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Index and constellation order lowering for OFDM with index modulation
, Abhijith Nambi S.
Published in Institute of Electrical and Electronics Engineers Inc.
Volume: 24
Issue: 5
Pages: 1129 - 1132
Orthogonal frequency division multiplexing with index modulation (OFDM-IM) is a promising variant of OFDM where indices of symbol carrying sub-carriers also convey information bits besides the complex symbols themselves. Recently, a lower order modulation variant has been proposed for OFDM-IM, where the baseband constellation is lowered with appropriate rotations and index reuse, so as to lower the number of sub-blocks whose pairwise error probability is inversely related to the signal to noise ratio (SNR). In this work, we demonstrate that the number of symbol carrying sub-carriers and hence the number of used indices can also be lowered along with modulation order lowering. This reduces the aforementioned number of worst case sub-block pairs even further. The resulting unused sub-carriers can now be used to enhance the spectral efficiency as well. Numerical results reveal SNR gains up to 5dB for uncoded systems and 2dB for coded systems. © 1997-2012 IEEE.
About the journal
JournalData powered by TypesetIEEE Communications Letters
PublisherData powered by TypesetInstitute of Electrical and Electronics Engineers Inc.
Open AccessNo