Wednesday 18 July 2018

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.
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:
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.

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