Excerpt From《ICT TODAY》of BICSI

Wi-Fi 6E for the 10Gb Era

A high-speed wireless highway for tomorrow’s fastest devices and services.

By Sundar Sankaran, Ph.D. of RUCKUS

Imagine taking a nice, fast car onto a wide-open highway with plenty of lanes and minimal traffic. For once, the ability to get to the destination, as fast as possible, is unencumbered by the other cars on the road. That is the experience of Wi-Fi 6E. It is like a private highway for the latest and greatest devices and services.

THE Wi-Fi EVOLUTION

Wi-Fi has come a long way since the late 1990s. The first and second generations of Wi-Fi (802.11b and 802.11a) were game changers when they were released; they unteth ered computers from the wired Ethernet connections that were a standard of the time. 

The third and fourth generations of Wi-Fi, also known as 802.11g and 802.11n, upped the ante with new features for the 2.4 GHz band, as well as faster speeds respectively. With more wireless devices in the 2000s, such as smart phones, tablets, set-tops, and gaming consoles, these gen erations ushered in the mainstream adoption of Wi-Fi. In fact, the uptick in traffic on the common 2.4 GHz Wi-Fi band already had consumers and their devices looking toward the faster and less congested 5 GHz band for reprieve.

In 2014, 5 GHz Wi-Fi got a big upgrade with Wi-Fi 5 (also known as 802.11ac). This fifth generation of Wi-Fi finally brought the 5 GHz band of Wi-Fi into the realm of gigabit speeds (Figure 1).

In 2019, Wi-Fi 6 (or 802.11ax) went even further by increasing general performance on both 2.4 GHz and 5 GHz bands. It also laid the groundwork for the next generation of Wi-Fi that would leverage the FCC’s release of new spectrum to compose a new 6 GHz band.

UNLICENSED 6 GHZ SPECTRUM

In April 2020, the FCC released a 1.2 GHz plot of unlicensed spectrum—from 5.925 GHz to 7.125 GHz—to serve as the basis for new wireless communications. 

This spectrum is significant for a number of reasons:

• It is the first addition to consumer wireless frequencies in 20 years. 

• It triples the amount of spectrum available for Wi-Fi, adding 1.2 GHz to the previous 

~600 MHz of available spectrum. 

• Because it is unlicensed, its use is not restricted to a single company or geography in the way that 5G is, for example. As a result, it is open to multiple uses by various users throughout the country. 

Furthermore, this additional spectrum would represent the effective doubling of lanes on the wireless highways. 

THE Wi-Fi 6E STANDARD

How does Wi-Fi 6E benefit from 6 GHz unlicensed spectrum? In short, it makes things, especially devices, much faster. The “E” in Wi-Fi 6E refers to “extended” spectrum and includes operation in the new 6 GHz band. This is not to be confused with current Wi-Fi 6 technology, which simply denotes the sixth generation of the Wi-Fi standard and operates over the usual 2.4 GHz and 5 GHz bands (Figure 2).

As the only Wi-Fi standard to use the new 6 GHz band, Wi-Fi 6E is in a unique position to deliver faster speeds, lower latency, and higher overall performance than previous generations of Wi-Fi. The reason is that these new lanes on the proverbial highway can only be used by Wi-Fi 6E devices, which will be the latest and fastest devices available.

An analogy to illustrate this scenario involves the highways in India. Today, on these highways, it is not unusual for drivers to encounter any number of obstacles, including the usual debilitating density of other drivers, foot traffic, bicycles, and narrow lanes. Much like today’s 5 GHz Wi-Fi bands, these highways are already full, and some, like the 2.4 GHz band, are overflowing. 

Additional challenges include dynamic frequency selection (DFS) and false detection issues on 5 GHz. These challenges can be thought of as the highway equivalent of drivers assuming that road construction crews will close off a lane, preemptively overburdening other lanes to avoid it, only to realize later that there was no road construction in the first place. This scenario gives a sense of how busy, fragile and overtaxed the current Wi-Fi situation really is.

With Wi-Fi 6E, it is similar to adding brand new lanes, but it is much more like adding a completely separate parallel highway where the road surface is smooth, the lanes are wide, and the only things allowed are the fastest, most efficient, and intelligent cars that do not get in the way of one another. Greater spaces between cars afford a greater margin of safety or reliability, and the wider lanes make room for larger vehicles to carry more things and deliver them more efficiently.

It is a completely different world that allows Wi-Fi to be used in a way it has never been used before.

