On the Capacity of Multiple Antenna Systems in Rician Fading

TL;DR

This paper analyzes how Rician fading affects the capacity of multiple antenna systems, providing exact capacity for no transmitter knowledge, bounds for partial knowledge, and a new signaling scheme to improve capacity when Rician-ness is known.

Contribution

It introduces a new signaling scheme leveraging Rician-ness knowledge at the transmitter and derives capacity bounds under different CSI assumptions.

Findings

Exact capacity for no transmitter CSI

Capacity bounds with known fading distribution

Significant capacity gains with the new signaling scheme

Abstract

The effect of Rician-ness on the capacity of multiple antenna systems is investigated under the assumption that channel state information (CSI) is available only at the receiver. The average-power-constrained capacity of such systems is considered under two different assumptions on the knowledge about the fading available at the transmitter: the case in which the transmitter has no knowledge of fading at all, and the case in which the transmitter has knowledge of the distribution of the fading process but not the instantaneous CSI. The exact capacity is given for the former case while capacity bounds are derived for the latter case. A new signalling scheme is also proposed for the latter case and it is shown that by exploiting the knowledge of Rician-ness at the transmitter via this signalling scheme, significant capacity gain can be achieved. The derived capacity bounds are evaluated explicitly to provide numerical results in some representative situations.