Towards energy-efficient modulation: PIM-QSM and EPIM-QSM schemes
Physical Communication, cilt.77, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 77
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.phycom.2026.103176
- Dergi Adı: Physical Communication
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC
- Anahtar Kelimeler: Hermite-Gaussian pulse, Multiple-input multiple-output (MIMO), Pulse index modulation, Spatial modulation
- Kocaeli Üniversitesi Adresli: Evet
Özet
The sixth-generation (6G) network is anticipated to meet energy efficiency (EE) standards while enabling data transmission speeds much faster than current networks. Quadrature spatial modulation (QSM) can effectively meet the requirements of EE. Meanwhile, pulse index modulation (PIM) is another innovative scheme that satisfies the EE demands of communication systems. However, spatial size limitations hinder the ability of QSM to achieve high spectral efficiencies (SEs); similarly, bandwidth constraints restrict the potential of PIM to reach high SEs. This paper introduces two novel techniques that utilize the PIM scheme: pulse index modulation QSM (PIM-QSM) and enhanced PIM-QSM (EPIM-QSM). By combining QSM and PIM schemes, the proposed methods leverage their respective advantages, enabling higher SE (and EE at the same time) without forcing the excessive bandwidth requirements of PIM or the antenna size limitations of QSM. Although the PIM-QSM scheme enhances the SE potential of both methods with a limited number of indices, the EPIM-QSM scheme improves the SE of PIM-QSM by independently selecting transmit antennas for each pulse and I/Q components. Another proposed scheme is the enhanced PIM-SM (EPIM-SM), which is a simpler version of EPIM-QSM in which a single antenna is selected for transmission. The proposed schemes allow for more adaptable allocation of information bits across both waveform and spatial domains, resulting in an improved trade-off between bandwidth and data rate. The EPIM-QSM outperforms all the schemes considered in this study, achieving a BER of 10−3, approximately a signal-to-noise ratio of 15 dB, and an SE of 14 bpcu.