As the only Wi-Fi standard to use the new 6 GHz band, Wi-Fi 6E is in a unique position to deliver faster speeds, lower latency, and higher overall performance than previous generations of Wi-Fi.

THE UNIQUE ADVANTAGES OF Wi-Fi 6E

Distinct advantages of Wi-Fi 6E over previous generations of Wi-Fi include:

Faster Real-World Speeds 

Wi-Fi 6E does not deliver faster max physical layer (PHY) rates than Wi-Fi 6, but it does achieve faster real-world transfer rates because these are dependent on factors thatit facilitates, such as wireless signal strength, associated device capabilities, and traffic from legacy devices. For 

example, while 802.11b devices will work on an 802.11ax connection, they will not be able to fully realize the faster speeds associated with the new standard. Meanwhile, all Wi-Fi 6E devices will be fast.

Deterministic Operation 

Orthogonal frequency-division multiple access (OFDMA) was introduced into the Wi-Fi standard via Wi-Fi 6. It is a new way of handling traffic between a wireless access point (WAP) and various client devices, such as cellphones, tablets, and laptops. If one thinks of the relationship between WAPs and client devices as a package delivery service, the old way of modulating traffic might look something like a fleet of cars traveling to and from the shipping center and various receivers, 

delivering one package at a time.

By comparison, OFDMA is a semitruck carrying boxes destined for multiple receivers in a single trip. It is more efficient, reduces the overall shipping time (or latency), and reduces traffic on the roads. The wider lanes on the 6 GHz highway enable more semis to deliver more packages.

The ability to improve package delivery service enables much higher levels of quality of service (QoS) for these connections that, in turn, can be leaned on to fulfill specific service level agreements (SLAs) to support time-sensitive and high-bandwidth applications, such as gaming and telemedicine.

Latency 

In addition to OFDMA, minimal congestion on the 6 GHz highway also allows Wi-Fi 6E to bring packet latency down to around 2 ms—much less than the blink of an eye and much more in line with competing technologies. This low latency enables a host of real-time applications over the convenience of a wireless connection. 

Dedicated Channels 

Specifically, Wi-Fi 6E addresses an increasingly relevant shortcoming of previous Wi-Fi generations, which is their inability to keep up with the demands of multiple devices vying for the same wireless bands. Wi-Fi 6E opens up seven discrete 160 MHz channels (or fourteen 80 MHz channels) for transmission.

To put this in perspective, today’s 2.4 GHz and 5 GHz bands deliver a total of 49 discrete channels, while 6 GHz offers 109. Thus, the addition of the 6 GHz band more than triples the number of Wi-Fi channels available—as it goes from 49 channels to 158. These additional channels will not only help to lower congestion by keeping less demanding devices on more common channels, but will also allow faster traffic to fly through dedicated high-speed lanes.

Additionally, the new Wi-Fi 6E standard allows the same power spectral density across all channel bandwidth, thereby reducing the penalty for accessing larger channels. This, in conjunction with less congestion due to more spectrum and lack of legacy devices, will enable the latest devices to make use of larger bandwidths.

A Wi-Fi network, due in large part to its attendant frequencies and equipment, has a comparatively much shorter range than cellular networks using commercial towers to transmit radio signals.

LEAD APPLICATIONS

The advantages of speed, latency, and reliability make Wi-Fi 6E purpose-built for a number of demanding applications:

Wire Replacement

Ever since Wi-Fi took the place of a wired Ethernet connection, it has struggled to deliver comparable performance. If the connection is to work and work well, a cable has always been a simple solution. However, Wi-Fi 6E narrows the gap so closely that the differences between wired and wireless are almost negligible. It makes Wi-Fi 6E a particularly good candidate for applications in which running wires through existing structures can be both costly and inconvenient.

6 GHz Backhaul 

Most internet service providers install modems at the edge of the home where cable or optical fiber enters the house, but this is not the best place for a router to deliver Wi-Fi to the entire home. Oftentimes, either operators or consumers will install two or more WAPs in order to achieve consistent speeds throughout the domicile. These WAPs need to communicate with one another, especially in a mesh system, in order to relay data to and from devices and the operator’s network. The connection between WAPs in this system is called a backhaul, and the faster it is, the faster devices will connect through this chain to the internet.

