NTT and partners develop technology to reduce wireless delay jitter, demonstrate remote drone operation from about 60 km away

Key points: ◆ The companies developed a technology that reduces delay jitter occurring over wireless links when transmitting drone video to an operator, stabilizing video quality. ◆ They built a remote drone operation environment connected by Local 5G and FLET'S VPN from a site about 60 km away, and demonstrated the effectiveness of the technology. ◆ Stable video transmission enabled precise remote drone operation, confirming that inspection work can be performed without dispatching personnel to the site. NTT Corporation, NTT-ME Corporation, and NTT e-Drone Technology Corporation have developed technology that reduces delay jitter occurring over wireless links, and demonstrated it in a remote drone operation environment connecting sites about 60 km apart. In the trial, the companies confirmed that stable video transmission to the operator and remote drone operation are possible via Local 5G and FLET'S VPN. This enables precise inspection work in hazardous locations without sending personnel to the site. The technology is scheduled to be exhibited at Tsukuba Forum 2026, held on May 27 and 28, 2026. 1. Background Japan faces a worsening labor shortage, and securing workers for infrastructure and equipment inspections has also become a challenge. As a result, expectations are rising for remote inspections using drones, which are attracting attention as a way to perform inspections without dispatching personnel on site. For fixed inspection points across relatively large areas, automated flight is suitable. However, for construction sites or factory inspections where inspection points change by day, or in relatively narrow spaces, drones must be operated remotely with precision, safety, and real-time responsiveness. This requires not only uninterrupted communications but also stable video transmission without video distortion. A key issue has been that packet delay jitter causes video distortion, leading to reduced operation accuracy. In wireless links, jitter occurs because uplink and downlink communications share the same frequency band, and retransmission control is triggered when wireless quality deteriorates. To address these issues and enable operators to control drones remotely with confidence, the companies demonstrated a technology that reduces delay jitter over wireless links and stabilizes video quality. 2. Research results In the demonstration, the companies built an environment in which a drone operator remotely controls a drone while watching camera video transmitted over a network. The drone was placed at the Robot Test Field in Minamisoma, Fukushima Prefecture, and operated from Koriyama, Fukushima Prefecture. The two sites, approximately 60 km apart in a straight line, were connected via FLET'S VPN, with Local 5G used for the wireless link. In this environment, the companies confirmed that the drone could be operated remotely. The system also implemented a function to compensate for delay jitter occurring over the wireless link. During high-load video transmission, video distortion was detected during 12% of the total transmission time. By applying this technology, the time with video distortion was reduced to 5%. The companies also evaluated travel time, since significant video distortion can cause operators to interrupt control and take longer to reach the destination. A movement that took an average of 35 seconds under visual operation in Minamisoma was completed in an average of 32 seconds under remote operation from Koriyama without interrupting control, confirming video quality sufficient to avoid affecting operation. 3. Technical highlights In wireless links, delay jitter caused by retransmission control and other factors makes video frame intervals fluctuate, leading to video distortion. This technology analyzes the video rate with a controller based on traffic information collected from the wireless base station, then uses optical network equipment to correct frame intervals according to the video rate. This reduces delay jitter generated over the wireless link. While it is difficult for a wireless base station alone to handle wireless delay jitter, coordinated optical-wireless control covering both wireless and optical sections reduces delay jitter and stabilizes video quality. The technology consists of three steps: 1. Collection: Continuously collects information from the wireless base station to track changes in video rate. 2. Analysis: Accurately calculates the video rate from traffic information. 3. Control: Corrects frame intervals through shaping control matched to the video rate. The closer the distribution of video frame intervals is to the ideal value, the more stable the video quality is. Before applying this technology, delay jitter in the wireless link caused large variation in frame intervals and video distortion. By applying the technology, delay jitter is reduced, frame intervals are brought closer to the ideal value, and video distortion is eliminated. 4. Roles of each company NTT: Implementation of the video quality stabilization technology and verification of its usefulness in remote operation. NTT-ME: Design, construction, and operation of Local 5G in the demonstration. NTT e-Drone: Provision of drones and the operation environment for the demonstration, and confirmation of beyond-visual-line-of-sight operability. 5. Future development This technology can deliver stable video quality to remote operators. The companies will promote commercialization of the technology, aiming for broad application not only to drones but also to the operation of unmanned aircraft and robots. The technology can also be used for remote work beyond inspections. The companies will promote remote operation across various fields and work to help address labor shortages.