Ericsson and KT have successfully completed a trial of mid-band Frequency Division Duplex Massive MIMO (MB FDD Massive MIMO) in Korea. Seven years after KT was among the first global communications service providers to launch commercial 5G with Ericsson solutions, the partners are again setting the pace—this time by prioritizing uplink performance to power the next wave of innovation and lay the groundwork for 6G.
For decades, mobile networks prioritized downlink technology, due to disproportionately large amounts of downlink traffic compared to uplink in the past. However, the future will be defined by uplink traffic with physical AI, sensing-rich apps, collaborative robotics, and immersive experiences demanding robust UL capacity, consistent coverage, and low latency—especially indoors and at the cell edge.
Standalone 5G (5G SA), including network slicing, already enables programmable, differentiated experiences. To deliver those experiences consistently at national scale—and to meet rising concurrent uplink demand from consumers and AI workloads—operators are augmenting SA with evolved radio underlays.
FDD Massive MIMO addresses this need. With stable uplink/downlink separation and advanced beamforming, mid-band FDD strengthens uplink performance and indoor penetration—exactly where AI workloads intensify—creating dependable foundations for SA, AI-RAN, and ecosystem growth.
The trial was conducted using Ericsson’s commercialized mid-band FDD Massive MIMO radio, AIR 3284. The lab trial result indicated clear user experience benefits:
Throughput uplift (FDD Massive MIMO NR vs. LTE): up to +95% in downlink and up to +127% in uplink.
Stronger coverage: up to +60% improvement in downlink at 50 Mbps and up to +64% in uplink at 15 Mbps.
These results validate an uplink-first design that improves coverage consistency, efficiency, and real-world performance—foundational for SA slicing and AI-RAN optimization.
By prioritizing uplink capacity and a consistent experience, KT and Ericsson are enabling an AI‑ready network that accelerates device and app innovation and enterprise adoption, advancing Korea’s domestic ecosystem. At the same time, MU‑MIMO (Multi-User MIMO) boosts capacity and spectral efficiency by serving multiple users at once to support dense consumer and industrial AI traffic.
Under the 6G MOU signed in 2025, Ericsson and KT are collaborating across next-generation Massive MIMO technology, spectrum sharing, and AI RAN technology.
Jong-sik Lee, EVP and Head of KT’s Future Network R&D Center, stated, “FDD Massive MIMO is key to further enhance usability of mid frequency bands, which will be critical to build 6G mobile networks.” He added: “We will continuously develop core technologies required for ubiquitous networks to enable a strong customer experience in the future as well to cope with 6G era.”
Sibel Tombaz, President of Ericsson Korea, says: “This milestone helps unlock the uplink performance, coverage, and efficiency needed to power Korea’s 5G evolution and prepare the network for the AI-driven future. It also lays the foundation for the transition toward 5G Advanced and 6G, where intelligent spectrum usage and programmable networks will be essential. By bringing Massive MIMO to the mid-band FDD environment, we’re strengthening the foundations for SA, AI-RAN, and programmable networks—setting new benchmarks in quality, reliability, and user experience across Korea.”
