The sum would meet the proposed reserve price and ensure that the spectrum would not be sold off at a discount over traditional 'closed' frequencies.
However, Google's pledge is largely a symbolic show of support for Martin's plan, as the final selling price of the two bands is expected to be well above $4.6bn.
"Today we are putting consumers' interests first, and putting our money where our principles are," Chris Sacca, Google's head of special initiatives, said on the official Google blog.
Google chief executive Eric Schmidt has written to Martin (PDF) explaining the search giant's proposals.
Schmidt wrote that Google would bid at least $4.6bn as long as the FCC ensured that the band would be free for any device, service plan, network provider and software application.
"I want to personally applaud your leadership and courage in making the public case for new market entry," Schmidt told Martin.
"In short, when Americans can use the software and handsets of their choice, over open and competitive networks, they win."
Google to offer $4.6 bilion for wireless spectrum?
Posted on Tuesday, Jul 24 2007 @ 14:02 CEST by Thomas De Maesschalck