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Enhanced Index Modulation Aided Non-Orthogonal Multiple Access via Constellation Rotation

Ronglan Huang, Fei ji, Zeng Hu, Dehuan Wan, Pengcheng Xu, Yun Liu

TL;DR

This work tackles the spectral efficiency limitations of downlink NOMA by introducing a rotation-constellation based index modulation scheme (IM-NOMA-RC). It partitions users into far and near groups and applies IM via constellation rotation only to near users across all subcarriers, yielding additional index bits without inactive subcarriers; the system's SE is given by φ = N log2 M + floor(log2(N−B+1)). The authors derive an optimal ML detector and a low-complexity SIC detector, and provide a closed-form APEP/BER bound; extensive simulations show SE gains over conventional NOMA and competitive BER performance. The approach enables serving more users per OFDM resource block and offers practical gains for massive connectivity in 6G downlink scenarios.

Abstract

Non-orthogonal multiple access (NOMA) has been widely nominated as an emerging spectral efficiency (SE) multiple access technique for the next generation of wireless communication network. To meet the growing demands in massive connectivity and huge data in transmission, a novel index modulation aided NOMA with the rotation of signal constellation of low power users (IM-NOMA-RC) is developed to the downlink transmission. In the proposed IM-NOMA-RC system, the users are classified into far-user group and near-user group according to their channel conditions, where the rotation constellation based IM operation is performed only on the users who belong to the near-user group that are allocated lower power compared with the far ones to transmit extra information. In the proposed IM-NOMA-RC, all the subcarriers are activated to transmit information to multiple users to achieve higher SE. With the aid of the multiple dimension modulation in IM-NOMA-RC, more users can be supported over an orthogonal resource block. Then, both maximum likelihood (ML) detector and successive interference cancellation (SIC) detector are studied for all the user. Numerical simulation results of the proposed IM-NOMARC scheme are investigate for the ML detector and the SIC detector for each users, which shows that proposed scheme can outperform conventional NOMA.

Enhanced Index Modulation Aided Non-Orthogonal Multiple Access via Constellation Rotation

TL;DR

This work tackles the spectral efficiency limitations of downlink NOMA by introducing a rotation-constellation based index modulation scheme (IM-NOMA-RC). It partitions users into far and near groups and applies IM via constellation rotation only to near users across all subcarriers, yielding additional index bits without inactive subcarriers; the system's SE is given by φ = N log2 M + floor(log2(N−B+1)). The authors derive an optimal ML detector and a low-complexity SIC detector, and provide a closed-form APEP/BER bound; extensive simulations show SE gains over conventional NOMA and competitive BER performance. The approach enables serving more users per OFDM resource block and offers practical gains for massive connectivity in 6G downlink scenarios.

Abstract

Non-orthogonal multiple access (NOMA) has been widely nominated as an emerging spectral efficiency (SE) multiple access technique for the next generation of wireless communication network. To meet the growing demands in massive connectivity and huge data in transmission, a novel index modulation aided NOMA with the rotation of signal constellation of low power users (IM-NOMA-RC) is developed to the downlink transmission. In the proposed IM-NOMA-RC system, the users are classified into far-user group and near-user group according to their channel conditions, where the rotation constellation based IM operation is performed only on the users who belong to the near-user group that are allocated lower power compared with the far ones to transmit extra information. In the proposed IM-NOMA-RC, all the subcarriers are activated to transmit information to multiple users to achieve higher SE. With the aid of the multiple dimension modulation in IM-NOMA-RC, more users can be supported over an orthogonal resource block. Then, both maximum likelihood (ML) detector and successive interference cancellation (SIC) detector are studied for all the user. Numerical simulation results of the proposed IM-NOMARC scheme are investigate for the ML detector and the SIC detector for each users, which shows that proposed scheme can outperform conventional NOMA.
Paper Structure (8 sections, 15 equations, 6 figures, 1 table)

This paper contains 8 sections, 15 equations, 6 figures, 1 table.

Table of Contents

  1. Introduction
  2. proposed IM-NOMA-RC System Model
  3. IM-NOMA-RC Detection and Performance Analysis
  4. Maximum Likelihood Detection
  5. Low Complexity SIC Detector
  6. Error Performance Analysis
  7. Numerical and Simulation Result
  8. Conclusion

Figures (6)

  • Figure 1: The basic system model of IM-NOMA-RC.
  • Figure 2: IM-NOMA-RC system with a two-user case.
  • Figure 3: Diagram of the superimposed constellation with IM operation for a two users case, where a far user is paired with a near user to perform NOMA.
  • Figure 4: The SE comparison between NOMA, IM-NOMA-RC, and IM-NOMA.
  • Figure 5: The BER comparison between NOMA, IM-NOMA-RC, and OFDM.
  • ...and 1 more figures