Hierarchical multi-stage interference alignment for downlink heterogeneous networks. - Tomoki Akitaya; Takahiko Saba (APSIPA, 2013)

Time-domain artificial noise generation technique using time-domain and frequency-domain processing for physical layer security in MIMO-OFDM systems. - Tomoki Akitaya; Shunta Asano; Takahiko Saba (ICC Workshops, 2014)

Energy Efficient Artificial Fast Fading for MISO-OFDM Systems. - Tomoki Akitaya; Takahiko Saba (GLOBECOM, 2015)