Given the recent developments in the deployment of LTE networks in unlicensed spectrum, wireless carrier AT&T is quite happy with its decision to focus on the License Assisted Access (LAA) protocol rather than LTE-U. At this point, rivals T-Mobile and Verizon have both deployed network equipment that utilizes the LTE-U protocol. However, AT&T decided that the time between the release of products that support LTE-U and LAA are actually quite minimal that it might not make sense to invest in LTE-U, which it views as an interim protocol. Given that the finalization of LAA is only one or two months behind LTE-U, it could be more beneficial for the carrier to wait for quite a bit and deploy the technology that is more likely to be widely supported.
While both protocols operate in unlicensed spectrum, there are major differences between LTE-U and LAA. The LAA technology will have the listen-before-talk feature. This feature checks if a certain channel is occupied by another device before transmitting over it. If it works properly, it prevents interference with other devices that occupy the aforementioned spectrum. By comparison, the LTE-U protocol, which is developed without the supervision of the standards body, may not have the necessary features to reduce interference. This concern led to the statements released by cable companies and other internet service providers, as these companies distribute routers that also utilize the 5GHz frequency.
Right now, AT&T is testing both LAA and 4-carrier aggregation on its network as part of its "5G Evolution" initiative. The carrier plans to install small cells that are capable of supporting LAA in place of Wi-Fi, as it could result in a smoother call and data connectivity experience especially when subscribers leave the areas serviced by small cells. This technology, along with 4-carrier aggregation, should result in increased data speeds for subscribers with devices that support these technologies. At this point, devices equipped with Snapdragon 835 chipset from Qualcomm support both 4-carrier aggregation and LAA. However, these handsets may require software updates to activate the desired features. Aside from AT&T, T-Mobile is also looking into the possible deployment of network equipment that supports LAA protocols in the near future. However, by skipping LTE-U, AT&T managed to reduce capital expenditures costs while deploying a far superior and standardized protocol.