## 5 Conclusions  
In this paper, we explore the use of hierarchical 16 QAM with IL-FEC for transmitting 3D video in MVD format over a Two-Way Relay Channel (TWRC), where two users communicate with the assistance of a single relay node. Additionally, we propose a novel network and channel coding method for DF relaying and compare it with two other referenced methods. The proposed method not only reduces the number of relayed bitstreams by half but also provides initial API information to both receiving ends before the iterative decoding process begins. These enhancements significantly improve BER performance, which directly impacts the quality of the reconstructed videos.  
Figure 11: The subjective assessment of the _Champagne Tower_ test sequence.  
For performance evaluation, we assess the SSIM performance based on the quality of the reconstructed left and right view videos, as well as the virtually generated center view video. For the left and right view videos, both the proposed and referenced methods demonstrate improved SSIM performance, with minor variations depending on the hierarchical value \(\alpha\), irrespective of the relay location. However, for the virtually generated center view video, only the proposed method with \(\alpha=0.6\) consistently meets the target SSIM of 0.9, regardless of the relay location.  
The main contribution of this paper is the introduction of a network and channel coding method suitable for use in the relay node, and the identification of the optimal \(\alpha\) value to enhance SSIM performance for reconstructed left and right view videos, as well as the virtually generated center view video when transmitting MVD-formatted 3D video in a TWRC setting. This study not only contributes to the field of 3D video transmission but also lays the groundwork for future research in optimizing transmission strategies for other high-dimensional media formats.  
In addition, there are several potential directions for future research to expand upon our findings. These include exploring higher-order modulation schemes (e.g., 64 QAM, 256 QAM) to enhance data rates, developing adaptive coding and modulation techniques to dynamically adjust based on real-time channel conditions, and extending the approach to MIMO systems (e.g., movable antennas [27; 28]) to leverage spatial diversity for improved transmission reliability. Additionally, applying the method to other 3D formats, such as Point Cloud Compression (PCC) [29] or Light Field (LF) video, testing it under more realistic channel models and network conditions, and pursuing cross-layer optimization strategies could further enhance its applicability and performance. Evaluating our approach against other advanced error correction techniques, like LDPC or polar codes, and developing a prototype for real-world testing are also promising areas for future exploration.  
Conceptualization, D.Y.; methodology, D.Y.; software, D.Y.; validation, D.Y. and D.H.K.; formal analysis, D.Y.; investigation, D.Y.; resources, S.-H.K.; data curation, D.Y.; writing--original draft preparation, D.Y.; writing--review and editing, D.Y., S.-H.K. and D.H.K.; visualization, D.Y.; supervision, D.H.K.; project administration, S.-H.K.; funding acquisition, D.Y. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the Electronics and Telecommunications Research Institute (ETRI) grant funded by the Korean government [24 ZC1100, The Research of The Basic Media Contents Technologies].  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The authors declare no conflicts of interest.