Radio frequency 101

The topic of spectrum — the radio frequencies that are used to transmit and receive signals that form the heart of modern wireless networks — is a crucial part of the 5G story. The two main types of spectrum are referred to as licensed (meaning it can only be used by the company that owns the license to those frequencies) and unlicensed (such as the 2.4 and 5 GHz frequencies used for WiFi, which any company can use).

Control over the spectrum and who can use what frequencies is so critical that it is regulated by government agencies around the globe. In order to avoid complete wireless chaos, government organizations (such as the Federal Communications Commission, or FCC, in the case of the US) essentially take ownership of the entire radio frequency spectrum and then split wireless frequencies into different chunks. Bidders recently spent a record-shattering $81 billion to charter critical frequencies in a part of the spectrum called the mid-band in an auction by the FCC offering 280 megahertz.

Many important new capabilities and services that are at the heart of 5G are based around spectrum. For example, the phrases millimeter wave (often shortened to mmWave, also known as high-band) and sub-6 (also known as low-band) are commonly used when talking of 5G. Both of those names are based on the frequency bands they use within the overall radio spectrum. In order for devices to properly communicate on those frequencies, a radio access standard called 5G NR (short for New Radio) was developed.

Millimeter wave signals can’t travel far, but they’re very dense, making them well suited to carry a lot of data very quickly. That means the very fast data transfer speeds you may have heard associated with 5G networks and devices are all done using phones and network equipment that support millimeter wave.

In the case of sub-6, the name refers to radio frequencies that are below 6 GHz, hence sub, or less than, 6. Sub-6 spectrum waveforms can travel farther, but they’re less dense. That means coverage with sub-6 spectrum is much broader from a given cell tower than millimeter wave, but the data transfer speeds are much slower.

Mid-band spectrum offers an attractive compromise between the two — sending data at broadband speeds to users a few miles away from a tower. This Goldilocks position within the spectrum is what has everyone clamoring for frequencies in the mid-band range. It can carry much further than mmWave and has far more capacity and higher speeds than low-band spectrum.

Aggregating low-band with mid-band spectrum improves the coverage of mid-band spectrum since the uplink/upload is the weakest link in a connection — if you can offload the uplink to low-band you can improve higher band coverage. Eventually, carriers will need mmWave (high-band) to alleviate congestion in dense areas like stadiums, plazas and other places where people are packed in tightly. Additionally, mmWave could help deliver affordable gigabit broadband to the home or small business via fixed broadband.

The amount of capacity and bandwidth that mmWave affords will be paradigm shifting for entertainment. With concerts by and large on hold, now is a good time for venue owners to upgrade their infrastructure to 5G mmWave if they can afford it. An upgrade will do much to prepare venues for the return of concert goers, while enabling new revenue opportunities that require mmWave’s reliable low-latency, high-bandwidth connectivity.

Mid-band frequencies are what’s going to unlock much of 5G’s promise. That signal range will provide users with a far better online experience than 4G afforded and create a sizable and solid foundation for the machine-to-machine communications at the heart of the Internet of Things. The mid-band’s combination of speed, coverage and low latency — the time delay between sending and receiving data — will do incredible things. Companies will use it to improve supply chains, autonomous driving and virtual reality for a much bigger population swath than millimeter-wave will reach.

5G will be the most capable generation of cellular connectivity ever deployed, once fully operational. It will supply download speeds up to 100 times faster than its predecessor, reach into areas that lack service and provide other significant benefits. 5G is able to accomplish all this because it uses a broader range of the radio spectrum than previous generations of cellular networks. A complete 5G network hence needs to be standalone, implementing low, mid, and high-band spectrum together as one.