My Google Scholar profile is available here.

Ph.D. Thesis

Space-, time-, and frequency-domain permutation modulation designed for microwave and optical wireless communications

Authors: Naoki Ishikawa
Published in: Tokyo University of Agriculture and Technology Ph.D. Thesis, February 2017.

First-Authored IEEE Journal (Refereed)

2. Differential-detection aided large-scale generalized spatial modulation is capable of operating in high-mobility millimeter-wave channels

Authors: Naoki Ishikawa, Rakshith Rajashekar, Chao Xu, Mohammed El-Hajjar, Shinya Sugiura, Lie-Liang Yang, and Lajos Hanzo
Published in: IEEE Journal of Selected Topics in Signal Processing, in press.

3. Nulls in the air: Passive and low-complexity QoS estimation method for a large-scale Wi-Fi network based on null function data frames

Authors: Naoki Ishikawa, Yasuhiro Ohishi, and Kaori Maeda
Published in: IEEE Access, vol. 7, pp. 28581—28591, February 2019.

4. Differential space-time coding dispensing with channel-estimation approaches the performance of its coherent counterpart in the open-loop massive MIMO-OFDM downlink

Authors: Naoki Ishikawa, Rakshith Rajashekar, Chao Xu, Shinya Sugiura, and Lajos Hanzo
Published in: IEEE Transactions on Communications, vol. 66, no. 12, pp. 6190—6204, December 2018.

5. 50 years of permutation, spatial and index modulation: From classic RF to visible light communications and data storage

Authors: Naoki Ishikawa, Shinya Sugiura, and Lajos Hanzo
Published in: IEEE Communications Surveys and Tutorials, vol. 20, no. 3, pp. 1905—1938, March 2018.

6. Rectangular differential spatial modulation for open-loop noncoherent massive-MIMO downlink

Authors: Naoki Ishikawa and Shinya Sugiura
Published in: IEEE Transactions on Wireless Communications, vol. 16, no. 3, pp. 1908—1920, March 2017.

7. Generalized spatial modulation based reduced-RF-chain millimeter-wave communications

Authors: Naoki Ishikawa, Rakshith Rajashekar, Shinya Sugiura, and Lajos Hanzo
Published in: IEEE Transactions on Vehicular Technology, vol. 66, no. 1, pp. 879—883, January 2017.

8. Subcarrier-index modulation aided OFDM — will it work?

Authors: Naoki Ishikawa, Shinya Sugiura, and Lajos Hanzo
Published in: IEEE Access, vol. 4, pp. 2580—2593, May 2016.

9. Maximizing constrained capacity of power-imbalanced optical wireless MIMO communications using spatial modulation

Authors: Naoki Ishikawa and Shinya Sugiura
Published in: Journal of Lightwave Technology, vol. 33, no. 2, pp. 519—527, January 2015.

10. Unified differential spatial modulation

Authors: Naoki Ishikawa and Shinya Sugiura
Published in: IEEE Wireless Communications Letters, vol. 3, no. 4, pp. 337—340, August 2014.

Co-Authored IEEE Journal (Refereed)

11. ``Near-perfect'' finite-cardinality generalized space-time shift keying

Authors: Chao Xu, Peichang Zhang, Rakshith Rajashekar, Naoki Ishikawa, Shinya Sugiura, Zhaocheng Wang, and Lajos Hanzo
Published in: IEEE Journal on Selected Areas in Communications, in press.

12. Finite-cardinality single-RF differential space-time modulation for improving the diversity-throughput tradeoff

Authors: Chao Xu, Peichang Zhang, Rakshith Rajashekar, Naoki Ishikawa, Shinya Sugiura, Li Wang, and Lajos Hanzo
Published in: IEEE Transactions on Communications, vol. 67, no. 1, pp. 318—335, January 2019.

13. Single-RF index shift keying aided differential space-time block coding

Authors: Chao Xu, Rakshith Rajashekar, Naoki Ishikawa, Shinya Sugiura, and Lajos Hanzo
Published in: IEEE Transactions on Signal Processing, vol. 66, no. 3, pp. 773—788, February 2018.

14. Algebraic differential spatial modulation is capable of approaching the performance of its coherent counterpart

Authors: Rakshith Rajashekar, Chao Xu, Naoki Ishikawa, Shinya Sugiura, K. V. S. Hari, and Lajos Hanzo
Published in: IEEE Transactions on Communications, vol. 65, no. 10, pp. 4260—4273, October 2017.

15. Full-diversity dispersion matrices from algebraic field extensions for differential spatial modulation

Authors: Rakshith Rajashekar, Naoki Ishikawa, Shinya Sugiura, K. V. S. Hari, and Lajos Hanzo
Published in: IEEE Transactions on Vehicular Technology, vol. 66, no. 1, pp. 385—394, January 2017.

IEEE Conference (Oral / Refereed)

1. EXIT-chart-based design of irregular-precoded power-imbalanced optical spatial modulation

Authors: Naoki Ishikawa and Shinya Sugiura
Presented in: IEEE 82nd Vehicular Technology Conference (VTC Fall), Boston, USA, September 2015.
Acceptance rate: not yet public

2. Single- and multiple-RF aided non-coherent generalized spatial modulation

Authors: Naoki Ishikawa and Shinya Sugiura
Presented in: IEEE 79th Vehicular Technology Conference (VTC Spring), Seoul, Korea, May 2014.
Acceptance rate: 62%