The question of how to handle the spectrum crunch made headlines again this week when several prominent senators proposed bills that would allow broadcasters to voluntarily auction off unused spectrum, but might also derail the Federal Communications Commission's plan to auction off the so-called "d-block" for public safety use.

First up is Sen. Jay Rockefeller, a West Virginia Democrat, who said Wednesday that he plans to introduce legislation "that promotes smart use of our airwaves—and provides public safety officials with the wireless resources they need to keep us safe."

Specifically, he backed a plan supported by the FCC that would allow broadcasters to auction off unused spectrum to mobile providers. The FCC has said this will allow struggling stations to bring in some much-needed cash, but is not mandatory for those who want to hold on to their spectrum. Rockefeller on Wednesday stressed that the auctions must be voluntary.

The National Association of Broadcasters (NAB) was initially skeptical of the auction plans, but said earlier this week that broadcasters have "no quarrel" with this option provided they are "truly voluntary."

NAB president and CEO Gordon Smith warned against choosing an arbitrary number of megahertz that need to be re-allocated, and said his organization would only support the plan if it did not interrupt current TV broadcasts.

"Our goal is simple: to work collaboratively on a two-track strategy that accomplishes the administration's goals without compromising the future of America's robust and reliable digital television service that remains free, local and ubiquitous," Smith said.

Sen. Rockefeller said his plan is built on the recently announced White House memorandum, which is intended to free up 500 MHz of spectrum over the next 10 years.

While broadcasters would benefit financially from the spectrum auctions, a piece of the proceeds would also be used to build an interoperable wireless communication network – something that has been in the works since the Sept. 11, 2001 terrorist attacks.

Rockefeller's plan calls for the government to hand over an additional 10 MHz of spectrum to public safety officials, a swath of spectrum known as the "d-block."

The January 2008, 700-MHz spectrum plan set aside the D-block for public safety use, but it failed to attract a bidder willing to pay the $1.3 billion reserve price.

The FCC's national broadband plan supports re-auctioning the d-block sometime in 2011. But Rockefeller's bill – as well as a similar bill from Sens. Joseph Lieberman and John McCain –would eschew an auction approach and just hand it over to public safety officials, an approach supported by the public safety community.

"This spectrum allocation will provide those who wear the shield with the resources they need to do their jobs," Rockefeller said.

The broadcaster incentive auctions, meanwhile, "will offer a revenue stream to assist public safety with the construction and development of their network," he said.

The Lieberman-McCain bill, unveiled Wednesday, takes a similar approach.

"Today, public safety communicates on slices of scattered spectrum that prevents interoperable communications among departments and cannot support large data transmissions," Lieberman said in a statement. "Securing the d-block for public safety will allow us to build an interoperable network for emergency communications that could prevent the kinds of communication meltdowns we had during 9-11 and Hurricane Katrina."

McCain said it is "disgraceful" that police officers, sheriffs, and fire fighters are still without an interoperable network nearly nine years after the terrorist attacks.

Reps. Peter King, a New York Republican, and Yvette Clark, a New York Democrat, introduced companion legislation in the House. Sen. John Kerry and Olympia Snowe also introduced a spectrum bill earlier this week that would push the White House plan forward.

The Lieberman-McCain bill also directs the government to use $5.5 billion in revenue from the auction of "a different block of spectrum" for the construction of towers, transmission facilities, and equipment for the new public safety network, and another $5.5 billion for maintenance and operational costs. They did not elaborate on which block of spectrum that would include.

Though the proposed bills would take the d-block auction option off the table, the FCC did not seem particularly fazed, and instead said that Rockefeller's announcement was "fantastic news."

Rockefeller's announcement is a "big win for public safety and a big win for America," according to an FCC senior official.

The official declined to comment directly on whether the FCC would abandon its plan for a d-block auction.

"We are reviewing the [Rockefeller] announcement [and] we are obviously going to be in support of Congress," the official said. "But the important thing is that we have made progress on the goal, which is much bigger than the technical issue around the d-block, which is to fund and build out a public safety network. That's the goal that everybody cares about, that's the goal that the 9/11 commission identified."

Verizon Wireless, which spent $9.4 billion on 109 licenses during the 2008 700-MHz auction, was quick to praise the Rockefeller and Lieberman-McCain bills.

"The American people deserve to know our first responders have the resources, including wireless spectrum, they need to protect us," Steve Zipperstein, Verizon Wireless general counsel, said in a statement.

Abandoning an auction approach to the d-block, of course, means that some of Verizon's smaller competitors will not have the opportunity to pick up some of the highly coveted 700 MHz spectrum. AT&T was other big winner in 2008, picking up 227 licenses for $6.6 billion. Some smaller outfits picked up spectrum in that auction as well, but not many were able to compete financially with Verizon and AT&T.