Orthogonal frequency division multiplexing with index modulation (OFDM-IM) has been recently proposed as an efficient technique to improve the error performance and enhance the spectral efficiency achieved by the classical OFDM. In this letter, we minimize the presence of intercarrier and intersymbol interference, experienced by OFDM-IM systems under mobility conditions and multipath scenarios, by selecting the appropriate tone spacing between adjacent subcarriers. Finally, we prove that the optimal value of tone spacing increases the system capacity, occupying only the necessary amount of bandwidth, and provide closed-form expressions for the interference power per active subcarrier.
['Georgia D. Ntouni', 'Vasileios M. Kapinas', 'George K. Karagiannidis']
On the Optimal Tone Spacing for Interference Mitigation in OFDM-IM Systems