5G vs Wi-Fi: the battle for the 6 GHz band is well underway

Berners-Lee 6 GHz
Image by Rudall30 | Bigstockphoto

ITEM: The 3GPP says it has started standardization work on 5G NR for the upper part of the  6-GHz band and hopes to complete work by the end of this year. That could open up a whole new swath of spectrum for 5G operators – provided Wi-Fi doesn’t commandeer it first.

The 6-GHz band is a big deal because it offers around 1,200 MHz of new spectrum (between 5925 MHz and 7125 MHz) for wireless services. The attraction of 6 GHz is pretty obvious – it’s not just extra spectrum, it’s spectrum that enables faster data throughputs compared to lower sub-6 GHz bands being used for both licensed cellular and unlicensed wireless networks. Little wonder the GSMA – which has called for 2 GHz of mid-band spectrum to be cleared for IMT usage over the next decade – wants to use it for 5G.

According to a document from the 3GPP RAN Plenary on December 17, “the so-called mid-band frequency range can provide a good balance between coverage needs and capacity needs, and the 6 GHz band is the most promising band in the mid-band frequency range to provide new spectrum for 5G development in middle-long term.”

For mobile operators, it also offers a potential workaround for the problem of using the 3.5-GHz band for 5G in markets where satellite players are using those frequencies. For the exclusion zones where 3.5 GHz 5G can’t be deployed, operators could use the 6-GHz band instead – especially in Asia-Pacific, where satellite usage of the extended C-band is more prevalent.

The challenge is that the band hasn’t been harmonized yet – not officially. The 6-GHz band is on the agenda for the next WRC conference in 2023. And the GSMA isn’t the only wireless industry group that wants to use it. For example, the Wi-Fi Alliance already plans to use it for Wi-Fi 6E, the next iteration of Wi-Fi. And the Wireless Innovation Forum wants to use it specifically for controlling Automated Frequency Coordination (AFC) systems.

Which highlights a major challenge with the 6-GHz band – who gets to use it, and should it be licensed?

In theory, the answer is both – among the various proposals on the table for 6 GHz at WRC-23 is to split the band, leaving the lower end (5925–6425 MHz) for unlicensed usage and the upper band (6425–7125 MHz) for licensed mobile usage. (The latter band is the one for which the 3GPP has started its standardization work.)

The snag is that in April last year, the US FCC officially designated the entire band (5925-7125 MHz) for unlicensed use cases, and countries such as South Korea, Brazil and Saudi Arabia have followed suit. Wi-Fi 6E devices using that band are already appearing at this year’s CES. Big Tech and OTT companies have also expressed support for unlicensed 6 GHz.

However, that doesn’t mean the band can’t be used for 5G – it means it has to be on an unlicensed basis. As it happens, the 3GPP already has a plan for that – Release 16 includes 5G New Radio Unlicensed (NR-U), which is the evolved version of License Assisted Access (LAA) for 4G networks. The principle is the same – mobile networks can use unlicensed spectrum as part of their carrier-aggregation schemes to offload traffic. Release 16 also supports a standalone mode which enables private 5G deployments for factories, ports and campuses without having to get a spectrum license first.

Still, mobile operators have generally preferred licensed (and thus dedicated) spectrum it can control over sharing unlicensed spectrum with everyone else. The 3GPP made this point in its decision to standardize the 6425–7125 MHz portion of the band specifically for licensed usage: “5G technology and its evolution are increasingly foreseen to be used in various application scenarios, demanding more and more spectrum with the required quality of service that only licensed bands can offer.”

So the 3GPP decision indicates that the mobile sector fully intends to carve out a licensable slice of the band in preparation for WRC-23. The question is to what extent that can still happen if both the upper and lower 6-GHz bands are being widely used for unlicensed apps by then.

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