WASHINGTON-The Federal Communications Commission is becoming increasingly concerned about anecdotal stories about public-safety operations experiencing interference from commercial systems.
“We on a regular basis hear anecdotal stories on how radios are susceptible to interference from commercial systems and in some cases don’t work at all,” said Thomas Sugrue, chief of the FCC’s Wireless Telecommunications Bureau.
The problem would be easier to solve if anyone-including the FCC-knew exactly what the problem was.
It appears to be a “series of situations and issues, depending on equipment and where the tower is located,” said Gerald P. Vaughan, WTB deputy bureau chief.
In some areas, interference occurs from emissions from cellular phone towers. In other cases, interference is cause by the proliferation of enhanced specialized mobile radio systems-owned primarily by Nextel Communications Inc. In yet another case, it has been suggested that sometimes when too many people dial 911 from the scene of an event that is too far away from a base station, these calls can block the public-safety wireless transmissions.
Police in Anne Arundel County, Md., say that as more base-station towers increased, the number of “dead zones” have increased. Yet a check by the FCC found all the commercial mobile radio services providers in Anne Arundel County were operating within the parameters of their licenses. The FCC encouraged wireless carriers to work with police and today believes the problem has been solved.
While no one has a handle on the exact nature of the problem, there is enough blame to go around.
Some people have suggested public-safety agencies should use better filters.
“As the spectrum gets more crowded, all services need to deploy technologies that are less susceptible to interference,” said Brian Fontes, senior vice president for policy and administration for the Cellular Telecommunications Industry Association.
In addition to the towers causing interference, the FCC has heard that Nextel’s integrated Digital Enhanced Network system at 800 MHz may interfere with public-safety systems. In this scenario, the problem supposedly arises in places where Nextel relocated an SMR operator whose system was not always on.
Nextel did not return phone calls for comment by RCR’s deadline.
To get a better handle on the situation, the FCC has asked Nextel, public-safety representatives and Motorola Inc. to find actual examples of interference and figure out the best way to solve the problem.
The parties have been given 60 days to report back to the FCC.
“The rules of the road will have to be adjusted as we increase the amount of people using the spectrum and the time people are using the spectrum,” Vaughan said.
Going forward, the FCC hopes to solve interference problems as part of the 700 MHz public-safety proceeding, including creating guard bands between public-safety and commercial operations and voluntary standards for handsets that would include filters designed to keep out stronger emissions.
