Clarifying WiMax Certification

By Jeff Goldman

November 21, 2005

The process of getting fixed (or mobile) wireless broadband interoperability is seldom understood.

A recent white paper from Senza Fili Consulting entitled The Evolution of WiMax Certification clarifies the process of certification for both fixed and mobile WiMax. The paper, available as a PDF download from Senza Fili’s Web site, breaks the process down into five anticipated waves of certification, and looks at the ways in which various companies are approaching the process.

Monica Paolini, the president of Senza Fili and the paper’s author, says she wrote it because, while writing a larger report on WiMax, she discovered that most of the people she spoke to had different perceptions of the certification process. “The information is out there, but it’s a little scattered,” she says, “So I thought it would be useful to put it all together.”

According to the white paper, WiMax certification will occur in five successive waves, with each wave adding new profiles and functionality:

  • Wave 1, enabling a simple air link, is currently in process
  • Wave 2, in Q1 2006, will add QoS, security, and advanced radio features for outdoor CPEs
  • Wave 3, in Q2 2006, will add indoor CPEs and PCMCIA cards for fixed and nomadic networks
  • Wave 4, in Q1 2007, will add hand-offs and simple mobile for 802.16e or mobile WiMax
  • Wave 5, later in 2007, will add full mobility

Of course, nothing’s finalized past the first wave, which promises little more than the air link itself – but, Paolini notes, you have to start somewhere.

“They needed to start with something that was manageable, and then extend it,” she says. “From one side, there’s a complexity issue – you can’t have it too complex at the beginning – and the other issue is the availability of a solution.”

Compliance and Interoperability

While you can certify compliance to a specification for a product that’s made by just one vendor, you can’t determine interoperability without three vendors’ products to compare – and that’s where availability becomes an issue. “For instance, with 5.8 [GHz spectrum], there is a profile and everything is ready to go, but unless you have three products, you’re not going to have interoperability,” Paolini says.

Within each wave of certification, interoperability has to be established for a number of different profiles. “You need to have interoperability for each spectrum band, and separately for TDD [Time Division Duplex] and FDD [Frequency Division Duplexing] and for different channels,” Paolini says. “And for each one of these possible combinations, you need to have at least three vendors.”

The same issue, Paolini says, didn’t come up during the Wi-Fi Alliance’s certification process for wireless LAN products both because there was only one profile and because there were far more vendors involved. In the case of WiMax, not only are there fewer vendors, but many of those vendors are smaller startups with limited resources – and that makes participating in all of the waves of certification more of a challenge.

As a result, some companies are waiting to participate until later in the process, and others are targeting specific spectrum bands and channels, all to ensure that their time and money are well spent. “They do not have the resources to have a product in every single band, so they go for ones for which they see more demand,” Paolini says.

With a small number of vendors made even smaller by their segmentation into different bands and channels, finding three vendors to certify interoperation will be a challenge in some cases – which will further complicate matters.

“When you have three vendors, let’s say that one fails,” Paolini says. “Then the other two cannot get certified either.”

A Communication Problem

It’s frustrating, Paolini says, that the WiMax Forum hasn’t done a better job of explaining the certification process. “It’s very difficult if you are, say, a service provider that’s looking for different solutions, to understand what’s best for you,” she says. “It would be useful to have more clear information about what’s going on and what the different waves are, and then you can decide – especially if the Forum gives you a clear road map.”

Part of the problem, she says, may be the challenge of getting every one of the Forum’s members to agree on the content of any such road map. “If you try to work by consensus, then it’s difficult to say anything,” Paolini says. “But I think it’s really important for the Forum to send out a clear message, even if the message is a little bit more complicated than what people expect – because at some point people will find out that it’s not that easy.”

One side effect of the lack of information about the process has been some confusion about why some companies aren’t participating in the initial steps. “The fact that you do or do not participate in the first round doesn’t necessarily mean a whole lot in terms of your WiMax strategy,” Paolini says. “If you want to add the additional functionality to your product, you may not see much to gain from the initial wave of certification.”

Other companies, such as Motorola and Navini, are skipping the fixed WiMax process entirely and waiting for mobile WiMax – which Paolini says is an equally legitimate strategy.

“They’re basically saying they don’t want to have a fixed product – that’s not a market they want to go in,” she says. “It’s an individual company’s decision – it doesn’t reflect their commitment to WiMax one way or the other.”

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