Does sleep = consciousness, unconsciousness or something else?
The dictionary definition  of "unconscious" is to not be capable of conscious thought, ie, be asleep and unaware. Technically, you are unconscious when you are asleep.

When you get knocked out ie. a concussion, it is thought that the forces from the injury disrupt the normal cellular activities in the reticular activating system located in the areas impacted and that this disruption produces the loss of consciousness. 

Terminology wise, I believe this would be considered a temporary coma. (The definition of a coma is: a state of unconsciousness in which a person: cannot be awakened; fails to respond normally to painful stimuli, light, or sound; lacks a normal wake-sleep cycle; and does not initiate voluntary actions.)