Dynamic spectrum sharing (DSS) technology makes it possible to use LTE and 5G NR mobile communications technologies in a single, existing LTE frequency band. This allows mobile network operators to avoid two costly alternatives to DSS: refarming the existing LTE spectrum or buying new 5G spectrum. The disadvantage of using DSS in an existing frequency band is using an existing frequency band: the available bandwidth in this band has to be shared between LTE and 5G. Thus, the achievable data rate of 5G in this DSS mode is certainly limited.
The first 5G NR networks are mostly relying on the so-called non-standalone (NSA) mode. In this mode, an LTE anchor is required to exchange control and signaling information and to configure, add, modify, and release the connection towards the 5G NR Radio Access Network (RAN).
Short-term DSS enables network operators to deploy 5G NR in their lower frequency bands, still requiring an LTE anchor. However, mid to long-term service provider can use DSS as a smooth transition towards standalone mode (SA). In SA mode, the 5G NR connection works independently, without requiring an existing LTE anchor.
The importance of DSS based technology is indicated by the increasing number of 5G NR consumer equipment on the market, and the need for an ever-growing number of 5G NR networks around the world. Consequently, vast commercialization of DSS is expected in the upcoming months.
Rohde & Schwarz has built a comprehensive portfolio of mobile network testing instruments supporting DSS, including the smartphone based RF optimizer QualiPoc Android, the network measurement software R&S®ROMES4 and the R&S®TSMx family of network scanners.
QualiPoc Android
QualiPoc Android now shows relevant DSS information enhancing the UE capabilities with DSS support parameters. On the technology monitors, QualiPoc Android displays the relevant parameters that indicate whether DSS is being used.
ROMES4
R&S®ROMES4 offers DSS scanner support since several releases ago.
With this release, we are introducing the DSS support for information coming from the connected UE (either rooted or unrooted). For a quick DSS overview and its performance, several new signals are now available, including:
- "DSS State indicator" (based on layer 3 messaging)
- "DSS LTE Center Frequency"
- "DSS LTE carrierFreqDL"
- "DSS LTE Band"
- "DSS LTE Bandwidth".
With the activated DSS feature, it is important to understand the ratio of 4G and 5G traffic. The new signal per cell type displays the actual usage in percent of the scheduled 5G NR PDSCH resource blocks compared to the total available DSS carrier bandwidth (carrierBandwidthDL).
Additional new DSS events are included in the "Layer 3 View" and "Events list" under R&S®ROMES4 "Preferences".
Mobile network testing products supporting DSS
