Rectangular Differential OFDM with Index Modulation

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) with Index Modulation (OFDM-IM), which conveyed information bits via the activated indices and constellation symbols is a promising technique in the next wireless communications. In the OFDM-IM scheme, only part of subcarriers are activated to transmit information, the inactive subcarriers transmit zero symbols, so that the conventional differential coding is not suitable for the adjacent subcarriers. In order to address this issue, in this paper, a novel Rectangular Differential OFDM-IM (RD-OFDM-IM) scheme is proposed to exploit the benefits of OFDM-IM dispensing with Channel State Information (CSI). In the proposed RD-OFDM-IM scheme, N subcarriers are partitioned into G subblocks and index modulation is employed in each subblock first. Then rectangular differential coding is invoked during two adjacent subblocks, so that nocoherent detection can be employed for the proposed RD-OFDM-IM scheme. Simulation results are shown that the proposed RD-OFDM-IM scheme is capable of providing considerable performance gain over conventional Differential OFDM (D-OFDM) scheme with lower Peak Average Power Ratio (PAPR).

Differential-Detection Aided Large-Scale Generalized Spatial Modulation is Capable of Operating in High-Mobility Millimeter-Wave Channels

“…This has been an open issue since 2000, and it was solved in [51,52] by invoking a simple square-to-nonsquare matrix mapping, which achieved a high throughput of R = 12 [bps/Hz] for M = 1024 transmit antennas. This high-rate capability was also verified by other authors in [53,54] based on [51].…”

“…Instead of the high-complexity square-matrix-based DSM, the low-complexity nonsquare-matrix-aided DSM scheme of [51][52][53][54] may be the best solution for high-rate mmWave communications. Nevertheless, the conventional nonsquare scheme of [51][52][53][54] requires a carefully designed forgetting factor relying on time-consuming optimization in a specific channel environment. Thus, it is a challenge for the conventional scheme to communicate over time-varying mmWave channels.…”

Bit-Interleaved Coded Energy-Based Modulation With Iterative Decoding

“…Since early DSM systems utilize differentially-encoded unitary matrices, they suffer the lack of scalability. This issue was later addressed in [28]- [30], which develops rectangular DSM. As research on differential IM schemes is vast, the interested reader is referred to [15], [31], [32] for more complete surveys of recent advances.…”