Imperfect CSI Muting With Time-Domain Thresholding for Cooperative Intercell Interference Cancellation

Abstract

This article improves spectral efficiency performance of the cooperative intercell interference (ICI) cancellation by channel state information (CSI) muting with time-domain thresholding. In the original scheme, each transmitter superposes ICI replica signal to the original transmission signal so as to cancel them at the receiver side. Suppose uplink CSI estimation, its imperfection becomes significant since the transmission power of the user terminal is generally lower than that of the base station; ICI cancellation capability is limited. In order to overcome this problem, incorrect CSI needs to be properly muted. However, the qualification of CSI around the noise level is a challenging issue. A key proposal is to focus on the time-domain impulse response wherein the channel power is concentrated to the specified part in the observation range. It can accurately differentiate useful CSI even in the noise-limited region; generation of erroneous ICI replica signals is prevented and remaining transmission power can be re-allocated to the desired signal. Therefore, the ICI cancellation capability can be fully provided to maximize overall spectral efficiency. Simulative evaluation validates its possibility and effectiveness; average spectral efficiency can be improved by up to 11.9% compared to the original approach using full CSI.