Adaptive Spatial Intercell Interference Cancellation in Multicell Wireless Networks

TL;DR

This paper investigates when to use intercell interference cancellation versus standard beamforming in multicell wireless networks, proposing an adaptive strategy that improves sum rate and fairness based on user location and SNR levels.

Contribution

It introduces an adaptive transmission strategy that dynamically chooses between ICIC and beamforming, optimizing network performance based on SNR and user location.

Findings

Beamforming preferred at low SNR (<0 dB).

ICIC preferred at high SNR (>10 dB).

Adaptive strategy outperforms static methods and enhances fairness.

Abstract

Downlink spatial intercell interference cancellation (ICIC) is considered for mitigating other-cell interference using multiple transmit antennas. A principle question we explore is whether it is better to do ICIC or simply standard single-cell beamforming. We explore this question analytically and show that beamforming is preferred for all users when the edge SNR (signal-to-noise ratio) is low ($<0$ dB), and ICIC is preferred when the edge SNR is high ($>10$ dB), for example in an urban setting. At medium SNR, a proposed adaptive strategy, where multiple base stations jointly select transmission strategies based on the user location, outperforms both while requiring a lower feedback rate than the pure ICIC approach. The employed metric is sum rate, which is normally a dubious metric for cellular systems, but surprisingly we show that even with this reward function the adaptive strategy also improves fairness. When the channel information is provided by limited feedback, the impact of the induced quantization error is also investigated. It is shown that ICIC with well-designed feedback strategies still provides significant throughput gain.