Last week's announcement of a standard for femto cells took a lot of people by surprise. How did it happen so fast, and how important will it be? And are there other issues that might cause problems in future?

Standards often take forever to develop. This time round, the Femto Forum appears to have created a compromise which the 3GPP standards group is happy with, very quickly indeed. From all accounts, it will be a

There are two main reasons for this.

Customers come first

Firstly, the actual customers have been involved much more heavily than in many other standards.

Many technology standards are made in groups like IEEE, where a series of vendors push a set of technology solutions, more or less in isolation from users. Eventually one wins, or compromises are made, but these are often based on abstract technological features, with a not-so-hidden commercial advantage for one supplier or another.

Simon Saunders, chair of the Femto Forum, puts it more diplomatically: "What you are usually doing is making it up by committee, creating a paper standard, which you then go off and implement." In this case, there were existing products, he says.

Femtos have the advantage that in the telecoms world, standards are made for a comparatively small set of customers (the mobile operators), all of whom could have a large stake in the success or failure of femtos.

The Femto Forum has raised their consciousness and, in this instance, apparently inspired them operators to make a collective ultimatum: one standard only please. "Raising expectations was the best way to move things forward quickly," says Femto Forum chair, Simon Saunders, and much of this was done by the chair of the Forum's working group, Chris Fenton. Once they saw the problem, the operators put forward absolute requirements.

Faced with a list of user requirements, the vendors did something rarely heard of in a standards meeting - they accepted that none of their solutions met all the requirements, and developed a common answer,

SIP/IMS can wait

A second factor helped bring about this consensus. Inspired by the operator ultimatum, vendors pushed back more long-term approaches based on two elements: IMS, the multimedia platform that telecoms networks are supposed to be adopting over the next few years, and on SIP, the protocol used in VoIP.

"The idea of IMS-connected femtos seems to have been kicked into the long grass for now as far as 3GPP and Release 8 is concerned," says Dean Bubley of Disruptive Analysis.

Shaw agrees: "IMS and SIP adds a lot of complexity, and operators are looking for a short term pragmatic approach. They don't want to have to jump into IMS just to do one thing." Operators still believe that SIP and IMS are the next step for mobile operators, but no-one expects them to be implemented fundamentally until LTE rolls out.

This meant a radical pruning of femto contenders: "Three months ago, there were something like 14 different proposals, including four or five really fundamentally different attitudes to the world," says Rupert Baines, vice president of marketing at picoChip, which designs silicon for femtos.

As well as SIP/IMS, the traditional IUb protocol was rejected as were new standard protocols.

The process left only four proposals, all of which were roughly similar, based on a RAN (radio access network) gateway. "None of them are SIP based, and all work with existing GSM protocols," says Steve Shaw, vice president of marketing at Kineto which backed the UMA process based on GAN.

With this smaller set of more similar standards to go for, diplomacy behind the scenes was enough to persuade the vendors to all agree, and make a standard that can be implemented on today's mobile networks, using today's broadband services.

The eventual Iuh standard includes elements of Kineto's UMA/GAN, and other contributions for Nokia Siemens, Huawei and Alcatel Lucent.

"We'd have loved this to be 100 percent GAN but we aren't foolish enough to believe that would be the case," said Steve Shaw, director or marketing at Kineto. "It's got some of the principles of GAN in it."

More on the timetable

Saunders is pleased to see the femto standard scheduled for Release 8 of the 3GPP standards, which also includes the LTE standards. That's a good landmark to aim for.

Although the femto standard won't actually work with an LTE radio interface, it may be useful to LTE networks. LTE handsets will be able to fall back to 3G - and while indoors will work better with a big share of a nearby 3G femtocell's bandwidth, than fighting for some attention from a remote LTE base station.

The Femto Forum also hopes to inspire other standards, to make sure femtos can fit with billing systems, and be managed remotely by the same management and provisioning systems currently used by broadband providers. The Forum now has an architecture which can make sure these are done efficiently says Baines.

This will also allow femtos to adapt to new technologies such as LTE, he says: "We have a generic framework. Whether you are talking about LTE, 3G or WiMax, an awful lot of what is needed is consistent. This 3GPP announcement, for a W-CDMA femtocell, is the first of many of those instances."

Future standards may arrive just as quickly, he suggests.

Will it work, though?

Although Saunders and the others are optimistic, things could still go wrong. Firstly, although the timetable is good, it could slip simply through the complexity of creating a standard to such a tight deadline.

It's possible that some vendors might show reluctance to sign off on a standard if they see others getting an advantage, but this is much less likely now the operators have flexed their muscles.

Some observers commented that the new standard might give some advantage to Ubiquisys, which makes all the femtocells for UMA vendors like NEC and Motorola. Ubiquisys has already promised its devices will be upgradeable - but others are very sceptical given the standard is still not complete.

In any case upgradeability of current products won't be very important, as proper roll-outs won't take place till the standard is finished. "Now it's a race to the finish line," says Shaw.

And there may still be other complications. The standard is designed to work with existing networks, but what if handsets need to be tweaked? "Although existing 'legacy' 3G handsets can work with femtocells, they are not optimised for them," warns Dean Bubley. Operators may have to alter their handsets to get the best out of femtos, which could make a large dent in the business model, he warns.

But in the end, the creation of the standard brings its own message. A standard driven by the operators who will use it much be more likely to succeed. "It’s the carriers who are driving this," says Baines. "Some people are interested in the technology, but what counts is customer pull, rather than white papers about funky technology."