SoftBank Corp. and Ericsson to deploy AI-powered external control system to optimize Massive MIMO coverage

SoftBank Corp. (“SoftBank”) and Ericsson Japan K.K. (“Ericsson”) today announced that they have deployed an AI-powered, externally controlled coverage optimization system for Massive MIMO at multiple large-scale event venues in Japan, including major arenas and dome-type facilities in the Tokyo metropolitan area, which automatically enhances coverage patterns in response to traffic changes. This follows a successful commercial network trial at the Expo 2025 Osaka, Kansai, Japan (“Expo 2025”).

At large-scale event venues and theme parks, user distribution varies significantly between normal periods and during events, requiring flexible base station control in response to these distributions and changes. In particular, for events subject to weather-related cancellations or schedule changes, such as fireworks displays, or where specific area access restrictions occur, conventional methods that preset coverage pattern changes by time slot were sometimes unable to respond appropriately. Therefore, a system capable of automatically controlling and optimizing coverage patterns according to the situation was needed. To address these challenges, SoftBank and Ericsson have repeatedly conducted trials to validate automated traffic optimization using AI-driven external base station control^*1.

When deployed at base stations installed in outdoor areas of the Expo 2025, the system delivered clear improvements in communication quality, including an approximately 24 percent increase in downlink throughput, from 76.9 Mbps to 95.5 Mbps, during periods of rapid traffic fluctuation.

Building on these results, SoftBank and Ericsson have begun operating the system at large-scale event venues where user distribution varies significantly by time of day.

Overview of the system

• An external control device (server) uses user distribution data collected from base stations at one-minute intervals to automatically determine event occurrence using AI
• Dynamically and automatically optimizes the horizontal and vertical coverage patterns of Massive MIMO base stations

Overview of demonstration at Expo 2025:

(1) Location
Massive MIMO-compatible base station installation areas within the Expo 2025 venue

(2) Content
An AI model was constructed using performance results obtained when multiple coverage patterns were changed in advance as training data. Based on user distribution-related data such as Massive MIMO beam estimation information^*2 acquired by an external control device from base stations at one-minute intervals, the system automatically determined event occurrence status and switched base station coverage patterns to optimal configurations.

(3) Key Results
Downlink throughput for 5G users across the entire area during event periods improved by approximately 24 percent^*3. This result contributed to avoiding "packet stalling" phenomena where data transmission and reception stagnate due to congestion that tends to occur during rapid traffic fluctuations.

Roles of each company

• SoftBank
  Use case examination and demonstration evaluation of the system
• Ericsson
  Provision of the system

The two companies will continue to actively expand deployment of the system.

*1 In September 2023, successful demonstration of automated traffic optimization through external base station control was achieved. For details, please refer to the press release dated February 22, 2024: "SoftBank Corp. and Ericsson Japan K.K. successfully demonstrate high-speed automatic optimization of 5G networks through external control of base stations."

*2 Reference signals used when terminals report the quality of Massive MIMO beams or channels back to the base station. These signals serve as an indicator of users’ spatial distribution.

*3 Base station data acquired on days without and with the system applied were compared and evaluated under conditions with equivalent visitor numbers and event time periods.

ABOUT SOFTBANK CORP.:

Guided by the SoftBank Group’s corporate philosophy, “Information Revolution – Happiness for everyone,” SoftBank Corp. (TOKYO: 9434) operates telecommunications and IT businesses in Japan and globally. Building on its strong business foundation, SoftBank Corp. is expanding into non-telecom fields in line with its “Beyond Carrier” growth strategy while further growing its telecom business by harnessing the power of 5G/6G, IoT, Digital Twin and Non-Terrestrial Network (NTN) solutions, including High Altitude Platform Station (HAPS)-based stratospheric telecommunications. While constructing AI data centers and developing homegrown LLMs specialized for the Japanese language, SoftBank is integrating AI with radio access networks (AI-RAN), with the aim of becoming a provider of next-generation social infrastructure. To learn more, please visit https://www.softbank.jp/en/corp/