There's been much joy in the femtocell industry this week, as 3GPP has decided on a standard architecture for connecting HSPA femtos (they call them Home NodeB's) into the network. This should make life an awful lot easier, given that there have been assorted proprietary and semi-standard approaches suggested up until now. The consensus among operators is that standardisation is mandatory for widespread large-scale deployments.
The output is a hybrid of the UMA/GAN approach advocated by Kineto, and some of the other "RAN Gateway" approaches advocated by the likes of ip.access, NSN and others. It's called the Iuh interface, and it's pretty much kicked the IMS/SIP approach into the long grass for the medium term, at least for 3GPP networks - although that architecture is more likely to be adopted by CDMA operators.
This is in the latest version of 3GPP's specifications, Release 8.
So far, so good for the femtocell proposition.
But unfortunately, the picture is likely to get a little murkier. I've been working for some time on what's going to be a rather controversial report. This post is a bit of a teaser before its publication in the next week or two.
In a nutshell, I think that one of the fundamental assumptions about femtocell business models has serious flaws.
Although existing "legacy" 3G handsets can work with femtocells, they are not optimised for them. There are some enhancements also likely to be in 3GPP Release 8.... and quite a lot of other considerations outside R8's scope that the vendors, and the standards and requirement-setting bodies haven't considered yet.
I have.
If you're interested in getting a heads-up on "The Argument for Femtocell-Optimised Handsets", keep an eye on this blog. And if you pre-register your interest via email at information AT disruptive-analysis DOT com, I'll let you know as soon as the full report is published.
Dean Bubley's Disruptive Wireless: Thought-leading wireless industry analysis
9 comments:
"Need" or "want"? Yes, there will be some optimisations for femtocells in Release 8 standards for handsets. But just as Release 99 handsets continue to be supported by the latest HSPA networks, so these will work with pretty much any handset.
There are some optimisations in Release 8, which are likely to include handover into femtocell zones and others. These would benefit from minor tweaks in both macro cellsites, femtocells and handsets.
However, unlike WiFi, you don't *need* a dual mode handset (from a limited but growing choice) to use a femtocell. This is a compelling benefit of femtos, and its a bit mischevious to suggest otherwise.
And there may be no compulsion on the latest handsets to include these optimisations - they could be optional rather than mandatory and deprioritised/deferred depending on the market demands on the handset vendors.
david, have not read the 3GPP spec, but somehow this does not surprise me. i have heard from several operators that it is difficult to make sure the handset is locked in to the femto, and not to the macro, when it is within the formers coverage zone. are these recommendations related to this issue? if 3gpp has come to this conclusion and made these recommendations for reasons such as these, i have to say dean is spot on.
- anonymous1
Interesting post Dean. I tend to agree with David that the current handsets will work as normal. Some of the features like support for Hierarchical cells have not been correctly implemented/tested on all mobiles and this may cause some problems for some of the handsets as they might keep on doing handovers between the femtocell and mrcro cell.
By the way, if femtocells become big then this will put a lot of strain on the ISP and the era of cheap/unlimited broadband may be over. Do you have an opinion on this?
There is a lot more to be done than just the optimisations in R8, if femtos are to be as useful as proponents seem to think.
There are also a range of hardware & software modifications which I'll talk about in greater depth when I publish the report.
David - actually, WiFi gives some interesting examples of the sorts of problems that will arise. Until recently, the only real uses of WiFi on phones have been for VoIP (either operator-based like UMA or 3rd-party like Truphone or Skype), and for shared Internet access. There have not been many innovative applications that exploit dual-mode local connectivity, which is one of the reasons that WiFi is of little appeal in massmarket devices.
Zahid - hmm, not really. The aggregate traffic on broadband from femtos is unlikely to surpass that from wired ethernet, WiFi, and especially IPTV. Some people are suggesting femtos as an alternative for WiFi for PC connectivity in the home, but that's just wishful thinking by the cellular infrastructure industry.
Femtocells will require no changes to
the radio terminals. The issues for
femtocells specifically are :
1. Ensuring QoS for all services
provided by a RAN, when the transport
bearers are over "best-efforts"
external party networks (ISP xDSL
networks) tand may be shared (Internet
access, IPTV etc) .
14/5Mb HSDPA/HSUPA femto-cell ??
No good if your ADSL connection is
2/0.5Mb (when nothing else is using
it) .
2. The OAM model.
Femtocells are more like Internet
CPEs than canonical base stations.
Which brings a different model of
management. Current 3GPP OAM does not
consider the notion of 100,000s of
base stations, or cells.
3. Macro to femto handover.
Think of the monitoring on cell area
updates, and per-UE SIB traffic. A
nightmare.
And of course, if you must ensure that
the users' femtocell is currently
switched on and is active.
Hi Dean,
Re "Some people are suggesting femtos as an alternative for WiFi for PC connectivity in the home, but that's just wishful thinking"
I'm not so sure. People are lazy. If you've got a femtocell and an HSPA enabled laptop, why would you bother to switch it over to WiFi when you get home?
I don't know what David is going to write in his upcoming article, but assuming the issue is locking onto the femto instead of the macro, I don't see this as a issue. Why? Because the first adopters are going to be people that can't get a signal in their house, so the issue is moot.
Once enough new femto services come on board where the main stream users will want to get a fetmocell base station, all these issues will have been solved either via a fw update or people getting new handsets (as we all know, the carriers love to give away cell phones or sell them to you very cheap to lock you into another 2 years of service).
Oops, I mean Dean of course, not David.
Dean,
I'm not sure if you've been following the airave product, which is a femtocell from sprint in the US.
But its now available nationwide, and some of the early users have been complaining that the airave blocks out cell phones that aren't on the restricted list of the airave.
Meaning, if the airave is set to only allow certain cdma phones on the airave, all other cell phones are blocked from making calls, even if there is a usable cell tower signal.
There's been some discussion on the sprintusers message board.
http://tinyurl.com/56zxqf
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