I have worked in a few open floor plans. I currently work in one. They can be very difficult. One in particular was almost impossible to work in because of the mix of jobs they had and amount of people. I have always resorted to head phones for the times I need to focus a lot. I would talk with your co-workers and find out if it really would be a problem to use head phones. I have not found anyone having a problem with it. If it helps you do your job and does not bother anyone else most companies don’t have a problem with it. I would also bring something up to your manger to help find a solution that works for the company and you. I would be shocked if the rest of the office is not suffering in the same way to.