Back to Front: How Ericsson is enabling SKT to drive 5G in South Korea

Mountains, forests and physical infrastructure are proving no obstacle to Ericsson’s determination to help South Korean communications service provider SK Telecom (SKT) deliver the benefits of 5G to everyone in the country. The key? Using a backhaul solution for a fronthaul application.

Fronthaul is the radio to baseband connection usually provided via optical fiber. Microwave links are usually used in the backhaul segment, connecting the basebands to the core network.

Network Infrastructure

Fronthaul is seen as increasingly important as 5G rollouts ramp-up. However, as it involves optical fiber, fronthaul deployment can present a new challenge for communications service providers (CSPs): how to deploy cable in modern infrastructure environments that already include a complex maze of cables and essential utility pipes, or other physical barriers. Aside from the physical engineering difficulties, such challenges can also be both costly and require long installation time.

This was one of the challenges that Ericsson and SKT engineers sat down to discuss as part of the CSP’s ongoing efforts to make 5G connectivity available to all in South Korea. As a country with a well-earned reputation as a technology leader – where 5G connectivity and uptake is already widespread across major cities and towns – finding a workable solution quickly was a key ambition in the discussions.

Other scenarios were added to the discussions. Connectivity in national parks and archipelago islands, where digging is prohibited; mountain cabins; resorts in forests; and buildings that cannot be reached by cable.

Resulting Ericsson innovation saw a new way of connecting these antenna sites using wireless technology: connecting a 5G radio using eCPRI (Ethernet-based Common Public Radio Interface) and Ericsson’s E-band product MINI-LINK 6352, usually used for backhaul.

SKT and Ericsson have trialed the solution in a proof of concept (PoC) live network deployment. The PoC has shown MINI-LINK 6352 to be equally effective as a fronthaul solution.

The PoC, carried out in October, delivered very encouraging results. It showed that SKT can easily deploy a compact and lightweight wireless solution to enable 5G network in areas where it is challenging to lay underground optical cables.

Following its successful verification in an end-to-end 5G network, Ericsson is pressing ahead with plans to add the solution to the commercial portfolio.

Hans Mähler, Head of Microwave Systems, Business Area Networks, Ericsson, says: “We continue to support our partner SKT in their 5G journey, now progressing from initial rollouts in cities to wider coverage in suburban and remote areas. This latest collaboration shows the versatility of our products. We don’t always have to reinvent the wheel to support our customers. MINI-LINK 6352, typically used for backhaul, is now proven to be equally effective as a fronthaul solution. The solution has already attracted interest from customers around the world who are facing similar rollout challenges. We are looking forward to helping customers globally with this solution in the near future.”

How the PoC worked

Ericsson microwave links have much better system gain, meaning they enable longer distances between the radio site and the baseband hotel and have proven more efficient in capacity by supporting eCPRI.

The MINI-LINK 6352 adopts eCPRI, a standard 5G fronthaul interface that can considerably increase traffic capacity compared to the previous alternative (CPRI), thus maximizing network operation efficiency. A strong system gain is important for microwave-based fronthaul solutions as it determines the distance between radio sites and baseband hotels.

Using a 3D map, SKT engineers carefully analyzed the installation height and angle of Ericsson 5G equipment so that radio waves could be accurately transmitted.