Robust coordination for multi-cell distributed antenna systems with selective transmission

Abstract

Coordinated transmission is an effective way to deal with the inter-cell interference (ICI) problem in a multi-cell distributed antenna system (DAS). However, in a practical scenario, the inter-cell channel state information (CSI) is usually imperfect, consequently causing a significant performance degradation of coordinated transmission. In this paper, to tackle this difficulty, we propose a coordinated selective transmission scheme, which is robust to the inter-cell CSI uncertainty. Particularly, we consider a composite inter-cell CSI model that consists of perfect large-scale CSI and imperfect small-scale CSI. An accuracy parameter is used to indicate different degree of uncertainty of the small-scale CSI. We then formulate a coordinated antenna selection problem, which is a non-convex integer programming problem. Using the successive approximation method and the Geometric Programming tool, we propose an iterative solution to the problem. Simulation results show that the proposed coordinated selective transmission scheme provides a significant sum rate gain over the existing methods, since it is more robust to the inter-cell small-scale CSI error.