Analysis of firms' innovative performance in Japanese mobile telecommunication industry based on patent data

Mobile telecommunication industry has show remarkable technological progress in these twenty years. Recently, cell phones in Japan are equipped with unique high functions based on cutting-edge technologies such as one-seg television or non-contact payment system. In the present work, we investigate the technological characteristics of R&D in Japanese telecommunication carriers by using patent data. We also analyze the relationship between R&D activities and subsequent firm's performances based on panel data analysis. Similar to former studies concerning pharmaceutical industry or machine tool manufacturing industry, strong correlation between the number of patent applications and that of subscribers is found. It is also shown that regression model with shorter time-lag gives better description of the relationship between R&D inputs and outcome in this sector.