Channel Charting Based Pilot Allocation in MIMO Systems

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Volume Title

A4 Artikkeli konferenssijulkaisussa

Date

2025-01-01

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Mcode

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Language

en

Pages

7

Series

2024 IEEE 35th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2024, IEEE International Symposium on Personal, Indoor, and Mobile Radio Communications workshops

Abstract

We consider uplink pilot allocation based on multipoint channel charting (CC) to mitigate pilot contamination in a multi-cell network with spatially correlated MIMO channels. The channel chart is created in an offline phase with full information, i.e. user channel covariance matrices are estimated at multiple base stations (BSs). In the online phase, we assume that only partial information about a user’s channel covariance is known, i.e., it is available only at the serving BS. A machine learning framework is developed to predict the CC locations in the online phase. Pilots are allocated to active users in the online phase based on weighted graph colouring. CC locations are used as proxies of user locations; similarity weights between users are constructed from CC distances. Simulation results show that the CC based approach with partial information in the online phase outperforms a solution based on full angle-ofarrival information, and performs closely to an algorithm with full covariance information. We also consider a partial information machine learning framework to predict the channel covariance matrices at other BSs, which slightly outperforms CC based approach, with the price of a

Description

Keywords

pilot allocation, Multi-cell systems, channel charting, channel covariance

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Citation

Shaikh, B, Garau Burguera, P, Al-Tous, H, Juntti, M, Khan, M B & Tirkkonen, O 2025, Channel Charting Based Pilot Allocation in MIMO Systems. in 2024 IEEE 35th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2024. IEEE International Symposium on Personal, Indoor, and Mobile Radio Communications workshops, IEEE, IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Valencia, Spain, 02/09/2024. https://doi.org/10.1109/PIMRC59610.2024.10817455