Femtocell Opinion, comment and reviews

CBRS commences Initial Commercial Deployment

USmountainpeakAfter much-longer-than-hoped-for delays, CBRS was granted Initial Commercial Deployment approval by the FCC, NTIA and DoD this week. It’s a major step forward for small cells and for independent cellular adoption as a whole. A market leading first for the USA. We consider what this now allows, what’s still to come and implications for the wider marketplace.

Putting the jigsaw pieces together

CBRS delivers a full 4G LTE ecosystem: everything from handsets and terminals to basestations, core networks, test gear, cellular expertise, approval tests, certification procedures, planning tools, network performance management solutions, and much more besides. Training/certification for installers and a highly secure digital certification process are just two aspects that have caused some of the more recent delays.

I’d highlight three unique aspects about CBRS:

  • the frequency band allocated (Band 38 = 3500 to 3650MHz). This requires specially modified small cells and smartphones
  • sharing with US Department of Defence Radar systems. Spectrum Access Systems from several competing suppliers combined with Environmental Sensing Capability provide the intelligence to issue chunks of frequency and maximum power levels to each individual small cell
  • that spectrum will be available locally on an on-demand basis to almost anyone, anywhere in the US.

Limited spectrum availability means that almost all LTE deployments worldwide have been through nationally licenced mobile network operators, although a few private LTE networks exist for specialist purposes such as Defence, Mining and Industrial markets. CBRS will open up a huge range of commercially viable opportunities that have not been as attractive to the large cellular operators to date.

What CBRS allows today

The Initial Commercial Deployment (ICD) phase is a proving stage whereby the industry can demonstrate that the system works as advertised. Regulations require a period of at least 30 days and the industry forecasts Full Commercial Deployment approval before the end of 2019.

A wide range of products has already been approved for use, with more in the pipeline. So far, at least 15 CBSDs (CBRS small cells) from 8 manufacturers have gained full OnGo certification although dozens have passed the FCC CBRS certification [ip.access joined that list this week but it has not yet been updated].

Over 40 end user devices – smartphones, fixed data terminals and USB dongles – are also listed with OnGo certification. The most important ones are mainstream smartphones such as the iPhone 11, Samsung Galaxy and other popular models.

Currently CBRS supports only two modes or priorities

  • Incumbent mode, used by Naval military radar, satellite operators and some local area fixed wireless operators.
  • GAA (General Authorized Access), typically with allocations of 10MHz within the 150MHz available.

Fundamentally, incumbent users always take priority and if one is switched on, any potentially conflicting CBSD will be reconfigured to use another frequency within a matter of seconds.

The third mode (Priority Access Licence) has not yet been implemented.

Different emphasis of the SAS providers

The FCC has approved five SAS providers to date:

Federated Wireless – arguably the most vocal and prolific supporter, since it’s basically all they do. They’ve had substantial funding to get this far, raising another $51 million last month, taking investment to $120 million to date. They’ve worked tirelessly to open up the market to new entrants, interoperating with all comers and providing support for a wide variety of business models.

Google – clearly technically competent, and with deep pockets (more than enough to fund the project). They have also been one of the front runners promoting the project and enabling new entrants. Google’s business model doesn’t require them to make profits in the same way as other companies and there is a risk they could undercut pricing for their competitors. The recent debacle with their Nest acquisition (where many third party applications and products will stop working due to a migration to Google Home) may also concern vendors choosing this route.

CommScope – their target market has been the major network operators, and they have been selected by ATT. They’ve also invested in their own ESC network, while some of the smaller players have chosen to partner and save on upfront investment.

Amdocs ­– perhaps a surprise player in this space, known principally for billing and customer-care systems. They bring some expertise in managing network equipment, transmission and configuration.

Sony – the wildcard participant with little publicity to date.

[Keybridge had also been listed as a potential SAS provider but has not yet gained approval.]

What’s still to come

Full Commercial Deployment is forecast before the end of the year. Forgive me for observing that regulatory milestone dates have been missed so far, but I’m hopeful it won’t be too long.

During this initial proving period, some additional paperwork will be required for each installation. Pent-up demand has meant that many suppliers already have this in place and systems can be switched on quite quickly.

It will take time for the proportion of deployed handsets with CBRS capability to gain critical mass, but perhaps two years isn’t an unreasonable timeframe for a modern office and it can be accelerated where clear benefits exist. It’s also a good excuse to require an upgrade.

Initially I believe these networks will either be

  1. completely private (independent of public mobile networks), without handover or roaming using existing cellphone numbers.
  2. operated by and completely integrated with one national mobile network. This includes those operated by Cable TV companies.

It may be some time before mobile network operators come to terms with allowing seamless roaming (with or without handover) to third party CBRS networks. Perhaps this might be pioneered by Cable TV companies using their MVNO arrangements. It’s something the CBRS Alliance is working on, but I suspect may take some time until there is a critical mass and/or one of the national networks opens up.

Before then, there will be plenty of other uses where cellphone numbers aren’t so crucial – fixed broadband service, data-only devices, machine-to-machine applications, etc.

Priority Access Level (PAL)

The vision of CBRS included a mid-tier, above the General Access default, which gives priority access over wider areas for 10 years, for a licence fee. These are to be auctioned off, with higher prices likely in the more densely populated areas. Rules and procedures remain to be finalised, and there is no date set for the first auction.

Some in the industry want to see just how well GAA works first, and one outcome may be that PAL never sees the light of day. It seems sensible to me to assess real-world experience and determine first where the problems lie, before mandating a solution.

4G or 5G

While 5G technology represents an advancement from 4G, it comes with a cost. Experts tell me that you really need a single allocation of at least 100MHz for it to be spectrally more efficient than 4G, whereas CBRS will be issued in blocks of 10 or 20MHz. It seems to me far more commercially sensible to make wide use of the lower-cost/longer-proven and stable technology of 4G/LTE rather than embark on an immediate upgrade to 5G.

Perhaps if additional/different spectrum (say in the mmWave region) were made available for use on a shared basis, then this might justify reassessment Otherwise, I believe it is just a distraction that risks diluting the considerable investment and regulatory approval gained to date.


This has been a great week for the CBRS community who deserve hearty congratulations for progress to date. This period of initial commercial deployment should demonstrate the feasibility and thoroughness of the overall solution.

It’s by no means the end of the journey – only the end of the beginning.

The reward should not only be a widespread US CBRS ecosystem, but also exporting this to other countries. Regulators, investors, analysts and technologists will be watching further developments with a keen eye, from all around the world.

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