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Spectrum Explosion to Fuel Fresh Wave of Wireless Innovation


Illustration of wave of sound in radio Wi-Fi transmission
Image: Chatchawan -
Regular readers of my posts will note that I am far more inclined to deflate rather than overinflate predictions for “the next big thing.” However, I do find the impact on the infrastructure front easier to predict — at least in big-picture terms — because major developments don’t come along too often. And what we’re seeing now in wireless is a fundamental shift, with the most significant increases in the availability of licensed and unlicensed radio spectrum we’ve ever seen. This new spectrum essentially removes the single biggest impediment to growth in the dynamic market for wireless services of all types.
In a series of moves over the past few years, the Federal Communications Commission (FCC) has added significant licensed spectrum in three bands: low (<1 GHz), mid (1 GHz to 6 GHz), and millimeter wave (>20 GHz). Now it has added significantly more spectrum, particularly in the mid bands. For unlicensed spectrum like we use in Wi-Fi networks, the FCC has more than doubled the available spectrum capacity.
In wireless, we’ve been increasing available capacity by developing marvelously complex techniques to encode more information on the radio spectrum that we had available. Those efforts have been phenomenally successful, but we have this thing called Shannon’s Law that essentially sets out the limits of how far we can push that efficiency.
What this new spectrum means is that what used to be a six-lane highway is now a 12-lane highway. The cars will be going just as fast, but we’ll be able to accommodate way more of them.
The two primary elements in the enterprise wireless market are cellular and Wi-Fi, and those two industries should benefit enormously from the new spectrum bonanza. However, with all of the new spectrum that is becoming available, the big hope is an overall wireless market expansion for all manner of services (broadband data, Internet of Things, video, etc.), with new entrants finally being able to challenge the incumbents in both the licensed and unlicensed spaces. This type of development can only be good news for enterprise buyers.
The Short Story of U.S. Radio Spectrum
Among other responsibilities, the FCC administers the radio spectrum in the U.S. Myriad public and private applications utilize this radio spectrum, from the Global Positioning System to land mobile radio systems (fire/police radios), to vehicle recovery systems (LoJack), but what interests us are those parts of the frequency spectrum used in enterprise communications: licensed cellular bands and unlicensed bands for Wi-Fi and other short-range applications (e.g., Bluetooth, garage door openers, cordless phones, etc.).
In 1983, the cellular telephone industry launched 1G Advanced Mobile Phone System service with a total of 66 MHz of radio spectrum (824 MHz to 890 MHz, later expanded). As a point of reference, that’s the equivalent of three Wi-Fi channels to cover a city. Even at prices like 50 cents/per minute for local calls, demand exploded. However, the initial price point essentially reserved mobile communications for businesses and the relatively wealthy.
Virtually from day one, carriers recognized they were going to have to increase capacity if they had any hope of meeting demand. The first major boost came in the early 1990s with the opening of the Personal Communications Service (PCS) spectrum, which added 120 MHz to the pot (1.850 GHz to 1.990 GHz, later expanded).
The advent of PCS was accompanied by the arrival of second-generation digital cellular technologies — time-division multiple access, the Global System for Mobile Communications, and code-division multiple access — that could pack more calls into the available spectrum capacity. The result was better quality, improved security, and, most importantly, a rapid drop in prices that expanded mobile communications squarely into the consumer market and led to an explosion in the number of cellular lines.
During the early 2000s, the cellular carriers scored big as the FCC reallocated large swaths of the sub 1-GHz broadcast TV bands, and raised billions of dollars auctioning the 700-MHz and, subsequently, 600-MHz bands. AT&T and Verizon took most of the 98 MHz of paired channels in the 700-MHz band; that includes the 20 MHz of public safety spectrum (Band 14) AT&T scored for the FirstNet network for emergency response. T-Mobile got most of the 70 MHz in the 600-MHz band. Together, those bands added about 170 MHz of licensed spectrum, almost doubling the spectrum available to the carriers.
Importantly, this sub 1-GHz spectrum boasts excellent coverage range for a macro network (i.e., it requires fewer towers) and provides good building penetration characteristics for better indoor coverage.
With most of the available lower frequencies spoken for, the carriers also have been focusing on licenses for millimeter-wave spectrum, the general reference for radio frequencies above 20 GHz (currently 24 GHz, 28 GHz, 37 GHz or 39 GHz). Those bands offer hundreds of megahertz of spectrum, but the physical properties of those signals limit transmission range and building penetration. As a result, assessing their value relative to lower-frequency bands that can extend to a range of kilometers rather than just meters is difficult. For now, millimeter wave is limited to densifying network coverage in high-use areas like stadiums, commercial buildings, and transportation hubs.
