17 problems

In a multi-antenna transmission system with non-linear hardware, let the hardware distortion denote the distortion introduced by the transceiver hardware when transmitting multiple…

Consider the one-bit precoding scheme … where $\hat{\mathbf{x}}$ solves a convex relaxation with objective … $R(\mathbf{x})$ is a convex regularization function, and…

Let NAFD CF-mMIMO denote non-orthogonal access full-duplex cell-free massive MIMO, and let IBFD CF-mMIMO denote in-band full-duplex cell-free massive MIMO. Their energy efficiencie…

For users indexed by $k$, let $mathcal{N}(k)={i:lVert bm{x}k-bm{x}irVert<r}$ be the neighbor set determined by device locations, and let the GLASSO groups be the neighbor sets…

Let massive multiple-input multiple-output (MIMO) systems operate in frequency-division duplexing (FDD) mode, with uplink (UL) and downlink (DL) channels at different frequencies.…

For Algorithm, let the vectors $\boldsymbol{u}^{\ell}=\beta\boldsymbol{H}{\boldsymbol{x}}^{\ell-1}-\boldsymbol{\theta}^{\ell-1} \circ\boldsymbol{z}^{\ell-1}$ and…

Let $K$ be the number of active devices, $L$ the pilot length, $N$ the total number of devices, and $M$ the number of antennas or observation dimensions. In the covariance-based ma…

Let $K_a$ be the number of active users, $K_\text{tot}$ the number of potentially active users, and $L$ the signal dimension in the covariance-based activity-detection problem. A l…

Low-complexity ML scaling-law conjecture. The low-complexity ML algorithm achieves the same scaling law as the constrained ML scheme, namely successful activity-pattern detection f…

Low-complexity ML scaling-law conjecture. The low-complexity approximated ML algorithm achieves the same scaling law as the rigorously analyzed NNLS and constrained ML methods, nam…

A base station may use channel estimates from user equipments in other cells to develop multicell interference-suppression schemes. Multicell interference-suppression conjecture. S…

Channel-hardening conjecture. Channel hardening also appears in Cell-free mMIMO.

The covariance matrix of interfering user $k$ is modeled as … where $r_k$ is the rank of $\mathbf{\Sigma}_k$ with probability $1$, and the entries of $\mathbf{x}_{k,i}$ are indepen…

Let ${\vartheta}_k$ denote the Ricean factor for user $k$, and consider the achievable uplink rate in the described multi-cell, multi-user massive MIMO system. Ricean-fading rate c…

Coherent–non-coherent detection conjecture. Coherent and non-coherent detection achieve the same $\operatorname{DoF}$.

Consider an LSE precoder using a finite $M$-PSK constellation, with a finite antenna-to-user factor $\alpha$. Let $D$ denote its asymptotic distortion. Nonzero-distortion conjectur…

Let small-cell systems and M-MIMO systems be compared in terms of their energy efficiencies, denoted by $\text{EE}_{\text{SM}}$ and $\text{EE}_{\text{M}}$, respectively. The compar…