  In this paper, we propose two novel modulation concepts based on a simple
maximum distance separable (MDS) code { and show that these concepts can
achieve better error performance than index modulation (IM) and related
schemes.} In the first concept, we use amplitude and phase levels to form a
simple MDS code, whereas, in the second one, in-phase and quadrature components
of codeword elements are used to construct the MDS code. We depict practical
schemes for using the proposed concepts with orthogonal frequency division
multiplexing (OFDM). We analyze the performance in terms of the minimum
Euclidean distance and bit error rate. We also show that the proposed
techniques exhibit desirable properties such as efficient low-complexity
detection, very simple bits-to-symbols, and symbols-to-bits mappings, and a
better error performance when compared to the OFDM-IM and related schemes. More
importantly, contrary to the vast majority of IM studies that focus on showing
the superiority of the IM techniques against conventional modulation
techniques, we show that modulation concepts based on a well-known MDS code can
achieve better error performance than the IM and related schemes while
exhibiting a structure as simple as these schemes.
