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# Subcarrier subset selection aided transmit precoding achieves full-diversity in Index Modulation

Mysore rajashekar, Rakshith, Xu, Chao, Ishikawa, Naoki, Yang, Lieliang and Hanzo, Lajos (2019) Subcarrier subset selection aided transmit precoding achieves full-diversity in Index Modulation. IEEE Transactions on Vehicular Technology, 1-11.

Record type: Article

## Abstract

Index modulation (IM) is a recently proposed multi-carrier transmission scheme, which conveys information both by conventional symbols as well as by the specific subcarrier activation patterns conveying them. However, an impediment of IM is that it lacks transmit diversity gain. In this paper, we circumvent this limitation by proposing a limited-feedback assisted IM transmission scheme. Specifically, Euclidean distance based subcarrier subset selection (ED-SSS) is proposed and its attainable transmit diversity order is shown to be $N_c-N_{IM}+1$, where $N_c$ is the total number of subcarriers in an IM block and $N_{IM}$ is the number of subcarriers used for IM. Furthermore, the ED-SSS is shown to be amenable to low-complexity implementation owing to the orthogonality of its subcarriers. In order to attain the maximum transmit diversity order of $N_c$, ED-SSS is further extended with the aid of transmit precoding and its transmit diversity order is quantified. The proposed precoding assisted ED-SSS is shown to subsume several of the existing precoding aided IM transmission schemes. Simulation studies are conducted for validating our theoretical claims and also for quantifying the attainable performance gains of the proposed schemes. Specifically, at a BER of $10^{-3}$ an SNR gain as high as 8dB is observed in case of precoding when compared to its counterpart operating without precoding.

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OFDM_IM_SSS_TVT_two_col_v2 - Accepted Manuscript

Accepted/In Press date: 17 September 2019
e-pub ahead of print date: 20 September 2019

## Identifiers

Local EPrints ID: 434425
URI: http://eprints.soton.ac.uk/id/eprint/434425
ISSN: 0018-9545
PURE UUID: e449b787-892d-4b1c-a021-d9c93058bc70
ORCID for Rakshith Mysore rajashekar: orcid.org/0000-0002-7688-7539
ORCID for Chao Xu: orcid.org/0000-0002-8423-0342
ORCID for Lieliang Yang: orcid.org/0000-0002-2032-9327
ORCID for Lajos Hanzo: orcid.org/0000-0002-2636-5214

## Catalogue record

Date deposited: 23 Sep 2019 16:30

## Contributors

Author: Rakshith Mysore rajashekar
Author: Chao Xu
Author: Naoki Ishikawa
Author: Lieliang Yang
Author: Lajos Hanzo