Getting Ready for 6G

Now that 5G is well-established in the low, middle, and high spectrum bands and 5G has found a unique niche as an alternative to cable for residential broadband, mobile engineers are focusing their attention on 6G. There are a lot of ideas about what 6G needs to do, mostly not well formed; AI is among them.

China has made the first move toward allocating spectrum in the upper 6 GHz band specifically for 6G. The mobile industry isn’t surprised, as GSMA head of spectrum Luciana Camargo observed:

China’s efforts towards the 6 GHz band don’t come as a surprise. Conducive spectrum policies for the mid-bands, especially the 2.6 GHz and 3.5 GHz, have helped China to deploy the world’s largest 5G networks with over 2.7 million 5G base stations by the end of April 2023, and to be on track to become the first country to reach 1 billion 5G connections in 2025.

The rising number of connections have in turn demanded greater capacity and capability for 5G nationwide where additional mid-band will be crucial. The ability for 6 GHz to reuse the 3.5 GHz grid also makes it attractive for cost-effective upgrades of the 5G networks. Deutsche Telekom’s test in Bonn, Germany, confirmed gigabit speeds and that the right inter-site distances can allow the use of existing grids. This will accelerate the roll-out process, allowing users to reap the benefits quicker.

Broad Consensus and One Outlier

Camargo notes that Europe, Asia, Africa, and Latin America are also eyeing 6 GHz:

China is not alone in Asia in considering 6 GHz development, and other countries have also formally expressed interest at recent ITU meetings. Countries of all sizes – from Singapore to India – are evaluating their options in preparation for WRC-23. Earlier this year, Mexico announced it is contemplating broader harmonisation of the 6 GHz range. Late last year, Chile’s Ministry of Transport and Telecommunications decided to go for the same approach, overturning a decision to make the whole band available for Wi-Fi.

In EMEA, meanwhile, there is already preliminary support in Africa and the CIS for 5G in the upper 6 GHz band, as well as several major Middle Eastern and European markets.

Harmonization is the name of the game for makers of mobile devices and base stations, so nations that fail to assign the upper 6 GHz band will find themselves with limited options for completing 5G and moving into 6G at the head of pack. The major outlier is the USA, where all of the 6 GHz band has been assigned to Wi-Fi by a unanimous decision of the Pai FCC.

Over-Enthusiastic about Wi-Fi

As we noted at the time of the FCC’s 6 GHz proceeding in 2020, the agency should have been circumspect about industry claims:

While the NPRM’s interference analysis emphasizes interference between Wi-Fi and non-Wi-Fi systems, the fundamental dilemma is the way Wi-Fi networks treat each other. In principle, a 160 MHz channel using Wi-Fi 6 with 1024 QAM and 980 sub-carriers can teach a top throughput of 9.6 Gbps.

It stands to reason that a properly shared 9.6 Gbps channel should be able to meet the needs of the handful of access points that can all see each other on at any given time. We only need a massive number of channels if access points are not coordinating with each other efficiently. Enterprise systems that coordinate well are able to work well on a single channel.

So the challenge for Wi-Fi is to take up the mantle of inter-access point coordination in a serious way. This has always been a problem that 802.11 has swept under the rug by pleading “privacy” or some other nonsense.

Wi-Fi was created to use junk bands not well suited for professional networks. It now wants to move into prime spectrum bands before solving its coordination problem. This should never have been allowed.

What Can We Do Now?

It’s not too late to revoke the allocation of the upper 6 GHz band for Wi-Fi. While it’s been on the books for a couple of years, there is very little action in upper 6 GHz. Customer uptake of the Wi-Fi 6E and Wi-Fi 7 devices needed to use 6 GHz has been extremely slow.

There is also very little harm in limiting Wi-Fi to the lower half of the 6 GHz band. There is still enough spectrum there for 320 MHz channels, if they really prove necessary. Wi-Fi simply moves data short distances around the home and office, so high powered base stations simply aren’t needed.

With low power comes simple re-use. Ultimately, additional spectrum can be allocated to Wi-Fi as and when it is needed. This is an international problem for which there will be international solutions. We don’t need to believe that Wi-Fi causes brain damage (as Robert Kennedy Jr. does) to put it on a diet.