6G: Learning from the mistakes of past Gs

According to several top industry executives, the next big generation of wireless networking technologies won't create the same types of problems that previous generations did.

"Every G is different, and there's always the lessons learned," Qualcomm's John Smee, head of wireless research at the chipmaking giant, told Light Reading recently. In his role, Smee is charged with developing the company's strategy for next-generation technologies like 6G. "There's always a mixture of evolution and revolution with any G," he said.

Smee isn't alone in hoping to apply lessons from the past to 6G.

"There's a potential big cycle coming," acknowledged T-Mobile CEO Mike Sievert during his company's recent quarterly conference call. "But on the other hand, it may be a cycle that's fundamentally more efficient to roll out than prior cycles."

Indeed, 5G demanded billions of dollars of investment by network operators into new spectrum bands and networking equipment. But the return on all that investment is difficult to discern when operators' revenues today remain relatively flat, and they aren't chasing many new revenue streams beyond fixed wireless.

Regardless, the global wireless industry has officially begun work on 6G technologies through the 3GPP standards body. Its Release 21 batch of specifications is expected to standardize 6G radio access network (RAN) by 2029. The group hopes to finish Release 19 next year.

The NSA problem

There is no demand for an early version of the 6G standard, according to Smee.

"One of the things that's true for 6G is that we don't want to have that sort of double step," he said referring to the non-standalone (NSA) version of 5G.

5G NSA was the first iteration of the networking technology released by the 3GPP. It essentially requires a 4G core network to serve as an anchor for a new 5G RAN. The NSA standard was released on an expedited basis to allow network operators to quickly move from 4G to 5G.

But that upgrade has caused trouble for operators that now want to move to the standalone (SA) flavor of the technology. 5G SA eliminates the need for a 4G anchor network and supports technologies like voice over 5G new radio (VoNR) and network slicing. It has proven difficult to deploy.

"NSA [5G] kind of set various operators on different timelines," Smee said.

He predicted that 6G, when it's released, will feature a clear upgrade path that all operators can follow together, thereby scoring economies of scale.

The China question

Another misstep industry execs are hoping to avoid is a geographical bifurcation of the 6G standard.

For example, a top Chinese official recently urged the industry to set a "unified global 6G standard." Zhang Yunming, a Ministry of Industry and Information Technology (MIIT) vice minister, said China is "willing to work with global partners" to develop that next-gen standard.

That's noteworthy given fears that souring US-China relations might drive a technological wedge between the two countries on 6G.

Indeed, there is precedent for that kind of bifurcation. The US widely embraced the CDMA standard in 2G and 3G while the Chinese government worked to fund the rival TD-SCDMA standard – both of which represented alternatives to Europe's GSM standard. The 3GPP's 4G LTE technology represented the first time that the global wireless industry coalesced around a single wireless networking standard.

Smee said there is no indication of a geographic split within the 3GPP on 6G.

"We see very, very active participation on the global standard ecosystem, whether it's Japan, China, the US, Europe, India," he said. "The benefit of that single global standard is very, very important in terms of scale, and so we are seeing that kind of unified view."

Spectrum issues

Smee noted that most 6G discussions are focused on communications in the 6GHz to 7GHz range. That will allow wireless network operators to use their existing macro cell site footprints to deploy 6G.

There are ongoing investigations of 6G in the Terahertz spectrum bands, Smee said, but they are more of an "interesting research topic." Transmissions in such bands may only stretch a few hundred feet.

A focus on lower spectrum bands may stem from operators' 5G learnings. Early 5G activity in the US market focused on communications in the higher millimeter wave (mmWave) spectrum bands. But signals in those bands can't travel very far. That created major 5G deployment challenges, considering that widespread mmWave networks would require the construction of thousands or millions of new cell sites.

5G deployments in the US quickly pivoted to midband spectrum – in the 3GHz band like the C-band – when it became available in the US. That's because operators can use their existing macro site footprint to deploy midband spectrum.