T-Mobile USA's Indoor CellSpot (a.k.a. Femtocells)

Sometime back I saw this tweet by T-Mobile CTO Neville Ray

I don’t care if it’s satire, I’m still going to get a field tech out there 🏃🏻‍♂️ https://t.co/22qpeHfZyS

— Neville (@NevilleRay) January 31, 2019

I started wondering if T-Mo had femtocells and voila!

Pic Source: Dane Powell

According to the T-Mobile website, there are 4 types of devices:

1. 4G LTE CellSpot V1 
2. 4G LTE CellSpot V2 
3. 4G LTE Signal Booster 
4. 4G LTE Signal Booster Duo

The product comparison chart can be seen below

Now let's look at the Functionality comparison chart

As you can see, the cellspots require an ethernet connection as they create a small coverage bubble while the Signal boosters are just repeaters.

You can get detailed specifications here on 4G LTE CellSpot V1 and 4G LTE CellSpot V2.

Detailed specifications here on 4G LTE Signal Booster and 4G LTE Signal Booster Duo.

In Addition, T-Mobile also supports Wi-Fi calling and also sells T-Mobile 'Wi-Fi CellSpot AC1900 Gigabit Router'

T-Mobile USA: Anatomy of A Mobile Wireless Network

T-Mobile has a nice educational video on what makes a network looking at backhaul, small cells, etc. I have posted about T-Mo small cells here and here before. I have also pointed out that the definition of Small cells varies from country to country and USA is no exception. In the USA, RRH's are often referred to as small cells due to their small form factor but I disagree. You can see this earlier post on Macrocells, Small Cells & Hetnets Tutorial.

Here is the video on the anatomy of a mobile wireless network.

Wireless: Anatomy of A Network from T-Mobile National Development on Vimeo.

T-Mobile USA is deploying 25K small cells with LAA

Source: PCmag

T-Mobile keeps talking up its small cells and 5G deployments. ICYMI, I recently wrote about the 5G rollout in 600MHz on 3G4G blog here. In a recent interview in Fierce Wireless, T-Mobile’s SVP of radio network engineering and development, Mark McDiarmid reminded everyone that the company plans to deploy up to 25,000 small cells this year, some just a few hundred yards away from one another.

This is all following on from the announcement last year that T-Mobile has contracted to deploy 28,000 small cells. Since then T-Mo has quietly changed its strategy from LTE-U to 3GPP standards based LAA. This was on back of a successful trial with Ericsson where they achieved speeds of 1.1 Gbps using 12-layer Licensed Assisted Access (LAA) technology – the first in the world to hit speeds beyond the 1 Gbps threshold on unlicensed spectrum.

We aren't announcing any other cities at this time. However, the small cells being deployed today are LAA ready while we upgrade existing small cells. These all use our existing bands.

— Neville (@NevilleRay) March 1, 2018

For the PCMag article, Milan Milanovic, Technical Evangelist for Ookla did some tests and the article had the following to say:

At a cell site at 45th St. and Third Avenue in Manhattan, T-Mobile is combining 20MHz of its Band 4 spectrum with 60MHz of LAA spectrum. Phones connect to the cell site and send data up using the 1700MHz/2100Mhz Band 4 spectrum, and then get downloaded data via a combination of Band 4 and LAA.

Those speeds are insane. In 13 tests, we got an average of 503Mbps down and 42.7Mbps up. Just to compare, in Ookla's Speedtest Intelligence database, the top 10 percent of T-Mobile download speeds in that ZIP code are only around 70Mbps down.

LAA-capable phones can get up to ten 100Mbps download streams on this cell site, with four on the licensed spectrum (4x4 MIMO) and two on each of three channels of LAA spectrum, Milanovic said.

Other users on this cell site will do well, but not as well as LAA users, Milanovic notes. The site is also equipped with T-Mobile's workhorse Band 2 and the low-frequency Band 12, which penetrates inside buildings.

LAA is only a solution for dense urban areas, though. This cell site has a coverage diameter of about four blocks (a bit over 1,000 feet), which is considered pretty good for LAA. That's a little better than what the coverage probably would be if the site was sending down 5GHz Wi-Fi, and it's a little better than New York's LinkNYC public Wi-Fi posts.

A nearby LinkNYC post doesn't appear to be interfering with the T-Mobile signal, Milanovic said. That's good news, because one of the concerns about LAA is whether or not it will coexist well with powerful public Wi-Fi.

You'll need the right phone to hit these speeds, and that's not an iPhone. Currently, LAA is supported by T-Mobile's Samsung Galaxy S8, Note 8, Galaxy S8 Active, Galaxy S9/S9+, LG V30, and the unlocked Huawei Mate 10 Pro £399.00 at Amazon. We'll make sure to test LAA when we go on the road with our Fastest Mobile Networks drive tests this spring.

