It might be at least six years before the first expected commercial launches, but already 5G is shaping up to be a beast that is different from any preceding cellular generation.
The divergence is driven mainly by the need to build out a platform for more than just human communication. There's an almost universal industry view that it should support low latency and high-volume connections for IoT, deliver high capacity for the forecast 1,000-fold increase in traffic, massively improve energy efficiency, and be deployable in high-frequency spectrum.
Another difference is that the industry hasn't broken down into factions over radio interfaces.
At its annual mobile broadband forum in Shanghai last week, Huawei Technologies Co. Ltd. , which has committed US$600 million towards 5G R&D up to 2018, kept the volume down on its candidate technology, SCMA (sparse code multiple access). (See Huawei CEO Pledges 5G R&D Investment.)
In fact, Eric Xu, one of Huawei's "rotating" CEOs, didn't even mention SCMA during his presentation. Instead he talked about 5G in general, noted that he couldn't truly identify what 5G is, and without nominating anything specific, called on the industry to develop "breakthrough technologies."
While it's hard for anyone to truly pin down what 5G will encompass, that vagueness may also be in deference to customers such as NTT DoCoMo Inc. (NYSE: DCM) and the three major Chinese operators, which are canvassing other radio technologies.
Takehiro Nakamura, managing director of NTT DoCoMo's 5G Laboratory, said it was expecting 5G to include "enhanced LTE" as well as another radio access technology. In lower frequency bands -- up to 30GHz -- it is trialing OFDM (orthogonal frequency-division multiplexing) and is also considering NOMA (non-orthogonal multiple access) or a new technology for higher (and possibly also existing) spectrum bands.
Wang Zhiqin, deputy chief engineer at the Chinese Academy of Telecom Research (CATR), nominated PDMA (polarization division multiple access), MUSA (multiple unit steerable antenna) and Huawei's SCMA as under consideration, but added there were others.
Rahim Taffazolli, head of the 5G Innovation Center at the University of Surrey, agrees that a new air interface is needed, but describes OFDM is a "lousy technology for carrier aggregation" in high frequencies.
"We need a new wave form that does low data rate for IoT, all the way to broadband as well, and which is scalable," he said. With spectrum likely to be highly fragmented, the new waveform needed to support flexible aggregation, such as 20MHz with 1MHz. "It will not always be 20MHz and 20MHz."
Taffazolli unnerved the audience by suggesting that "the 5G we define is supposed to stay to serve the market until at least 2041. If you say the volume of traffic to 2020 will be 1,000x over 2010, and design it for 1,000x, that's not sufficient."
He said IoT would carry "most of the national critical infrastructure, from energy, water, all the way to transport and policing" right up to 2040 or 2050. In "modernizing these 100-year-old industries" and supporting smarter cities, it ultimately would have a greater impact than the improved connectivity between people, Taffazolli said.
However, Huawei's Xu appeared skeptical about the commercial potential of IoT. "IoT on its own is not sufficient to support 5G development," he said.
"Different industries have to build connectivity into their machines, and that cannot be dominated by the telecom industry alone," he added, calling for partnerships between industry verticals and the telecom industry.
— Robert Clark, contributing editor, special to Light Reading