MWC Americas 2017 CBRS Seminar

CBRS AllianceFor me, CBRS was undoubtedly the key topic of the MWC Americas event. This lightly regulated 3.5GHz spectrum band using standard TD-LTE cellular service is unique to the US, and will open up a variety of new business models.

A half day seminar by the CBRS Alliance featured several strong supporters and painted a picture of how it will become available and who will use it first.

Three milestones are required before commercial services can commence:



  • FCC approval of the Spectrum Access Servers, expected at or shortly after end 2017. These can immediately serve areas inland which have no conflict with naval radar etc., but it will take until mid-2018 before the environmental sensors have been fully deployed across Continental US to provide nationwide service.
  • Small Cell approval. The CBRS Alliance has delegated certification testing to CTIA and this should start by November. There are plenty of products already in trials and which conform with the specs, so this should be mostly a formality.
  • Handset/Device availability. There are already several USB dongle devices compatible with CBRS Band 48. Some smartphones support Band 42 for the Japanese market and should be fairly easily adapted. A timeframe of 2H 2018 is quite feasible, especially if operators prioritise it as is likely.

Spectrum Access Servers

The two most prominent SAS providers are Google and Federated Wireless.

Federated Wireless announced a $42M round of funding from investors including Charter Communications, American Tower and Arris. (Arris are buying Ruckus Wireless for $800 million). Federated have completed interoperability testing with over 30 different small cell vendors (including well known names such as Nokia, Ericsson, Ruckus Wireless, SpiderCloud). Rajeev Shah, VP Product Management, said they were gearing up for certification in November with many active trials ongoing. An extensive program to deploy environmental sensors has begun, due to cover the US continental landmass (excluding Alaska) by mid 2018. Read more with our exclusive interview with CEO Iyad Tarazi published earlier this year.

Google will also have a SAS solution but are much more elusive about their plans. Many vendors (Ericsson, ZTE, Samsung) were displaying signs on their stands promoting their compatibility.

There are a few other SAS providers at varying stages of maturity. CommScope were visible at the show, demonstrating a live ESC (Environmental Sensor), and a schematic of how it could be deployed shown below (taken from this more comprehensive slide deck). They are relatively compact and could be installed on regular cell towers. Other SAS vendors conditionally approved by the FCC include Amdocs, CTIA, Keybridge, iPosi and Sony.

There were some concerns that the SAS fees charged might be too high. Healthy competition between the multiple SAS providers should ameliorate that. With initial figures as high as $300 per small cell per year being rumoured, I asked Federated Wireless who confirmed to me that they would have a tiered pricing model ensuring even the smallest users could access volume discounts when buying through a reseller channel.

CommScope ESCCommScope ESC Sensor

Small Cell Vendors

There is no shortage of product to choose from, from leading OEMs (Ericsson, Nokia, ZTE, Samsung) to independent small cell vendors (SpiderCloud, Accelleran, Baicells). Ruckus Wireless are slightly unusual in that their only small cell products will be CBRS. Huawei are notable by their absence, with the US being one of the few markets they aren’t successful. The TD-LTE format should give Korean, Taiwanese and Chinese vendors a head-start.

Outdoor products were on show from the major vendors with more emphasis on low powered Enterprise small cells from the independents. Ericsson, Nokia, Samsung and ZTE had both.

Arris are shortly expected to complete the purchase of Ruckus Wireless from Brocade. Dan Rabinovitsj (CEO Ruckus Wireless) was pleased to report the business had had a very good year, making or exceeding its sales figures each quarter. They were showing off their CBRS compatible small cell range, which includes a “clip-on” format that plugs into their existing Wi-Fi access points.

The CBRS Alliance reports over 50 trials completed or in progress, each with their own specific trial licence from the FCC. Results are good and confidence in the operation is high. The Alliance has delegated managed of a small cell certification program to the CTIA, which will operate similar to the Wi-FI scheme for the Wi-Fi Alliance. Compliance testing should commence around November and few problems are expected with existing products.


The first uses will provide a data only service using USB data dongles. Dongles and handsets already exist at 3.5GHz for the Japanese market (Band 42/43) and it should be a relatively straightforward engineering task to adapt these for Band 48 which sits within these – perhaps even a software update. The latest iPhone 8 model A1906 for the Japanese-only market now includes Band 42.

I’m told that US operators are all very keen to adopt CBRS and have been encouraging handset vendors to bring forward plans for CBRS support in their 2018 models. Samsung were showing a live demo with their Note 8 smartphone on their booth.

Initial deployment outdoors by mainstream service providers

The seminar indicated that the first use cases of CBRS are likely to be outdoors, connected to existing mainstream operators such as Verizon and Charter. Rural fixed access is another potential use case.

There will also be plenty of large private LTE networks – the Port of Los Angeles which together with Long Beach handles 40% of US trade imports provided a great example of new opportunities. Their use cases include security (streaming video to first responders), environment (monitoring pollution) and supply chain management (17.2 million untracked containers). It’s just not feasible to do this with Wi-Fi today when covering such a large area and connecting to many moving vehicles.

