LTE-U coexistence test plan pushed back to September

The Wi-Fi Alliance-led test plan to ensure fair coexistence between Wi-Fi and LTE-U at five gigahertz is now expected to be delivered in September, about a month later than originally planned.
“Wi-Fi Alliance hears and shares the desire of all the stakeholders, particularly in the LTE space, to accelerate the pace of progress. Some members have been very vocal around that pace of progress,” said Kevin Robinson, VP of marketing for Wi-Fi Alliance, who added that the test plan is expected to be delivered “in the September timeframe.
“We are exploring literally every option to accelerate that work while still ensuring the objective for fair coexistence is met,” he said.
Wi-Fi Alliance held its first workshop in December on coexistence between Wi-Fi and the Verizon Wireless and Qualcomm-backed LTE-U version of LTE in unlicensed spectrum, which is a partly proprietary technology based on duty-cycling and carrier sensing technology as coexistence mechanisms. A listen-before-talk approach is taken by the License Assisted Access technology developed within LTE Release 13.
The issue of how well LTE-U will play with Wi-Fi at five gigahertz has been hotly debated, with Qualcomm and others showing testing that reflects LTE-U can be a “better neighbor to Wi-Fi than Wi-Fi is to itself,” while other tests showed significant degradation to Wi-Fi performance in the presence of LTE-U – particularly at low Wi-Fi power levels.
Wi-Fi Alliance in March released an “alpha” draft test procedure for ensuring coexistence that contained more than 100 individual tests “covering all aspects of Wi-Fi coexistence, including channel selection, dynamic channel sharing and Wi-Fi calling,” according to an Ericsson filing with the Federal Communications Commission. The equipment vendor complained at the time that the proposed tests also included some that did not pertain directly to Wi-Fi coexistence, but to what information a device displays; and that other tests aren’t technology neutral. Robinson said the industry group working under the auspices of WFA has pared those tests down and continues to look for ways to speed up the test plan development and slim down the number of tests required to give a good view of coexistence. Robinson added that Qualcomm provided some equipment that has been integrated into a test bed at a Wi-Fi Alliance lab as part of the test plan validation process, which was a sticking point at the last workshop.
In addition to working on the plan itself, according to a recent filing it made with the FCC, the alliance has also been working in parallel to qualify at least one third-party test lab to provide coexistence testing as soon as the final plan is in place.
“This is really a massive industry effort to address these issues of fair coexistence – that isn’t something that has been previously attempted. It crossed multiple industries, and to achieve it is not an easy feat,” Robinson said.
Qualcomm also has been doing product development testing with Verizon Wireless and T-Mobile US under Special Temporary Authority from the FCC. The STA with Verizon was recently extended until mid-2017, but as those tests are product-related, the results are not expected to be made public.
The next Wi-Fi Alliance coexistence workshop is scheduled for the first week in August. Robinson said that some elements of the testing should begin to be finalized in the next several weeks.