LTE will be exhausted soon, insists Nokia, while Qualcomm dreams of 6G

One of the important debates at Mobile World Congress next week will be that of LTE versus 5G – and Qualcomm has already managed to insert ‘6G’ into the discussion too.

While the show will be full of trials and product plans for the newly standardized 5G New Radio, there has been an intensifying focus in recent months on the longevity of 4G. Operators may feel obliged to portray themselves as 5G frontrunners, for political or shareholder reasons, but the majority expect to enhance LTE for as much as a decade, alongside 5G.

For vendors, then, one challenge is to keep revenues flowing by supporting those LTE enhancements, while not allowing that to delay operator investment in 5G. We expect to hear plenty of discussion in Barcelona about the advances in performance which really are unique to 5G, and how soon those will become essential to operators.

Nokia’s North American CTO Mike Murphy has already kicked off the conversation, arguing that, while LTE will be part of the network for a long time for most operators, most will also need to start introducing 5G at an early stage, alongside 4G, in order to address specific challenges. Otherwise, he said in a recent presentation, those operators will start to suffer from “LTE exhaust”.

The 5G-specific technology which he identified as crucial was Massive MIMO, which he believes will be essential to help MNOs keep pace with the rise in data rates and usage, driven by trends like 4K mobile video.

“There is a limit to how far LTE will go,” Murphy told FierceWirelessTech. “We can actually fairly accurately calculate LTE exhaust.” That involves looking at an existing LTE network, advancing it as far as it can possibly go, and calculating how much traffic that network will carry until it hits its limit.

Some options remain firmly in 4G – small cell densification, offload to unlicensed spectrum, acquiring new licensed spectrum. But he believes that, now 5G and Massive MIMO are close to commercial reality, they should be weighed up against those 4G options, not considered as a futuristic solution.

“Now is the time to make this kind of calculation,” he said. “If you think LTE can take you to 2025 or so, that would be mistaken. We’re not going to get that far.” He thinks that, by 2023 or 2024, most MNOs will have to start the move to 5G (even if they also enhance LTE in parallel, keeping 5G for certain locations or applications).

Meanwhile, as some vendors try to push often reluctant operators to accelerate their moves from 4G to 5G, others want to entice them with what might follow that. No surprise that Qualcomm was leading this particular discussion last week, since it has built so much of its business on cutting edge R&D and getting first to market with the latest radio generation (though if it gets acquired by Broadcom, that pattern could change).

“There will be a 6G probably,” said Qualcomm’s Durga Malladi, head of R&D, speaking at the company’s press event in San Diego last week. He elaborated, saying the 5G standards were developed with the aim of being sufficiently flexible to support significant changes and upgrades in the future.

In theory, that should make 5G “the last G”, but Malladi is probably too seasoned an industry man to believe that would be allowed to happen. “We will probably do another G,” he acknowledged.

Not that he is the first to mention the dreaded term. Tom Rutledge, CEO of US cableco Charter Communications, said on the firm’s most recent earnings call: “Our 5G wireless tests are also going well, as are our 6G tests.” He had rather a specific interpretation of 6G, which did not seem to relate to 3GPP, but to “our pre-spec definition of the integration of small cell architecture using unlicensed and licensed spectrum working together interchangeably with our advanced DOCSIS roadmap to create high capacity, low latency product offerings.”

Other Qualcomm executives at the press event were less futuristic. Serge Willenegger, SVP and general manager for 4G/5G and IIoT, said it was “way too early for 6G”, adding that the “economics of the network” would need to change to require a new standard. “It’s more philosophical thinking at this point,” he said. “But we’re definitely thinking about how to support the industry in the next 6, 7, 10 years.”