Femtocells: Small is Beautiful

It's bizarre that some are talking about a 16 call femtocell. The whole idea of a femtocell is that it's a compact consumer device that provides adequate coverage and capacity within the home or place of work. Having a 16 call femtocell at home or in a shop is like driving your own bus to work everyday. It will get you to work, inefficiently, painfully and probably late...

My view is that what is often flagged as a high capacity femtocell is a re-branded picocell. This is because some vendors got the wrong end of the stick when they assumed that a femtocell is simply a downsized picocell, so they picked their existing picocell products, massaged transmission power and capacity to make it feel like a femtocell, and then branded it as a femtocell product.

A femtocell is not about putting a transmission mast at home or work. It is not a shrunk picocell. It is not a picocell with cheap IP backhaul. I believe that the term "femtocell" should get a better and clearer definition to avoid muddying the water and confusing customers.

Nobody will gain out of reducing the femtocell race to a simple "umph" comparison. Why? because operators who examine the so-called "high capacity femtocells" closely will lose faith in the whole femtocell technology. The femtocell concept is about deploying thousands and thousands of these small cells everywhere. Potentially the number of femtocells in a network will be many folds the number of macro sites the operator owns. Operators should not be drawn into the "My femtocell is bigger and meaner than yours" rhetoric and should concentrate on what the product offers in terms of simplicity of deployement, provisioning, configuration and management.

What's the point of having thousands of high capacity small picocells "aka big and mean femto :-)" if:
1. you do not have the processes to provision them and distribute them to your consumers in an efficient and streamlined fashion?
2. you have to partially or fully configure and radio engineer each one?
3. You have to manually change their configuration every time you do an optimisation sweep on your macro network?
3. you can't manage them in volume?

It's unfortunate that some vendors have concentrated on the technology parity with traditional indoor solutions and totally ignored what is truly important and exciting about the femtocell concept.

There is an urgent need to better clarify and define what a femtocell is. I will make few attempts to do so in my next few postings.

The business case for femtocells in the Middle East.

Etisalat is the first operator in the Middle East who shows interest in FemtoCells, and therefore they asked us at Ubiquisys to showcase their femtocell on the Etisalat stand at Gitex 2008. They branded the product “Etisalat Home Cell”.

So we took few units and demonstrated the first commercial femtocell ever in the Middle East and I ended up spending a week in Dubai during the Gitex technology week at Gulfcomms 2008.


Etisalat were very surprised at the level of maturity of this technology: first they were amazed how far the femtocell coverage can extend with only 10mW of transmission power! Then the surprise turned to admiration when we showed some of the applications of femtocells that go beyond the traditional voice + mobile broadband. The spare femtocell I had with me kept disappearing from time to time, and then I figured out that Etisalat marketing folks were borrowing it to show to journalists and TV stations covering the event . They also kept bringing VIPs to the stand from various ministries and governmental bodies as well as investors to have a look at the femtocell.

After the news hit the net and newspapers that our femtocell is at Gitex2008,
I had a busy week talking to delegates from almost every operator in the region, all keen to find out more about this interesting product. I even had a number of industry analysts who were keen to see the femtocell in action: they heard a lot about this product but never had the chance to see it in action before.

After talking to CTOs and CMOs of the top operators in the Middle East, it was very obvious why there will be a clear winning business case for 3G femtocells in the region. First of all, all operators without exception are struggling with 3G coverage indoors. One CTO has complained that UMTS technology means that the inter-site distance has to be relatively smaller in comparison to GSM in order to provide adequate indoor coverage even for the taken-for-granted voice telephony. Many operators have expansion plans to beef up their 3G networks and add sites in order to improve the quality of coverage indoors. The budgets allocated for these expansion projects can almost buy them a femtocell for every household in the country! So at least from a cost-effectiveness point of view femtocells are a clear winner

The building material and density of urban structures in the Middle East is particularly challenging to cover with a conventional network. Reinforced concrete is widely used, and towers from 30 stories upwards are springing up every day. Some of the commercial towers have expensive distributed indoor systems which are usually installed during construction. Clearly the femtocell proposition is a more cost effective way of providing indoor coverage for the office and home apartment. In summary, most of the commercial people I met immediately recognised the opportunities that femtocells can bring.

However, there are few things that have to be said about the commercial challenges to bring complete femtocell networks to the region. First of all, innovation and the desire to try new ideas is still not an outlook that you face regularly among the Middle Eastern operators. This however is slowly changing. I was positively surprised at the number of innovative offerings Etisalat was offering during the event.

Second, it did seem to me that decision making is not based on any clear or spelt out processes. For example, one operator explained that they ruled out femtocell in the past because their “3G expert” has suggested that (from a technical point of view) the idea will not fly off the ground. After checking with their3G expert, it turns out his source was a single IEE paper written by opponents of femtocells when they were trying to dilute the discussion at 3GPP (the standard body). The number of people involved in the decision process is fairly limited and not diligent enough.

A major difficulty is also lack of visibility of small and innovative companies involved in the development and making of femtocells. Operators want to deal with big vendors directly, and they get suspicious of vendors trying to become System Integrators of smaller companies. Therefore operators are more willing to work with the likes of Huawei and Alcatel. The big vendors have got the most to lose out of introducing femtocells, and therefore they take any opportunity to badmouth the concept and the technology.

