Pilot Assignment for Cell Free Massive MIMO Systems: A Successive Interference Cancellation Approach

Year 2024, , 1739 - 1751, 31.07.2024

Osman Dikmen

https://doi.org/10.29130/dubited.1448494

Abstract

In the contemporary era, considerable attention has been directed towards exploring cell-free massive multiple-input multiple-output (CF-M-MIMO) systems. This novel network paradigm has gained prominence as a potential solution for tackling the persistent challenge of inter-cell interference prevalent in traditional cellular MIMO networks. This study investigates a pilot assignment approach based on Successive Interference Cancellation (SIC) aimed at alleviating pilot contamination issues inherent in CF-M-MIMO systems. Through comprehensive numerical analyses and simulations, we demonstrate the efficacy and enhanced performance of the SIC-based approach competed with common random and greedy pilot assignment strategies. The proposed methodology addresses the critical challenge of pilot contamination, a phenomenon that severely impacts system performance and spectral efficiency. By iteratively decoding signals and canceling interference, the SIC algorithm optimizes pilot assignments, resulting in improved data rates and more efficient resource utilization. Our findings underscore the robustness and scalability of the SIC-based scheme across diverse system parameters and deployment scenarios, affirming its potential as a promising solution for enhancing the performance of CF-M-MIMO systems. Overall, this study contributes valuable insights into the design and optimization of pilot assignment strategies, offering a pathway for further research and development in the field of CF-M-MIMO systems.

Keywords

Cell-free massive MIMO, Pilot assignment scheme, Successive interference cancellation (SIC), Spectrum efficiency

Pilot Assignment for Cell Free Massive MIMO Systems A Successive Interference Cancellation Approach

Abstract

Son yıllarda, hücresel MIMO ağlarında yaygın olan hücreler arası girişim sorununu hafifletmek için yeni bir ağ mimarisi olarak hücresiz devasa çoklu giriş-çoklu çıkış (CF-M-MIMO) sistemlerinin keşfi önemli ölçüde dikkat çekmektedir. Bu çalışma, CF-M-MIMO sistemlerinde yaygın olarak görülen pilot kirliliği sorunlarını hafifletmeyi amaçlayan Ardışık Girişim İptal (SIC) temelli yeni bir pilot atama şemasını incelemektedir. Kapsamlı sayısal analizler ve simülasyonlar yoluyla, SIC tabanlı yaklaşımın geleneksel rastgele ve açgözlü pilot atama şemalarına göre etkinliğini ve gelişmiş performansını gösteriyoruz. Önerilen şema, sistem performansı ve spektral verimlilik üzerinde ciddi etkisi olan pilot kirliliği sorununu ele almaktadır. Sinyalleri ardışık olarak çözerek ve girişimi iptal ederek, SIC algoritması pilot atamalarını optimize eder, bu da daha iyi veri oranlarına ve daha verimli kaynak kullanımına yol açar. Bulgularımız, SIC tabanlı şemanın çeşitli sistem parametreleri ve dağıtım senaryoları üzerindeki sağlamlığını ve ölçeklenebilirliğini vurgulayarak, hücresiz devasa MIMO sistemlerinin performansını artırmak için umut vadeden bir çözüm olarak potansiyelini doğrulamaktadır. Genel olarak, bu çalışma, pilot atama stratejilerinin tasarımı ve optimizasyonu konusunda değerli bilgiler sunarak, CF-M-MIMO sistemleri alanında daha fazla araştırma ve geliştirme için bir yol haritası sunmaktadır.

Keywords

: Hücresiz büyük MIMO, Pilot atama şeması, Ardışık girişim iptali (SIC), Spektrum verimliliği

