Multiple-Mode MIMO With Index Modulation And Its In-phase/Quadrature Extension

Motivated by multiple-mode orthogonal frequency division multiplexing with index modulation (MM-OFDM-IM) and multiple-input multiple-output (MIMO) technologies, a new modulation technique named multiple-mode MIMO with IM (MM-MIMO-IM) is proposed, which is implemented over the virtual parallel channels resulting from singular value decomposition (SVD) of the MIMO channel. Moreover, coordinate interleaved technique is employed to improve its diversity gain. Compared with traditional MIMO systems, the spectral efficiency (SE) of MM-MIMO-IM systems is significantly improved due to the introduction of the mode permutation. We further extend MM-MIMO-IM to in-phase/quadrature (I/Q) dimension, yielding MM-MIMO-IM-IQ, which achieves a double SE with respect to MM-MIMO-IM. Asymptotically tight upper bounds on bit error rates (BERs) of the proposed schemes are derived to evaluate their performance. Monte Carlo simulation results demonstrate the advantages of the proposed schemes.