We will be hearing a lot about extending 4G LTE into new spectrum bands in the coming year even as 5G trials and pre-standard commercial deployments get underway in 2018.
Repurposing the 600 MHz band.
In August 2016, T-Mobile US lit up the first base stations using its newly acquired 600 MHz spectrum become the first mobile operator worldwide to activate commercial LTE service using this frequency band. A second 600 MHz location was activated in Scarborough, Maine about 2 weeks later and T-Mobile now says it is on track to light up 600 MHz cell sites in rural locations across the United States over the coming months.
T-Mobile’s 600 MHz rollout is interesting on a couple of fronts. First, the pace of the rollout is impressive. The first activation, which occurred in Cheyenne, Wyoming, came only two months after T-Mobile received its spectrum licenses from the FCC. Most of the spectrum licenses were previously held by broadcasters, such as public TV stations, or educational or religious entities which in the days before the commercial Internet really took off had once imagined a future where they would be broadcasting TV directly consumers in their local market. In rural areas, at least, it is proving easier to clear the spectrum for T-Mobile.
Second, T-Mobile now has plenty of 600 MHz licenses, which it acquired in the FCC’ Broadcast Incentive Auction in April for $7.99 billion, covering all of the U.S. and Puerto Rico. T-Mobile acquired 31 MHz of spectrum nationwide on average, quadrupling its low-band holdings, for a total of $7.99 billion. With the purchase, T-Mobile claims to hold more low-band spectrum per customer than any other major provider, and nearly 3x the low-band spectrum per customer held by Verizon, which did not bid in the auction to the surprise of many observers. Other companies picking up 600 MHz spectrum in that auction were Parker B Wireless (Dish Network) $6.2 billion; CC Wireless Investment (Comcast) $1.7 billion; AT&T $902 million; Channel 51 $859 million; Bluewater Wireless $568 million; US Cellular 329 million; NewLevel $296 million; Tsar 600 $131 million; and Omega Wireless $99.7 million. There was a handful of other local or regional auction winner, implying that some deal-making is likely.
Third, 600 MHz will provide great building penetration and range. It also will be instrumental to T-Mobile’s 5G strategy. In addition to the 600 MHz bands, T-Mobile has 200 MHz of spectrum in the 28/39 GHz bands covering nearly 100 million people in major metros. The company says both resources will be used for 5G. In various company blog posts, T-Mobile argues that 5G should not be equated only with high-band, or millimeter wave, spectrum, even though these bands support massive throughput capacity. The limited range of the 28/39 GHz bands means that vast numbers of small cells will be required for ubiquitous coverage which will be a major capital expenditure.
Fourth, LV’s V30 announced at the end of August is the first smartphone to support 600 MHz LTE. Qualcomm has said that its Snapdragon X20 and X16 modems support 600 MHz. We don’t know yet whether the upcoming iPhones will support 600 MHz – it could be a game changer either way. If yes, it could be a home run for T-Mobile. If no, it could be a big strike-out.
GSA (the Global mobile Suppliers Association) recently reported that Argentina, Canada, Mexico and New Zealand are considering re-purposing and re-licensing 600 MHz spectrum in a similar fashion.
Refarming 450 MHz (Band 31)
Another area of activity around the world is 450 MHz, otherwise known as Band 31, which was widely used for CDMA networks. GSA tracks over 100 CDMA networks worldwide that relied on Band 31 for wide area reach and in-building penetration. The first carriers began deactivating CDMA 450 in 2014. Currently, GSA counts ten networks that have re-farmed this spectrum to extend their LTE coverage.
• Ukko Mobile, Aland Islands (Baltic Sea)
• Vimplecom (Beeline), Armenia
• Net1, Denmark
• Ukko, Finland
• MVM, Hungary
• Net1, Indonesia
• Ice.net, Norway
• Broadband Everywhere, Philippines
• Tele2 (Skylink), Russia
• Net1, Sweden
3.5 GHz Mid-band spectrum for 5G
Lots of activity around 5G in the “mid-bands” of 3.5 GHz spectrum is underway in carrier test labs and with regulators, including the FCC. In April 2015, the U.S. Federal Communications Commission (FCC) adopted rules for CBRS, which opens 150 MHz of spectrum (3550-3700 MHz) for commercial use — while providing necessary protection of incumbent users of the band. Spectrum access is actively coordinated based on priority and granular location, making previously allocated spectrum available to new entrants and services. In 2016, the Citizens Broadband Radio Service (CBRS) Alliance was formed with the goal of making LTE-based solutions in the 3.5 GHz CBRS band widely available, Big name players are backing this initiative, including AT&T, American Tower, CableLabs, Intel, Nokia, ZTE, and others.
Another big milestone for 3.5 GHz spectrum came in late August, when Verizon, Ericsson, Qualcomm, and Federated Wireless demonstrated LTE Advanced carrier aggregation using CBRS band 48 spectrum. The demo, which was conducted in an Ericsson lab in Plano, Texas included the end-to-end CBRS communication flow, using 2x20 MHz LTE carriers on the CBRS band 48, and employing a 256 QAM modulation in the downlink. Ericsson provided the band 48 Radio Dot System and Domain Proxy for communication with Federated SAS. Qualcomm Technologies provided a Qualcomm Snapdragon LTE modem test device, and Federated Wireless provided the spectrum management service with their Spectrum Controller.
A month earlier, in July 2017, ZTE and China Unicom announced a field test in Shenzhen that achieved data rates of up to 2 Gbit/s using the 3.5 GHz frequency band with a 100 MHz bandwidth. This test was conducted by ZTE working with the Guangdong branch of China Unicom and the operator's network construction department and the China Unicom Network Technology Research Institute. The field test was designed to verify the 5G technical performance and product commercial capabilities in a live network environment and builds on the established partnership for 5G network development between China Unicom and ZTE.
Licensed Assisted Access (LAA) looks ready to go
After several years of incubation, Licensed Assisted Access (LAA) appears to be on the cusp of commercial rollout. The magic with LAA is that it enables operators to use unlicensed spectrum in combination with licensed bands. It co-exists with Wi-Fi and other unlicensed spectrum technologies using 'listen before talk', which promises fair coexistence, Multiple carriers are the world are now trialling LTE-LAA or beginning commercial rollouts, boasting of downlink speeds nearing the gigabit mark. In June, AT&T and Ericsson conducted a live LTE-LAA technology field trial, during which initial wireless data rates of more than 650 Mbps were achieved in downtown San Francisco. Also in June, T-Mobile completed the nation’s first mobile broadband data session live in the field using License Assisted Access (LAA) on its commercial network. Italian operator TIM has achieved speeds of nearly 1Gbps on its live advanced 4G network in Milan using Ericsson’s LAA technology. In addition, Ericsson, Verizon and Qualcomm have reported downlink performance of 953 Mbps in a joint commercial network deployment in Boca Raton, Florida.