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I have traveled across the country this past year visiting several military bases. I have been testing various wireless technologies on airfields, in hangars and ammo dumps. These are some of the most under served and difficult locations to provide wireless connectivity services at any military base. I have been listening to, and learning from, the men and women who are the backbone to our military operations. Throughout these travels I have come to recognize a misunderstanding, even a distrust, our armed services have in Wi-Fi technologies. This distrust has caused many to look for new solutions like 5G. My goal in this article is to re-introduce Wi-Fi as the predominant network medium into the military large campus conversation.
There are many that have fallen under the belief that 5G has taken over as the preferred wireless connectivity and networking. Marketing around 5G is competing for your attention and your dollars in supporting your wireless networks, and for good reason. Wireless, be it LTE, Wi-Fi, satellite, or others, is the predominate way we communicate today. The need for this medium is continually growing especially as we look to include the Internet of Things (IoT). All the buzz and marketing around 5G seems to have overshadowed some other big news. Just as 5G is the next generation of LTE delivery, Wi-Fi 6E is the greatest advance to Wi-Fi in the last 20 years. I believe this advance will once again show the value of Wi-Fi for the military.
In April of 2020 the FCC adopted rules that made 1,200 megahertz of spectrum in the 6 GHz band (5.925–7.125 GHz) available for unlicensed use. Using the 802.11ax standards, the use of the spectrum for Wi-Fi has been designated Wi-Fi 6 Enhanced; Wi-Fi 6E. Today’s Wi-Fi is 560Mhz of available use between the 2.4 GHz and 5 GHz spectrums; 240Mhz if you exclude 5 GHz. DFS channels.
The primary benefit to Wi-Fi 6E is less congestion in having 59 new, non-overlapping channels as compared to 3 in the 2.4 GHz and 23 non-overlapping channels in 5 GHz. With more non-overlapping channels you will be able to provide better coverage without co-channel interference; something we struggle with today in 2.4 GHz and 5 GHz. This will be especially valuable in large maintenance hangars such as Hill Air Force Base in Utah.
There is also the capability to bond up to 8 channels together. Bonding channels allows for more throughput between the client and network. In today’s Wi-Fi, your power remains constant as you bond channels. Bonding channels inherently creates noise; 3 dBm per MHz. Bonding channels increases your Signal to Noise ratio (SNR). As the SNR increases (gets worse), the potential throughput goes down, consistent connection and reliability suffer. The introduction of Power Spectral Diversity (PSD) improves channel bonding by allowing for increase in power per channel. With 802.11ax and 6E, as you bond channels you are allowed to increase your signal 5 dBm/MHz. As you do this you maintain a consistent SNR allowing you to maintain a higher throughput as you bond channels together. This will improve overall reliability of bonded spectrum. For the military, this will make for faster and more reliable connections supporting large file transfers and real-time video communications across the military campus.
Another significant performance increase inside the Wi-Fi 6E standard is that it is no longer supporting 1997 connectivity. Up to and including Wi-Fi 6, the standard has still been supporting 802.11b using Direct Sequence Spread Spectrum (DSSS) modulation. Supporting this modulation adds a lot of overhead. In fact, Wi-Fi 6E no longer supports any client not capable of orthogonal frequency-division multiple access (OFDMA); this includes clients up to Wi-Fi 5 or 802.11n. By supporting only clients capable of OFMDA the 6 GHz standard will have a substantial performance increase.
With these improvements, we will see higher performance, lower latency, faster data rates across simultaneous connections. The Wireless Broadband Alliance reports trials with chip providers Broadcom and Intel that show connection latency of 2ms and throughput of 2Gbps.
I would be remised if I did not include a few sentences on Wi-Fi 7. Expected to hit the market in 2023, Wi-Fi 7 is improving on the Wi-Fi 6E standards. We will see continued improvements in latency, throughput, and spectrum use efficiency. Compatible with Wi-Fi 6E, Wi-Fi 7 is expected to double the channel bonding capability and provide up to 46gb throughput.
