When I am in this situation, I’ll generally try to ‘close the space’ between myself and the other person. This may not necessarily involve getting physically closer but more around creating the conditions for talking to happen. For you I’d suggest ‘accidentally’ dropping something in his general vicinity. If he doesn’t bend over and pick it up for you, you might ask him to. Then give him a nice smile when he hands it to you. This makes it subconsciously easier for him to strike up a conversation with you, say, after class.
You can keep doing little things like this until he actually nuts up and says something to you. You can conceptualize it as having a large gap between where you are now, and the place where you guys are comfortable chatting with each other. You build a little bridge over that gap each time until he takes the hint and starts building on his side too.
I’m introverted so just walking over and saying hi to someone I don’t know is a bit much for me. I need to feel comfortable doing so. Say a pretty lady comes into the coffee shop. She’s at the cabinet ordering. I know I have a small window to do something before she gets her drink and leaves. So often times I’ll get up and say something to the barista or someone I know, just as an excuse to shift position and let her know I’m there. I might look at her a few times to see whether she’s in ‘don’t bother me’ mode. If I feel comfortable my brain will come up with something to say to her and I’ll just say it.
You can’t count on women to help bridge the gap, as a guy you have to do it all yourself. But as a female, you can use whether he’s willing to jump across as a reliable gauge as to whether he’s interested or not. You don’t just send passive signals, you actively but not aggressively start tearing down the natural walls keeping you from interacting.