Unconscious and Subconscious are two totally seperate mind states.
Unconsciousness rarely happens except for deep deep sleep. Where only delta waves are present.
Subconscious is not Consciousness or Unconsciousness, nor are these three states of consciousness the total of all brain wave states. It is just a sweeping generalization.

There are four types of brain waves.
Alpha
Beta
Theta
Delta
The Subconscious is always working, however, Beta Waves allow the bridge between Subconsioucness and Consciousness. Think of the subconsciousness of all the workers in the bottom deck of the Cruise Liner. Running checks on all the engines operating the electrical systems, monitoring safety systems, keeping things in check. The consciousness would be all the people on the deck of the boat, sun tanning, playing, swimming, partying. Reaping the benefits of the people on the lower decks supporting the medium for those on the upper decks....
All this comes back to brainwaves as well. Each brain wave can have a degree of intensity. Differnt combinations power different states of mind.
For example.

Alpha - - - - -0- - - -
Beta - - - - -0- - - - -
Theta - - - - - - - - -0
Delta- -0- - - - - - - -

Or

Alpha 0 - - - - -- - - -
Beta -0- - - - -- - - - -
Theta - - - -0 - - - - -
Delta- - - - - - - - - -0