2) -- (m-3-3);

draw[->] (m-10-2) -- (m-10-3);
draw[->] (m-10-2) -- (m-11-3);

% S1
path[-] (m-1-3.south) edge [bend left=90,looseness=1] (m-2-3.north);
path[-] (m-6-3.north) edge [bend left=90,looseness=1] (m-5-3.south);
path[-] (m-10-3.south) edge [bend left=90,looseness=1] (m-11-3.north);

end{tikzpicture}

end{document}