Noise correlation and its effect on capacity of inhome MIMO power line channels

In this paper we study the characteristics of in-home multi-input multi-output (MIMO) power line channels in the 0 - 100 MHz frequency band. Channel measurements are obtained in several US homes by transmitting two independent signals over two wire pairs (line-neutral and line-protective earth) and receiving on all three wire pairs (line-neutral, line-protective earth and neutral-protective earth). Noise measurements on all three wire pairs are also performed and spectral properties of noise in MIMO power line channels are presented. In particular, noise is characterized in terms of correlation among the receive ports. We analyze the effect of noise correlation on the eigenspread of the channel matrix, and also its effect on MIMO channel capacity. It is shown that while noise correlation contributes to an increase in the eigen-spread and therefore correlation of a composite channel, it ultimately improves channel capacity. The capacity of MIMO power line channels is compared for 2×2 and 2×3 MIMO configurations, showing the gain of a third receive port. Finally, capacity gains of various MIMO configurations over the single-input single-output (SISO) power line systems are provided.