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Feature Articles: Keynote Speeches and R&D on Access Networks Presented at Tsukuba Forum 2025 Vol. 23, No. 9, pp. 41–47, Sept. 2025. https://doi.org/10.53829/ntr202509fa5 R&D toward Operational Innovation and New Value Creation of Social InfrastructuresAbstractAiming at operational innovation through digital transformation of access network system business, we at the Access Network Management Project of NTT Access Network Service Systems Laboratories are researching and developing smart engineering (design/construction) and smart maintenance (maintenance/operation) technologies. We are also taking on the challenge of creating new value in fields other than communications by using the assets of communication facilities. The technologies developed for these communication infrastructures will be applied to other infrastructures such as electricity, gas, and water, and will contribute to the maintenance and management of social infrastructures of Japan and address social issues. Keywords: operational innovation, advanced operation, access network facilities  1. Operational innovation in access network services and contribution to maintenance of social infrastructuresNTT has been providing various services, from fixed telephones using metal (copper) cables to data communications using optical fiber, while being responsible for the construction and maintenance of access facilities. The rapid deterioration of facilities, severe and frequent disasters, shortage of construction and maintenance personnel due to the rapid decrease in population, increasing unevenness in population density, and increase in management costs are threatening the development and maintenance operation of infrastructures, which are assumed for long-term use. This situation poses a threat not only to NTT’s communication facilities but also to social infrastructures, including electricity, gas, and water, of Japan. Looking ahead to the coming era of IOWN (Innovative Optical and Wireless Network), we at the Access Network Management Project of NTT Access Network Service Systems Laboratories are taking on the challenge of creating new value in fields other than communications by using the assets of communication facilities as well as contributing to the maintenance and management of social infrastructures in Japan and addressing social issues. 2. Current situation and issues facing Japan’s social infrastructuresTo clarify the threats to communication infrastructure and their challenges, we analyzed the aging of facilities and population dynamics with increasing unevenness in density, which have a significant relationship with NTT’s communication facilities and a significant impact on management. Regarding the aging of facilities, the maintenance, management, and removal of metal cables for fixed telephones, the number of subscribers of which is decreasing significantly, are becoming major management issues for NTT operating companies. With regard to population dynamics with increasing unevenness in density, the increase and decrease in population and degree of density vary from municipality to municipality. Since NTT has an obligation to provide universal services, if the maintenance requirements for facilities remain uniform, there is a high possibility that its business operations will not be able to continue due to resource shortages. Therefore, we anticipate that the provision of services and the design, construction, and operation of facilities in accordance with the characteristics of each area will become major issues. As an example of the aging of facilities, we analyzed and simulated the number of telephone poles by construction year (Fig. 1). As shown in Fig. 1(a), a large number of telephone poles were constructed around 2000 when the number of telephone subscribers reached its peak and from the late 1990s to 2010 when a large number of optical-fiber lines were opened. If the service life of telephone poles after construction is assumed to be 70 years in the simulation, it is assumed that in 15 to 20 years, about 7 million poles, which is about 60% of the total number of telephone poles in the NTT EAST and WEST areas (i.e., 12 million poles), will require frequent inspection, reconstruction, etc. This is also assumed for all other access-system outside-plant facilities. The total amount of facilities, not limited to telephone poles, continues to increase, and it is clear that there is a limit to the current technology and maintenance methods to renew them all.
Next, I would like to introduce the results of our analysis of population dynamics with increasing unevenness in density. On the basis of the analysis results of “2024 Municipality Sustainability Analysis Report (April 24, 2024)” by the Population Strategy Council (Chair: Akio Mimura, Vice Chair: Hiroya Masuda) [1], we examined the ideal form of access facilities in the medium and long term by comparing the future population transition of each municipality in Japan and the situation of NTT facilities for this transition. In the above-mentioned report, all 1729 municipalities in Japan are classified as either black hole municipalities, self-sustaining municipalities, general municipalities, and potentially disappearing municipalities on the basis of their characteristics related to population conditions and dynamics. We calculated the number of telephone poles installed by NTT for each municipality and estimated the number of telephone poles per household. We found that the rapid decrease in the size and density of population will increase the cost of facility maintenance per population, as shown in Fig. 2, and approximately 30% of NTT’s facilities (telephone poles) exist in potentially disappearing municipalities, which account for 40% of total municipalities and approximately 10% of total households, as shown in Fig. 3. We assume that this result applies to NTT’s overall facilities for providing communication services.
