China’s ZTE claims to be ahead of its competitors in the development of advanced triple RAT DSS, with the first commercial deployment in September 2020 for China Unicom. Developing Telecoms spoke with Shen Jianda, VP and General Manager of RAN Products at ZTE, to find out more.
How does SuperDSS differ from DSS and how does it address the technical challenges inherent in DSS?
SuperDSS is an innovative technology which goes one step beyond conventional DSS. While the latter only considers the dynamic sharing of 4G and 5G, SuperDSS is the first in the industry to support triple-RAT sharing – either 2G, 4G and 5G dynamic sharing, or 3G, 4G and 5G dynamic sharing. With SuperDSS, operators can fast-track their 5G deployments using existing spectrum assets while continuing to deliver legacy services.
SuperDSS can address the technical challenges in DSS from the following aspects. In many markets, operators have used spectrum in the sub-3GHz range, such as in 1800MHz and the 2100MHz for 2G and 3G services respectively. Although some operators have refarmed the bands for 4G, a large percentage of operators continue to make limited use of this band for 2G and 3G. In such situations, operators cannot implement DSS on the full-band of both 1800MHz and 2100MHz bands, which lead to low utilization of spectrum as 2G or 3G traffic reduces.
In addition, SuperDSS can make dynamic spectrum sharing much more accessible to the operators who still offer 2G and/or 3G legacy services. It not only allows operators to improve 5G coverage, but can also lead to high efficiency for dynamically sharing the spectrum to high-value 4G and 5G service once 2G or 3G has low traffic load.
What are the main advantages of SuperDSS over DSS for operators?
SuperDSS will deploy 5G and become first mover in their market to provide diverse 5G services and ensure that the existing legacy services - those that require either 2G or 3G networks - remain unaffected. There are several examples of such services, with voice as the most important, especially in markets where there is little or no VoLTE service. Other use cases include smart meters, POS devices, or vending machines which use IoT devices and are dependent on 2G and 3G networks.
ZTE fulfilled SuperDSS commercial deployment with China Unicom in September 2020, implementing fast 5G deployment without impact on legacy network performance. After the introduction of SuperDSS in 2.1GHz spectrum, 3G/4G/5G dynamic sharing has been implemented on 20MHz bandwidth. Compared with 15MHz DSS solution, SuperDSS solution improves 4G throughput by 35% at most while the UMTS MOS keeps stable without any impact on voice service experience.
How far is SuperDSS an “out-of-the-box” solution and to what extent will operators need to tailor it to meet specific needs?
SuperDSS is a very flexible solution that can automatically adapt, once deployed, to operators’ specific needs and network traffic changes without extra human intervention, which can greatly reduce the cost of network operation.
SuperDSS implements simultaneous 2G/3G, 4G and 5G dynamic sharing in the same band. 2G or 3G bandwidth changes according to traffic load, while 4G and 5G dynamically share via delicate scheduling algorithms. When 2G or 3G traffic is on the wane, more bandwidth should and can be used for 4G and 5G, so 4G and 5G user experience can be improved without impacting the user experiences of the legacy services.
DSS has been criticised for increasing the complexity and cost of network management. How does SuperDSS address these operator concerns?
Unlike other dynamic spectrum sharing technologies, both DSS and SuperDSS introduce a new access technology (5G) resulting in increased network complexity and cost. However, SuperDSS considers the network evolution characteristics of the different access technologies including legacy RATs and the new one, which enables it to balance out the increased complexity and possible cost found with standard DSS.
SuperDSS will take account of network development to minimize the complexity. Legacy 2G or 3G services are kept while introducing new 4G and 5G services. SuperDSS has simple network operation and maintenance: one-time deployment can meet future network demands.
This image demonstrates how SuperDSS impacts 3G, 4G and 5G:
Stage 1: 3G and 4G co-exist, enabling dynamic spectrum sharing between LTE and UMTS.
Stage 2 : 5G is introduced, implementing tri-RATs dynamic spectrum sharing.
Stage 3 : 3G shutdown, fulfilling dynamic spectrum sharing between LTE and NR.
Therefore, a single deployment of SuperDSS can meet the demands of different stages of networks and ensure smooth evolution.
SuperDSS also reduces costs by:
- Reusing existing spectrum - no need to wait or acquire new 5G spectrum.
- Reusing legacy RAN equipment - only software upgrade is needed.
How does ZTE’s SuperDSS solution differ from DSS solutions provided by other vendors?
The release and commercialization of ZTE’s SuperDSS is ahead of other vendors. SuperDSS is the industry first 2G/4G/5G and 3G/4G/5G DSS (Dynamic Spectrum Sharing) solution, enabling quick 5G rollout while offering smooth migration of legacy voice services over the same carrier.
Furthermore, IoT technologies，such as NB-IoT and LTE-M are also included in SuperDSS solution to meet increasing demands from different industry verticals. In the future, even AI techniques will be adopted in SuperDSS to get better network performance and user experience based on the whole network’s perspective, adapting to traffic load in different frequency bands and user distribution.
