Wi-Fi’s continuing evolution … or revolution?
How is Wi-Fi adapting to soaring demand and the growing range of applications? With Wi-Fi 7 on the horizon, let’s look at the way the technology is keeping pace with connectivity trends.
Evolution or revolution? Both words refer to a change. But there is a difference. Evolution refers to a slow and gradual change whereas revolution refers to a sudden, dramatic and complete change.
Where does Wi-Fi fall? In both camps.
The 802.11 Working Group established in 1990 – more than 30 years ago – published its first standard in 1997. Since that time, faster modulation and coding schemes (MCSs), wider channels, and technologies such as multiple input multiple output (MIMO) and orthogonal frequency-division multiple access (OFDMA) – to name a few – have increased both performance and throughput, with speeds increasing from a maximum of 2Mbit/s up to 10Gbit/s.
While early generations of Wi-Fi would follow the pattern of evolution, both Wi-Fi 5 and now Wi-Fi 6/6E represent significant leaps in functionality, with both generations offering speeds that exceed what is currently available to the average broadband user. And Wi-Fi isn’t stopping there – as work on Wi-Fi 7 (802.11be) is currently underway (more about that later).
Similar to all broadband technologies, each generation continues to adapt and evolve to meet new connectivity challenges as the number of devices and applications (and their requirements) continues to change and grow.
If you think about the early days of Wi-Fi – there was no streaming video. There were no smart phones. And the only devices equipped were laptops where the primary applications were connecting to email and simple web browsing.
So where was the turning point when Wi-Fi became a must have capability? It can be traced to the smartphone – which significantly increased the opportunities for connectivity and introduced the world to the power of the app.
Comcast recently issued its 2021 Wi-Fi Trends Report which provides some interesting trends related to how its consumers use Wi-Fi. The report showed that within its own network, the number of Wi-Fi devices connected had reached nearly 1 billion – a 12x increase from 2018. Additionally, smartphones were the largest connected device category, accounting for nearly one third of all devices – a 23x increase from 2018. But perhaps more telling was this statement: 45% of Americans said that Wi-Fi is more important to their daily lives than transportation.
Wi-Fi 6/6E: Welcome to the revolution
In the past decade, the way the world is connected has drastically changed. This includes the overall growth in the number of internet users along with the exponential growth and usage of connected devices and applications. For example, between 2016 and 2020, the number of hours watched on Netflix grew by more than 10x, while the total number of apps in the App Store nearly doubled from 2.6 million to 4.3 million in the same period.
What does this mean? Wi-Fi networks need to become more efficient to address not only the increasing demand, but the growing range of applications.
Wi-Fi 6 has addressed these changes in connectivity trends – with its greatest benefit being its ability to address dense user populations with high throughput and lower latency. Anyone attending an event in a convention center, arena or stadium knows the challenge of getting on a Wi-Fi network where there are thousands of users competing for connectivity.
While Wi-Fi 6 offered many enhancements over previous generations, its most significant feature enhancement has been OFDMA (in both the uplink and downlink) which subdivides the Wi-Fi channels into smaller frequency allocations called resource units. Why does this matter? It allows multiple users with different traffic profiles to transmit simultaneously over the same channel. OFDMA combined with multi-user MIMO (in both the uplink and downlink) allows more data to be transferred at one time, enabling access points to concurrently handle more devices.
Wi-Fi 6E takes Wi-Fi into the 6GHz band representing 1200MHz of spectrum between 5.925GHz to 7.125GHz – more than twice the available capacity of the 2.4 and 5GHz bands together. This allows for wider channels (80MHz and 160MHz) enabling a range of higher bandwidth and latency sensitive applications. Additionally, this additional spectrum will help ease congestion, contention and degradation issues in the legacy 2.4GHz and 5GHz bands.
But Wi-Fi 6E is not without its challenges – most notably the fact that not every country or region has made the 6GHz band (in part or full) available for unlicensed use.
Other challenges include cost (as 6E has not started to benefit from economies of scale), distance limitations (higher frequencies = shorter distances), and the need for 6GHz specific equipment (meaning those existing Wi-Fi 6 routers and devices cannot work in 6Hz).
But the upside is these 6GHz devices will not need to compete with 802.11na/b/g/n/ac devices for airtime.
Wi-Fi 7: Boldly going where no Wi-Fi has gone before
IEEE has proposed amendment P802.11be, currently referred to as Wi-Fi 7 and also known as Wi-Fi Extremely High Throughput (EHT). Wi-Fi 7 will support a throughput of at least 30Gbit/s, operating between 1 and 7.250GHz. Enhancements over Wi-Fi 6 include support of 320MHz transmissions (double the 160MHz of Wi-Fi 6); optionally supporting 4096 QAM (up from 1024 QAM in Wi-Fi 6) as well as the allocation of multiple resource units, such as groups of OFMDA tones.
Similar to operators launching multi-gigabit broadband options, the practical applications for these speeds are limited. The same is true for features such as 320MHz channels and 4096 QAM modulation. While these will be very important for a handful of niche use cases, it’s difficult to see the applicability to the general population. However, other proposed features of Wi-Fi 7 (such as multi-link operation, multi-RU and multi-AP) will improve support for applications that require deterministic latency, high reliability and quality of service – making it more appealing for certain industrial and enterprise applications.
IEEE plans to publish the 802.11be amendment during 2024, with commercial deployment occurring around the same time.
Just in time for 6G and 50G PON …