Orthogonal frequency division multiplexing with index modulation by using multiple constellation sets

Abstract

In this article, a new transmission method named enhanced orthogonal frequency division multiplexing (E-OFDM) is proposed to increase the spectral efficiency (SE) of the OFDM. The proposed method conveys information bits not only by the M-ary symbols but also by the multiple different constellation sets. In the proposed method, we build the sub-blocks by splitting the whole OFDM into pieces. Then, we use different constellation sets in each sub-block and we assign the extra bits to them to increase the SE of the OFDM systems.Consequently, at the same modulation level, the proposed method has higher SE than the conventional OFDM system. The simulation results also show that the proposed method achieves better bit error rate (BER) performance than the conventional OFDM system with tolerable complexity. For example, the proposed method with a sub-block size 2 doubles the SE of the conventional OFDM method with BPSK modulation, and also it has approximately 1.6 dB better BER performance than the conventional OFDM at BER =10 −4 . New constellation designs and receiver algorithm for the detection of additional bits are also presented.

Potential of sixth‐generation technologies for emerging future wireless networks

“…In the contribution by Acar "Orthogonal frequency division multiplexing with index modulation by using multiple constellation sets," authors build the subblocks by splitting the whole OFDM into pieces. 2 Then, the authors use different constellation sets in each subblock and the authors assign the extra bits to them to increase the SE of the OFDM systems. Consequently, at the same modulation level, the proposed method has higher SE than the conventional OFDM system.…”

“…The proposed method conveys information bits not only by the M‐ary symbols but also by the multiple different constellation sets. In the contribution by Acar “Orthogonal frequency division multiplexing with index modulation by using multiple constellation sets,” authors build the subblocks by splitting the whole OFDM into pieces 2 . Then, the authors use different constellation sets in each subblock and the authors assign the extra bits to them to increase the SE of the OFDM systems.…”

Index and mode modulated orthogonal frequency division multiplexing with enhanced spectral efficiency

“…Concept of employing multiple number of distinguishable constellation sets to modulate data symbols has come out to address this issue. [19][20][21][22][23][24][25][26] Dual-mode OFDM (DM-OFDM), [19][20][21] Multimode OFDM-IM (MM-OFDM-IM) 22 and few more schemes [23][24][25][26] have employed multiple signal constellations to transfer supplementary information bits over all the available subcarriers in a subblock, thereby getting deprived of the beneficial features of index modulation, like less energy consumption and peak to average power ratio (PAPR). 27 In super-mode OFDM-IM, 26 partial subcarrier activation with multiple modes pattern is used.…”

“…Consequently more reliable detection capability is obtained. All the prior relevant schemes 8,[19][20][21][22][23][24][25][26] have been implemented either with index modulation or multiple mode patterns, all of which contribute toward improvement of either spectral efficiency or BER performance or energy efficiency, but one at a time. Full subcarrier activation schemes usually offer high SE, but at the cost of energy efficiency.…”

A new hexagonal quadrature amplitude modulation aided media‐based modulation

“…From this point of view, index modulation (IM) techniques have received considerable attention from researchers in recent years and has been shown as a promising candidate for next‐generation wireless communication systems. IM provides alternative ways of transmitting information; in this technique, the indexes of the units such as antenna, subcarrier, frequency carrier, space‐time matrix, spreading code, et cetera, are considered for data transmission 6–8 . The indices are embedded in the transmitted or received signals.…”