AT&T Despite Rivals Haste: Patient on LTE-U

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AT&T, unlike competitors Verizon and T-Mobile, is not in any kind of a hurry to test and deploy unlicensed LTE (LTE-U) systems, because of possible damage to nearby Wi-Fi systems. AT&T's Tom Keathley said that the carrier would be willing to wait for a standardized version of the technology known as a Licensed-Assisted Access or LAA. During an interview given last week at AT&T Wireless headquarters in Atlanta Georgia he said that, philosophically, the company would support the use of unlicensed spectrum, to be aggregated with "a foundation LTE carrier", but AT&T would only use the technology if it would not interfere with other technologies using the same spectrum, such as WiFi, therefore assuring some form of fair use. Currently, LTE-U does not have that assurance. LAA would be the equivalent of the system checking for any available channels on which to broadcast, to check for WiFi activities, and if the channels were in use, the system would not transmit, therefore reducing the chance of damaging any active systems .

AT&T owns a large amount of WiFi hotspots themselves, numbering over 34,000 such hotspots in the United States, located in such establishments like Starbucks, Barnes and Noble, and many other hotels and restaurants in the U.S. The WiFi Alliance has, in February, urged caution in the testing and deployment of any LTE-U systems. One fairly good reason is that this new technology doesn't really have a final standard yet. Some proponents worry about the control of LTE-U, that carriers will control more of the spectrum than WiFi. The 3GPP standards body (3rd Generation Partnership Project), is currently working on one, but the details of that won't be worked out until later this year.

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The idea is that the best channels for LTE-U is at the 5 GHz band along with the 3.5 GHz band also becoming a viable option as well. Qualcomm, who is also a huge proponent of LTE and WiFi, has suggested a channel selection method that would work out fairly well in low to medium density areas. Qualcomm has also noted that certain countries such as South Korea, China, and the United States do not have a requirement to have another standard for listen before talk on current systems, this is called LBT (Listen Before Talk). Qualcomm has advocated several possible solutions, so as not to damage any WiFi nodes or hotspots such as channel selection (cycling through spectrum while seeking open channels), to a signal release method at low levels of operation.

Despite the fact that standards have yet to be set or methods established to protect possible damage to WiFi, T-Mobile plans to go online with LTE-U by 2016, as part of a partnership with Qualcomm and Alcatel-Lucent using spectrum in the 5 GHz band, utilizing equipment from both companies such as Alcatel-Lucent cells, and Qualcomm chips. In fact, testing of the system is already underway. Verizon has also stated that it plans to deploy LTE-U technology in the 5 GHz and 3.5 GHz bands starting in 2016. Possibly leading AT&T to act; however, Tom Keathley stated that AT&T has not completed its evaluation of LTE-U and couldn't guarantee "fair use" of the U. (unlicensed) in the spectrum. The AT&T executive also said that since LTE-U was mainly used for small cells, that it might make sense to wait for a standard, like LAA, should it come quickly.

 

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