SKT Tests Put 4G in Touching Distance of 5G

SK Telecom has perhaps inadvertently dealt a blow to the business case for 5G with tests that cut latency on a 4G network to a level that can support 5G-like services.

The South Korean operator said it had cut latency -- the delay that occurs when sending signals over data networks -- to just two milliseconds on a connection between a 4G basestation and handset.

That compares with ordinary 4G levels of about 25 milliseconds and is even a millisecond less than Germany's Deutsche Telekom AG (NYSE: DT) managed last week during a demonstration of pre-5G technology in Berlin. (See Deutsche Telekom Touts Europe's First '5G' Connection.)

It means that a self-driving car traveling at 150 kilometers per hour would move a distance of just eight centimeters after receiving an instruction to stop. At 25 milliseconds, the vehicle would move a whole meter.

Always eager to parade its cutting-edge credentials before the press, SK Telecom (Nasdaq: SKM) says the tests bring it a step closer to "realizing 5G" and that its two-millisecond technology could support the launch of various "real-time" services, including autonomous driving, that are expected to become more widespread with the rollout of 5G.

But for critics the development could provide further evidence that 5G technology is a solution in search of a problem.

There is already doubt that consumers and businesses will need the ultra-fast connections that 5G promises, especially given the recent improvements to 4G technology, which can now handle gigabit-speed services in a trial environment.

Conscious that 5G may not excite consumers, or boost revenues from existing customers, many operators are instead highlighting 5G's other attractions, including its latency advantages over older network technologies. (See Ericsson CTO Prioritizes Non-Consumer 5G.)

This super-low latency, they argue, will open up new service opportunities in non-consumer areas, including the autonomous vehicles sector and the market for remote-control surgery.

But if latency on a 4G network is low enough to support these services, there may be little need for an entirely new technology, critics may reply.

SKT points out that latency will fall even lower with 5G, to as little as one millisecond. So the question may be whether a one-millisecond difference between 4G and 5G is important for some services. In the case of autonomous driving, the answer would seem to be "not very," judging by SKT's example.

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Even if it does raise questions about the 5G business case, progress on 4G is unlikely to upset the momentum behind the next-generation technology, however. (See The Growing Pains of 5G.)

Most operators believe the rollout of 5G will entail a broader network transformation than previous mobile standards, bringing efficiency benefits and helping them stand up to their Internet rivals.

Besides deploying a new radio technology, they plan to introduce more software and virtualization technologies into their networks and make investments in capabilities such as mobile edge computing.

Carried out in conjunction with Finland's Nokia Corp. (NYSE: NOK), SKT's two-millisecond trials used a technology called uplink pre-scheduling to send data from the handset to the basestation. Another system called transmission time interval (TTI) reduced the transmission time between the basestation and the handset to about a seventh of its usual level, said the operator.

SKT and Nokia said they would work on getting TTI accepted as part of the 3GPP's global standards.

— Iain Morris, Circle me on Google+ Follow me on TwitterVisit my LinkedIn profile, News Editor, Light Reading

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