[bobby6]

What does 3 years fixed sentence mean.

[smoothy]

It means serving three years... no time off for good behavior, etc... There are certain offences that have mandated minimum sentencing, its possible this falls under one of those.

[Fr_Chuck]

Is it a state or federal sentence (if in the US) if not in the US where is it.
While the term generally means, as smoothy said, you will serve the full 3 years in prison. There may be slight changes or allowances in some areas.