Smokers are three times more likely to have to get sleep apnea than people who have never smoked. Smoking can increase the the amount of inflammation and fluid retention in the upper airway. This risk can possibly be reversed after you quit smoking.
Sleeping while being a smoker can be more stressful. You could get 8 hours of sleep and it could seem like 2 hours. You have to sleep longer than people who don't smoke to feel more energized.
The first few nights of sleep after quitting will be really hard to sleep because your body is adjusting. After awhile you can get less sleep and feel more energized, which is reversed from before. Even though how your sleeping can be getting better, it will never be how it was before you started smoking.