I am speaking from the traditional viewpoint.

Cold smoking would be no heat at all just smoke. It is the drying process used for making Lox. What you are doing is really called Kippering when you use heat and smoke. The brine cures the meat and preserves it. The smoke adds flavor and a bit of cure and traditionally kept the bugs off. The heat speeds up the cure process by drying the meat out. Having a smoker at 160 degrees and completeing the process is 4 to 6 hours is really cooking the meat with a smoked flavor and defeats the purpose of the brine.