The technology, which is part of the 3GPP Release 15, allows operators to dynamically allocate some of their existing 4G LTE spectrum to 5G.
The idea is to give the service provider a coverage layer for 5G NR in low band frequencies that are already used by LTE without refarming. In the U.S., DSS is being promoted, in part, as a way to overcome the fact that little new low- and mid-band spectrum will be available in the near term.
In Switzerland, Swisscom introduced 5G in April using 3.6 GHz spectrum, with Ericsson as its sole 5G equipment vendor. It also was expected to be the first to deploy Ericsson Spectrum Sharing (ESS) software in 2019.
Nokia has said it will introduce DSS as a software upgrade in 2020, in line with commercial 5G FDD mass market device availability.
Some say the real advantages from DSS will happen when operators move to a 5G standalone (SA) core, when the technology can help to make features like network slicing possible. Initially, U.S. incumbent operators are using non-standalone (NSA) cores for their 5G offerings, but they’re moving to SA in 2020.
In a proof-of-concept demonstration in the U.S., Verizon, Ericsson and Qualcomm Technologies conducted a trial of DSS. Verizon says DSS will complement its primary strategy of offering a differentiated 5G service using millimeter wave spectrum. With DSS, when customers move outside Verizon’s 5G Ultra Wideband coverage area, their 5G-enabled devices will remain on 5G technology using lower bands of spectrum.
The attitude toward spectrum sharing is on the upswing, with both suppliers and operators discussing their spectrum sharing roadmaps, according to Stefan Pongratz, vice president and analyst at Dell’Oro Group, who foresees DSS taking off in 2020. “In addition to the spectral efficiency gains of 15% to 20%, operators are considering the benefits from a marketing perspective,” he wrote in a blog post.
Operators also see the extended 5G NR coverage with a lower spectrum band as a key enabler for 5G SA and network slicing. “The technology is expected to play a pivotal role in upgrading existing low-band LTE sites to NR in the year 2020,” he added.