Promising Practical Infrastructure Solutions for 6G Based on RIS and Cell Free Massive MIMO network

Document Type : Original Article

Authors

Faculty Of Electrical Engineering, Sahand University of Technology, Tabriz, Iran

Abstract

Cell free massive MIMO system is a promising candidate to overcome the shortcomings of the conventional cellular system and a suitable technique to achieve the goals of the sixth generation (6G) networks. Costs of implementing on large scale is one of the major disadvantages of this system. Recently, with the emergence of reconfigurable intelligent surfaces (RIS), we can hope for the reduction of these costs and the practical implementation of this system. In this regard, in this paper we have investigated the spectral performance of the scalable form of cell free with and without RISs. Lower bounds of uplink spectral efficiency involving imperfect channel estimation and pilot contamination effects for L-MMSE and LP-MMSE decoders is derived. The simulation results confirm the superior spectral efficiency performance of RIS-based proposed system (especially in centralized RIS- cell free mode) compared to the Scalable cell free system.

Keywords

Main Subjects

References

[1] Rajatheva, I. Atzeni, S. Bicais, E. Bjornson, A. Bourdoux, S. Buzzi, C. D’Andrea, J.-B. Dore, S. Erkucuk, M. Fuentes, et al., “Scoring the terabit/s goal: Broadband connectivity in 6G”, arXiv preprint arXiv:2008.07220, 2020.
[2] I. F. Akyildiz, A. Kak, S. Nie, "6G and beyond: The future of wireless communications systems", IEEE Access , vol.8 , pp.133995–134030, 2020.
[3] E. Björnson, L. Sanguinetti, "Making cell-free massive mimo competitive with mmse processing and centralized implementation", IEEE Transactions on Wireless Communications, vol.19, pp. 77-90, 2019.
[4] A. M. Saray, J. Pourrostam, "Spectral efficiency analysis and optimal power allocation for uplink multi-user cell-free massive mimo networks employing stbcs", Computer Communications, vol. 170, pp. 42–49, 2021
[5] H. Q. Ngo, A. Ashikhmin, H. Yang, E. G. Larsson, T. L. Marzetta, "Cellfree massive mimo versus small cells", IEEE Transactions on Wireless Communications , vol.16, pp.1834–1850, 2017
[6] A. M. Saray, J. Pourrostam, S. H. Mousavi, M. M. Feghhi, "A lowcomplexity space time block codes detection for cell free massive mimo systems", in: 2020 28th Iranian Conference on Electrical Engineering (ICEE), IEEE, pp. 1–5, 2020.
[7] A. M. Saray, A. Ebrahimi, "Max-min power control of cell free massive mimo system employing deep learning", in: 2022 4th West Asian Symposium on Optical and Millimeter-wave Wireless Communications (WASOWC), IEEE, pp. 1–4, 2022.
[8] S. Buzzi, C. D’Andrea, "Cell-free massive mimo: User-centric approach", IEEE Wireless Communications Letters, vol.6, pp.706–709, 2017.
[9] E. Björnson, L. Sanguinetti, "Scalable cell-free massive mimo systems", IEEE Transactions on Communications, vol.68, pp.4247–4261, 2020.
[10] Y. Zhang, B. Di, H. Zhang, J. Lin, C. Xu, D. Zhang, Y. Li, L. Song, Beyond cell-free mimo: energy efficient reconfigurable intelligent surface aided cell-free mimo communications, IEEE Transactions on Cognitive Communications and Networking 7 (2021) 412–426.
[11] X. Wei, D. Shen, L. Dai, Channel estimation for ris assisted wireless communications—part i: Fundamentals, solutions, and future opportunities, IEEE Communications Letters 25 (2021) 1398–1402.
[12] D. Mishra, H. Johansson, Channel estimation and low-complexity beamforming design for passive intelligent surface assisted miso wireless energy transfer, in: ICASSP 2019-2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), IEEE, 2019, pp. 4659–4663.
[13] C. Hu, L. Dai, S. Han, X. Wang, Two-timescale channel estimation for reconfigurable intelligent surface aided wireless communications, IEEE Transactions on Communications (2021).
[14] Z. Zhang, L. Dai, A joint precoding framework for wideband reconfigurable intelligent surface-aided cell-free network, IEEE Transactions on Signal Processing (2021).
[15] Q. N. Le, V.-D. Nguyen, O. A. Dobre, R. Zhao, Energy efficiency maximization in ris-aided cell-free network with limited backhaul, IEEE Communications Letters (2021).
[16] E. Björnson, L. Sanguinetti, Rayleigh fading modeling and channel hardening for reconfigurable intelligent surfaces, IEEE Wireless Communications Letters 10 (2020) 830–834.
[17] E. Björnson, J. Hoydis, L. Sanguinetti, Massive mimo networks: Spectral, energy, and hardware efficiency, Foundations and Trends in Signal Processing 11 (2017) 154–655.
[16] D.-S. Shiu, G. J. Foschini, M. J. Gans, J. M. Kahn, Fading correlation and its effect on the capacity of multielement antenna systems, IEEE Transactions on communications 48 (2000) 502–513.
[17] H. Alwazani, A. Kammoun, A. Chaaban, M. Debbah, M.-S. Alouini, et al., Intelligent reflecting surface-assisted multi-user miso communication: Channel estimation and beamforming design, IEEE Open Journal of the Communications Society 1 (2020) 661–680.
[18] Q. Wu, R. Zhang, Intelligent reflecting surface enhanced wireless network via joint active and passive beamforming, IEEE Transactions on Wireless Communications 18 (2019) 5394–5409.
[19] T. L. Marzetta, H. Q. Ngo, Fundamentals of massive MIMO, Cambridge University Press, 2016.
[20] M. Bashar, K. Cumanan, A. G. Burr, M. Debbah, H. Q. Ngo, On the uplink max–min sinr of cell-free massive mimo systems, IEEE Transactions on Wireless Communications 18 (2019) 2021–2036.
[21] O. Y. Bursalioglu, G. Caire, R. K. Mungara, H. C. Papadopoulos, C. Wang, Fog massive mimo: A user-centric seamless hot-spot architecture, IEEE Transactions on Wireless Communications 18 (2018) 559–574.
[22] E. Nayebi, A. Ashikhmin, T. L. Marzetta, B. D. Rao, Performance of cell-free massive mimo systems with mmse and lsfd receivers, in: 2016 50th Asilomar Conference on Signals, Systems and Com
 
 
Tabriz Journal of Electrical Engineering
Volume 55, Issue 4 - Serial Number 114
December 2025
Pages 665-671

Files

Share

How to cite

Statistics