There are 'gadgets' that you can buy to 'pull down' a sub-floor from the basement (assuming you have access in the basement.) This would be MOST appropriate where you have vinyl or hardwood or ceramic flooring. (No one wants to solve your problem from the top ...)
For carpeting, visit McFeelys.com and Worksavers.com for info. And to boot, see if they have a gadget to use from the basement. I know they're screwed to the sub-floor and the floor joist as well, then 'tightened'. I'm sorry but I don't know what they're called. Maybe the 2 web sites can tell you if you describe it to them as I did.