Qualcomm has submitted an FCC filing stating that its own tests have shown that LTE Unlicensed (LTE-U) technology does cause interference with other technologies such as Wi-Fi, reports Telecompaper.com on July 1, 2015. The National Cable & Telecommunications Association, whose members use Wi-Fi to offer Internet access to mobile devices, and others have expressed concern that LTE-U and License Assisted Access (LAA) could affect devices that use Wi-Fi and even those that do not, such as baby monitors.
Qualcomm wrote in its filing: "We have shown numerous demonstrations to key Wi-Fi equipment vendors and service providers in our labs and over the air on our San Diego campus in hyper-dense settings showing LTE Unlicensed successfully coexisting with Wi-Fi. Qualcomm's demonstrations have proven that adding a neighboring LTE Unlicensed node does not impact an existing Wi-Fi node any more than would adding another Wi-Fi node. In fact, in many cases, replacing a Wi-Fi node with an LTE-U node improves throughput for nearby Wi-Fi users."
In mid-June Google submitted a white paper summarizing its investigations into the issue, finding that in many circumstances, LTE-U coexists poorly with Wi-Fi in the 5 GHz band. The study found that LTE transmissions interrupt Wi-Fi transmissions, causing them to slow down in response to increased error rates. It also found that Wi-Fi operation in the presence of moderate interference from LTE experiences substantial degradation. It recommended that LTE operators work with other users of unlicensed bands to overcome these technical issues.