Transmit Beamspace DDMA Based Automotive MIMO Radar

TL;DR

This paper introduces a transmit beamspace DDMA method for automotive MIMO radar that enhances power efficiency and Doppler ambiguity mitigation, improving parameter estimation for medium/long range applications.

Contribution

It proposes a novel TB DDMA approach using phase modulation and DFT-based beamforming to improve energy distribution and Doppler resolution in automotive MIMO radar.

Findings

Improves transmit energy concentration in a fixed spatial region.

Mitigates Doppler ambiguity using a test function based on sequential detection.

Outperforms conventional TDMA in simulation results.

Abstract

The time division multiple access (TDMA) technique has been applied in automotive multiple-input multiple-output (MIMO) radar. However, it suffers from the transmit energy loss, and as a result the parameter estimation performance degradation when the number of transmit elements increases. To tackle these problem, a transmit beamspace (TB) Doppler division multiple access (DDMA) approach is proposed. First, a phase modulation matrix with empty Doppler spectrum is introduced. By exploiting the empty Doppler spectrum, a test function based on sequential detection is developed to mitigate the Doppler ambiguity in DDMA waveform. Then, a discrete Fourier transform (DFT)-based TB in slow-time is formed.The proposed method can achieve waveform diversity in Doppler domain and generate a TB in slow-time that concentrates the transmitted power in a fixed spatial region to improve the transmit energy distribution for automotive MIMO radar, which is favored by medium/long range radar (MRR/LRR) applications. As compared to the conventional TDMA technique, the proposed TB DDMA approach can fully exploit the transmission capabilities of all transmit elements to ensure that the emitted power is efficiently used and inherits easy implementation. Moreover, the proposed TB DDMA method avoids the trade-off between the active time for each transmit antenna and the frame time. Simulation results verify the effectiveness of the proposed TB DDMA approach for automotive MIMO radar.