Here is latest on the LAA speed front from Milan Milanović:

The Galaxy S9 puts you in a fast LAA lane even during the peak hours in the middle of Manhattan. @TMobile @SamsungMobile @QualcommTech pic.twitter.com/tWzUh4LoPT

— Milan Milanović (@milanmilanovic) July 17, 2018

Not everyone agrees that LAA has a long term potential or performs well where 5GHz Wi-Fi channels are very busy. Others (mainly vendors) disagree.

You may also enjoy reading Juny Song's article on LinkedIn!

Note: I should point out here that what T-Mobile refers to as Small cells are actually RRU's and not complete base stations. You may want to refer to my tutorial here to understand this better. The bottom picture on this post will help too.

Some pictures of Small Cells from California (USA)

I came across them on various LinkedIn/Twitter posts

Two Small Cells on adjacent light poles in SF (signs used to somewhat shroud mRRU) - Source: Omar Masry

The comment mentions that One is Verizon. Other is likely ATT
I would argue that if this is an RRU (Remote Radio Unit) then its probably not a small cell but let's leave that one for another day.

Small Cell. Financial District. San Francisco - Source: Omar Masry

Comment mentions: Either T-Mobile or Verizon.  Likely done by Modus. Might be worth checking out this earlier post here too.

The next one is from Steve Blum's Blog of T-Mobile Small cell in Gage Canal, Riverside, California

The final one is from Santa Rosa, California. From a PressDemocrat article titled 'New Verizon antennas generate unwelcome buzz in Santa Rosa'

From the article (more pictures of this installation in the article):

A city-sanctioned bid to improve wireless connectivity for internet and cellphone users in Santa Rosa has run into opposition from some residents and generated concern among city officials after the first round of “small-cell” antennas went up on utility poles in recent weeks. 

The equipment — including large metal in-ground utility boxes about 5 feet tall — varies greatly in design from anything the city was previously shown by Verizon, the wireless provider installing the antennas, said Eric McHenry, director of Santa Rosa’s Information Technology Department. 

While the city had no role in the equipment design, Santa Rosa officials went through a significant amount of back-and-forth with representatives of the wireless carrier on what the units would look like on city-owned streetlights, McHenry said. Officials took pains to make sure the antennas would be as unobtrusive as possible, he said. 

“We frankly as a city were also surprised by what these first ones looked like,” he said, referring to the units Verizon is installing on utility poles. “They look nothing like what we had discussed with Verizon for our city streetlights or even the pictures that we shared with the council (of the installations) on wooden poles.”

Definitely a scope for improvement out there.

Related Article:

• Macrocells, Small Cells & Hetnets Tutorial

T-Mobile USA Small Cells - backhauled via dark fiber

Picture Source: Reddit

Picked this one up from Wireless Week (emphasis mine):

Speaking at the Wells Fargo 5G Forum this week, T-Mobile VP of Radio Network Technology and Strategy Karri Kuoppamaki said the Un-carrier carefully considered its options before settling on a small cell strategy that utilizes dark fiber for densification. Kuoppamaki explained T-Mobile works with a number of partners who provide the fiber, real estate, and manpower for the build outs while the Un-carrier supplies the equipment and facilitates municipal dialogs. The result is an overall cost structure that has been whittled down to a “manageable level,” he said. 

“We work together in deploying those small cells. This strategy has worked for us really, really well,” Kuoppamaki commented. “Ultimately small cell deployments, or successful small cell deployments, depend on the cost structure, especially the backhaul piece. If you can do that by partnering up with the right people, and bring that cost down a fraction of the cost of a macro then it makes sense.” 

According to Kuoppamaki, T-Mobile currently has about 15,000 small cells today, including 13,000 DAS nodes. The Un-carrier is on track to add “several thousand” more by the end of 2017, and has another 25,000 in the pipeline for the next few years, he added.

While fiber is a great strategy in the long run, especially for densification and 5G, it drives the initial cost up. Its not a great strategy for operators who may be more interested in deploying small cells for coverage mainly.

In earlier posts, I have argued for in-band backhauling (IBBH). A similar concept by the name of self-backhauling is used in 5G. In another post we also looked at Sprint MagicBox which uses similar approach to improve coverage and capacity. The main advantage of this approach is quicker deployment at a far lower cost. Backhaul can always be improved after initial deployments once coverage obligations are met.

Anyway, finally coming back to the T-Mobile small cells, here is a much more detailed picture from Omar Masry's slide-deck.