References

• [1] H. Q. Ngo, A. Ashikhmin, H. Yang, E. G. Larsson, and T. L. Marzetta, “Cell-Free Massive MIMO Versus Small Cells,” IEEE Trans. Wirel. Commun., vol. 16, no. 3, pp. 1834–1850, Mar. 2017, doi: 10.1109/TWC.2017.2655515.
• [2] E. Nayebi, A. Ashikhmin, T. L. Marzetta, H. Yang, and B. D. Rao, “Precoding and Power Optimization in Cell-Free Massive MIMO Systems,” IEEE Trans. Wirel. Commun., vol. 16, no. 7, pp. 4445–4459, Jul. 2017, doi: 10.1109/TWC.2017.2698449.
• [3] J. Zhang, E. Bjornson, M. Matthaiou, D. W. K. Ng, H. Yang, and D. J. Love, “Prospective Multiple Antenna Technologies for Beyond 5G,” IEEE J. Sel. Areas Commun., vol. 38, no. 8, pp. 1637–1660, Aug. 2020, doi: 10.1109/JSAC.2020.3000826.
• [4] O. Ozdogan, E. Bjornson, and J. Zhang, “Performance of Cell-Free Massive MIMO With Rician Fading and Phase Shifts,” IEEE Trans. Wirel. Commun., vol. 18, no. 11, pp. 5299–5315, Nov. 2019, doi: 10.1109/TWC.2019.2935434.
• [5] M. Bashar, K. Cumanan, A. G. Burr, M. Debbah, and H. Q. Ngo, “On the Uplink Max–Min SINR of Cell-Free Massive MIMO Systems,” IEEE Trans. Wirel. Commun., vol. 18, no. 4, pp. 2021–2036, Apr. 2019, doi: 10.1109/TWC.2019.2892463.
• [6] D. Maryopi, M. Bashar, and A. Burr, “On the Uplink Throughput of Zero Forcing in Cell-Free Massive MIMO With Coarse Quantization,” IEEE Trans. Veh. Technol., vol. 68, no. 7, pp. 7220–7224, 2019, doi: 10.1109/TVT.2019.2920070.
• [7] Y. Jin, J. Zhang, S. Jin, and B. Ai, “Channel Estimation for Cell-Free mmWave Massive MIMO Through Deep Learning,” IEEE Trans. Veh. Technol., vol. 68, no. 10, pp. 10325–10329, Oct. 2019, doi: 10.1109/TVT.2019.2937543.
• [8] H. Huang, J. Yang, H. Huang, Y. Song, and G. Gui, “Deep Learning for Super-Resolution Channel Estimation and DOA Estimation Based Massive MIMO System,” IEEE Trans. Veh. Technol., vol. 67, no. 9, pp. 8549–8560, Sep. 2018, doi: 10.1109/TVT.2018.2851783.
• [9] J. Zhang, S. Chen, Y. Lin, J. Zheng, B. Ai, and L. Hanzo, “Cell-free massive MIMO: A new next-generation paradigm,” IEEE Access, vol. 7, pp. 99878–99888, 2019, doi: 10.1109/ACCESS.2019.2930208.
• [10] H. Huang, Y. Song, J. Yang, G. Gui, and F. Adachi, “Deep-Learning-Based Millimeter-Wave Massive MIMO for Hybrid Precoding,” IEEE Trans. Veh. Technol., vol. 68, no. 3, pp. 3027–3032, Mar. 2019, doi: 10.1109/TVT.2019.2893928.
• [11] W. Fan, J. Zhang, E. Bjornson, S. Chen, and Z. Zhong, “Performance Analysis of Cell-Free Massive MIMO Over Spatially Correlated Fading Channels,” in ICC 2019 - 2019 IEEE International Conference on Communications (ICC), IEEE, May 2019, pp. 1–6. doi: 10.1109/ICC.2019.8762051.
• [12] S. Buzzi, C. D’Andrea, M. Fresia, Y.-P. Zhang, and S. Feng, “Pilot Assignment in Cell-Free Massive MIMO Based on the Hungarian Algorithm,” IEEE Wirel. Commun. Lett., vol. 10, no. 1, pp. 34–37, Jan. 2021, doi: 10.1109/LWC.2020.3020003.
• [13] M. Attarifar, A. Abbasfar, and A. Lozano, “Random vs Structured Pilot Assignment in Cell-Free Massive MIMO Wireless Networks,” in 2018 IEEE International Conference on Communications Workshops (ICC Workshops), IEEE, May 2018, pp. 1–6. doi: 10.1109/ICCW.2018.8403508.
• [14] C. Pan, H. Mehrpouyan, Y. Liu, M. Elkashlan, and N. Arumugam, “Joint Pilot Allocation and Robust Transmission Design for Ultra-Dense User-Centric TDD C-RAN With Imperfect CSI,” IEEE Trans. Wirel. Commun., vol. 17, no. 3, pp. 2038–2053, Mar. 2018, doi: 10.1109/TWC.2017.2788001.
