Identical? Noooo brah. Battlefield is basically a combination of the good aspects of CoD and Halo, with a little bit of its own stuff. It has the vehicles (But better done IMO, it's actually possible for anyone to kill them, unlike Halo) and the large maps of Halo, and the weapons of health system of CoD.
Everything is far more balanced, though. Guns are far more realistic in their accuracy, and it's still possible to survive being blindsided, unlike instadeath CoD. Literally nothing is overpowered, everything that was has been nerfed. There's no ridiculous Killstreaks that reward higher level players to be even more high level, everything is based on skill. It's pretty much the closest thing to a perfect FPS right now.