On $2 \times 2$ MIMO Gaussian Channels with a Small Discrete-Time Peak-Power Constraint

Autor:	Dytso, Alex, Barletta, Luca, Kramer, Gerhard
Rok vydání:	2024
Předmět:	Computer Science - Information Theory
Druh dokumentu:	Working Paper
Popis:	A multi-input multi-output (MIMO) Gaussian channel with two transmit antennas and two receive antennas is studied that is subject to an input peak-power constraint. The capacity and the capacity-achieving input distribution are unknown in general. The problem is shown to be equivalent to a channel with an identity matrix but where the input lies inside and on an ellipse with principal axis length $r_p$ and minor axis length $r_m$. If $r_p \le \sqrt{2}$, then the capacity-achieving input has support on the ellipse. A sufficient condition is derived under which a two-point distribution is optimal. Finally, if $r_m < r_p \le \sqrt{2}$, then the capacity-achieving distribution is discrete. Comment: 8 pages, 1 figure. Submitted to IEEE ISIT 2024
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/2401.17084 Zobrazit plný text záznamu View this record from Arxiv