From these results, we can imagine that unless NTT takes drastic measures, this will hinder business operations and have a major impact on management. Therefore, as shown in Fig. 3, we considered it is necessary to organize the requirements for business operation as an ideal form of access facilities on the basis of population density and examine the ideal form of facility construction and maintenance with different strategies for each of the aforementioned municipal divisions. As competition with other companies is expected to be fierce for black hole municipalities and self-sustaining municipalities, it is necessary to actively promote the construction of facilities that deliver highly competitive services. For general municipalities and potentially disappearing municipalities, it is necessary to consider resource sharing with other infrastructure providers for inspection and maintenance, longer life and maintenance-free facilities, and structural design based only on optical-fiber services. We are also planning to apply these advanced and efficient maintenance operations to black hole municipalities and self-sustaining municipalities. It is important to consider the efficient removal of unprofitable metal cables, especially in potentially disappearing municipalities. We are accumulating technologies while keeping in mind the future state of access facilities on the basis of population density. We have analyzed the aging of facilities and population dynamics with increasing unevenness in density. We plan to address severe and frequent disasters, shortage of construction and maintenance personnel due to a rapid decrease in population, and increase in management costs, which are also major threats and have become targets for solving problems, with the technology we are developing. I now introduce the operational innovation technology in communication infrastructures we are currently developing and the content of our research and development (R&D) toward the creation of new value, which will lead to the solution of problems in social infrastructures. 3. Smart maintenance/smart engineering for operational innovationIn this section, I introduce smart maintenance and smart engineering, which are examples of operational innovation technologies for access facilities. 3.1 Smart maintenance (digitization of facility information)As a measure for standardization and labor saving through digital transformation of social-infrastructure maintenance and management, we are advancing research on deterioration diagnosis of overhead structures using three-dimensional (3D) point-cloud data. We have developed a structural-deterioration-assessment system for diagnosing the state of pole deterioration from 3D point-cloud data acquired from mobile mapping system (MMS) measurement and have been disseminating the research results throughout the NTT Group. However, commercial MMSs are designed for measuring road surfaces, etc., and it is difficult to measure point clouds from small-diameter objects such as cables. Therefore, it has become clear that drastic improvement in accuracy is difficult only with approaches to software technology. To achieve further high precision of the digitization of outside-plant facilities, we evaluated coordinate-positioning technologies and point-cloud measuring instruments on the market and examined the feasibility of and problems with these technologies and instruments. By combining high-density laser and LiDAR (light detection and ranging), it became possible to obtain point-cloud data even from the thinnest optical drop cable by optimizing the vehicle-mounting condition. By applying the modeling technology to the point-cloud data, we were also able to confirm the efficiency of inspection by further increasing the accuracy in measuring pole deflection and the applicability to new areas such as the building limit near trees (Fig. 4).
