Dynamic Spectrum Sharing (DSS) has emerged as a key part of mobile service providers’ 5G strategy at Mobile World Congress Los Angeles. DSS allows an existing LTE carrier to operate 5G NR and LTE simultaneously – with a simple software upgrade allowing a nice transition to 5G. This is especially critical in the low band where there are not a lot of users so dedicating just 5G usage there would be way too expensive to deploy. R&S gave a great technical talk on DSS to a packed room of interested attendees.

This technology has always been a part of the 3GPP Release 15 but only recently have network and mobile equipment providers been able to design hardware to utilize it. The first generation of 5G devices are not able to utilize it but the second generation will be able to use it. The Ericsson solution at MWC LA is based on intelligent scheduler algorithms that enable optimal performance as the mix of 4G and 5G devices in the network changes over time.

According to a recent Ericsson release, they worked with Qualcomm Technologies to achieve the first 5G data call using spectrum sharing on a  3GPP  Frequency Division Duplex (FDD) low band using commercial hardware and software based on Ericsson Radio System, and a mobile test device powered by the Qualcomm® Snapdragon™ X55 5G Modem-RF System. This was a major breakthrough for wireless communication given that frequency sharing had never been done between any cellular generation since 2G. This technology is poised to change how new generation radio access technologies are introduced in operator networks using one of the most limited resources in mobile, spectrum.

The dynamic spectrum-sharing data call was set up earlier in August at Ericsson’s lab in Ottawa, Canada using an Ericsson macro radio that supports both 4G and 5G, along with a  mobile test device powered by the Snapdragon X55 5G Modem-RF System, and a commercial LTE smartphone. The LTE smartphone and 5G testing device data call sections were running simultaneously on the same FDD spectrum. Making this 5G call aided by DSS is an important milestone as it shows that operators can avail of this unique solution to share spectrum for fast and smooth deployment of 5G coverage.

Ericsson also stated that traditionally, new generation radio access technologies are deployed on separate spectrum blocks – as was the case with 2G, 3G and 4G. This would require operators to buy new spectrum or re-farm the existing spectrum to allocate the new generation. This is a very slow and costly process. Spectrum re-farming could take a decade but with spectrum sharing, this can be done overnight. Dynamic spectrum sharing revolutionizes the introduction of new technologies with a breakthrough innovation that allows the deployment of both 4G and 5G in the same band and dynamically allocates spectrum resources between 4G and 5G based on user demand.

Verizon CEO Hans Vestberg said that beginning next year, software-based dynamic spectrum sharing will hit the market and shift that paradigm for them. According to FierceWireless, European operator Swisscom said that it will use DSS from Ericsson as part of its 5G deployment. Swisscom said it expects to have 90% of its population covered with 5G by year-end so it is becoming available in some areas this year. Ericsson said they have equipped several network providers with capable equipment so Swisscom might not even be the first but is certainly ahead of the pack.