Will Franks - femtocell pioneer

Femtocell Pioneer has moved to a new home!
Thanks for visiting - all my femto pioneer posts are now appearing on The Femtocell Blog - I look forward to seeing you there - Will Franks

26 June 2009

Femtocell Industry Awards 2009: NEC and SoftBank recognised, Ubiquisys the Common Factor

My warmest congratulations at the Femtocell Industry Awards last week went out to NEC and SoftBank, mainly because both are part of an ecosystem that relies on Ubiquisys femtocells.

NEC won the award for Progress in Commercial Deployments. This recognised NEC's strong traction in the market. NEC has secured an impressive number of commercial contracts and has many live trials underway with operators around the world. All of these utilise Ubiquisys femtocells.

SoftBank won the award for Social Vision – the use of femtocells for social, economic or environmental development. Their Niimi project illustrates how femtocells can be cost-effectively deployed to deliver services in rural environments where existing coverage is limited. SoftBank's commercial deployment uses Ubiquisys femtocells supplied through NEC Japan.

17 June 2009

Enterprise Femtocells: Easy to Underestimate

Enterprise femtocells, forming a grid of self-organising coverage, are genuinely new. So it’s not surprising that they are often misunderstood.

On one hand they offer the low cost and self-install simplicity of enterprise WiFi. Yet they also offer all the benefits of 3G cellular with massive data capacity. This is a heady combination, and promises to make in-building cellular affordable for small companies because the femtocells are based on mass-produced hardware, because no radio planning is required and because they can be self installed by the IT guys. They also promise to multiply the uptake of in-building cellular in large enterprises by providing added flexibility and simplicity at a fraction of the cost of today’s manually engineered pico/DAS systems.

John Spindler, in his article for Wireless Week, makes a couple of familiar assumptions about enterprise femtocells, which I’m happy to put right.

Assumption 1: minimum coverage overlap
The first assumption is that a grid of enterprise femtocells has minimal coverage overlaps. It doesn’t. In fact the femtos deliberately organise themselves into a grid with extensive overlaps.

What femtocells do that’s different to picocells is manage interference themselves in real-time rather than rely on the complex RF engineering that would otherwise be required. The femtocells obey the policies set by the mobile operators so will never produce unmanaged interference between each other or with the macro network. For example, femtocells in the grid use algorithms to ensure maximum spatial diversity between scrambling codes.

Signal dominance
Making the wrong assumption about coverage overlap leads to worrying about phones flip-flopping in and out of the macro network. But enterprise femtocells provide a strong indoor signal and also hold onto phones using “sticky cell” technology. Together these ensure that flip-flopping doesn’t happen, and that's true of any 3G phone.

Assumption 2: underestimating femtocell capability
The second assumption is that femtocells can support only a handful of calls and have a range which is a fraction of a picocell. Not quite: enterprise femtocells can range in capacity from 8-16+ users, and each one has a range approaching today’s picocells.

Femtocells in the grid don’t need to do soft handovers because of strong cell overlap, and they don’t have to handover very often because their range is not far short of picocells. There is always a battery life penalty when handing-over, but this is more than offset by the massive reduction in handset transmit power. In any case additional battery consumption only occurs when on a call, not when the phone is moving but idle. So the net effect is a major boost in battery life over the macro network.

In a grid of enterprise femtocells every femto handles not a handful of users but 8 or 16 or more - providing robust coverage and high capacity throughout the building. Most importantly, it does so more cost-effectively than Pico/DAS solutions that require radio engineers to deploy them.

Bottom line
Ever wondered why wifi access points tend to be installed in a modular fashion, rather than in a pico/DAS-style hierarchy? The answer is because they can be – it’s simpler, easier and cheaper. And the same is true of enterprise femtocells.

05 June 2009

New Femtocell Reference Book

Femtocells are not just a new type of device, they change traditional technical boundaries and they open new commercial models for mobile.

There have been some good introductions to femtocells, such as David Chambers' Femtocell Primer, but what has been missing is a comprehensive reference covering both technology and commercial aspects in detail.

Enter the unambiguously-titled "Femtocells - Opportunities and Challenges for Business and Technology", available now for pre-order at Amazon.

The book examines the market, exploring commercial and technical factors which are critical in the initial deployment and long-term success of femtocells. Business, standards and regulatory aspects are also considered to provide a complete but concise overview.

  • One of the first authoritative texts to concentrate on femtocells
  • Written by expert authors from industry including leading analysts, femtocell and system vendors
  • Covers both technology and business aspects in detail
  • Provides overview of the relevant standards across WCDMA, LTE, CDMA, WiMAX and GSM air interfaces.
The authors of the book are all acknowledged femtocell experts, including Ubiquisys guru Andrea Giustina.

04 June 2009

Femtocells - a network planning and management nightmare?

Kevin Fitchard asks some key questions about femtocells in his article in Telephony Online. He was commenting on how femtocells might be the answer to mobile networks reaching Shannon’s Limit of available capacity. Femtocells can easily provide the capacity relief, but with millions of them deployed, wouldn’t they “create a network planning and management nightmare”?

These are the challenges that faced femtocell pioneers from day one, and the solutions are fundamental to the femtocell concept.

1. How do you make femtocells self-installable under an existing macro network deployment deployed on the same spectrum?

This is addressed by the much talked-about principle of Self-Organising Networks. In reality, this means femtocells having autonomous cognitive radio capabilities that scan the relevant spectrum and optimise a complex set of parameters to work symbiotically with the macro network. It also means femtocells continuously monitoring the spectrum to adapt to any changes, such as a macro re-plan or the installation of a femto neighbour. This ensures that femtocells remain the adaptive subsidiary partners to the dominant manually-engineered macro network.

2. How do you enable millions of plug-and-play femtocells and keep them under control once they are out there?

The principle is to make the installation easy for the consumer and manageable for the Mobile Service Provider, and to do this in very large numbers. That’s why the DSL Forum approach for management (TR069) has been widely adopted for femtocells. TR069 is a proven method used to remotely manage millions of home gateways and set-top boxes around the world.

These two functions, fundamental to the femtocell concept and proven in real deployments, effectively eliminate the risk of nightmares.