LTE Femtocells

The Need for LTE Femtocells
Over the next few years, billions of devices will be connected to the Internet and cloud-based applications using 3G and LTE mobile wireless networks, creating tremendous demand for mobile wireless capacity and ubiquitous coverage.  In their 2011 Visual Networking Index, Cisco projects that global mobile data traffic will increase 26-fold between 2010 and 2015. This has been called the “mobile data tsunami”.

Traditional macro cellular networks alone, even with advances in 4G technology, simply cannot meet this demand because:

  • There is a limit to how many outdoor cell sites can be built.  Cell sites are costly, and new site proposals often encounter local resistance.
  • The spectrum available to any particular operator is limited; the growth in capacity from 4G spectral efficiency plus anticipated new spectrum will still be outstripped by increase in demand.
  • Cell site backhaul, though available, is expensive


As a result, macro radio access networks will not be able to keep pace with the growth in demand for mobile data.  Meanwhile, the price that consumers will pay, on a per megabit basis, is declining. In 2007, BlackBerry dominated the smartphone market. Users paid $30-$45 a month and typically consumed 25 MB of data. Today, an iPhone or Android user pays $30/month and often consumes over 500MB of data.


To handle the data tsunami cost-effectively and provide ubiquitous coverage, operators must offload data traffic from the macro-cellular network to the fixed line broadband network when users are inside buildings. Consumers expect this offload to be done in a transparent fashion, wherever they are—especially indoors. As consumers become accustomed to LTE speeds, they will expect these speeds whether they are outdoors or in-building.
 
Airvana believes Femtocells provide the best solution for seamless, transparent offload and ubiquitous coverage for high-speed data. 

LTE Femtocells Need to be Multimode
Leading mobile operators are planning aggressive LTE service roll-outs.  However, even in the most optimistic of scenarios, 3G subscriber devices will outnumber LTE devices for many years to come.  Historically there has been a 10-year interval between the ratification of a new generation standard and the time when its device shipments overtake those of the previous generation.  As an example, ABI Research reported that shipments of 3G handsets overtook 2G handset shipments only in Q1 of 2010.

The data below from Deutsche Bank suggests that this pattern will continue in the migration from 3G to 4G.

Operators will need to support of mix of subscriber device generations.  Source: Deutsche Bank

Furthermore, while LTE standards for data are well established, there are still multiple proposed ways to deliver voice services over LTE networks.  The likely outcome of this will be that operators will continue to deliver voice via their 3G networks even as they move data to LTE.

As a result, subscriber devices will be a mix of 3G-only and 4G plus 3G, with very few being 4G-only.  To support these subscribers comprehensively across all types of mobile services, operators must similarly deploy a multi-mode radio access infrastructure including multimode femtocells.

3G Femtocell 4G Femtocell Multimode
Data on 4G/3G Device X XX XX
Data on 3G-only Device X via  macro X
Voice X via macro X

Multimode femtocells will be needed to effectively support all user services.

Airvana strongly believes that multi-mode femtocells will dominate the market for the next decade.

Airvana and LTE femtocells
Airvana is a femtocell pioneer and market leader in 3G CDMA femtocells. Multimode femtocells present technical challenges, for example the need to simultaneously manage multiple radios without interference, and to keep the total system cost low. Airvana is well positioned to address these challenges.  All current Airvana CDMA femtocells are dual-mode today. They support a 2G voice technology (CDMA20001X) and a 3G data technology (1xEV-DO). Key technology elements that Airvana has developed include:

  • Hardware designs with multiple radios. All Airvana CDMA femtocells actually have three transmitters and three receivers.
  • Software frameworks for consistently managing two different femtocell radios – for performance management, alarms, logs and security.


These advancements are already field-proven in commercial femtocell deployments at some of the largest CDMA operators in the world.

Airvana has selected Freescale’s system-on-chip (SoC) platform for our LTE and multi-mode products. Freescale is a leader in the DSP market for LTE base stations. Freescale’s product range is both scalable and highly programmable, making it ideally suited for low-cost 3G, 4G and multi-mode small cells with advanced features for consumer, enterprise and public space markets.

In addition to femtocells, Airvana offers its field-proven, standards-based, Femtocell Service Manager for LTE and multi-mode femtocell deployments.

Airvana’s innovative LTE femtocell technology, combined with our expertise in multi-mode femtocell development will lead to a compelling solution for operators.