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Table 3 Mathematical notations and definitions

From: Application of cell-free massive MIMO in 5G and beyond 5G wireless networks: a survey

Notations Definitions
K, M, Nap Number of UEs, APs, and antennas per AP
(·)T, (·)D, (·) Transpose, conjugate transpose, and the complex conjugate of a matrix
tr(R), R, |R| Trace, Euclidean norm, and the determinant of matrix R
Kronecker product between two matrices
In n identity matrix
\( \mathbbm{E} \) Expectation operator
k, l Index of the UEs and index of the APs
τc, τs The length of the channel coherence time, length of the UL training phase
Boldface lower case x Column vectors
Boldface upper case X Matrices
\( w\sim \mathcal{N}\left(0,{\sigma}^{{}^2}\right) \) Real-valued Gaussian random variable
\( w\sim C\mathcal{N}\left(\mu, {\sigma}^{{}^2}\right) \) Circularly symmetric complex Gaussian random variable with mean μ and variance σ²