There’s lot of room in the unlicensed bands, but it isn’t limitless. Your Wi-Fi network router wouldn't see the LTE-U device on the network; all your Wi-Fi network router might notice is that there's suddenly less spectrum available for it to use. “There’s real potential for interference,” says Chris Lewis, vice president for government affairs of consumer advocacy group Public Knowledge.
It’s no secret that the exponential growth of wireless traffic has put all of the carriers in a bind. Nor is it a secret that T-Mobile’s cellular network is weak outside of major metro areas, although the carrier disputes that claim. It makes sense that the “uncarrier” has been leading the charge to implement LTE-U.
Poor cellular coverage and saturated cellular towers are why the carriers encourage customers to connect via Wi-Fi whenever possible. Because Wi-Fi usage doesn’t count against a user’s data bucket, customers come out ahead. That’s why consumer advocates are so sensitive to anything that could make Wi-Fi harder to use.
Lewis notes that high-bandwidth uses of Wi-Fi, particularly video and VoIP, are the most susceptible to latency caused by interference. If video or voice calls get choppy, users would likely jump onto LTE, which they have to pay for. “The carriers have some incentive to push them there,” he says.
Such fears pushed four consumer advocacy groups -- Public Knowledge, Free Press, Common Cause, and the Open Technology Institute -- to lobby the FCC to prohibit or restrict the use of LTE-U. “Carriers also have powerful incentives to use LTE-U to deter mobile market entry by ‘Wi-Fi First’ providers, such as [traditional Internet service providers: the cable companies and landline phone companies]. Carriers deploying LTE-U will have the apparent option to adjust their access points to introduce just enough latency to frustrate consumer use of real-time applications, such as video calling,” they wrote in a filing to the FCC.
Tech companies concur with the consumer advocates. The FCC filing cites studies by Google, Broadcom, and others that claim that LTE-U can severely degrade Wi-Fi throughput, speeds, and latency (time delay) of packet delivery for real-time applications such as VoIP.
T-Mobile says the tests are flawed: “Claims by LTE-U opponents, particularly cable companies, that the technology will adversely impact Wi-Fi operations are based on testing with parameters set at extremes that do not represent realistic deployments or do not reflect actual LTE-U specifications,” Steve Sharkey, the carrier’s director of engineering, told the FCC.
If you’re wondering why Comcast and other cable operators care about this, the answer is simple: broadband and wireless increasingly go together. Comcast has more broadband customers than pay-TV customers, and anyone with a cable modem can (and usually does) use it with a Wi-Fi router.
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