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README.md

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 |60|[End-to-end learning for RIS-aided communication systems](http://oa.ee.tsinghua.edu.cn/dailinglong/publications/code/End-to-End%20Learning%20for%20RIS-Aided%20Communication%20Systems.zip)|Linglong Dai, etal.|
 |61|[Positioning Information Based High-Speed Communications with Multiple RISs: Doppler Mitigation and Hardware Impairments](https://github.com/ken0225/Multi-RIS-Doppler-Mitigation-Hardware-Impairments)|Ke WANG, etal.|
 |62|[Codebook design and beam training for extremely large-scale RIS: Far-field or near-field?](http://oa.ee.tsinghua.edu.cn/dailinglong/publications/code/Codebook%20design%20and%20beam%20training%20for%20extremely%20large-scale%20RIS%20Far-field%20or%20near-field.txt)|Linglong Dai, etal.|
+|63|[Distributed machine learning based downlink channel estimation for RIS assisted wireless communications?](http://oa.ee.tsinghua.edu.cn/dailinglong/publications/code/Distributed%20machine%20learning%20based%20downlink%20channel%20estimation%20for%20RIS%20assisted%20wireless%20communications.zip)|Linglong Dai, etal.|
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