Craig Cowden of Charter Communications (a large MSO Cable operator) is actively trialling 200 outdoor CBRS small cells from 8 vendors in 2 cities (Charlotte and Tampa). Today they are a “thin MVNO” reselling Verizon Wireless service and he plans to become a “thick MVNO” with their own core cellular network. He believes cable technology of HFC is ideal for small cell deployment, combining power and signal in a single cable. Timescale and scope will depend somewhat on their commercial relationship with Verizon, but clearly they would want to deliver as much traffic on their own network as possible.

Ed Chan, SVP Technology Strategy and Planning for Verizon Wireless is a strong CBRS advocate and said he will be aggressively deploying it, perhaps looking at this as additional free spectrum to boost speeds and capacity. Again, I sensed this was for outdoor use first and most likely as a speed booster using Carrier Aggregation alongside licenced spectrum.

Bill Bloomingdale of Samsung Networks thought that MSOs (Cable Operators) would adopt CBRS more aggressively while MNOs (Cellular Operators) might take a little longer. He sees great opportunities for privately operated networks indoors, such as in hospitals, industry and enterprise. Ideally this would allow staff and visitors to bring their own device but first is most likely to be private using dedicated devices.

Cris Kimbrough from CBRE (a property management group with over 3 Billion sq feet) talked about the value-add of good cellular service in-building. She discusses the options with tenants and property managers frequently, finding that there is a need for a lot of education about potential options. While DAS is technically capable of full multi-operator service, often this isn't achieved because operators may not all decide to support it. She would very much like a single combined technical solution and finds that whenever talking about the future, she talks about CBRS. It is hoped that within 3-5 years, full interoperability with all four will be the default.

DAS, Small Cell and Wi-Fi provider Boingo are also enthusiasts for CBRS. They have a variety of business models, ranging from operator offload (eg Sprint offloading to Wi-Fi using Passpoint), advertising (watch a short video ad for free access to Wi-Fi), paid for Wi-Fi by brand names (eg American Express) alongside retail models. My view is that CBRS access will have to be both seamless and secure to become popular - if you have to enter passwords or divulge personal details to access a CBRS network then there will be no perceived advantage to users over today's Wi-Fi.

Neutral Hosts and Roaming

This led me to ask about neutral hosts and roaming to the major operators, where there is still some level of uncertainty. Ultimately it depends on what the existing mobile operators will accept. Perhaps neutral host solutions such as ip.access VIPER, tailor made for this scenario, will come to the fore. A few I spoke to expected that SAS providers such as Federated Wireless or Google would also handle the roaming aspects, which I understand is very much not the case. Ruckus Wireless explained that their comprehensive offering would provide a central Cloud Managed service including SAS, roaming and other aspects for a monthly fee.

One example is the question of what an end user would see on their handset when connected to a private CBRS network. Will this be their regular provider (ATT, Verizon etc.) who would have to be confident you will receive good service because they would be held accountable for it? Or will it be the building operator (e.g. Hilton, McDonalds etc.) who is directly providing the service? Or will it be a neutral host (e.g. American Tower)? These questions need to be answered.

Work still to do on Priority Access licences

The rules for Priority Access Layer (PAL) spectrum have been published but may change before launch – draft proposals are for up to 40MHz of bandwidth per organisation with a maximum of 6 years tenure. It is said that the FCC might increase that to something like 10 years to fit better with longer term investment plans. PAL spectrum will be auctioned off with fees paid directly to the FCC, on top of the usual service charges levied by SAS providers.

PAL spectrum will be auctioned on a per voting district basis (so-called Census Tracts from the 2010 census), which are geographic blocks each with a population of between 1,200 and 8,000 people. Their geographic size varies enormously between dense urban districts and the wilds of Wyoming. With a national population of around 320 million, there are some 73,057 Census tracts each with their own set of PAL licences areas (each with up to 7 separate 10MHz licences) for sale = so just over 500,000 in total. No single organisation may own more than four per licence area, and current proposals are for fixed terms of three years with a limit of two consecutive PAL terms for any given licence area during the first auction.

The mechanism and rules for how the auction will be implemented remain to be seen.

GAA (open access) spectrum is available to all comers for just the SAS fees. For these reasons, it’s likely that CBRS will launch with GAA spectrum only and this will be perfectly adequate in many circumstances. It remains to be seen if PAL licences will be considered essential in the longer term.


A very useful, upbeat and comprehensive seminar well organised by the CBRS Alliance. We can expect a flurry of CBRS deployments during 2018, with early take-up by both MSOs and MNOs. Private LTE, initially for data only, will rollout in parallel.

The medium to long term success of CBRS will depend on smartphone compatibility (which is likely) and what roaming and neutral host arrangements MNOs will support. This is the biggest area of work that the CBRS Alliance has ahead of it, and I would expect to see good progress throughout the coming year.

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