Dynamic Spectrum Sharing Promises Bridge to 5G

The days of network operators having to dedicate specific spectrum to different technology generations could be numbered, thanks to an emerging technology called Dynamic Spectrum Sharing (DSS).

By enabling operators to make more efficient use of current – and expensive – spectrum assets, service providers could deploy 5G services faster and more cost-effectively.

With DSS, network operators can dynamically share spectrum among two different technologies, such as 4G and 5G. Today, these operators have to split spectrum and dedicate separate chunks to different cellular technologies.

DSS enables the sharing of spectrum based on traffic demand between 4G and 5G resources. Better still, the allocation of spectrum between can be done instantaneously, giving the best possible performance for a mix of 4G and 5G devices on the available capacity.

The hybrid network-like capability enabled by the promise of DSS aids in network evolution by supporting both 4G and 5G phones. It’s designed for operators who struggle with emerging bandwidth needs. It’s also expected to smooth the anticipated gradual migration to 5G.

What it takes

At its core, DSS requires a software upgrade and 5G NR-capable (New Radio) gear.  5G NR is a newish air interface designed to support advanced capabilities in 5G networks. It’s part of 3GPP Release 15 and allows operators to dynamically allocate some of their existing 4G LTE spectrum to 5G.

Some wireless carrier infrastructure suppliers are working on the software upgrade needed to support DSS on 5G NRs. Ericsson is a DSS believer, with its spectrum sharing software, which can transform current 4G towers into hybrid 4G/5G towers.

When used with the NR radios, the software essentially enables interoperability between 4G and 5G by creating a sharable overlay service for operators who are still in relatively early stages of 5G service rollouts in the U.S., and beyond.

The top projected use of DSS is with mid-band spectrum, which will is used to cover long distances that comprise nationwide network deployments. By contrast, millimeter-wave spectrum is used for shorter distance in dense urban areas.

The reality is that some operators would love to put DSS to use with their mid-band spectrum as their frequency assets in this category are limited. To worsen matters, the spectrum earmarked for auction by the Trump administration later this year falls into other categories. DSS could help fill the void without hamstringing operators.

Purported benefits

Among promoted benefits, using the software upgrade can lessen the need for new towers to support 5G services. This should lead to faster rollouts. And then there’s cost avoidance as the FCC claims the process of setting up 5G networks with only 5G radio hardware will cost more than $200 billion in the U.S.

Another purported benefit for operators is easy installation and setup. Ericsson claims the DSS software upgrade can be installed remotely via software on its radios. The 5G NR global specification was fast-tracked to standard status by the 3GPP at the behest of operators worldwide anxious to accelerate their deployment efforts.

Early interest

Verizon is already working with chip makers and equipment vendors to advance DSS, which its CEO Hans Vestberg envisions applying across its full spectrum holdings.

The carrier identified DSS as a key feature for their broader 5G deployment.

It's tough to pinpoint when DSS will be deployed in wireless operator networks as several stakeholders are involved in its development and delivery. Vestberg, however, said in April that the technology wouldn't be available until next year.

On the phone front, Qualcomm is already developing chips for consumer devices that will enable them to make use of DSS-enabled spectrum. Dean Brenner, senior vice-president of Spectrum Strategy and Technology at Qualcomm, has called DSS a game-changer. Phones that use DSS will need chips that support the different cellular standards. It’s not completely clear when the chips needed for the flexible phones will be commercially available.

The road ahead

Smooth migrations are rarely smooth when it comes to rollouts of next-generation technology services. However, DSS is designed to soften many of the rough spots and lower barriers on the road to accelerated 5G deployment. It could help change the game when it comes to flexibly extending 5G deployments in spectrum-challenged times.