LONDON -- 5G World -- UK-based Vodafone has slammed reports of NB-IoT interoperability problems as "misinformation" stemming from the way the standard took shape.

NB-IoT network equipment from Ericsson is said to be incompatible with that from Huawei, according to a number of industry figures and analysts, leading to complications for module makers that are supporting the technology and operators rolling it out. (See Ericsson, Huawei incompatibility threatens NB-IoT – sources.)

But Vodafone Group plc (NYSE: VOD) says that recent interoperability tests involving both vendors uncovered no problems and blames "history" for the recent reports.

"There is some history and a rationale behind it," said Lory Thorpe, who heads up Vodafone's low-power, wide-area (LPWA) deployment program, during a presentation at today's 5G World conference in London. "Before the standardization took place there were a lot of discussions around which direction the final technology should take."

Nick Hunn, the chief technology officer of consulting group WiFore, says that Ericsson AB (Nasdaq: ERIC) and Finland's Nokia Corp. (NYSE: NOK) have pursued an approach that represents a "cut down, lower power variant of 4G," while China's Huawei Technologies Co. Ltd. has come up with more of a "clean sheet" version that owes much to the Weightless standard developed by Neul, a UK firm that it bought in 2014.

He has described the 3GPP's efforts to resolve the differences as a "fudge" and says it is still causing firmware problems for module makers like Telit and u-blox.

Telit declined to comment on the issue when approached by Light Reading.

Thorpe, however, scoffs at any suggestion a 3GPP standard could lack interoperability. "Anyone involved with 3GPP standardization and who understands the process knows that not having interoperability is out of the question," she says. "We've been doing RAN [radio access network] and core interoperability tests and expect the central core to interwork with all of the RAN footprint regardless of the vendor."

Vodafone flagged its work on interoperability testing in a recent public statement that came several weeks after it had missed targets for the introduction of NB-IoT in certain European markets.

The operator appeared to blame the slippage on a lack of customer "readiness" for NB-IoT services rather than any technical difficulties or problems sourcing modules. (See Vodafone to Miss NB-IoT Launch Targets.)

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Even so, the operator has introduced a commercial service in Spain and says the gap between standardization and that service launch was just seven months. "With HSDPA [a high-speed 3G technology] it took 44 months from standardization to commercial deployment and with LTE it was 20 months," says Thorpe.

The NB-IoT standard was included in the 3GPP's Release 13 standards update last summer and seems to have been hastily developed in response to the challenge from Sigfox and LoRa, two LPWA technologies that use unlicensed spectrum and come from outside the cellular industry.

European operators including KPN Telecom NV (NYSE: KPN) of the Netherlands and France's Orange (NYSE: FTE) have swung behind LoRa in the absence of a cellular alternative, although Orange this week hinted at plans for an NB-IoT launch outside its domestic market. (See Orange Plots NB-IoT Launch Outside France.)

Thorpe says Vodafone's interoperability testing will continue as new functionalities become available.

She also indicated that the NB-IoT Forum, an industry association that Vodafone helped to establish, now features 36 of the world's biggest operators and 23 equipment vendors.

Vodafone claims to be involved in more than 50 NB-IoT trials globally and says there are more than 74 devices in laboratory development.

— Iain Morris, , News Editor, Light Reading