5G’s different bands, explained

If you read an article about 5G last month, chances are it mentioned C-band spectrum (and airplanes, and regulators, and frustrated telcos).

But C-band is just one type of mid-band spectrum, which itself is just one of three broad buckets of 5G, alongside low band and high band (often called mmWave). Each has its own benefits and drawbacks, and carriers pull from each to give consumers or businesses the 5G we all know today.

As 5G’s rollout chugs along, let’s break down the different bands.

Low band

On the low end of the 5G spectrum, this connection provides faster speeds than the 4G LTE standard of today, but not by much: 5G’s access to wider channels of spectrum means that there is less congestion than on legacy 4G networks—but speed limits still exist, even when you add lanes to the highway.

• Low band was the first iteration of 5G to roll out, and has been made widely available around the country since its launch in 2019.
• It can travel hundreds of square miles—further than mid- and high-band 5G—but it can’t transfer as high a volume of data at the speeds those bands can achieve.

Abdallah Khreishah, associate professor of electrical and computer engineering at the New Jersey Institute of Technology, told us that cellular networks use low-band, or low-frequency 5G because of its ability to penetrate through obstacles with minimal interference.

Today, low-band 5G is mostly built on the shoulders of existing 4G infrastructure, meaning it’s generally available wherever LTE is. But that availability also means it could become more congested as more 5G-enabled devices come online.

“The early stage of cellular networks utilized low frequency—the companies that started in the beginning, they reserved this part of the spectrum. That’s why they have good coverage,” Khreishah told us. “As time goes on, as more demand [rises], this part of the spectrum gets congested. Because of that, in 5G, [carriers] started to utilize higher frequencies and they have many techniques that will solve the issue of the weak coverage of the high-frequency bands.”

Mid-band

One of 5G’s biggest near-term obstacles is the ongoing saga involving the FCC, FAA, and major carriers like AT&T and Verizon over airport safety measures in the wake of C-band, a form of mid-band 5G.

C-band is often called the Goldilocks spectrum because it can achieve high speeds (albeit lower than high-band) and travel farther distances than high-band.

AT&T and Verizon had hoped to deploy C-band 5G in December, after spending a collective $70 billion to secure the spectrum, but the FAA voiced eleventh-hour concerns that the deployment could interfere with cockpit-safety systems. AT&T and Verizon agreed to delay turning on the spectrum not once, but twice.

• T-Mobile currently leads the pack in mid-band deployments (though most are not C-band) and spent nearly $10 billion in the FCC’s C-band auction.
• As of now, C-band 5G has been deployed broadly across the US, but AT&T and Verizon have created buffer zones around 50 select airports but are also reportedly pausing the rollout of additional towers.

In practice, mid-band will most likely be the type of 5G that consumers notice as a step up from 4G. It has faster speeds and capacity compared to low-band 5G and 4G LTE, but will be more widely available than high-band 5G, which will generally be deployed only in densely populated areas.

High band

Also called mmWave, the 5G band with the fastest speeds and lowest latency is seriously limited in its range. It can only travel over very short distances—like a city block—and even trees can disrupt those signals, according to a recent study from NIST.

Khreishah told us that mmWave can also be affected by adverse weather conditions and also by the direction in which the signal is transmitted.

That lack of range needs to be made up by building an abundance of connection points grouped closely together—an expensive task, given that, in some cases, a small tower and a 5G cell site could cost between $30k$50k. One workaround is to use lampposts to double as connection towers, something that cities like New York City are exploring. While this workaround might be practical for urban areas, less populated areas won’t have the same opportunity.

• Due to its challenges, mmWave deployments have lagged behind. As of April 2021, Verizon lead all US carriers in availability of mmWave 5G, but its users only had access to the high-speed connection 0.8% of the time.

Today, the major carriers have different approaches and viewpoints on mmWave. T-Mobile and AT&T see it more as a nice-to-have, while Verizon sees it as a must-have, doubling down on investments and marketing to promote it. In 2020 alone, it spent at least $1.6 billion on its mmWave network.

“It’s a business decision as to how these networks navigate their decisions as to where to deploy, and as a result of this, you will see most mmWave deployments will be happening in downtown areas,” Monisha Ghosh, professor of electrical engineering at the University of Notre Dame, told Emerging Tech Brew.