Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Channel Estimation for 6G V2X HybridSystems using Multi-Vehicular
  Learning   Channel estimation for hybrid Multiple Input Multiple Output (MIMO) systems
at Millimeter-Waves (mmW)/sub-THz is a fundamental, despite challenging,
prerequisite for an efficient design of hybrid MIMO precoding/combining. Most
works propose sequential search algorithms, e.g., Compressive Sensing (CS),
that are most suited to static channels and consequently cannot apply to highly
dynamic scenarios such as Vehicle-to-Everything (V2X). To address the latter
ones, we leverage \textit{recurrent vehicle passages} to design a novel Multi
Vehicular (MV) hybrid MIMO channel estimation suited for
Vehicle-to-Infrastructure (V2I) and Vehicle-to-Network (V2N) systems. Our
approach derives the analog precoder/combiner through a MV beam alignment
procedure. For the digital precoder/combiner, we adapt the Low-Rank (LR)
channel estimation method to learn the position-dependent eigenmodes of the
received digital signal (after beamforming), which is used to estimate the
compressed channel in the communication phase. Extensive numerical simulations,
obtained with ray-tracing channel data and realistic vehicle trajectories,
demonstrate the benefits of our solution in terms of both achievable Spectral
Efficiency (SE) and Mean Square Error (MSE) compared to the Unconstrained
Maximum Likelihood (U-ML) estimate of the compressed digital channel, making it
suitable for both 5G and future 6G systems. Most notably, in some scenarios, we
obtain the performance of the optimal Fully Digital (FD) systems.

25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas