Key digital technology innovation patterns in cities of China: The role of technological relatedness

The rapid development and widespread integration of digital technologies have profoundly transformed the economic structure, becoming a key force in reshaping national innovation patterns and empowering newquality productivity. Based on the invention patent data for key digital technologies in cities of China from 2014 to 2022, this study identified indicators such as the number of key digital technology patents and the technological relatedness density of key digital technologies, to depict the trends of change of China's key digital technology innovation landscape. The study divided cities into digital technology innovation core zones, sub-core zones, potential zones, and peripheral zones, and explored the impact of technological relatedness on urban specialization in new digital technologies. The findings reveal that: 1) China's key digital technology innovation was highly concentrated spatially, with a pronounced siphon effect. 2) The gap in new digital technology development potential between cities was narrowing, with many cities in the central and western regions showing a high degree of digital technology integration, ranking among the top 10 nationally in terms of technological relatedness. 3) Fifty-nine core zones have been identified, thirty of which are located in the Yangtze River Delta, the Pearl River Delta, and the Beijing-Tianjin-Hebei urban clusters. Nine potential zones were distributed around the core zones, contributing to regional technological complementarity. 4) Technological relatedness played a key role in the specialization of new digital technologies in cities of China. A 10% increase in technological relatedness led to a 9% increase in the likelihood of specialization in new digital technologies, with the largest increase observed in sub-core zones. Among the seven categories of technologies, the Internet of Things showed the greatest growth. This study reveals the spatial differentiation patterns of digital technology innovation, providing a scientific reference for formulating region-specific digital technology development strategies and promoting high-quality growth of the digital economy.