While Globalstar says a trial Chicago deployment confirms there are no interference or compatibility issues between the terrestrial low power service (TLPS) and Wi-Fi, nor with TLPS and Bluetooth operations in the 2.4 GHz ISM band, a short seller begs to differ.
In his latest 38-page filing with the FCC, Gerst Capital manager Greg Gerst laid out reasons he believes the FCC should terminate the Globalstar proceeding that seeks to use the TLPS spectrum to relieve what it calls the Wi-Fi traffic jam. Gerst, a former Cisco engineer, has been sharing his technical analysis of the proposal with FCC staff.
He also took issue with the lack of demonstrations using a newer smartphone model like the iPhone 6 and/or the 6s. "Their latest demonstration allegedly used an iPhone 4 which Part 15.247 data shows does not utilize a modern coexistence filter," he said. "If Globalstar was provided with software enabling TLPS demonstrations with an iPhone released over five years ago, why didn't they have Apple provide software that enables TLPS demonstrations on modern versions such as the iPhone 6 or 6s? What about other modern, popular LTE-enabled devices?"
As for radio resource management, which is a key concern for wireless operators in managing their networks, Gerst told FierceWirelessTech that he believes the presence of TLPS will introduce more interference into the networks. The presence of TLPS will "push" users from Channel 11 to Channels 1 and 6, resulting in more congestion on the lower two channels.
Gerst argued that the single quantitative test of TLPS's impact on Bluetooth Low Energy was conducted more than six months ago by the Bluetooth SIG, not Globalstar, and showed the device's packet error rate doubled in the presence of TLPS. He also questioned Globalstar's claims about increasing aggregate throughput more than 90 percent, saying close inspection of the methodology raises far more questions than it answers.
"Most importantly, adding TLPS creates NEW INTERFERENCE which negatively impacts Bluetooth Low Energy and Wi-Fi Channel 11 … while adding FREE 5 GHz Wi-Fi channels presents zero additional interference/risk to Bluetooth, Bluetooth Low Energy, or other 2.4 GHz Wi-Fi services," Gerst said in his filing with the FCC.
Meanwhile, the Wireless Communications Association International (WCAI) says Globalstar's Sept. 10 filing "does nothing to address the unanswered questions as to how Globalstar will meet its absolute obligation" to protect adjacent licensed Broadband Radio Service and Educational Broadband Service operations from harmful interference from its proposed TLPS. "Globalstar has yet to establish that it can provide the protection required of it, in particular were it to operate TLPS with the reduced out of band emissions (OOBE) mask at 2495 MHz that it has proposed," WCAI said in its filing with the FCC.
- see this FCC filing
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