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27 July 2020

Fixed broadband vendors tout clear channels in case for WiFi 6E

Threatened in some cases by fixed wireless access (FWA) over 5G, traditional landline broadband operators have been eagerly touting the advantages of the latest WiFi 6E for the final leg of distribution to consumers and enterprises.

Even when such providers do not offer the routers and other kit directly WiFi has become vital to their cause since it has become the effective last mile of their infrastructure and services. They see WiFi 6E as being crucial for their continuing success in the 5G era when threatened by rival broadband operators as well as FWA.

This realization has become more acute during the current Covid-19 coronavirus pandemic given the boom in videoconferencing that has exposed the limitations of WiFi networks based on earlier standards, which have often failed to cope with multiple simultaneous user sessions, even when some of them are little more than casual internet browsing. With the number of connected devices proliferating and prospect of increased home working, expectations of domestic WiFi capacity, performance, reach and reliability have all increased.

With hindsight, the WiFi Alliance can be seen to have made rather a hash of the latest generation, with 6E following hot on the heels of WiFi 6, which was only finalized itself in September 2019. This led to the situation where some consumers purchased WiFi 6 routers that almost immediately were obsolete in the sense that they would need replacing again to support WiFi 6E with its extra spectrum and wider channels.

But there are mitigating circumstances. WiFi 6 was driven by concerns over inability to cope with mounting numbers of devices in the home, resulting in poor performance when several users were online at once, especially for high bandwidth applications like video. The issue was even worse when low latency was required for interactive applications such as gaming and zooming, as many homes have discovered recently.

A quick fix was needed and WiFi 6 on its own resolves some of these problems by incorporating multiuser (MU) MIMO to increase throughput over a given spectral band and OFDMA to reduce overheads associated with contention and the preamble involved in gaining access to the physical medium. WiFi 6 enabled higher bit rates and improved QoS when viewing high definition video. It also worked better with multiple users, especially with new devices supporting the later standards.

But it still suffered from the same dearth of spectrum that led to RF congestion and interference, inhibiting scalability in public arenas such as venues, shopping malls and transport hubs. The original 2.4 GHz band provided just 70 MHz of spectrum, while the newer 5 GHz band yielded a further 500 MHz, but at shorter range.

Another mitigating factor for the industry was reluctance at first on the part of regulators to release the additional spectrum in the 6 GHz range. It was not clear two years ago when that spectrum would be cleared for use in the key markets and that also encouraged release of WiFi 6 as it was, even if did prove to be an interim standard.

Those spectrum issues have now largely been resolved, with the USA’s FCC, for example, announcing in April 2020 that it was opening up the 6 GHz frequency band for use by WiFi 6 E. In fact new spectrum is becoming available for WiFi in amounts that vary between regulatory domains but up to 1.2 GHz, in the range 5.925 GHz to 7.125 GHz.

This meets the spectral budget identified by the WiFi Alliance for 2025 and so gives plenty of headroom for now, even though it is dwarfed by the amount that will be available for 5G, which will begin at around 5 GHz and then reach 19 GHz when the emerging high-band unlicensed frequencies in the range 57 GHz to 71 GHz are available.

It is true that WiFi 6E’s range at 6 GHz will be even less than in the 5 GHz band, but it is still better than the higher frequency millimeter wave bands providing most of 5G’s extra capacity. Again, the range will be enough to meet most of the proposed use cases, which are precisely in areas with dense device populations, such as sporting arenas.

Then in the home, WiFi 6E should provide adequate coverage at the higher frequencies with the help of mesh and range extenders or repeaters. BT in the UK has found that many homes can be covered with a single range extender and most with two, while having three addresses the largest and least RF-friendly homes.

Latency is also a key factor in closing the gap on 5G, so the Wireless Broadband Alliance (WBA) was relieved by the results of the first phase of WiFi 6E trials enabled by two key members, Broadcom and Intel, in March 2020. This appeared to show that use of the 6 GHz band could support the low latency required for those demanding use cases identified under the 5G mMTC (massive machine-type communications) category covering mobile gaming, virtual and augmented reality (VR/AR) applications, and the Industrial IoT. During the trials involving Broadcom and Intel, two millisecond latencies were consistently achieved, approaching the levels promised for 5G.

Another factor of interest to fixed line operators and ISPs is that the new 6 GHz bands will be shared only by the latest devices that support the standard, unlike the legacy 2.4 GHz band. This will finally solve what has sometimes been called the ‘rotten apples’ problem where performance for advanced devices is impaired by legacy ones hogging the band for longer because they are not capable of transmitting data onto the medium as quickly. The avoidance of slow legacy devices will help ensure that WiFi 6E scales effectively to multiuser operation with less diminution in performance per user.

For fixed line operators delivering high speed broadband pipes to homes, business premises and public arenas, 6E will encourage further incorporation of WiFi into their service proposition. It will offer a more compelling alternative to 5G for dense public arenas, even if WIFI does seem to be losing the battle in one of its target sectors, automotive. But then we prefer to view WiFi and 5G as complementary, even if inevitably given sectors and use cases will gravitate more to one or the other.