In fact, these two different technologies, 5G and Wi-Fi 6E, are resolving similar problems. With each of these technologies the lower latency and throughput are enabling uses in Healthcare, Digital Learning, Augmented Reality, Virtual Reality and supporting devices that make up the Internet of Things (IoT). That stated, there is a 5G New Radio Unlicensed (NR-U) standard being considered by the FCC. This radio is designed to operate in the 6 GHz bands share spectrum with Wi-Fi. As of this writing I do not believe any standard has been approved. While there are some in the industry that believe this function is imminent, there are significant technological hurdles to sharing spectrum between LTE and Wi-Fi. If smarter people than me can figure it out, this would be a further convergence of these two technologies.
The most impactful difference between these technologies is Wi-Fi 6E is unlicensed. Wi-Fi 6E gives industry 5x that of the currently available spectrum for unlicensed use. For comparison to emerging 5G sub-millimeter wave technologies, the closest unlicensed use is CBRS (3550 – 3700 Mhz) and that is shared spectrum with only 80Mhz available for general availability. There is some LTE co-channel use with Wi-Fi in the 5 GHz spectrum (5150-5925) known as Band 46. Although considered LTE-Unlicensed, this band is not intended for standalone LTE operations but rather as an offload solution for carriers. There are significant issues and interference when LTE-U and Wi-Fi share the same space. The proliferation of 5 GHz Wi-Fi makes the use of Band 46 very rare.
And while the technical aspects of wireless communications seem to be converging, another significant difference between the licensed and unlicensed space is how these networks are managed. 5G and LTE networks are typically managed by large mobile network operators (MNOs) such as Verizon, AT&T and T-Mobile in the United States. These carriers have licensed large quantities of spectrum from the US Government and recoup those costs through subscription fees for access to this licensed spectrum. With dedicated, low frequency, spectrum 5G will be used for connecting self-driving cars, smart city deployments, backhaul and, in some cases, large campus environments.
Wi-Fi uses unlicensed spectrum, 2.4 GHz, 5 GHz and now 6 GHz. Use requires no subscription and products are commercially available. Arguably, Wi-Fi has a lower cost of ownership with lower cost to deploy, maintain, and scale. There is huge flexibility in how to support a Wi-Fi network from local support on campus to contracting with smaller independent MNOs.
There are incumbents in the 6 GHz space. The FCC did not simply open the entire spectrum for use due to the desire to protect these other services already in place. The table below, provided by the FCC-20-51A1 Report and Order, shows the primary use of the 6 GHz band by licensed incumbents. To protect these incumbents the FCC have adopted a couple of rules for manufactures and MNOs.
The first major rule is any access point operating at Standard power, defined later in this document, will be required to receive channel availability from an Automated Frequency Coordination (AFC) service. This AFC is not much different than the Spectrum Allocation Service (SAS) employed by the unlicensed Citizen Band Radio Service (CBRS). Unlike CBRS, an AFC enabled access point will not require professional installation. It will instead rely on GPS information to be transmitted to the AFC provider for verification of location, height above ground and power. These services will gather geo-location information from the access point, compare it to a centralized data repository updated from the FCC Universal Licensing System (ULS) and determine if the requested power and channel are clear of incumbent’s registered frequency use. There will be a capability of providing geo-location information from a single source for many access points to support those cases where access points will not have GPS visibility. Outdoor access points will only be able to operate in UNII-5 and UNII-7 bands.
The second major rule defines RF power output limitations; Standard-Power vs. Low-Power access points. Low-Power is defined as no more than 30 dBm EIRP and can be used across the entire spectrum. This is the same EIRP as 2.4 GHz and 5 GHz UNII-1 and UNII-3; UNII-2 is slightly different. This is for indoor access points only. Unlike the standard powered outdoor units, these will NOT require AFC access nor geo-location capability.
Standard Power access points can be indoor or outdoor. However, they will need to provide geo-location information to the AFC and will only be used in the UNII-5 and UNII-7 bands as shown in the FCC supplied table above. This will affect the design and capabilities of some outdoor applications but overall will be a huge improvement over current outdoor deployment.
