DUDe – Where’s my signal?

How Downlink and Uplink Decoupling (DUDe) can be used to expand 5G coverage.

5G is not just another ‘G.’ As anyone in the telecom space will tell you, it’s far more transformative, and behind all this transformative power resides a marvel of radio engineering. 5G radio networks are a highly complex, dense, heterogeneous mix of various spectrum bands and antenna types, including macro, micro, and picocells—each with different features, capabilities and requirements. This mix of technologies must all work together to support a world of connected things and data-intensive applications, including network slicing capabilities for ultra-reliable, low latency (URLLC) and massive machine-type communications (mMTC).

Massive MIMO is one of the technologies developed to help 5G deliver on its promises by increasing the coverage and capacity that a cell tower can provide. It uses specialized antenna arrays to achieve this, and when paired with new beamforming technology it can deliver highly targeted coverage to where subscribers need it most. These abilities mean that networks can get away with building fewer cell towers, which means lower CAPEX. All good stuff, right? Unfortunately, while the technology does a great job of extending downlink coverage and capacity, the same level of improvements are not seen in the uplink. This creates a situation where subscribers at the edge of a cell might be able to receive data from a nearby cell tower but are unable to communicate back, causing their session to be terminated. Suddenly, the advantages of massive MIMO aren’t so beneficial. There is a solution to this problem however, and that comes in the form of DUDe.

What is DUDe and how can it help?

DUDe stands for Downlink and Uplink Decoupling. It allows an additional, lower frequency signal to be configured on the uplink of a cell to complement the existing uplink signal.  Since lower frequencies travel further, the uplink/downlink difference at the cell edge is rebalanced. By way of an example, a 5G cell configured with a 3.5GHz frequency and massive MIMO antennas will have a significant difference between its downlink and uplink coverage. However, by adding an 1800MHz frequency as a supplementary uplink signal, subscribers at the edge of the cell will now have sufficient coverage and receive excellent service.

An additional benefit of this technology is that each cell now has two signals in the uplink and hence uplink capacity is increased. An important consideration as mobile services move from downlink heavy services such as video streaming, to much more balanced services such as video calls and multi-player video games and even uplink heavy services such as Tik Tok uploads from your daughter’s smartphone!

Downlink and uplink decoupling is just one example, but it exemplifies the growing need for accurate modeling and scenario planning when it comes to new 5G features. By modeling the various options available, an operator can be sure they have selected the best combination of technologies for each and every situation, ensuring maximum network performance for minimum CAPEX spend.

How TEOCO Can Help

TEOCO’s ASSET Radio is a network planning tool used by many of the world’s leading mobile operators. It provides RF planning and modeling for mobile networks, including the modeling of 5G Downlink and Uplink Decoupling.

Given the available sites and carriers, and the required coverage and capacity, ASSET Radio can be used to model the various downlink and uplink carrier configurations to determine the one best suited to a specific scenario. Standalone and Non-standalone 5G Downlink and Uplink Decoupling scenarios are supported, as are all the 3GPP defined carrier configurations. Additionally ASSET allows any TDD or FDD SUL carrier to be configured for decoupling and can even model Downlink and Uplink Decoupling in combination with Dynamic Spectrum Sharing.

For more information about ASSET Radio or our full suite of ASSET network planning solutions, contact us or click here.