On the Asymptotic Performance of Multiple Antenna Channels with Fast Channel Feedback

TL;DR

This paper investigates how different levels of channel feedback influence the asymptotic performance of multiple antenna systems, revealing that even minimal feedback significantly enhances diversity and that perfect information yields infinite diversity order.

Contribution

It provides a detailed analysis of the impact of finite and perfect channel feedback on diversity-multiplexing tradeoff in multiple antenna channels, highlighting the role of location-dependent power control.

Findings

One-bit feedback increases diversity order compared to no feedback.

More channel information at the transmitter improves diversity order for each multiplexing gain.

Perfect transmitter information leads to infinite diversity order.

Abstract

In this paper, we analyze the asymptotic performance of multiple antenna channels where the transmitter has either perfect or finite bit channel state information. Using the diversity-multiplexing tradeoff to characterize the system performance, we demonstrate that channel feedback can fundamentally change the system behavior. Even one-bit of information can increase the diversity order of the system compared to the system with no transmitter information. In addition, as the amount of channel information at the transmitter increases, the diversity order for each multiplexing gain increases and goes to infinity for perfect transmitter information. The major reason for diversity order gain is a "location-dependent" temporal power control, which adapts the power control strategy based on the average channel conditions of the channel.