Wi-Fi 6 Technical Benefits for Early Adopters

Today I'm going to discuss Wi-Fi 6 and the underlying technology that is different in Wi-Fi 6.

Wi-Fi 6 is the current name for 802.11ax. The Wi-Fi Alliance is not expected to ratified the current Wi-Fi 6 standard until the end of 2020. The Wi-Fi Alliance went back through and renamed all of the 802.11 standards such as 802.11 and 802.11b and 802.11a and 802.11g, 802.11n and named them Wi-Fi 1, 2, 3, 4, 5 and 6. You could also see Wi-Fi 6 referred to as high efficiency wireless or HEW.

The modern workplace

The evolution of the modern workplace now has open floor plans. Our modern office is an all-wireless office and we use wireless collaboration tools through voice and video and streaming apps. There is an exponential growth in wireless traffic through mobile devices, Internet of Thing (IoT) devices, smart devices and how people work has changed. Wireless is typically the primary network within an office. Wi-Fi 6 is designed to solve the problem of more devices, more simultaneous users, more applications, more bandwidth hungry apps and devices that need longer battery life.

Designing for capacity, not coverage

Given that the design of the modern office has changed substantially, that means that we have to rethink our current wireless deployment design. We have to plan for higher density AP placements, because you need to be closer to the access point to get the higher speeds in Wi-Fi 6. If the client device isn't close to the Wi-Fi 6 Access Point (AP), your Wi-Fi session will downshift to lower connectivity speeds. 

Fundamentally, we changing our wireless designs to support capacity not just coverage. In previous days, we designed strictly for coverage models where APs were put wherever they were most likely to be used; like conference rooms, lunchrooms, break rooms or wherever people gathered.

When designing for capacity, ultimately more access points will be deployed. The goal is give every end user device an optimal experience — fast connectivity and supporting many more concurrent users than ever before.

Channel bonding and spectrum

It may seem that there are plenty of non-overlapping channels available in the 5GHz spectrum, and bonding channels together to make 40, 80 or 160 MHz wide channels, is ideal, but that's not considered "best practices" and here is why. In the 5GHz spectrum, if bond channels together, and create 160 MHz wide channels, you've created a Wi-Fi network where there are only 2 non-overlapping channels to choose from. The best practice is still to set the channel widths to 20 MHz, and let the algorithm within your wireless vendors' hardware determine when it is possible to bond channels. The channel bonding decisions being based upon what client devices are currently present in the RF environment and what channel widths those client devices can support.

New spectrum

On the radar for the Americas, there will be some channels that will be added in the 6 GHz spectrum, but that's kind of outside the scope of the conversation for today, but just be aware that it's coming.

Capacity over coverage

Your current Wi-Fi deployment is probably not designed for capacity. It's probably not designed for mission critical applications, it's probably a dated standard like 802.11n.  It may be difficult to operate, you may have weak security configured, you may have legacy networks.

Wi-Fi 6 enhancements

Let's talk a little bit about Wi-Fi 6 enhancements we can expect. The enhancements in Wi-Fi 6 are uplink and downlink Orthogonal Frequency Division Multiple Access, also known as OFDMA. OFDMA increases network efficiency and lowers latency for high demand environments.

Multi-User Multiple Input Multiple Output also known as MU-MIMO allows more data to be transferred at once and enables an access point to transmit to a larger number of concurrent clients at once.

Parallel processing enables greater capacity by allowing MU-MIMO and OFDMA to function in parallel and then adding in improved channel reuse with BSS coloring.

Increases in throughput for Wi-Fi devices is achieved by encoding more data in the same amount of spectrum. This is called 1024 Quadrature Amplitude Modulation mode, also known as 1024 QAM.

Target Wait Time (TWT) significantly improves battery life of Wi-Fi devices such as Internet of Things (IoT) devices.

Wi-Fi 6 speeds improve

What determines Wi-Fi speed? The improvements in encoding (1024 QAM) is the process by which more bits of data are added to the constellation points. To describe it another way, more data is crammed into the same spectrum by improving the patterns by which the data is transmitted.

Spatial multiplexing allows for parallel transmit and receive; being able to send and receive data at the same time. It is a transmission technique used in MIMO wireless communication to transmit independent and separately coded data signals (streams) from each of the multiple transmit antennas in a Wi-Fi 6 Access Point.

MU-MIMO means more simultaneous transmissions are possible. MU-MIMO decreases the time each device has to wait for a signal and dramatically speeds up your network. Beamforming is where we can add reflected signals to increase the receive signal strength at the end client device. Beamforming improves data rates and extends range by directing signals toward specific clients instead of in every direction at once.

OFDM compared to OFDMA

OFDM (Orthogonal Frequency Division Multiplexing) is divided into larger sub carriers, but only one user can ride the frame at a time over the air. The biggest difference between an OFDM and an OFDMA (Orthogonal Frequency Division Multiple Access) system, is in the OFDM network, the users are allocated on the time domain only; contrast with users an OFDMA system — the users would be allocated by both time and frequency.

OFDMA increases network efficiency and lowers latency for high demand environments. OFDMA can assign individual users to each resource unit, which means multiple users can have a frame in the air at the same time. Each sub carrier is a transport mechanism, and latency goes up when sub carriers go out half empty. OFDMA solves this by allowing multiuser packets to go out on one sub carrier. All packets big and small get processed much faster. OFDMA uses sub carriers more efficiently, maximizing client count and lowering latency.

