The issue of how LTE will be used on unlicensed 5GHz spectrum has been the subject of much debate – some of it friendly, some unfriendly – between the mobile carriers and the Wi-Fi sector for several months. The good news, and the reason that both sides of the LTE debate deserve kudos, is that the situation has evolved from one of enmity to one in which the sides are striving to work out their issues.
One of the big breakthroughs is that the Wi-Fi Alliance is writing the specification for the testing of the controversial version of the protocol under which LTE will be able to use the unlicensed spectrum. The Wi-Fi side, led by cable operators, were weary of the LTE-Unlicensed (LTE-U) approach, which was developed by Qualcomm. Now they are helping to test it.
Network World’s Jon Gold reports that the Wi-Fi Alliance has released the first draft of the test document, but that “there’s still plenty of work ahead.” The key, however, is that another step in the cooperation that could keep the Federal Communications Commission’s (FCC) role to a minimum has been taken:
Rob Alderfer, a vice president for technology policy at cable industry trade group CableLabs, said that last week’s meeting of the minds, which brought LTE-U’s boosters and skeptics together to hammer out mutually acceptable testing protocols, represents an important update on a process that has been going on for months.
A lot is at stake. One of the issues that got the Wi-Fi sector upset was that LTE-U, which was developed by Qualcomm, suggested a different approach to coexistence than that being developed elsewhere in the world. This is not random. The reason for this approach by Qualcomm was discussed at FierceWireless by analyst Peter Rysavy, who says carriers want an approach that is synergistic with techniques in use now and likely to be included in 5G:
Cellular operators today use Wi-Fi for offload and most smartphones can operate in either Wi-Fi or LTE mode. Despite various 3GPP specifications that integrate Wi-Fi and LTE operation, being able to use the same LTE access technology in both cellular and unlicensed bands promises to provide a better user experience. In addition, the final LTE-U and LTE-LAA mechanisms will almost definitely become the foundation of licensed/unlicensed operation in 5G standards. Finally, harnessing unlicensed spectrum for greater capacity will improve the economics of small-cell deployments. In LTE-U, the unlicensed channel, used on the downlink, can provide 20 MHz, and eventually 40 MHz of extra capacity.
LAA stands for License-Assisted Access, which is the version of LTE on unlicensed spectrum that – unlike LTE-U -- is going through the traditional standards-setting process.
Qualcomm clearly is a very important player in this mini-drama. For that reason, it is worth noting that Qualcomm’s Snapdragon X16 LTE modem was released earlier this month. It is a discrete LTE multimode chipset. Among other features is the X16’s support for both LAA and LTE-U.
Enabling LTE to use unlicensed spectrum is a confusing process that combines high technology and sensitive business roadmap issues. The good news is that the parties clearly understand the importance of avoiding a protracted battle and appear to be working to come to a conclusion that is fair to all sides.
Carl Weinschenk covers telecom for IT Business Edge. He writes about wireless technology, disaster recovery/business continuity, cellular services, the Internet of Things, machine-to-machine communications and other emerging technologies and platforms. He also covers net neutrality and related regulatory issues. Weinschenk has written about the phone companies, cable operators and related companies for decades and is senior editor of Broadband Technology Report. He can be reached at firstname.lastname@example.org and via twitter at @DailyMusicBrk.