While debate continues over the potential deployment of LTE-U in unlicensed spectrum in the United States, Huawei and NTT DoCoMo just completed a demonstration of co-channel coexistence between Licensed Assisted Access (LAA) and Wi-Fi systems in a dense small cell scenario.
The live demo, conducted during the DoCoMo R&D Open House 2015, was conducted at the DoCoMo R&D Center in Yokosuka Research Park near Yokohama, Japan.
Their demonstration complied with the version of LAA being standardized in the 3GPP, which is expected to be completed in the first quarter of 2016. That is not the same as the LTE-U technology that is being promoted by Qualcomm (NASDAQ:QCOM) in the United States and challenged by the likes of CableLabs. The two entities recently completed tests on LTE-U and came up with strikingly different results.
Cable operators and Wi-Fi proponents have been more concerned about LTE-U co-existing fairly with Wi-Fi than LAA in part because LAA is being developed through the 3GPP standards process. That process is perceived as more open and inviting to Wi-Fi than LTE-U, which was the basis of the LTE-U Forum formed by Verizon (NYSE: VZ), Qualcomm Technologies, Alcatel-Lucent (NYSE: ALU), Samsung and Ericsson (NASDAQ: ERIC). Since the LTE-U Forum was formed in 2014, some of its members and more companies -- and associations -- formed Evolve, a coalition to promote the benefits of LTE-U and LAA. AT&T (NYSE: T) and T-Mobile US (NYSE:TMUS) are part of Evolve as well.
In the U.S., the Wi-Fi Alliance has been urging the FCC to continue to monitor industry progress and encourage industry-led activities to come to some consensus on how LTE-U is deployed in unlicensed spectrum. It held a workshop in November that brought together more than 100 attendees from 54 companies, including AT&T, Verizon, Qualcomm, Microsoft (NASDAQ: MSFT) and Google (NASDAQ: GOOG). The alliance expects to facilitate another workshop the week of Feb. 8, 2016.
In this latest DoCoMo demonstration, which differs from a previous LAA demonstration the companies staged in July, a multi-access point/multi-user small cell network was used to model a practical field test scenario, with an unlicensed carrier operating in air-interface rather than a cable connection. "The results further confirmed the capability of LAA to provide fair co-existence as well as robust performance and thus promising use of a real commercial network," Huawei said in a press release.
As part of the demonstration, an enhanced (while still 3GPP standardization compatible) co-existence technology, called adaptive Listen-Before-Talk (LBT) proposed by Huawei, was tested. The vendor said that due to the flexible resource reuse in both time and power domain, adaptive LBT can further achieve 50 percent LAA performance gain over a baseline co-existence solution while still providing fair co-existence to neighboring Wi-Fi systems.
Huawei and DoCoMo began jointly working on LAA in early 2014.
- see this release
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