Fractional Spatial Reuse Precoding for MIMO Downlink Networks

A linear precoding scheme is developed for unbounded MIMO downlink networks with quasi-static channels that have a hexagonal cell architecture. In the scheme developed herein, the equivalent channel model is structured to be decomposable, and the linear precoders at the base stations are designed to be decomposable as well. The proposed scheme is based the principles of fractional spatial reuse precoding. Spatial reuse precoding (SRP) is a precoding scheme that exploits the fact that interfering sources that employ the same structured precoder arrive in the same subspace, regardless of the particular channel matrices between the interfering sources and the receiver. The proposed scheme is fractional in the sense that each cell is partitioned and different precoders, with different power levels, are assigned in each partition. The proposed fractional SRP scheme enables the elimination of the dominant sources of interference without requiring cooperation between base stations.