# Improved Low-Complexity, Pilot-Based Channel Estimation for Large Intelligent Surface Systems
## 3 Receiver Design Considerations for LIS: Proposed Improvements in Channel Estimation
### Optimized Pilot Design and Enhancing the Quality of Pilot Data
#### 3.1.2 Hadamard as Orthogonal Pilot Sequences
(2025) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] Pilot and Data Power Control for Uplink Cell-free massive MIMO. _arXiv_**2025**. [CrossRef]
* [PERSON] et al. (2009) [PERSON]; [PERSON]; [PERSON] Iterative Channel Estimation Using Superimposed Pilot for BICM-OFDM. In Proceedings of the 5 th International Conference on Wireless Communications, Networking and Mobile Computing, Beijing, China, 24-26 September 2009. [CrossRef]
* [PERSON] et al. (2011) [PERSON]; [PERSON]; [PERSON] How many known symbols are required for linear channel estimation in OFDM? In Proceedings of the IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). Prague, Czech Republic, 22-27 May 2011. [CrossRef]
* [PERSON] et al. (2023) [PERSON]; [PERSON]; [PERSON] Antenna Selection for Reconfigurable Intelligent Surfaces: A Transceiver-Agnostic Passive Beamforming Configuration. _IEEE Trans. Wirel. Commun._**2023**, _22_, 7756-7774. * [PERSON] et al. (2007) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] Turbo Receiver Design with Carrier-Frequency Offset Estimation for LDPC-Coded MIMO OFDM Systems. In Proceedings of the 9 th International Conference on Advanced Communication Technology, Gangwon, Republic of Korea, 12-14 February 2007. * [PERSON] et al. (2020) [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON]; [PERSON]; et al. Intelligent Surfaces for 6G Wireless Networks: A Survey of Optimization and Performance Analysis Techniques. _IEEE Access_**2020**, \(8\), 202795-202818. [CrossRef]
* [PERSON] et al. (2020) [PERSON]; [PERSON]; [PERSON]-K. Stochastic Geometry Analysis of Large Intelligent Surface-Assisted Millimeter Wave Networks. _IEEE J. Sel. Areas Commun._**2020**, _38_, 1749-1762. * [PERSON] et al. (2022) [PERSON]; [PERSON]; [PERSON]; [PERSON] [PERSON]; [PERSON] Enabling URLLC Applications Through Reconfigurable Intelligent Surfaces: Challenges and Potential. _IEEE Internet Things Mag._**2022**, \(5\), 130-135. * [PERSON] et al. (2020) [PERSON] [PERSON]; [PERSON]; [PERSON] [PERSON] A Low Complexity Channel Estimation and Detection for Massive MIMO Using SC-FDE. _Telecom_**2020**, \(1\), 3-17. [CrossRef]
* [PERSON] et al. (2006) [PERSON]; [PERSON]; [PERSON]; [PERSON] Channel Estimation for SC-FDE Systems Using Frequency Domain Multiplexed Pilots. In Proceedings of the IEEE Vehicular Technology Conference, Montreal, QC, Canada, 25-28 September 2006. [CrossRef]
* [PERSON] et al. (2024) [PERSON]; [PERSON]; [PERSON] [PERSON] An Assessment of Receiver Algorithms for Distributed Massive MIMO Systems: Investigating Design Solutions and Performance. _Electronics_**2024**, _13_, 1560. [CrossRef]
* [PERSON] et al. (2018) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] Iterative MRC and EGC Receivers for MIMO-OFDM Systems. In Proceedings of the 2018 IEEE 87 th Vehicular Technology Conference (VTC Spring), Porto, Portugal, 3-6 July 2018. [CrossRef]
* [PERSON] et al. (2015) [PERSON]; [PERSON]; [PERSON]; [PERSON] Pilot Signal Design for Massive MIMO Systems: A Received Signal-To-Noise-Ratio-Based Approach. _IEEE Signal Process. Lett._**2015**, _22_, 549-553. * [PERSON] and [PERSON] (2010) [PERSON]; [PERSON] New orthogonal pilot scheme for semi-blind channel estimation in MIMO Systems. In Proceedings of the International Conference on Networking and Information Technology, Manila, Philippines, 11-12 June 2010. [CrossRef]
* [PERSON] et al. (2021) [PERSON]; [PERSON]; [PERSON] Orthogonal Time Sequency Multiplexing Modulation: Analysis and Low-Complexity Receiver Design. _IEEE Trans. Wirel. Commun._**2021**, _20_, 7842-7855. * [PERSON] et al. (2013) [PERSON]; [PERSON]; [PERSON]; [PERSON] MIMO Channel Estimation and Tracking using a novel Pilot Expansion technique with Paley-Hadamard codes for future generation fast speed communications. In Proceedings of the Second International Conference on Future Generation Communication Technologies (FGCT), London, UK, 12-14 November 2013.