Hybrid Interference Mitigation Using Analog Prewhitening

TL;DR

This paper introduces a hybrid interference mitigation scheme called HIMAP that uses analog prewhitening with phase shifters to suppress strong interference signals before digital processing, enhancing wireless communication robustness.

Contribution

The paper presents a novel hybrid interference mitigation method using analog prewhitening with phase shifters, requiring only covariance estimates, and demonstrates its effectiveness through simulations.

Findings

Can suppress interference 80dB stronger than the signal

Uses off-the-shelf 6-bit phase shifters for implementation

Effective in various wireless scenarios including full-duplex and heterogeneous networks

Abstract

This paper proposes a novel scheme for mitigating strong interferences, which is applicable to various wireless scenarios, including full-duplex wireless communications and uncoordinated heterogenous networks. As strong interferences can saturate the receiver's analog-to-digital converters (ADC), they need to be mitigated both before and after the ADCs, i.e., via hybrid processing. The key idea of the proposed scheme, namely the Hybrid Interference Mitigation using Analog Prewhitening (HIMAP), is to insert an M-input M-output analog phase shifter network (PSN) between the receive antennas and the ADCs to spatially prewhiten the interferences, which requires no signal information but only an estimate of the covariance matrix. After interference mitigation by the PSN prewhitener, the preamble can be synchronized, the signal channel response can be estimated, and thus a minimum mean squared error (MMSE) beamformer can be applied in the digital domain to further mitigate the residual interferences. The simulation results verify that the HIMAP scheme can suppress interferences 80dB stronger than the signal by using off-the-shelf phase shifters (PS) of 6-bit resolution.