As the first tests of MulteFire get underway, the unlicensed LTE-based technology got a bit of a dousing at a mobile industry conference in London last week, where concerns were raised about the impact on WiFi and other technologies that already use unlicensed spectrum, particularly in the 5GHz band.

MulteFire is an LTE-based technology developed by Qualcomm Inc. (Nasdaq: QCOM) that operates only in unlicensed spectrum, such as 5GHz. The technology differs from LTE-Unlicensed (LTE-U) and Licensed Assisted Access (LAA) in that it does not require an "anchor" in licensed spectrum, which means anyone can deploy it, and not just licensed mobile operators. (See MulteFire: LTE-Like Performance With WiFi-Like Simplicity and Qualcomm Aims MuLTEfire at Unlicensed Bands.)

MulteFire is designed to support fair sharing and harmonious co-existence with other technologies in unlicensed bands, but not everyone is convinced that WiFi and other services will be unaffected.

During a panel discussion on MulteFire at the Small Cell World Summit last week, Sami Susiaho, head of edge technologies at Sky , said it's obvious that LTE will have an effect on WiFi users and that airtime will become a scarce resource in the 5GHz band. "The statement that it won't have an adverse effect on WiFi is 100% false," he said.

He also said that tests indicating how LTE coexists with WiFi in unlicensed bands don't "show the right results," because "they're not the right tests." That is, it would be a struggle to show the same results in the real world, he explained.

Susiaho would know about WiFi congestion. Sky, which acquired The Cloud in 2011, has 20,000 WiFi hotspots in the UK. At the busy Waterloo train station in London, the WiFi provider actually stopped offering services because there was so much congestion that "it was impossible to provide a good customer solution." And that's an example of congestion in an unlicensed band before LTE is even introduced.

In a separate development last week, UK regulator Ofcom proposed opening up an additional 125MHz of spectrum in the 5725-5850MHz range for WiFi use in anticipation of future congestion in the 5GHz band. In its consultation document, Ofcom noted that a discussion about these airwaves was relevant to other wireless variations, namely LTE-based technologies. Ofcom's priority is to improve the broadband experience for consumers by opening up more spectrum for WiFi, while ensuring existing services, such as radar and fixed satellite services, are not impaired.

Putting MulteFire to the test
Last week, Nokia Corp. (NYSE: NOK) announced results from the first tests of MulteFire with Saudi Telecom Co. (STC) . Using Nokia’s FlexiZone small cells, the tests showed MulteFire offered up to 50% more range than WiFi and twice the coverage capability. It also achieved "harmonious" co-existence with WiFi in the same frequency, according to Nokia. (See Eurobites: Nokia, STC Light MulteFire.)

But these are early days for MulteFire. In addition to the interference challenge, the panel at the SCWS conference raised concerns around the business case and device support for the technology.

Juan Santiago, product line manager for Ruckus Wireless Inc. , stressed the importance of getting MulteFire supported on all devices and noted that there were still questions about the business case, particularly for traditional WiFi users. "Enterprises love the idea [of MulteFire], but if they build it will they come?" he asked.

Sky's Susiaho reckons it will take more than device support from the likes of Apple Inc. (Nasdaq: AAPL) or Samsung Corp. to get MulteFire deployed. "It will take a push from the entire industry," he said.

Nokia aims to conduct MulteFire field trials in the fourth quarter of this year, according Stephen Litjens, chair of the MulteFire Alliance and vice president of innovation steering at Nokia.

In the meantime, the MulteFire Alliance, which was launched at the end of last year by founding members Qualcomm, Nokia, Ericsson AB (Nasdaq: ERIC) and Intel Corp. (Nasdaq: INTC), recently added SoftBank Corp. and Cisco Systems Inc. (Nasdaq: CSCO) to its ranks. The group is developing the specs for MulteFire and the first release is expected in the fourth quarter of this year.

— Michelle Donegan, contributing editor, special to Light Reading