Each user gets one time slot with OFDMA. If there is unused bandwidth, the next user still has to wait until the air is free. With OFDMA, data from multiple users can be transmitted at the same time the sub carriers don't go out half empty.

Voice capacity

802.11ax / Wi-Fi 6 provides higher voice and video capacity with lower latency and increased density. Wi-Fi 6 can achieve up to 3 times voice capacity over 802.11ac in high density deployments.

MU-MIMO compared to SU-MIMO

For SU-MIMO (Single User MIMO) one frame can be in the air, to any one client at a time. With Multi-User MIMO (MU-MIMO), the access point can send up to 3 spatial streams at the same time, so data could be directed to 3 different client devices at the exact same time.

Multi-User MIMO has been introduced in 802.11ac Wave 2 (Wi-Fi 5), but in MU-MIMO, clients are able to benefit in the downstream link for higher aggregate throughput by essentially tuning out portions of the RF to better decode their traffic, reducing interference. Wi-Fi 6 offers enhancements to the Multi-User MIMO capabilities present in 802.11ac. The ability to support simultaneous data streams to up to 8 end client devices, each MU-MIMO transmission could have its own MCS rate, and Multi-User and Single-User MIMO is decided by the AP, with Multi-User MIMO favoring larger packets. 

BSS coloring

BSS coloring allows Wi-Fi 6 stations to quickly identify whether the channel is occupied by a device of the same BSS (the same color), an intra-BSS packet, or one from another BSS (a different color) or an inter-BSS packet. The color in BSS coloring is actually an index number from 1 to 63 that is assigned either manually, or coordinated through Radio Resource Management (RRM) to individual access points along with the channel assignment. Access points sharing the same channel, in the same vicinity should have different colors. If two BSSs operating on the same channel, have the same color, this is a color overlap. In the event of a color overlap, the detecting station sends a color collision report to the alerted connected access point. The access point can now announce a BSS color change at any time to through BSS color change announcement element sent in each beacon and probe or frame response.

Internet of Things (IoT) Wi-Fi 6 enhancements

More IoT devices are coming on line every day, so there's a strong need for the 2.4GHz spectrum. With Wi-Fi 6 we're seeing superior battery life for IoT and mobile devices by leveraging the Target Wait Time (TWT) feature. We're seeing parallel processing for spectrum efficiency by leveraging Multiple-User MIMO, small packet aggregation using OFDMA for reduced latency, longer guard intervals for greater range in outdoor links, BSS coloring helps increase channel reuse and better spectrum coexistence with other technologies like Bluetooth and Zigbee. 2.4GHz is no longer a "junk band," it just simply needs to work in order to support IoT devices. Some of the Target Wait Time (TWT) benefits for IoT devices are better battery life and coexistence via RF efficiency improvements. Thanks to 2MHz channels, coexistence with other 2.4GHz IoT Technologies is possible.

The Target Wait Time provides an effective mechanism to schedule transmissions in time. Phones and IoT devices can sleep, conserving battery life and then awake to take advantage of Multi-User MIMO transmissions, and co-exist in high density RF environments with ease. With Target Wait Time, the AP can schedule phones and IoT devices to sleep for long durations — potentially up to 5 years and then wake the individual device up. Devices can be configured to wake up as a group to communicate at the same time, sharing the channel for increased network capacity and reduced battery drain.

OEM specific information

Wi-Fi 6 access points by Cisco are the 9115, the Catalyst 9117 and the Catalyst 9120 Access Point. Cisco Meraki has the Meraki MR45 and the MR55. Aruba has the 510 the 530 and the 550 AP.

Wi-Fi 6 controllers can come in a variety of styles. They can be physical hardware, they can be cloud managed hardware, virtual controllers or embedded in switches.

The Cisco product portfolio has the Catalyst 9800-CL virtual controller that can be a public, private cloud or virtual machine, the catalyst 9800 family of physical controllers or the embedded controllers in the Catalyst 9000 switch.

Cisco Meraki uses a cloud solution. The Cisco Meraki management platform has always been cloud and is still cloud.

Aruba has a virtual appliance, the 7200 family of controllers and the mobility master family of controllers.

Managing a Wi-Fi 6 environment varies from vendor to vendor. Cisco leverages DNA center, Meraki uses the dashboard (cloud managed), Aruba has Airwave on-premises or Aruba Central in the cloud.

Wi-Fi 6 client devices

There are a handful of smartphones, a few tablets and a few more laptops to support Wi-Fi 6 as of July 2020. Of course this list will increase over time, but as for right now, there's really not that many client devices that support Wi-Fi 6.

WWT has a depth and breadth of knowledge in the wireless space. Not only do we have significant relationships with the top OEMs in this space, but we can demonstrate our capabilities in our Advanced Technology Center through proof of concepts, or labs as a service. We can bring together multiple vendor technologies to demonstrate true solutions, in campus and branch deployments. WWT can successfully perform any and all manner of wireless site surveys, from software-based predictive to on site RF testing. Our Big Data team can enhance the business relevance of location aware Wi-Fi, and our Application Development team can create front-end and user interface to your location aware Wi-Fi network, ready for any business use case you can imagine.