Wi-Fi started life in the 83.5 MHz of spectrum available in the 2.4-GHz band (2.40 GHz to 2.4835 GHz) for industrial, scientific, and medical purposes. This provided three available non-interfering 20-MHz Wi-Fi channels (yeah, we could have gotten four, but that’s another story). The big boost came in January 1997, when the FCC opened the 5-GHz Unlicensed National Information Infrastructure (U-NII) band, adding 20+ channels, though some required the use of dynamic frequency selection to avoid some incumbent application or other restrictions. The addition of those 5-GHz channels allowed carriers to combine bunches of basic 20-MHz channels to produce wider bandwidth (now up to 160 MHz) channels supporting much higher-speed networks.
New-Found Bounty
Using the carriers’ published spectrum usage and the 3GPP’s defined 5G frequency bands, I’ve worked out that the U.S. cellular industry has now pieced together about 1 GHz of low- and mid-band radio spectrum. This includes the 194 MHz of the 2.5-GHz Band 41 spectrum used exclusively by Sprint/T-Mobile, but not the local-only millimeter wave bands. The unlicensed bands include roughly half a gigahertz of spectrum, but things are about to change.
The big news on the licensed front comes in two waves, both in the mid-band: Citizens Broadband Radio Service (CBRS) and the "formerly satellite” C-band.
CBRS launched last year when the FCC opened up 150 MHz in the 3.7-GHz mid-band (3.55 GHz to 3.7 GHz) spectrum using a three-tier licensing plan designed to encourage new market entrants while protecting incumbent users. What makes the CBRS allocation plan work is an automated frequency coordination (AFC) program to sense and protect incumbent users. A company called Federated Wireless has stepped up with the first AFC implementation. Federated also touts its ability to be a turnkey provider of CBRS-based private LTE/5G networks.
As the CBRS market starts to open, the FCC is already moving on the 3.7-GHz C-band, formerly used for satellite and other services. In early 2020, the FCC made 280 MHz of the 3.7- to 4.2-GHz band available for 5G services. This change required moving incumbent users to a higher part of the frequency band.
The combination of the CBRS and C-bands will increase the sub 6-GHz licensed bands by about 40%. When you add that to the even larger swaths being opened in the various millimeter-wave bands, carriers can continue to expand their networks or they might pursue plans to offer private 5G networks for large enterprise customers… or, maybe a competitor pops up with a better plan to put that spectrum into use.
On the unlicensed side, the big news from April is that the FCC opened 1200 MHz of spectrum in the 6-GHz band (5.925 GHz to 7.125 GHz), the band immediately above the 5-GHz U-NII band. That allotment essentially doubles the amount of unlicensed spectrum available in the U.S., potentially making way for wider-area services or other more specialized markets.
As with CBRS, there is an AFC system to prevent interference with incumbent systems. The initial target for this spectrum is Wi-Fi, and the Wi-Fi Alliance has already introduced a new certification for Wi-Fi 6e, which is essentially the Wi-Fi 6 radio link standard operating in the new 6-GHz band.
Happy Days Are Here Again
For decades, engineers have been rolling out innovation on top of innovation to enhance the capabilities of our various wireless networks. Those technology enhancements allow us to pack more traffic into the available spectrum, but this new spectrum means we now have more lanes, roughly twice what we had previously, to carry that traffic. For existing wireless networks and service providers, this new spectrum bounty is the most welcome news, because it extends the useful life of those technologies.
There is no denying the allure of wireless, this magical ability to access all types of information and entertainment, conduct business, and do all the other myriad tasks that have now migrated to the wireless world wherever you are and not encumbered by wires. In short, you don’t have to sell people on the benefits of wireless. However, there have been few success stories in terms of new wireless services. Sure, we have loads of successful wireless applications, but precious few (if any) large-scale network services that have been able to identify a need, meet it, and stay in business. Anyone remember Metricom’s Ricochet? How about WiMAX?
Maybe I’m getting senile, but I think that businesspeople will be smarter about the wireless opportunity this time around, and won’t be as gullible or naïve as the wireless martyrs that have preceded them.
Make no mistake about it, building and operating a large-scale, wide-area communications network that runs on radios is no simple undertaking. The cellular carriers have mastered the discipline, but that infrastructure focus has essentially reproduced the “carrier attitude” that I found so demoralizing in my short time in the old Bell System.
The wireless industry could use a good dose of entrepreneurship, and that’s what I’m really looking for from this fundamental expansion in the wireless business. I fully expect some will make the classic wireless mistake of underestimating the degree of difficulty involved in doing anything with radios over a long distance, but there are lots of smart people in the wireless business who the entrepreneurial types can potentially link up with should they desire.
The one statement I can make with no fear of being contradicted: The wireless playground just got a lot bigger.

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This post is written on behalf of BCStrategies, an industry resource for enterprises, vendors, system integrators, and anyone interested in the growing business communications arena. A supplier of objective information on business communications, BCStrategies is supported by an alliance of leading communication industry advisors, analysts, and consultants who have worked in the various segments of the dynamic business communications market.