A Multi-Interference-Channel Matrix Pair Beamformer for CDMA Systems

TL;DR

This paper introduces a novel multi-interference-channel matrix pair beamformer for CDMA systems that effectively suppresses structured interference and maintains stable performance under increasing interference power.

Contribution

It proposes a new design principle for the projection space in MPBs and develops an adaptive MIC-MPB that addresses threshold effects in structured interference scenarios.

Findings

The proposed MIC-MPB has a small, bounded threshold despite increasing interference.

Simulation results demonstrate improved interference suppression over existing MPBs.

The adaptive algorithm enhances robustness in dynamic channel conditions.

Abstract

Matrix pair beamformer (MPB) is a promising blind beamformer which exploits the temporal signature of the signal of interest (SOI) to acquire its spatial statistical information. It does not need any knowledge of directional information or training sequences. However, the major problem of the existing MPBs is that they have serious threshold effects and the thresholds will grow as the interference power increases or even approach infinity. In particular, this issue prevails in scenarios with structured interference, such as, periodically repeated white noise, tones, or MAIs in multipath channels. In this paper, we will first present the principles for designing the projection space of the MPB which are closely correlated with the ability of suppressing structured interference and system finite sample performance. Then a multiple-interference-channel based matrix pair beamformer (MIC-MPB) for CDMA systems is developed according to the principles. In order to adapt to dynamic channels, an adaptive algorithm for the beamformer is also proposed. Theoretical analysis and simulation results show that the proposed beamformer has a small and bounded threshold when the interference power increases. Performance comparisons of the MIC-MPB and the existing MPBs in various scenarios via a number of numerical examples are also presented.