Broadcom: LTE-U program proceeding faster than typical Wi-Fi Alliance plan

While the Wi-Fi Alliance has taken plenty of heat for not moving fast enough on the LTE-U/Wi-Fi Coexistence Test Plan, Broadcom is reminding FCC staff that indeed, the program is proceeding at a faster pace than the typical Wi-Fi Alliance program.

The Wi-Fi Alliance stepped up to the plate last year in an endeavor to do something that it traditionally hasn't been tasked to do: Create a coexistence plan that both the Wi-Fi and LTE-U communities can support. Historically, the IEEE and 3GPP have operated under different cultures from a technical specification development point of view, so getting them and everyone else to reach consensus is no easy feat.

In meetings with FCC staff last week, Broadcom Director of Product Marketing and Government Affairs Christopher Szymanski and Systems Engineering Technical Director Matthew Fischer gave a brief update on Broadcom's interpretation of the progress made in the Wi-Fi Alliance LTE/Wi-Fi Coexistence Test Plan. According to them, the program continues to advance even in light of member disagreement on a variety of important issues, including the appropriate signal levels to be tested.

The Broadcom representatives explained that while the IEEE 802.11 specification required that Wi-Fi devices listen for Wi-Fi signals at -82 dBm in conducting a clear channel assessment, chip manufacturers and OEMs commonly design Wi-Fi products to listen for signal levels well below -82 dBm (even as low as -90 dBm). They explained that the purpose of the Wi-Fi Alliance test is to determine if the impact of an LTE-U node on Wi-Fi users is any worse than the impact of another Wi-Fi network.

Based on the data provided by CableLabs, Szymanski and Fischer explained, a significant percentage of Wi-Fi network traffic occurs at signals at -82 dBm or below, meaning any coexistence testing to determine fairness must include -82 dBm signal detection level at the very least.

The Wi-Fi Alliance Coexistence Task Group has been working to develop a plan to test LTE-U devices and ensure they don't interfere with Wi-Fi users. The Wi-Fi Alliance earlier this year said the goal was to deliver a coexistence test plan by summer 2016, but in June that got pushed back to late September after stakeholders were unable to reach consensus on all the signal level tests.

Operators like Verizon (NYSE: VZ) and T-Mobile, 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.

Regardless of the time it's taking, several analysts believe the operators will still get a time-to-market advantage over LAA, which, while progressing through the standards process, takes more time to finalize and implement.

Kevin Robinson, vice president of marketing at the Wi-Fi Alliance, told FierceWirelessTech last month that it's important to keep in mind it's a multi-industry effort being led by the Wi-Fi Alliance and something that hasn't ever really been attempted before. Technical challenges exist and creating a testbed that can be reproduced in labs around the world is time consuming, and that's all playing out in the collaboration between Wi-Fi and LTE communities.

For more:
- see this filing (PDF) and this filing (PDF)

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