Dedicated Services 

Some of the biggest winners from the developments in Wi-Fi 6E will be applications, such as virtual reality (VR), augmented reality (AR), telemedicine, and tele-education. Each of these is incredibly bandwidth intensive and requires extremely low latency. The Wi-Fi 6E’s ability to control congestion and boost the physical layer’s throughput makes it particularly well-suited for enabling the growth and mainstream adoption of these applications and others like them. 

General Improvements in Existing Experiences

A rising tide of new spectrum lifts all connected experiences. As 6 GHz channels are carved out for specific devices or applications, such as set-tops, tablets, and streaming 8K video, they will arrive without the buffering, latency, time outs, adaptive bit rate (ABR) image quality adjustments, and many other compromises associated with today’s Wi-Fi.

Enterprises and Venues

With a renewed capacity to handle high-traffic scenarios in highly dense environments, such as large corporate campuses, public hotspots, multi-dwelling units (MDUs), concert halls and stadiums, Wi-Fi 6E can be an important complement to 5G networks. In fact, the divergence 

in design objectives between Wi-Fi and 5G allows these otherwise competing and overlapping technologies to play off of one another’s strengths in multi-modal wireless deployments (Figure 3).

FIGURE 3: Himachal Pradesh Cricket Association Stadium in Dharamsala, India. Bottom photo shows the Dharamsala Cricket Stadium’s dense wireless access point deployment. The Dalai Lama actually lives nearby.

CELLULAR VERSUS Wi-Fi

There is a big debate about whether Wi-Fi 6E will eventually win out over 5G. Whereas 5G offers incredible mobility, low latencies, and deterministic performance, Wi-Fi 6E provides more consistent and deterministic performance with comparatively low latency, cost, and complexity.

A reasonable and measured conclusion is that they will both coexist and complement each other’s strengths and shortcomings. The more important question is how?

Most consumers are agnostic when it comes to wireless networks; they care only that they work when they need them to work. Enterprises deploying these technologies, however, require a better understanding of how they compare and potentially interoperate. As such, it is important to compare the historical tenets of cellular and Wi-Fi networks:

Licensed Versus Unlicensed Networks

One of the primary differences between cellular networks, like 5G, and Wi-Fi is that cellular networks are licensed. Using licensed radio spectrum allows cellular networks to be implicitly more controllable. For example, companies that deploy cellular networks must pay for the 

exclusive right to broadcast data over those frequencies. Furthermore, in order to use those networks, clients must use SIM cards that confirm that the user has permission to gain access to a given network.

On the other hand, Wi-Fi networks run on unlicensed spectrum. On these networks, anyone can develop and deploy devices that run on supported frequencies. Traditionally, these have included the two bands discussed earlier: 2.4 GHz and 5 GHz. This also allows for a certain universality in access. For example, a Wi-Fi device can be used on a Wi-Fi network anywhere in the world, whereas cellular networks require validation (through an associated SIM) to attach to each network.

These very different uses of spectrum create commensurately unique approaches to the security and development of associated devices, as well as the inherent capabilities of those networks. For example, a Wi-Fi network, due in large part to its attendant frequencies and equipment, has a comparatively much shorter range than cellular networks using commercial towers to transmit radio signals. These fundamental differences in design have historically created a divergence in the applications of these technologies; Wi-Fi is normally used indoors, whereas cellular is normally used outdoors.

However, there are many other considerations involved in comparing these two general approaches to wireless connectivity:

• Cost: Because the licensing of cellular technologies makes cellular infrastructure more expensive for clients, Wi-Fi has a distinct advantage in terms of deployment costs. Also, Wi-Fi typically avoids the subscriber costs associated with paying a network operator to use its infrastructure and licensed spectrum.

• Ubiquity: Wi-Fi is everywhere. With its backwards compatibility, its evolving infrastructure ensures that investments in legacy devices are protected. This contrasts with cellular chipsets, which usually support only the latest generations of devices. The result is that there are billions more Wi-Fi devices in operation than cellular devices.

• Ease of Deployment: The two technologies’ divergent allegiances to licensed and unlicensed spectrum mean very different levels of speed and complexity in deployment. Wi-Fi can be set up in minutes by most consumers, whereas cellular still requires skilled administration. 

• Coverage and Mobility: Because of the aforementioned differences in design objectives between cellular and Wi-Fi, cellular has evolved to deliver wider outdoor coverage that can handle highly mobile devices. Wi-Fi thrives indoors but is most effective for short-range connectivity.

• Cadence of Innovation: Historically, Wi-Fi has evolved faster than cellular via a technology refresh cycle every five years versus cellular’s 10-year cadence. As bandwidth use continues to grow and as demanding new applications take hold, these innovation cycles will dictate the ability of each technology to cater to evolving global demands.

