Does LightSquared Interfere With GPS?

A second round of tests on LightSquared’s proposed land-based mobile data network again showed interference with a majority of GPS devices, except for cellphones, two U.S. federal departments stated Wednesday.

LightSquared wants to build a network of 4G LTE (Long-Term Evolution) base stations around the U.S. that would operate on frequencies close to those used by GPS (Global Positioning System) receivers. But the U.S. Federal Communications Commission (FCC) will not approve the company’s plan unless potential interference with GPS has been resolved. Tests earlier this year showed the network could cripple many GPS devices.

The second round of tests was conducted last month and concentrated on LightSquared operating in a lower block of frequencies farther from those used by GPS.

“Preliminary analysis of the test findings found no significant interference with cellular phones,” the Department of Defense and Department of Transportation said in a statement on Wednesday. “However, the testing did show that LightSquared signals caused harmful interference to the majority of other tested general purpose GPS receivers. Separate analysis by the Federal Aviation Administration also found interference with a flight safety system designed to warn pilots of approaching terrain.”

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Mobile Networks Near Capacity

Mobile networks in North America are using 80 percent of capacity, with 36 percent of base stations facing capacity constraints, according to a survey by investment firm Credit Suisse.

Networks in other regions also are more than 50 percent utilized, with the global average at 65 percent, Credit Suisse said after surveying carriers around the world. That level of use matches the average “threshold” rate that would trigger the service providers to start buying more network equipment, the report said. Looking ahead, on average the carriers expected their utilization rate to grow to 70 percent within 12 months.

Credit Suisse used the results to predict new sales by makers of cellular equipment, such as Ericsson, Alcatel-Lucent, Nokia Siemens Networks and Huawei Technologies. But at a certain level, heavy use of a base station can also affect the mobile experience of individual subscribers. The survey found that 23 percent of base stations worldwide had capacity constraints (defined as a utilization rate over 80 percent during busy hours), while 36 percent in North America were under that kind of pressure.

The North American networks were 72 percent utilized two years ago. The region’s carriers expect the rate to ease back down to that point within two years. North American service providers are likely to buy more equipment soon, because having their networks 74 percent filled is the threshold rate in that region, the survey said.

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