Expected differences in coverage will theoretically be worse than that of 2.4 GHz and 5 GHz due to the shorter wavelength of the 6 GHz frequency range. However, the difference between 5 GHz and 6 GHz frequency is relatively small: especially in the lower end of the 6 GHz range. The 5 GHz wavelength is measured at 5.8cm and the 6 GHz at 5.1. Relatively small difference considering a 2.4 GHz wavelength measures 12.5cm.
Given the wavelengths and frequency, the upper end of the range will see some additional loss. The need for an additional access point will depend on environment and use case. For instance, I used an online link calculator to approximate the received power for a client at 30 feet away from the access point with a typical wall in between. The difference between 5.72 GHz vs. 7.12 GHz is -2.8 dBm. Although slightly impactful it is not as different as 2.4 to 5.7 which is a full -10 dBm. Overall, for indoor use, 6 GHz will not be much different in a network designed for 5 GHz. Networks already properly designed for 5 GHz will need nominal changes to those designs. The areas of most impact will be those where a lot of walls and other attenuating architecture is present. More open areas such as cubical areas will be less impacted.
Something not many may clue in on will be the need for multi-gig switches. Wi-Fi 6E and Wi-Fi 7 will offer the ability to provide multi-gigabit access to the AP. However, the switch will also need to be capable of multi-gigabit to the port the AP is plugged into. Without improved switching the client will be bottle necked at the switch. Switch infrastructure must be considered as part of the re-engineering for 6 GHz.
When properly engineered, Wi-Fi 6E becomes a catalyst to improve wireless military communication campus wide with little capitalization as compared to deploying new private LTE. Through the adoption of 6 GHz spectrum, the military will have a pressure release for the currently over-burdened 2.4 GHz and 5 GHz Wi-Fi networks without fork-lift replacement of that network. Take, for instance, a large campus environment that currently cannot operate properly due to over saturation of 2.4 and 5 GHz Wi-Fi. There is the opportunity to strategically deploy new 6 GHz access points into those saturated areas. Clients will require new tri-band supported devices to access 6 GHz. Because it is Wi-Fi standards, the move between frequency bands is seamless. In fact, a client probing for a wireless network in a tri-band environment, will probe on the sub-6 GHz frequency then move to the 6 GHz. As clients move to the new spectrum, the currently overburdened spectrum becomes less burdened and start to work more efficiently which will save a lot of money. This route will require less money than a forklift upgrade in equipment and management of a private 5G network. This and engineering, is really what our military needs for improving their Wi-Fi LAN communications.
The question I was originally asked that sparked this article, surrounded the potential opportunity within the DoD for Wi-Fi 6E vs. 5G. There is over 2.6 billion tax-payer dollars being allocated by the DoD for 5G development. There is a huge need for this development to remain competitive in the global market, especially with China. But 5G is not the best solution for everything. With all the hype around 5G, the 6 GHz spectrum is seemingly being overshadowed as a viable solution to a lot of large campus needs, especially military bases. The 5G hype includes lower latency and throughput capabilities not ever seen in LTE. Well, for sub-millimeter unlicensed spectrum, the same is true with Wi-Fi 6E; arguably even better with Wi-Fi 7.
It is my opinion Wi-Fi will continue to be the predominant technology for home and Enterprise business environments. With Wi-Fi 6E being cheaper to deploy and operate while also improving existing Wi-Fi networks without a forklift upgrade, it is my opinion; Wi-Fi should remain the predominant technology for our military and base area network campuses. I encourage anyone with over saturated Wi-Fi to take a strong look at Wi-Fi 6E.
Per use case, there are many opportunities for 5G and Wi-Fi technologies to complement each other. Each use case should always be evaluated by a wireless professional and the best solution and technology applied. This article has been focused on military campus communications for Wi-Fi. ID Technologies is dedicated to offering the best wireless solution to your business use case be it mobile, large campus, non-classified, classified, private LTE or Wi-Fi networks. We are dedicated to evaluating emerging technologies and apply the best of class products to create a solution that fits your needs.
