Amplitude-Fluctuation Separation Based on BPM Waveform Reconstruction in MIMO Systems

Abstract

In Multi-input-multi-output (MIMO) systems, the orthogonality among sub-waves could be realized by binary phase modulation (BPM) encoding. Especially in the case of insufficient matched filters, Hadamard-matrix-based BPM encoding could be employed to separate the transmitted signal from echo effectively, which is verified firstly in this paper by utilizing target location, when introducing fluctuations in amplitude as well as in phase. Hence the amplitude-fluctuation separation method based on waveform reconstruction is put forward. The waveform is reconstructed on basis of the known array structure, and then the results are optimized obeying the minimum mean square error (MSE) criterion to obtain more accurate estimation. Compared with the traditional single-channel blind source separation approach, this method shows significant computation reduction by taking full use of the phase and structure information. Monte-Carlo experiments validate the method application in angle estimation improvement.

Solving Ambiguity in Target Detection for BPSK-Based MIMO FMCW Radar System

“…In general, orthogonal codes are used as c q (t) to lower the cross-correlation between signals transmitted from different antenna elements. For example, Hadamard code [18] can be used for the BPSK modulation.…”

Solving Doppler-Angle Ambiguity of BPSK-MIMO FMCW Radar System

“…In this method, four Tx antennas transmit with a code of (1, 1, 1, 1), (1, 0, 1, 0), (1, 1, 0, 0), and (1, 0, 0, 1). Then, the received signals from each Tx antenna are decomposed using the orthogonality between the codes [21]. As shown in the figure, four peaks occurred for each target, and the maximum detectable velocity was reduced by a quarter.…”