Multiuser MISO Transmitter Optimization for Inter-Cell Interference Mitigation

TL;DR

This paper develops efficient algorithms for optimizing multiuser MISO transmitters to mitigate inter-cell interference, considering various linear constraints and applying to multi-cell scenarios with partial cooperation.

Contribution

It introduces numerically efficient algorithms for transmitter optimization under general linear constraints, including interference mitigation in multi-cell MISO systems with partial cooperation.

Findings

Active ICI mitigation outperforms static fractional frequency reuse.

Algorithms effectively optimize precoders considering interference constraints.

Results highlight the importance of adaptive interference management.

Abstract

The transmitter optimization (i.e., steering vectors and power allocation) for a MISO Broadcast Channel (MISO-BC) subject to general linear constraints is considered. Such constraints include, as special cases, the sum power, the per-antenna or per-group-of-antennas power, and "forbidden interference direction" constraints. We consider both the optimal dirty-paper coding and the simple suboptimal linear zero-forcing beamforming strategies, and provide numerically efficient algorithms that solve the problem in its most general form. As an application, we consider a multi-cell scenario with partial cell cooperation, where each cell optimizes its precoder by taking into account interference constraints on specific users in adjacent cells. The effectiveness of the proposed methods is evaluated in a simple system scenario including two adjacent cells, under different fairness criteria that emphasize the bottleneck role of users near the cell "boundary". Our results show that "active" Inter-Cell Interference (ICI) mitigation outperforms the conventional "static" ICI mitigation based on fractional frequency reuse.