Multiband carrierless amplitude and phase index modulation

As 5G standards continue to evolve, the need for communication systems with higher data rates is clear. However, the available bandwidth in the spectrum in most of the cases is limited and is not sufficient to satisfy future demands. Higher data rates drive the need for more efficient schemes to transmit information. Currently, there are different physical-layer (PHY) technologies that enable increasing data rates with a limited bandwidth such as flexible multicarrier waveforms and channel coding schemes. Index modulation (IM), which uses alternative ways to transmit extra information compared to traditional communication systems, is an innovative PHY solution to increase capacity and spectral efficiency (SE). In this paper, a new IM scheme based on multicarrier quadrature amplitude modulation/carrierless amplitude phase (QAM/CAP) modulation is presented. The property used by this scheme is, provided a contiguous fixed bandwidth, the feasibility to transmit the same amount of data by transmitting different number of contiguous frequency bands by adjusting their bandwidths. To increase the SE, an extra degree of freedom is generated by dynamically changing the distribution of the frequency bands being transmitted, that is, the number of bands used and its bandwidths and subcarrier frequencies. Simulation results are presented to validate the feasibility of the proposed scheme.