There is little spectrum sharing between the government and private entities at the moment, said Mark Goldstein, GAO's director of physical infrastructure issues. "The business model does not work, because of the uncertainty involved," he said.
The private sector may not want to invest in shared spectrum, said Representative John Skimkus, an Illinois Republican. "Having it is better than sharing it," he said. "Give it to the dang private sector and see if they can turn a profit."
Commercial mobile providers would prefer spectrum that's not shared with government agencies, acknowledged Preston Marshall, deputy director of Information Sciences Institute at the University of Southern California and an adviser to PCAST. But with the predicted spectrum crunch, U.S. policymakers will need to find more spectrum than agencies can easily free up, he said.
The PCAST report estimated agencies could share up to 1000MHz of spectrum with commercial users, double the amount of new commercial spectrum targeted by the U.S. Federal Communications Commission in its 2010 national broadband plan.
Other subcommittee members urged the NTIA to continue looking at spectrum sharing. "Given the looming spectrum crunch, we cannot afford to take any options off the table," said Representative Henry Waxman, a California Democrat.
Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's e-mail address is email@example.com.