• [15] H. Liu, J. Zhang, X. Zhang, A. Kurniawan, T. Juhana, and B. Ai, “Tabu-Search-Based Pilot Assignment for Cell-Free Massive MIMO Systems,” IEEE Trans. Veh. Technol., vol. 69, no. 2, pp. 2286–2290, Feb. 2020, doi: 10.1109/TVT.2019.2956217.
• [16] W. Zeng, Y. He, B. Li, and S. Wang, “Pilot Assignment for Cell Free Massive MIMO Systems Using a Weighted Graphic Framework,” IEEE Trans. Veh. Technol., vol. 70, no. 6, pp. 6190–6194, Jun. 2021, doi: 10.1109/TVT.2021.3076440.
• [17] H. Liu, J. Zhang, S. Jin, and B. Ai, “Graph Coloring Based Pilot Assignment for Cell-Free Massive MIMO Systems,” IEEE Trans. Veh. Technol., vol. 69, no. 8, pp. 9180–9184, Aug. 2020, doi: 10.1109/TVT.2020.3000496.
• [18] S. Chen, J. Zhang, E. Bjornson, J. Zhang, and B. Ai, “Structured Massive Access for Scalable Cell-Free Massive MIMO Systems,” IEEE J. Sel. Areas Commun., vol. 39, no. 4, pp. 1086–1100, Apr. 2021, doi: 10.1109/JSAC.2020.3018836.
• [19] R. Khan, L. Jan, S. Khan, M. H. Zafar, W. Ahmad, and G. Husnain, “An effective algorithm in uplink massive MIMO systems for pilot decontamination,” Results Eng., vol. 21, p. 101873, Mar. 2024, doi: 10.1016/j.rineng.2024.101873.
• [20] A. Misso and M. Kissaka, “Pilot contamination mitigation by pilot assignment and adaptive linear precoding for massive MIMO multi-cell systems,” Telecommun. Syst., vol. 85, no. 3, pp. 389–400, Mar. 2024, doi: 10.1007/s11235-023-01093-3.
• [21] A. Misso, “Enhanced resource allocation strategies to improve the spectral efficiency in massive MIMO systems,” J. Electr. Syst. Inf. Technol. 2024 111, vol. 11, no. 1, pp. 1–16, Mar. 2024, doi: 10.1186/S43067-023-00132-Y.
• [22] J. Zhang, Y. Wei, E. Bjornson, Y. Han, and S. Jin, “Performance Analysis and Power Control of Cell-Free Massive MIMO Systems with Hardware Impairments,” IEEE Access, vol. 6, pp. 55302–55314, 2018, doi: 10.1109/ACCESS.2018.2872715.
• [23] T. H. Nguyen, L. T. Phan, and T. Van Chien, “An efficient location-based pilot assignment in Cell-Free Massive MIMO,” ICT Express, vol. 9, no. 5, pp. 795–802, Oct. 2023, doi: 10.1016/j.icte.2022.09.005.
• [24] T. Van Chien, H. Q. Ngo, S. Chatzinotas, M. Di Renzo, and B. Ottersten, “Reconfigurable Intelligent Surface-Assisted Cell-Free Massive MIMO Systems Over Spatially-Correlated Channels,” IEEE Trans. Wirel. Commun., vol. 21, no. 7, pp. 5106–5128, Jul. 2022, doi: 10.1109/TWC.2021.3136925.
• [25] L. Valentini, M. Chiani, and E. Paolini, “Interference Cancellation Algorithms for Grant-Free Multiple Access With Massive MIMO,” IEEE Trans. Commun., vol. 71, no. 8, pp. 4665–4677, Aug. 2023, doi: 10.1109/TCOMM.2023.3277891.
• [26] A. J. Muhammed, H. Chen, A. M. Seid, Z. Han, and Q. Yu, “Energy-Efficient Resource Allocation for NOMA HetNets in Millimeter Wave Communications,” IEEE Trans. Wirel. Commun., vol. 22, no. 6, pp. 3790–3804, Jun. 2023, doi: 10.1109/TWC.2022.3221469.
• [27] A. Pottier, P.-J. Bouvet, B. Tomasi, and C. Vanwynsberghe, “Data Rate Performance of Mobile Multiuser MIMO Underwater Acoustic Communication Systems,” IEEE J. Ocean. Eng., pp. 1–12, 2024, doi: 10.1109/JOE.2023.3331774.
• [28] J. Wang, J. Li, P. Zhu, D. Wang, B. Sheng, and X. You, “Adaptive Feedback-Aided Hybrid Random Access for mURLLC Service Over Cell-Free Networks,” IEEE Syst. J., pp. 1–8, 2024, doi: 10.1109/JSYST.2024.3379281.