User Scheduling for Cooperative Base Station Transmission Exploiting Channel Asymmetry

TL;DR

This paper introduces a low-overhead user scheduling method for cooperative multi-base station systems that leverages channel asymmetry to efficiently select users with minimal channel information, maintaining high data rates.

Contribution

It proposes a novel semi-orthogonal scheduler based on average channel gains exploiting channel asymmetry, reducing training overhead in coordinated multi-point transmission.

Findings

Performs close to full-information schedulers in simulations

Requires significantly less training overhead

Effective especially with more antennas and larger cell-edge regions

Abstract

We study low-signalling overhead scheduling for downlink coordinated multi-point (CoMP) transmission with multi-antenna base stations (BSs) and single-antenna users. By exploiting the asymmetric channel feature, i.e., the pathloss differences towards different BSs, we derive a metric to judge orthogonality among users only using their average channel gains, based on which we propose a semi-orthogonal scheduler that can be applied in a two-stage transmission strategy. Simulation results demonstrate that the proposed scheduler performs close to the semi-orthogonal scheduler with full channel information, especially when each BS is with more antennas and the celledge region is large. Compared with other overhead reduction strategies, the proposed scheduler requires much less training overhead to achieve the same cell-average data rate.