LTE-U has been seen as a potential solution to ongoing network operator woes but a panel at this week's Wi-Fi Global Summit was blunt about the scepticism that exists about the tech.
Neville Meijers, Vice President of Small Cells at Qualcomm, a company that has been one of the most vocal proponents of the technology, was given a rocky reception from fellow panellists as they questioned the absence of handsets, whether the technology can truly eliminate interference issues and whether it will ultimately cannibalise the 5GHz band.
Meijers was a vocal proponent of the technology, arguing: "What is wrong if we introduce a technology that makes Wi-Fi more efficient but it cooperates with other types of technology?"
LTE-U is still under scrutiny by 3GPP as part of its plans for the forthcoming Release 13, which is due next year. It can technically be separated in two. LTE-U aggregates LTE and spectrum on an unlicenced band, with 5GHz being seen as the likely contender.
Also used in this context is licenced assisted access. It does the same thing as LTE-U but there is one crucial difference. Some markets, including Europe, have strict regulations in place about the use of unlicenced bands. So-called "listen before talk" regulations mean a transmitter must detect the radio environment before starting to transmit.
This is to avoid interference but this week's panel on the subject was sceptical as to whether it will be borne out in reality. Discussing whether LTE and unlicenced spectrum in particular could co-exist and benefit all players, Sami Susiaho, Head of Edge Technologies at BSkyB, said: "All the talk is that we CAN make it so but what is the [evidence] that we actually will?"
Vikas Sarawat, Director of Wireless and Network Technologies at CableLabs, shared the rest of the panel's view that what works in a lab may not work in the field. He said the industry remained to be convinced that the technology would not create delays due to interference, which would have a knock-on effect on Wi-Fi calling, video streaming over Wi-Fi and other data intensive usage.
He said: "Co-existence and fairness is a requirement from day one."
The panel accepted operators were facing problems with soaring data demands and limited resources to cope with them but remained unconvinced LTE-U was the answer.
Sarawat raised laughs among the audience when he said the description of LTE-U as a marriage between licenced and unlicenced spectrum was a depressing one because it would be a matrimony of unequal rights. He said: "Licensed drives unlicensed spectrum however it wants – and that’s not a marriage."
Qualcomm's Meijer remained positive, amid considerable cynicism, that the testing and trialling of the technology, which is going on across multiple vendors, would mean it would come to market robust and interference free.
He said: "Both LTE-U and licensed assisted access were designed with Wi-Fi in mind. When we set out, we knew we needed to coexist fairly and have the mechanisms in place to do so. There has been huge R&D during the last 18 to 24 months to ensure this is the case."
But if this week's response is anything to go by, advocates for the technology have more work to do if they are to convince the rest of the industry that LTE-U will solve data demands.