Waveform Design and Accurate Channel Estimation for Frequency-Hopping MIMO Radar-Based Communications

TL;DR

This paper introduces a novel waveform design and estimation methods for FH-MIMO radar-based communication systems, enabling accurate timing offset and channel estimation without degrading radar performance, thus improving communication reliability.

Contribution

It proposes a new FH-MIMO waveform and estimators that accurately determine timing offset and channel parameters in dual-function radar communication systems.

Findings

Achieves near-perfect channel estimation accuracy.

Enables communication performance close to ideal conditions.

Designs waveform that does not impair radar ranging.

Abstract

Frequency-hopping (FH) MIMO radar-based dual-function radar communication (FH-MIMO DFRC) enables communication symbol rate to exceed radar pulse repetition frequency, which requires accurate estimations of timing offset and channel parameters. The estimations, however, are challenging due to unknown, fast-changing hopping frequencies and the multiplicative coupling between timing offset and channel parameters. In this paper, we develop accurate methods for a single-antenna communication receiver to estimate timing offset and channel for FH-MIMO DFRC. First, we design a novel FH-MIMO radar waveform, which enables a communication receiver to estimate the hopping frequency sequence (HFS) used by radar, instead of acquiring it from radar. Importantly, the novel waveform incurs no degradation to radar ranging performance. Then, via capturing distinct HFS features, we develop two estimators for timing offset and derive mean squared error lower bound of each estimator. Using the bounds, we design an HFS that renders both estimators applicable. Furthermore, we develop an accurate channel estimation method, reusing the single hop for timing offset estimation. Validated by simulations, the accurate channel estimates attained by the proposed methods enable the communication performance of DFRC to approach that achieved based on perfect timing and ideal knowledge of channel.