The US has a bit over 315 million people.
To pay everyone minimum (barely livable) wage, every person should get $15,000 ( http://poverty.ucdavis.edu/faq/what-are-annual-earnings-full... ). That's $4.5 trillion per year.
The GDP of the US is 16.77 trillion.
So unless we have close to 100% tax on above-(federal) minimum wage, UBI won't work.