First off, welcome to nopistons!! This isn't exactly the right area and I'm no expert by any means but I can tell you what I do know. For starters, there's no cam position sensor because there isn't a cam lol. If you look up wankel rotary engine on wikipedia.org they have a pretty good animated picture of how one runs. Now for the issue.....ignition can cause problems but isn't that common unless a harness has worked itself loose. On the rx-7's (forerunners to the rx-8) have essentially a crank trigger on the front of the engine right by the main pulley. FYI though, a rotary's crank is called an eccentric shaft, or e-shaft for short. What might be causing the no start, and is a very common issue with rotaries, is flooding. Very simple problem to fix, but a pain when it does it when you need to drive right now. Start off by pulling the fuse or relay for the fuel pump. Insert a small amount of trans fluid into the spark plug hole of each rotor (there are two plugs per rotor), pit the old plugs back in, then crank the engine a few times. Don't expect it to start, because there's no fuel going to it, you're just trying to get all the excess fuel out. After you've done all that, replace all 4 plugs with new ones (the old ones typically get fouled out when flooded) and start the car. To prevent flooding again in the future, try to always let the car completely warm up before shutting it off.
Best of luck!