T-Mobile says delay in approving LTE-U devices is stifling innovation

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Citing continued frustration with the process of developing a coexistence plan for Wi-Fi and LTE-U devices, T-Mobile US executives are keeping the pressure on the FCC to begin approving devices that incorporate LTE-U technology no later than September.

"The delay in approving LTE-U devices is stifling innovation and investment in the communications ecosystem – one of the most vibrant segments of our economy that directly affects all Americans. There is no reason, therefore, to wait beyond September 2016 to permit use of this innovative new technology," wrote Steve Sharkey, T-Mobile VP of government affairs, technology and engineering policy, in an ex parte filing (PDF).

T-Mobile also brought Nokia (NYSE:NOK) experts to the conversation, who said they're prepared today to test devices for coexistence based on the current version of the Wi-Fi Alliance (WFA) test plan. The Wi-Fi Alliance has said it expects to finalize the test plan by late September. It was delayed after stakeholders were unable to reach consensus on certain signal level tests.

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T-Mobile said in its most recent filing that while the test plan is nearly complete, it has seen numerous deadlines come and go without finalization of the procedure. Therefore, it's saying that it wants the commission to move forward with a process that doesn't allow delays to extend past September 2016.

According to the documents T-Mobile submitted to the FCC, Nokia's unlicensed solution is based on time division multiplexing between LTE-U and Wi-Fi devices. To provide fair coexistence, Nokia's solution is not using a duty cycle approach, which can occupy the unlicensed channel for a longer period of time. All the traffic is managed over the licensed spectrum and LTE-U is only used as a backup option in cases where the non-GBR data requires supplemental downlink support.

Further, it said Nokia plans to start the Wi-Fi coexistence testing based on WFA document version 0.8.4, with testing to be done internally within Nokia's lab. They will also submit the results from a third-party testing lab once they are ready to execute the WFA tests.

Nokia said it strongly believes in a fair coexistence between the devices operating in the unlicensed spectrum, and it has already started work to complete the Wi-Fi Alliance recommended coexistence tests. To expedite things, Nokia said it can provide results from test cases involving channel selection and how LTE-U eNB behaves when the Wi-Fi traffic load is increased, among other things.

Besides T-Mobile, Verizon (NYSE: VZ), along with vendors like Qualcomm (NASDAQ:QCOM) and Ericsson (NASDAQ: ERIC), have expressed frustration at the amount of time it's taking to create the coexistence test plan. They'd like to get LTE-U gear out into the market as soon as possible, but Wi-Fi proponents, including the cable industry, have pushed back, saying they need to ensure LTE-U doesn't unfairly hog the spectrum over Wi-Fi.

For more:
- read this ex parte filing (PDF)

Related articles:
Broadcom: LTE-U program proceeding faster than typical Wi-Fi Alliance plan
Wi-Fi Alliance: August target for coexistence test plan with LTE-U could slip into September
T-Mobile warns of delays on LTE-U as regulatory discussions continue
Broadcom: LTE-U as currently contemplated would be a 'disaster' for Wi-Fi

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