In grant-free non-orthogonal multiple access, the set of active users is unknown a priori. We address the challenging problem of dynamic channel estimation in this context. Assuming that inactive users are completely muted (in order to avoid unwanted pilot/preamble interference on active users), we investigate a channel estimation method performed jointly with user activity detection, multi-user detection and decoding. Leveraging conditional independence assumptions in probabilistic modeling, we introduce a low-complexity channel estimation performing expectation propagation in parallel for the measurements over all receive antennas. The proposed channel estimation technique is evaluated under different receive antenna correlation models and shows a good performance/complexity tradeoff with respect to joint measurement processing.
Low-Complexity Dynamic Channel Estimation in Multi-Antenna Grant-Free NOMA
01.06.2022
461859 byte
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
Uplink Performance Analysis of Grant-Free NOMA Networks
IEEE | 2022
|DOAJ | 2022
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