NTT DOCOMO Achieves Successful Outdoor Trial of AI-Driven Wireless Interface Toward 6G

NTT DOCOMO, INC. announced that they have successfully conducted the world’s first outdoor demonstration using real-time transceiver systems with AI-powered wireless technology for sixth-generation (6G) mobile communications. The demonstration was carried out in collaboration with NTT, Inc. (“NTT”), Nokia Bell Labs., and SK Telecom Co., Ltd. (“SK Telecom”). Field trials took place at three locations in Yokosuka City, Kanagawa Prefecture, and confirmed that the use of AI improved throughput (transmission speed) by up to 100% compared with conventional non-AI-based methods under the same environmental conditions, effectively doubling the communication speed.

In wireless communications, fluctuations in the radio propagation environment can cause unstable connection quality. To address this issue, the parties have been developing and testing “AI-AI technology,” which applies artificial intelligence to both the transmitting and receiving sides of the wireless interface to optimize modulation and demodulation schemes according to radio conditions, enabling stable communication across diverse use cases. The effectiveness of this technology had previously been verified in indoor environments.^*1

The latest field trials aimed to verify whether this new technology can maintain stable performance in outdoor environments, where radio conditions vary greatly due to temperature, weather, and obstacles.

In the field trials, DOCOMO and its partners evaluated the AI-AI technology under three outdoor environments with varying radio propagation conditions, such as the presence of obstacles and whether the terminal was stationary or in motion. The evaluations were conducted using devices equipped with the technology to compare throughput performance with and without its application.
Course 1: A public road with gentle curves where the test vehicle traveled at speeds of up to 40 km/h
Course 2: An environment with partial obstacles
Course 3: A road with few obstacles where the test vehicle traveled at speeds of up to 60 km/h

The results confirmed that applying the AI-AI technology improved communication speed by compensating for signal degradation across all test environments. In particular, under the most complex propagation conditions in Course 1, the technology achieved an average throughput improvement of 18% and a maximum of 100% compared to conventional methods. This improvement enables users to transmit larger volumes of data at higher speeds, while also allowing network operators to enhance spectrum efficiency and deliver higher-quality communication services.

These findings demonstrate that the AI-AI technology is effective not only indoors but also in complex outdoor environments, marking a significant step toward practical 6G systems that combine high wireless transmission efficiency with low power consumption.

DOCOMO will continue to refine this technology under diverse conditions and accelerate R&D toward 6G realization, while also collaborating with global partners to advance 6G standardization and implementation.

This technology will be showcased at the NTT R&D FORUM 2025, hosted by NTT from November 19–21 and November 25–26, 2025.
Further details on the official event website: https://www.rd.ntt/e/forum/2025/

1. 6G Radio-interface Indoor Test Using AI in the 4.8 GHz Band for the First Time in Japan Improves Throughput up to 18%(November 20, 2024)

About NTT DOCOMO

NTT DOCOMO, Japan’s leading mobile operator with over 91 million subscribers, is one of the global leaders in 3G, 4G and 5G mobile network technologies.
Under the slogan “Bridging Worlds for Wonder & Happiness,” DOCOMO is actively collaborating with global partners to expand its business scope from mobile services to comprehensive solutions, aiming to deliver unsurpassed value and drive innovation in technology and communications, ultimately to support positive change and advancement in global society.

https://www.docomo.ne.jp/english/AppendixOverview of the Field Trial

1. Overview
Since June 2022, DOCOMO has been conducting demonstrations with seven global partners, including major vendors and telecom operators, to develop next-generation wireless technologies for 6G across various frequency bands. In collaboration with NTT, Nokia Bell Labs, and SK Telecom, DOCOMO successfully completed the world’s first outdoor demonstration of AI-powered wireless technology, optimizing transmission and reception processing based on radio propagation conditions.

2. Field Trial
2.1. Experiment on public roads and within the DOCOMO R&D Center premises

DOCOMO conducted tests on public roads and within its R&D Center to evaluate the stability of wireless communication using the new technology under rapidly changing radio conditions with NTT.

Environment

• Course 1: A public road with gentle curves where vehicles can travel at a maximum speed of 40km/h.
• Course 2: An environment with partial obstructions.

Details

The baseband processing for AI-based transmission and reception was implemented on a GPU server using software-defined radio (SDR) hardware,^*1 operating at 4.8 GHz. A transmitting antenna mounted on a vehicle and a receiving antenna was installed on the R&D Center rooftop. along the route shown in Figure 1 and Figure 2. As the measurement vehicle equipped with the transmission antenna moved along the route shown in two figures, the reception signal was measured. For this experiment, 5G New Radio (NR)^*2 was used as a baseline to assess the impact of AI on transmission performance.

Results

From this experiment, it was confirmed that even in fluctuating environments, such as public roads with gentle curves (Course 1) and environments with partial obstructions (Course 2), communication using the new technology could provide stable transmission. Compared with conventional method, it showed an overall throughput improvement of approximately 18%, averaged across all courses. Furthermore, on Course 1, even in sections where conventional methods experienced reduced throughput due to surrounding trees and buildings, the new technology demonstrated up to a 100% improvement in throughput compared to conventional methods (Figure 1).

These results indicate that the technology can be applied not only in indoor environments but also outdoors, highlighting its potential for 6G communication in real-world scenarios. Going forward, DOCOMO will continue testing in more complex urban environments toward practical implementation.

2.2. Experiment at NTT Yokosuka R&D Center

At the NTT Yokosuka R&D Center, DOCOMO conducted throughput measurements to confirm that stable communication can be maintained regardless of the movement speed by utilizing the new technology for wireless processing with NTT.

Environment

• Course 3: A road with few obstacles where the test vehicle traveled at speeds of up to 60 km/h

Details
The transmitting antenna was mounted on a vehicle, while the receiving antenna was installed on a pole approximately 2 meters high, positioned as shown in Figure 3. Tests were conducted under both line-of-sight (LOS)^*3 and non-line-of-sight (NLOS)^*4 conditions, with vehicle speeds of 3 km/h, 30 km/h, and 60 km/h. (The experimental equipment used was the same as that described in field trial 2.1.)

Results
The results confirmed throughput improvements across all speeds and in various environments, achieving gains of up to 20% compared with conventional methods, demonstrating the effectiveness of the new technology.

Based on these findings, DOCOMO verified that stable communication can be maintained even when propagating environments, such as movement speed, LOS, or NLOS conditions, change, underscoring the robustness of this technology.

Going forward, DOCOMO will continue testing at speeds exceeding 100 km/h to further evaluate the technology’s potential in even higher-speed environments.

1. A platform for wireless research and development that enables implementation and testing of radio signal processing and algorithms using programmable hardware.
2. The standard interface currently used in commercial 5G systems.
3. A condition where there are no obstacles between the transmitter and receiver.
4. A condition where obstacles exist between the transmitter and receiver.

Press releases on NTT DOCOMO’s 6G initiatives:

• NTT DOCOMO and NTT to Collaborate on 6G Experimental Trials with World-leading Mobile Technology Vendors (June 6, 2022)
• DOCOMO and NTT Expand 6G Collaborations with World-leading Vendors Including Ericsson and Keysight Technologies (February 27, 2023)
• Nokia, DOCOMO and NTT make two key 6G advances #MWC23 (February 15, 2023)
• DOCOMO and NTT Expand 6G Collaborations with SK Telecom and Rohde & Schwarz (February 22, 2024)