Hello Burhan

I am little bit confused about your query. Do you mean link budget / power budget by the cost analysis here?
If so then i would like to mention that Link budget and power budget are two different things but are related to each other. A data link will only operate if the cable plant loss is within the power budget of the link.
The terms “power budget” and “loss budget” are often confused. The power budget refers to the amount of loss that a datalink (transmitter to receiver) can tolerate in order to operate properly. Sometimes the power budget has both a minimum and maximum value, which means it needs at least a minimum value of loss so that it does not overload the receiver and a maximum value of loss to ensure the receiver has sufficient signal to operate properly.
The link budget is the amount of loss that a cable plant should have. It is calculated by adding the average losses of all the components used in the cable plant to get the total estimated end-to-end loss. The link budget has two uses, 1) during the design stage to ensure the cabling being designed will work with the links intended to be used over it and 2) after installation, comparing the calculated loss to test results to ensure the cable plant is installed properly.
For your reference i am attaching the link which might help you in calculating link budget in FTTH networks.
http://scialert.net/fulltext/?doi=rjit.2010.127.138&org=10

Thanks