In addition to the traditional tradeoffs of cellular versus Wi-Fi, the evolution to 5G and Wi-Fi 6E has introduced new features and capabilities that further blur the lines between the two technologies.

Wi-Fi 6E AND 5G

In addition to the traditional tradeoffs of cellular versus Wi-Fi, the evolution to 5G and Wi-Fi 6E has introduced new features and capabilities that further blur the lines between the two technologies. In fact, as cellular and Wi-Fi have evolved, they have also begun to converge and share innovation. Some examples include OFDMA, multi-user MIMO (MU-MIMO), and beamforming, which are used across modern forms of both networks to manage growing data and device traffic and to improve transmission rates.

The FCC’s release of 6 GHz unlicensed spectrum, in addition to boosting the capabilities of Wi-Fi, also provides a new outlet for 5G to offload traffic. Even though cellular networks traditionally run on licensed spectrum, they can also use unlicensed spectrum to supplement bandwidth and coverage.

When Wi-Fi 6E and 5G are compared, there are some very obvious similarities and advantages to each approach:

• Speed: Wi-Fi 6E supports a peak data rate of 9.6 Gb/s, which is comparable to 5G, but Wi-Fi 6E also achieves a spectral efficiency of 62.5 bps/Hz, more than double that of 5G’s specified 30 bps/Hz. 

• Delivery: Both standards are capable of supporting the latest and most demanding AR, VR, and IoT applications (e.g., telemedicine) through high-speed data rates and extremely low latency. Both also support new protocols to extend the battery life of associated client devices. 

• Density: This is one area where Wi-Fi unequivocally comes out on top. Wi-Fi 6E works very well for extremely dense environments, such as stadiums, campuses, and large venues. A single Wi-Fi 6E WAP, for example, can serve up to 1,024 clients concurrently. Its trigger frame feature, which is related to OFDMA, enables scheduled access and results in improved transmission, bringing its reliability in line with 5G’s.

• Security: Today, Wi-Fi roaming and cellular roaming are relatively seamless, and the latest Wi-Fi security updates have made it as secure as cellular. These protocols allow for individualized encryption that potentially protects users from hackers.

Although consumer devices, such as cellphones and tablets, have evolved to include both cellular and Wi-Fi radios, enterprises considering how and when to implement one or both technologies should rely on a detailed assessment and plan. They should also work hand-inhand with vendors who understand both technologies and how they compare and complement one another.

PoE, CAT 6A, AND Wi-Fi 6E

Power over ethernet (PoE) is the preferred technology for delivering power to newer edge devices and WAPs. The latest 802.3bt PoE standard (also known as 4-Pair PoE or simply 4PPoE) stipulates support for a full 90 watts at the power source equipment (PSE), which is deliverable via Cat 6A cabling. Although older WAPs tend to draw a minimal amount of power, Wi-Fi 6E WAPs will likely require more power to drive all their radios and provide power for devices connected via their USB ports. As such, IT departments upgrading older WAPs to Wi-Fi 6E WAPs will also deploy Cat 6A cabling, which supports transfer rates of up to 10 Gb/s to prevent network bottlenecks and fully support new PoE demands.

Mission-critical use cases that involve the use of Wi-Fi 6E WAPs and connected edge devices will also demand the use of PoE to reduce faultfinding time, especially in far-flung locations. With a non-PoE system, a power failure event requires the on-premise attention of an electrician to investigate the root cause of the outage. With a PoE-fed Wi-Fi 6E WAP, power and data are combined and centralized at the network switch in an equipment room with dedicated power circuits, thus simplifying and automating the faultfinding process. This reduces the time it takes to track down and repair outages, significantly improving the mean time to recovery (MTTR).

THE Wi-Fi 6E OPPORTUNITY

The combined advantage of Wi-Fi 6E’s new performance characteristics and the technology’s favorable deployment and management costs make it a very competitive choice for indoor and enterprise applications. Its ability to leverage 6 GHz spectrum will create further improvements to latency and reliability for dedicated services and applications, as those are further carved out in the coming years.

The bottom line is that the future of Wi-Fi is promising—both as the evolution of an incredibly successful wireless networking standard as well as a complement to cellular technologies like 5G. Wi-Fi 6E is made for the 10 Gb era. It is an opportunity for operators and enterprises to usher in a new age of exciting new wireless experiences within the home and beyond.