The Key to Maximizing Spectral Efficiency for Network Optimization

By Derek Johnston, Head of Marketing & 5G Business Development, Networks Business, Samsung Electronics America

Spectrum is the foundation for a mobile network operator’s (MNO) service offering. As spectrum is relatively scarce and in some markets government regulators have been slow to allocate more, it’s a capital intensive requirement for network operators. As adoption of 5G has grown and data traffic rates continue to surge, the need for more efficient spectrum utilization is not just a technological necessity, but a business imperative for operators. The mobile industry is constantly seeking ways to optimally use the scarce spectral assets more efficiently to meet the digital demands of today’s consumers and businesses. Between 2010 to 2018, the industry drove 42x the amount of wireless data traffic over a MHz of spectrum[1], but the work continues as new spectrum gets added or, operators re-farm existing spectral assets. 

Gains in spectral efficiency generally drive transformative results for MNOs, starting with increased upload (UL) and download (DL) speeds, improving performance and quality of service for users. Additionally, by maximizing the efficient use of their spectrum holdings, MNOs can gain a competitive edge, while optimally leveraging their largest capital asset. There are multiple ways to achieve spectral efficiency, including three approaches which are implemented by FDD and TDD: aggregating various channels of spectrum—also known as carrier aggregation (CA); improving antenna capabilities; and enhancing radio resource management through Radio Access Network (RAN) software. Here are further details of each:

  • Adding Spectrum via Carrier Aggregation (CA) consists of taking the component carriers of spectrum, and combining them together to increase bitrate or throughput. CA essentially creates a bigger pipe by combining pieces of the same spectrum—or different blocks of spectrum— to increase the available ‘wireless pipeline.

    Recently, we shared test results showing CA’s capabilities in action. Qualcomm Technologies, Inc. and Samsung recently announced the world's first simultaneous 5G 2x uplink and 4x downlink leveraging CA for FDD spectrum, allowing them to combine traffic over different FDD frequency bands. The companies achieved 1.3Gbps DL speeds with 75MHz of bandwidth by combining 4 blocks of three different FDD spectrum bands. Meanwhile, UL speeds of 200Mbps were achieved with 35MHz of bandwidth by combining two blocks of two FDD spectrum bands.

    In addition, DISH Wireless recently became the world’s first network operator to test simultaneous 5G 2x uplink and 4x downlink CA using FDD spectrum. This test was completed in both DISH labs and the field using a mobile phone form-factor test device powered by Snapdragon® X75 5G Modem RF System from Qualcomm Technologies and Samsung's 5G vRAN solution as well as dual- and tri-band radios.

    With CA, operators can leverage fragmented pieces of spectrum to create optimal service levels, using their spectral assets in the most efficient way. For customers, this means enhanced experiences, whether it’s a consumer in a multi-player gaming session or a manager overseeing a production line using video analytics.
  • Densifying Cells via adding and improving antenna capabilities is another approach to driving efficient spectrum usage through antenna innovation. By using antenna technology like MIMO (multiple input, multiple output), a radio can improve wave propagation and increase signal quality when coupled with a technique called beamforming to amplify signals in the direction of a device to increase the quality of the link. Additional spatial multiplexing techniques can be used to lower interference and thus increase signal and data rates (throughput), further boosting spectral efficiency.

    Taking MIMO even further, multi-user or MU-MIMO is the latest technology to further improve network performance during traffic peaks. Where single-user or, a SU-MIMO radio transmits one or multiple data streams, or layers to a single device, a radio enabled with MU-MIMO, sends multiple data streams, or layers to multiple devices. The different layers in different beams are transmitted to different users simultaneously on the same physical radio resource (i.e. using the same frequency and time segment). MU-MIMO is another tool for network operators to effectively manage high-traffic events.

    An example is Samsung’s recent collaboration with MediaTek, in which the companies achieved an industry-first milestone in 5G UL technology. Using three transmit (3Tx) antennas to combine 5G Standalone UL 2CC CA with C-Band UL MIMO, we enhanced upload experiences, culminating in a peak throughput rate of 363Mbps, an uplink speed that is near theoretical peak using 3Tx antennas.

    Samsung focuses on radio design and advancing antenna technology to boost spectral efficiency. Recently, our radios were highlighted by analyst firm Signals Research Group (SRG), in independent tests[2] that showed Samsung’s 64T64R MU-MIMO radio increased capacity by up to 70%, while average gains are in the 30-40% range. Powered by Samsung’s vRAN solution, these MU-MIMO radios can support 16 layers, which can theoretically quadruple network capacity compared to a traditional 5G network using four layer SU-MIMO. The tests conducted by SRG were executed with four devices, meaning that the true capacity gains of the MU-MIMO are likely higher than what was observed during this study.
  • Enhancing 5G RAN software via continuous innovation of software-based RAN architecture–or virtualized RAN (vRAN)–continues to deliver above expectations. Some in the industry questioned its ability to address the performance levels and capacity of 5G wireless networks requiring large massive MIMO radios. Today, vRAN supports many types of radios and frequency bands, including massive MIMO, which has already been deployed in 5G SA and 5G NSA on large-scale commercial networks.

    Samsung’s vRAN is proving to be a tool for operators looking to drive more efficient use of spectrum, enabling them to take full advantage of the existing spectrum holdings with increased service differentiation and customer satisfaction. Samsung’s latest vRAN 3.0 offers improved software capabilities to handle up to three 64T64R massive MIMO radios at once, each supporting 200MHz on one virtualized Distributed Unit (vDU) as well as energy saving features.

    In addition, a vRAN solution has been leveraged in a test-bed to deliver cost-efficient network slicing[3]. Results from this test confirm that virtualized RAN leads to cost-efficient resource slicing with 10-15% reduction in radio resource consumption – while delivering performance, across data rate, isolation and more related to the service level agreements. 

As data demand continues to grow, optimizing spectral efficiency is a proven approach to assist in managing escalating demand and a financial imperative for network operators. These technologies will pay dividends for services adopting high-UL technologies such as video analytics, and robotic systems, as well as consumers that are uploading more life experiences via video on social media sites or using multi-player gaming platforms.

Samsung has been a forerunner in the advancement of 5G technology, and is now continuing to raise the bar on what’s possible through increased spectral efficiency. With our advanced solutions available to aid operators in deploying 5G networks—and by incorporating its latest vRAN 3.0 solution at the heart of MNO networks—we look forward to ushering in the next wave of performance-enhancing capabilities that enable network and business transformation for operators worldwide. 

[1] “Smarter and More Efficient: How America’s Wireless Industry Maximizes Its Spectrum, CTIA, July 8, 2019”
[2] From Signals Research Group Report: 5G: THE GREATEST SHOW ON EARTH! MU-MIMO and the Tower of Power (Chapter 2) 06/26/2023
[3] Science Direct: Cost-efficient slicing in virtual Radio Access Networks

The editorial staff had no role in this post's creation.