3.2 Smart engineering (machine replacement)To construct a safe working environment for on-site work, we aim to prevent accidents caused by human error by using machines (robotics). We are developing a construction-obstacle proximity-detection technology for accurately detecting construction obstacles, such as telephone poles and communication cables, during pole work and measuring their distances in real time. We are currently conducting system development and product evaluation. We are also aiming for remote and automatic construction of pole erection by heavy machinery through the combination of elemental technologies such as for acquiring 3D data of the on-site space, automatic object recognition, and automatic calculation for the heavy-machinery-operation plan together with the construction-obstacle proximity-detection technology. 3.3 Smart engineering (advanced construction methods)To reduce labor at work sites, we are investigating a technology that enables safe removal of cables even if the work of loosening tension or lifting poles is omitted. Telephone poles are always subjected to tension of several hundred kilograms or more by cables, and extreme imbalance of tension can cause the poles to collapse. Tension changes greatly when removing all cables, but it is not clear what amount of tension change occurs quantitatively. Therefore, it is necessary to carefully loosen the tension before removing cables. This requires a great deal of labor because wire strainers and aerial vehicles are used. We are thus aiming to develop a technology to cut and remove cables from telephone poles without loosening the tension of cables and without climbing poles. Specifically, we want to clarify the applicable range by quantifying and analyzing the impact of instantaneous unbalanced loads, cable drops, and the impact on equipment and communications for various types of equipment, degrees of equipment degradation, and line configurations. 4. Optical-fiber-based environmental monitoringThis section introduces environmental monitoring with fiber-sensing technology using existing optical fibers for creating new value. Optical-fiber-based environmental monitoring is a technology for obtaining and using various environmental information (vibration, temperature, strain, etc.) from optical fibers laid for communications. Because this technology uses communication buildings and installed optical cables, it does not incur additional costs, such as for laying new optical cables, installing a large number of sensors, and supplying power, and it is easy to introduce, develop, and maintain. We aim to address social issues by applying this technology to various industrial fields. 4.1 Analysis and use cases of vibration data obtained from communication facilitiesVibration sources that cause vibration to communication facilities vary from artificial vibrations, such as traffic vibration of vehicles and construction vibration of construction machinery, to natural vibrations such as from wind, rain, and earthquakes. This is not limited to the maintenance of NTT’s communication facilities, and we are considering other applications. Figure 5 shows some of the use cases we are investigating.
4.1.1 Construction monitoring (detection of road-excavation work)In excavation work at places where underground infrastructures, such as telecommunications, electricity, and gas, may be buried, consultation among infrastructure operators is necessary, and security measures are taken through burial surveys and construction attendance. However, the number of infrastructure-damage accidents due to unreported construction is increasing. Therefore, there is a need for infrastructure operators to monitor unreported construction at low cost. We are developing automatic detection technology for road-excavation work. Solving problems with such detection involves coping with various types of construction equipment and reducing the false detection rate. The construction equipment used at the start of excavation work varies depending on the situation, such as road cutters used for cutting pavement and choppers and backhoes used for breaking and removing pavement. In the outdoor living environment, there are many similar mechanical vibrations transmitted by pumps and fans, etc. We are investigating an automatic detection technology for eliminating as many false-detection factors as possible while maintaining a high detection rate of excavation work within a certain distance from communication facilities by using feature analysis and machine learning based on sensing technology involving high-precision distributed acoustic sensing (DAS) and actual data obtained from many field tests. 4.1.2 Road-surface monitoring (support for road-snow-removal decisions in heavy snowfall areas)In heavy snowfall areas, road-snow-removal decisions are usually made by human patrols, who daily determine the necessity of snow removal on each route and decide which roads should be cleared preferentially within the limited snow-removal budget. There is thus a need for local governments to make patrol work remote in the midst of labor shortage. We have been developing a snow-removal-support technology that involves applying traffic vibration, which has been used for traffic-flow analysis in cities. With this technology, the waveform of the vibration received by the underground optical-fiber cable is measured. By analyzing the vehicle speed from the moving vibration locus and the frequency response received from the road surface at the same time, a machine-learning model using the correlation between the ease of vehicle passage and road-surface condition is constructed, and the necessity of snow removal is classified using this model. Field verification conducted in an area with heavy snowfall confirmed the effectiveness of this technology, showing more than 90% agreement with the visual inspection results obtained by field investigators. 5. Application of technologies for telecommunications infrastructure to social infrastructures and future directionsAs determined from the road-cave-in accident in Yashio City, Saitama Prefecture, which occurred in January 2025, risks associated with aging social infrastructures have become apparent. Preparedness for threats to Japan’s social infrastructures is an urgent issue for Japan. At NTT Access Network Service Systems Laboratories, we believe that there are similar assets in telecommunications infrastructure and social infrastructures as well as similar issues in business processes (Fig. 6). Therefore, we would like to take advantage of NTT’s unique organizational structure, which has been built throughout Japan, and apply the technologies we have developed for the telecommunications infrastructure to other infrastructures. In addition to the smart engineering/maintenance and optical-fiber-based environmental monitoring introduced in this article, we would like to accelerate our R&D and disseminate technologies that contribute to addressing issues in Japan.
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