The SIMO Pre-Log Can Be Larger Than the SISO Pre-Log

TL;DR

This paper demonstrates that under certain conditions, the capacity pre-log of a noncoherent SIMO channel can exceed that of a SISO channel, challenging previous assumptions about capacity limits.

Contribution

It establishes a lower bound on the noncoherent capacity pre-log for SIMO channels and reveals conditions where SIMO pre-log surpasses SISO pre-log.

Findings

SIMO pre-log can be larger than SISO pre-log under certain conditions

A lower bound on the noncoherent capacity pre-log is derived

The capacity advantage depends on the channel covariance structure

Abstract

We establish a lower bound on the noncoherent capacity pre-log of a temporally correlated Rayleigh block-fading single-input multiple-output (SIMO) channel. Surprisingly, when the covariance matrix of the channel satisfies a certain technical condition related to the cardinality of its smallest set of linearly dependent rows, this lower bound reveals that the capacity pre-log in the SIMO case is larger than that in the single-input single-output (SISO) case.