France's Sigfox has shrugged off concerns that have recently surfaced about the potential shortcomings of its wireless technology.

Sigfox is among several companies developing the so-called low-power, wide-area network (or LPWAN) technologies used to provide connectivity for sensors installed in smart meters, industrial equipment and millions of other devices.

As reported by Light Reading, the company has recently faced a barrage of criticism over its business model -- under which Sigfox takes a huge cut of service revenues from its network partners -- and reliance on a proprietary technology, as opposed to an open standard. (See The Wolf at Sigfox's Door.)

Those criticisms have been made by Sigfox's rivals, which obviously have an axe to grind. But the latest attack on the company has come from Nigiloc, a French startup developing tracking gadgets for bicycles, which was last year reported by Fortune magazine to be a Sigfox customer.

A source close to the matter has recently told Light Reading that Nigiloc is one of several companies to have "terminated" rollout activities with Sigfox because of "bad coverage and failing technology."

Light Reading approached Nigiloc for a response to these comments and received a written statement from CEO Gilbert Wilhelm. "Sigfox's contract is not broken, but it is true that the test we have made with Sigfox for geolocation did not conform with our quality standard," said Wilhelm. "Indeed, I think that Sigfox is a good product for non-moving IoT. In mobility Sigfox has important troubles [sic] for transmitting the data."

According to Light Reading's source, other companies that have experienced problems with Sigfox include Clear Channel Outdoor, an advertising company, and French insurance player MAAF.

Clear Channel was previously reported to be using Sigfox technology to support billboard advertising in France, while MAAF struck an agreement with Sigfox in 2012 regarding the deployment of smoke detectors in homes. Neither of those services would require any mobility.

"We don't want to comment on Sigfox," said a spokesperson for Clear Channel when asked to confirm or deny if the company was still working with Sigfox. MAAF did not respond to requests for comment on the current status of its relationship with Sigfox.

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A second source with knowledge of internal goings-on at Sigfox claims to have heard similar "rumors" about the company's problems and says "things they assumed would be quite easy have turned out to be difficult or impossible using the approach they originally had in mind."

Sigfox would not deny that Nigiloc, Clear Channel and MAAF have experienced difficulties but said it has never provided any commitment to support "quick-moving devices" to Nigiloc and that all three companies are among its "earliest" customers.

"I don't want to go into details on specific customers of what has worked and what hasn't worked for them," says Thomas Nicholls, Sigfox's executive vice president of communications. "[These] are not large-scale customers today and some of them might have had issues not related to connectivity."

Nicholls also points out that other companies have satisfactorily engaged in much larger-scale deployments of Sigfox technology, singling out alarm-services company Securitas Direct, which accounts for nearly a sixth of the 7 million connections that Sigfox has so far agreed to support worldwide. "Sigfox has a commitment of 1.2 million connections and sells B2C [business-to-consumer] products in Spain and France -- indoor devices that use the Sigfox network today," he says.

Light Reading approached Securitas Direct for a comment on its relationship with Sigfox but had not heard back at the time of publication.

Next page: The LPWAN threats