Maximal Spectral Efficiency of OFDM with Index Modulation under Polynomial Space Complexity

Autor: Queiroz, Saulo, Silva, Wesley, Vilela, João P., Monteiro, Edmundo
Rok vydání: 2019
Předmět:
Zdroj: IEEE Wireless Communications Letters, 2020
Druh dokumentu: Working Paper
DOI: 10.1109/LWC.2020.2965533
Popis: In this letter, we demonstrate a mapper that enables all waveforms of OFDM with Index Modulation (OFDM-IM) while preserving polynomial time and space computational complexities. Enabling all OFDM-IM waveforms maximizes the spectral efficiency (SE) gain over the classic OFDM but, as far as we know, the computational overhead of the resulting mapper remains conjectured as prohibitive across the OFDM-IM literature. We show that the largest number of binomial coefficient calculations performed by the original OFDM-IM mapper is polynomial on the number of subcarriers, even under the setup that maximizes the SE gain over OFDM. Also, such coefficients match the entries of the so-called Pascal's triangle (PT). Thus, by assisting the OFDM-IM mapper with a PT table, we show that the maximum SE gain over OFDM can be achieved under polynomial (rather than exponential) time and space complexities.
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Databáze: arXiv