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.
Wi-Fi 6E – Technical.
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.
Unlicensed vs. Licensed.
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.