All in all, it was exciting to be able to show a really cool product to a very receptive audience. I have no doubt that femtocells will change the game of Middle Eastern operators. I’ll be there again at the Comms World GSM >3G event in December.

FemtoCells on BBC News

Here is a link to an article on BBC Technology News with a good summary of the case for Femtocells from a user's and operator's points of view.

Google invests $25 million in Ubiquisys

The recent news of Google's $25 million investment in Ubiquisys is the beggining of a major change in the race to win the Femtocell race.



While architecture, coverage and RF performance are some of the important areas to keep a close eye on, content and applications will be the major differentiating aspects. I talked in a previous post about content personalisation and customisation possibibilities with FemtoCell solutions, which is going to be an exciting area to watch over the next 6 months.

News coverage of the Femto Forum

Telecoms.com (Informa's telecomm business intelligence reporting outlet) has some interesting and insightful coverage of the Femto Forum meeting that took place in London on first week of July.

The article quotes Will Franks, CTO of Ubiquisys, as well as Dr. Simon Saunders, the newly appointed Chairman of the Femto Forum on the importance of bringing the femto vendors together and collaborate to reduce or eleminate femto solution fragmentation. There are various proposed architectures and it seems that one of the aims of the Femto Forum is to try to converge these solutions into a comprehensive standard that facilitates inter-working.

ABI research femtocell vendor ranking results

This has been out for a while, I don't know why I kept delaying linking to it:
ABI research has ranked the various femtocell vendors. Check the news release here.
Their ranking criteria is based on two aspects: Implemention and Innovation. This ranking is by no means a ranking of the femtocell prodcuts only. It also takes into account the overall position of the relavent company/division in terms of finances and partnerships. (you can see the criteria here).

Based on the matrix, ABI research has compiled a list of the top 10 femtocell vendors. The top 3 are: Ubiquisys, ip.access and RadioFrame networks.

One thing that surprised me is that Alcatel-Lucent is listed as number 4, which I thought is rather over rated considering that their offering oscilates between an imaginary concept or a modified picocell product ( not purpose built as a femto product from the outset). This ofcourse depends on who you talk to in Alcatel-Lucent: French or American.

Femto cell Architecture

The business case for indoor femto cells has gained increasing traction in the last few weeks, and lots of news comments about various femto cell development companies. For example, check here, here and here.

Although the femto cell concept is quickly gaining grounds towards complete and operational products, there is still some misunderstanding on how the overall network architecture will look like. I'll try to address this issue in this post.

A femto cell router is a small device, the size of any Wi-Fi router, which is in effect a miniature base station. The radio is a standard based radio such as UMTS/HSPA which the operator will likely require a license to operate on. The router connects to a DSL line. The idea is to enable the subscriber to make and receive mobile calls indoors, with low signal levels which has a number of benefits to the operator:
- Hopefully accelerate fixed line substitution.
- Reduce the cost of building a full macro layer network.
- Lock subscriber in to the operator and reduce the likelihood of churn.
- Provide a viable medium for content distribution (the ugly walled garden paradigm)

It is not my intention here to argue for or against these benefits. I will dedicate a full post on the business case for the femto cell and the potential cons sometime soon. So let us stay on the technology side and try to investigate how a UMTS based femto cell routers will be integrated with the operator's core network.

Basically, there are a number of ways, the first of which is the conventional hierarchy using an RNC . Just like any node-b is connected back to an RNC which is then in turn is connected to the core network, the femtocell routers can be treated like individual node-bs and connect to RNCs. This may appeal to big manufacturers who already have substantial deployments and many RNC on the ground. The downside to this approach is the limited chances of inter-operable devices if the operators chooses to diversify their suppliers. Although the Iub interface (base station to RNC) is standardised, the reality is most implementations are proprietary. Typically operators don't like to put all their eggs in one basket and would prefer to get solutions from various suppliers. The other downside of this approach is that most available RNC solutions are geared towards Macro/Micro type of deployments. In other words they are built in order to support relatively small number of cells with a huge number of subscribers in each cell. They don't scale very well to support Femto cell deployments with almost as many cells as there are subscribers, and a handful of subscribers per cell.

An alternative approach is to use UMA (or now called GAN). UMA was originally conceived to support dual mode cellular/WiFi-over-Internet type of connectivity. When the mobile is detected indoors within the range of pre-determined WiFi coverage, a UMA concentrator does the core network negotiation on behalf of the mobile, e.g. registering, and updating location ... etc. It is thought that a similar procedure can be used for femto cells. When the mobile is detected within the coverage of a femto cell, UMA kind of hand shaking takes place to ensure that: 1. the mobile is allowed to access the network at this particular femto cell, 2. the traffic between the mobile and the core network is forwarded accordingly. Using this method a UMA concentrator is required, so in a way, the solution is still hierarchical and it is certainly one of the criticisms of this method is that it is not a fully flat architecture. Kineto is one of the companies promoting this approach.

Yet another alternative approach is enabling femto cell connectivity through an IMS service. In this approach, the femto cell router talks SIP over the internet back to an IMS service which acts as a bridge between the femto layer and the rest of the network. Although this is considered the "flattest" approach, it is yet to understand how it will work in practice, the delay in working fully featured IMS platforms is one of the concerns of femto cell development companies.

Incidentally, my current clients are hedging their bets by supporting more than one approach and have developed partnerships with various companies in their respective fields to make the Femto architecture as flexible as possible.