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Wi-Fi 6 – the Secret Sauce

By Ernest Worthman, AWT Exec. Editor, IEEE Sr. Member

Ern’s Perspective


While most of the attention is being paid to 5G, behind the scenes, Wi-Fi 6 is changing the connectivity game. Wi-Fi 6 is not an evolutionary step in the Wi-Fi ecosystem, it is a revolutionary change. Why? Because it ups the ante in the dense environment game – something with which previous iterations struggle.

Wi-Fi 6, or 802.11ax for the geekier crowd, is not just about faster data rates. It is about being an enabling platform in dense environments.

One of Wi-Fi’s biggest challenges has been its limited functionality in highly dense environments – large office campuses, shopping malls, apartment complexes, airports, indoor arenas, outdoor stadiums – one gets the picture. As we all are aware, as current Wi-Fi versions load up, performance takes a hit, proportionally, and channel crowding and interference become more problematic.

This also makes it a no-win in the Internet of Everything/Everyone (IoX), once it gets traction, because there will be billions of low-power devices for which Wi-Fi would be the ideal platform.

Wi-Fi 6 changes that. It can take some of the 802.11ah features, such as dual-carrier modulation, where each symbol is mapped to a pair of subcarriers, and these are widely separated in frequency. This helps to increase receiver sensitivity which becomes a consideration for outdoor deployments.

Another promising feature is the TWT. Optimizing TWT reduces contention and, helps minimize power consumption in the remote device because it need not be listening, continuously, for communication.

Next come spatial re-use and its complement, BSS Coloring. This is a rather complex scheme that differentiates frames from a specific BSS against other, overlapping BSSs. By assigning each AP a specific color, individual stations can ignore signals carrying any other color code.

All this wraps into a set of core elements that Wi-Fi 6 will be defined by. They are:
·     Multiband support – 2.4, 5, 6, and 7 GHz, which offers  greater frequency agility in crowded environments
·     Channel bandwidths of up to 160 MHz for increased data throughput
·     A variety of modulation schemes – BPSK, QPSK, and 16, 64, 256 and 1024 QAM — that complement wider bandwidths, and, hence, further improve network performance
·     Variable guard interval durations of 0.8, 1.6 and 3.2 ms that improve functionality in multipath environments.
·     Improved symbol times – another scheme that improves multipath issues
·     Modulation schemes, OFDM and OFDMA, to improve transmission delays, and efficiency, in large user deployments
·     Wider subcarrier spacing of 78.125 kHz to reduce overhead
·     More spatial streams per user in MIMO mode: SU-MIMO ≤8, MU-MIMO ≤4, coupled with OFDMA, will improve up and download time and manage the complex activity of resource units

When implemented, these will create a HEW physical layer (PHY). This will put Wi-Fi 6 on par with cellular services in QoS. That is why it is going to integrate with 5G in applications and not conflict with it. It will also be capable of roaming and have improved Wi-Fi calling, positioning it to play a significant role in MEC.

Now that we have done a quick technology overview, what is the benefit of this improved Wi-Fi?

From the technical overview, the improved operation in dense environments is relatively obvious. But, how do these relate to other practical applications? Let us take a look.

Obviously, the enterprise comes in as a prime use case. Wi-Fi has been mediocre in the enterprise, in many cases. To make it work well often requires a significant investment in hardware and constant maintenance and reconfiguring. With Wi-Fi 6, that will be eliminated. Wi-Fi 6 will deliver improved efficiency and network performance.

Managed service providers will provide better data connectivity, throughput, and QoS. In building voice services with Wi-Fi Calling will see significant improvements. Coverage areas will also see significant improvement.

Retail is a prime target for Wi-Fi 6. Location-based technology will enable a slew of customer metrics, such as targeted advertising, dwell times and movement.

Transportation is another emerging use case. With roaming and improved signal metrics, payment and ticket services will increase. Improved outdoor performance enables Wi-Fi deployments to better serve connected car use cases, allowing Wi-Fi to offload the delivery of FOTA updates from the cellular network.

Industry will benefit from the 6 GHz spectrum by utilizing it for automation. The improved determinism, lower latency, longer range and higher throughput will facilitate the use of Wi-Fi 6 for supporting Wi-Fi-based industrial automation use cases.

And, let us not forget the IoX. Narrow dedicated channels, power saving options, and TWT, for example, will allow Internet of Everything devices to make greater use of the Wi-Fi service’s lower data rate, longer range, and low-power metrics. Other use cases include smart cities, last mile and residential dwelling (single and multi-units).

And, of course, while use cases are good, improved RoI is better. Wi-Fi 6 will cost less to deploy and offer a better return per network due to its use of a wider range of unlicensed spectrum. This will also be augmented with Wi-Fi 6’s improved efficiency and expanded services.

In the end, Wi-Fi 6 is rather a golden child because it will both improve the capabilities of all existing Wi-Fi systems, as well as deliver a raft of new features, which will enable a whole new set of use cases. It has evolved into a pretty exciting technology.