Sequency index modulation: A novel index modulation for delay-sequency domain waveforms

In this letter, the sequency domain is introduced as a novel resource to propose a new index modulation, which is named sequency index modulation (SeIM). In SeIM, information bits are implicitly conveyed through the indices of the activated sequencies enabling bit error rate (BER), spectral efficiency, and power efficiency enhancement. Also, two strategies are proposed to allocate power among the activated sequencies revealing a trade-off between BER and power efficiency. Moreover, results are analytically derived for the BER of SeIM decoder. Finally, the recently proposed orthogonal time sequency multiplexing modulation is utilized to evaluate the performance of SeIM over doubly-spread channels.