If you want to transmit the camera stream wirelessly in real time that effectively makes the phone an IP cam, with all the flakiness that often entails. It's not an easy problem.

I'm also not quite sure which problem is being solved by using your phone as a webcam. Actual webcams are quite cheap and come with way better mounting hardware than your phone. And for freehand videos like in the paper the realtime requirement isn't very common, and if it's there it's usually sufficient to do the processing on the phone and stream directly from there. There has to be something I'm not seeing?