I dont really know where the parameter is coming from , either its from a previous smartform or another place .
but oh well , recieving the parameter will need you to add Form's parameter on ur current smartform , it has to have the same name as the parameter (the one was sent to this smartform) .
then u could use this smartform paramter for reading or any other purpose .
In my case I had to fetch the ID parameter from query string and pass it to a field on the form. I followed your suggestion , created a parameter named "ID" in the form and leveraged it and made it work. Thanks for the useful tip.