PREPRINT

Impedance Variation Detection at MISO Receivers

Shaohan Wu

Submitted on 7 November 2022

Abstract

Techniques have been proposed to estimate unknown antenna impedance due to time-varying near-field loading conditions at multiple-input single-output (MISO) receivers. However, it remains unclear when a change occurs and impedance estimation becomes necessary. In this letter, we address this problem by formulating it as a hypothesis test. Our contributions include deriving a generalized likelihood-ratio test (GLRT) detector to decide if the antenna impedance has changed over two groups of packets. This GLRT formulation leads to a novel optimization problem, but we propose a binary search based algorithm to solve it efficiently. Our derived GLRT detector enjoys a better detection and false alarm trade-off when compared with a well-known, reference detector in simulations. As one result, more transmit diversity significantly improves detection accuracy at a given false alarm rate, especially in slow fading channels.

Preprint

Comment: 5 pages, 2 figures, journal

Subjects: Computer Science - Information Theory; Electrical Engineering and Systems Science - Signal Processing

URL: http://arxiv.org/abs/2211.03677