The commission, after initially approving a plan by LightSquared to offer mobile broadband service in satellite spectrum bands, decided in February 2012 to deny the service because of interference concerns to GPS devices operating in nearby bands.
The commission also overhauled the federal Universal Service Fund, a program that provides subsidies for telephone service and refocused the fund on broadband.
Genachowski's decision follows an announcement this week from Robert McDowell, the longest-serving member of the FCC, that he would leave the commission in the coming weeks. With the departures of Genachowski and McDowell, two of the three remaining members of the commission have served less than a year.
While Genachowski laid out several accomplishments, some consumer and digital rights groups said he didn't do enough to protect consumers and promote broadband competition. Genachowski's FCC has allowed large broadband and mobile providers to grow while doing little for smaller competitors, his critics said.
Genachowski's appointment raised "high hopes" that he would promote the public interest, Free Press President and CEO Craig Aaron said in a statement. "But instead of acting as the people's champion, he's catered to corporate interests," Aaron said. "His tenure has been marked by wavering and caving rather than the strong leadership so needed at this crucial agency."
Genechowski's net neutrality rules are "full of loopholes and offer no guarantee that the FCC will be able to protect consumers from corporate abuse in the future," Aaron said.
While the FCC took several positive steps during the past four years, Genachowski's term "can best be described as one of missed opportunities," digital rights group Public Knowledge said in a statement. "He had the opportunity, but declined, to solidify the agency's authority and ability to protect consumers with regard to broadband -- the communications system of the present and future."
With the agency under Genachowski declining to assert regulatory authority over broadband, the FCC could become "a powerless and irrelevant agency" as U.S. networks transition to an all-Internet Protocol core, the group said.
Other groups were more complimentary of Genachowski. He will be seen a the "spectrum chairman" who focused on expanding mobile spectrum for broadband, Consumer Electronics Association President and CEO Gary Shapiro said in a statement. CEA called Genachowski "a visionary leader, an adept regulator, and a true friend to the innovation society."