1. [1] Y. Kishiyama, “Initial thought on beyond 5G radio access technologies,” 2017 IEICE Society Conf., BS-2-2, Sept. 2017.
2. [2] Press release from NTT DOCOMO on Jan. 24, 2020. https://www.nttdocomo.co.jp/english/info/media_center/pr/2020/0124_00.html
3. [3] NTT DOCOMO, “Concept video of 5G evolution & 6G white paper,” Jan. 2020. https://www.youtube.com/watch?v=1Z5fMMGMysw
4. [4] NTT DOCOMO, “White paper: 5G evolution and 6G (revision 2.0),” July 2020. https://www.nttdocomo.co.jp/binary/pdf/corporate/technology/whitepaper_6g/DOCOMO_6G_White_PaperJP_20200820.pdf
5. [5] Press release from the Ministry of Internal Affairs and Communications, Japan on June 30, 2020. https://www.soumu.go.jp/main_sosiki/joho_tsusin/eng/pressrelease/2020/6/30_7.html