Commerce to test 4G technology for public safety network
New lab will establish a real-world environment for LTE equipment
- By William Jackson
- Jan 14, 2010
The Commerce Department plans to establish a lab for real-world testing of emerging 4G communications technology that could be used in a national public safety network.
The facility will be set up by the Public Safety Communications Research program, a partnership of the National Institute of Standards and Technology and the National Telecommunications and Information Administration.
“We’re not building anything; we’re talking about creating an environment,” said Dereck Orr, NIST’s PSCR program manager.
The lab will house vendor equipment being developed for the emerging Long Term Evolution standard. “It’s brand new,” Orr said of LTE. “It’s bleeding edge. This will be a neutral site for vendors to work out interoperability issues in a multivendor environment and a learning environment for public safety officials.”
LTE is a high-performance communications standard under development for cellular systems. It is a fourth-generation technology that saw its first commercial deployment last year in Stockholm, Sweden, and Oslo, Norway. The technology remains in the pilot stage in this country.
The PSCR lab will focus on LTE because the public safety community has endorsed it for a proposed nationwide public safety network to be established in the 700 MHz band.
“LTE has some very attractive features for public safety applications,” Orr said. It will allow prioritization of traffic and “is very flexible and will allow for a lot of adjustments on the fly.”
It has a high throughput, with download rates of at least 100 megabits/sec and upload rates of at least 50 megabits/sec. It can use both Frequency Division Duplexing and Time Division Duplexing. But functionality was not the reason LTE won over the public safety community over its main competitor, WiMax, said Harlin McEwen, chairman of the Public Safety Spectrum Trust.
“We selected it as a practical issue,” McEwen said. “It was a matter of looking at where things are going to go.”
The carriers are going to LTE. At least three major carriers, Verizon, AT&T and US Cellular, who among them hold 80 percent of the U.S. cellular market, have announced plans for LTE networks. “With the weight of numbers going to LTE, there is likely to be a lot more devices available,” McEwen said.
The Public Safety Spectrum Trust holds the nationwide license for two swaths of the 700 MHz band that have been set aside for a public safety broadband network that would enable nationwide interoperability and roaming with advanced capabilities. The spectrum was freed up by last year’s switch to digital TV broadcasting.
It's not a problem that LTE equipment is not yet readily available because plans for the public safety network have been put on hold until the Federal Communications Commission decides how to distribute the remainder of the 700 MHz band.
The trust holds a total of 10 MHz of the band, in separate 5 MHz pieces. But a workable network will require double that bandwidth, McEwen said. “We are convinced that we have to have access to 20 MHz of spectrum.”
So two adjacent 5 MHz swaths, called the D-Block, were to be auctioned off last year to a commercial carrier with the requirement that a sharing agreement be created with the Public Safety Spectrum Trust allowing use of the additional bandwidth. When the D-Block failed to sell, plans for the public safety spectrum were delayed.
FCC is expected to announce its intentions for the D-Block as part of its National Broadband Plan. The plan originally was due to be presented to Congress by Feb. 17, but FCC Chairman Julius Genachowski has asked for a 30-day extension.
For the demonstration network, the PSCR will provide lab space and staff to maintain vendor-donated equipment, which is expected to become available by late summer or fall of this year. The lab will be located in Boulder, Colo., and also will make use of Commerce’s Table Mountain Field Site, a radio-quiet zone used for research and testing.
William Jackson is a Maryland-based freelance writer.