# Dual discounted forward curve

I was wondering how to calculate the forward rates based on OIS discounting for the half year terms. I know how to do this for the full year terms -> just making sure that the two legs are equal to each other. The problem is that I don't have fixed payments on the half year terms. For example when one wants to calculate the 1,5 OIS discounted forward rate you only have 1 fixed payment versus 3 floating payments. How to deal with this? One method which can be used is just calculating the full year rates and then interpolate between these rates, but I wonder if there is a method which can calculate these rates without using interpolation?

Next to that what does a 1,5 swap rate exactly mean, is this just an interpolated rate because you will have the same problem here when there isn't a payment on the half years.

• What do you mean "you only have 1 fixed payment versus 3 floating payments". I have never heard about this new kind of swap. – noob2 Jan 14 '16 at 11:32
• I don't think this kind of swap is really common but it's more a fake instrument to calculate the forward rates based on OIS discounting. – Oamriotn Jan 14 '16 at 13:13