Hello,
Interestingly enough, nobody seems to have noticed this until now. A consciousness check can be made in the End Phase of a combat turn to see if any characters knocked out in a previous turn can wake up. This is mentioned directly in the Tactical Combat Addendum rules (on p. 218), but apparently are not mentioned overtly in the basic combat rules.
The effort to regain consciousness is simply a standard Consciousness Check, using all existing Consciousness modifiers.
Thank you,
- Herbert Beas
BattleTech
Catalyst Game Labs