Dynamic Spectrum Sharing Gains Ground

Technology helps operators maximize investment in spectrum

Dynamic spectrum sharing (DSS) received plenty of airtime in 2020, with the technology now starting to play an important role in a growing number of commercial 5G deployments.

DSS enables network operators to offer 5G connectivity using existing frequency bands and antennas. This means they can quickly achieve widespread coverage or launch services before national 5G frequencies have been assigned. It also lays the foundation for more efficient and intelligent networks, making it easier to allocate spectrum to areas where and when demand is highest. And by doing so, operators can better maximize their expensive investment into highly prized mobile airwaves.

In recent months, leading players in the mobile industry including Ericsson, Huawei, Nokia, Qualcomm, Samsung and ZTE have given DSS a shot in the arm.

In February 2020, ZTE announced SuperDSS, claiming the industry’s first solution capable of sharing spectrum between three radio access technologies: either 2G, 4G and 5G or 3G, 4G and 5G. It aims to help operators quickly light up 5G networks even if they only have limited spectrum resources or if 2G and 3G services are still very important to them. This is because SuperDSS can simultaneously maintain the quality of voice services, for example at 1800 MHz or 2100 MHz.

In April 2020, China Unicom implemented SuperDSS in its live network in Henan province. It represented the next stage of a collaboration between ZTE and China Unicom in spectrum sharing that dates back to 2015. According to ZTE, tests showed a 35% rise in throughput within the same bandwidth compared with a DSS solution based on LTE and 5G New Radio.

Ericsson Spectrum Sharing was also unveiled at the start of 2020, with early customers including Ooredoo, Play, Swisscom and Telstra. The technology won the prestigious Mobile Technology honour, also known as the CTO Award, at the GSMA’s annual Global Mobile Awards.

One of the most significant recent announcements in DSS was made in October 2020 by Verizon CEO Hans Vestberg at Apple’s launch event for the iPhone 12. Mr Vestberg said that DSS enabled the carrier to instantly switch on 5G to more than 200 million people in 1,800 towns and cities in the US. Its main partners for the DSS launch were Ericsson, Nokia and Samsung.

The move is vital to Verizon’s positioning of the eagerly awaited 5G iPhones, particularly as Apple users make up more than 60% of its mobile customers, according to comments by Ronan Dunne, CEO of Verizon’s consumer business, during CCS Insight’s recent Predictions Week.

With rivals AT&T and T-Mobile already touting “nationwide” 5G coverage — achieved by deploying low-band 5G spectrum, which is well-suited to wide-area and in-building coverage — Verizon had come under growing pressure to expand the reach of its limited 5G service. Until recently, the carrier has mostly deployed millimetre-wave spectrum using 28 GHz or 39 GHz frequencies, which offer phenomenal throughput but only over a limited coverage area.

But despite growing momentum for DSS, the technology has some naysayers. This is because there’s a trade-off in overall 4G and 5G capacity, varying by type of implementation and choice of supplier, so 5G speeds with DSS aren’t always notably faster than those with 4G. Given that the industry has moved to 5G with huge marketing hype, there’s a real risk that customers would quickly lose interest were they to perceive that it’s only incrementally better.

Typically, attitudes toward DSS depend on an operator’s spectrum position. T-Mobile US, for example, which has been offering nationwide 5G for more than a year using its 600 MHz spectrum, has been openly critical. And even Verizon chief technology officer Kyle Malady, speaking at a recent analyst conference, admitted of a slight “inefficiency” to enable 4G and 5G to work together in the same spectrum, before adding that he’s “extremely pleased” with its performance on the Verizon network so far.

In my view, any improvement to the customer experience should be considered a positive. The Covid-19 pandemic is only set to accelerate demand for high-quality connectivity among consumers and businesses, and new technologies like DSS will help address seemingly inexorable growth.

In some ways, the move to offer 5G services without dedicated 5G spectrum feels like a step toward a less-defined “G” hierarchy. This could be good news for consumers, who care only about how well they’re connected and not about what the underlying technology is.

Perhaps a blurring of the Gs has been underway for some time. In addition to spectrum sharing and reuse, a growing number of operators offer tariffs tiered by speed, irrespective of whether the connection comes over 3G, 4G or 5G. Many others sold 5G handsets some time before switching on their 5G networks.

It’s clear that 5G has vast potential, but its development will undoubtedly come in increments. DSS will be an important step on the long 5G journey ahead.