Parameter Estimation for Energy-Efficient 1-bit Bi-Static ISAC Network

The growing demand for robust, green, and wide-area sensing in applications like the low-altitude economy necessitates scalable, low-cost, and energy-efficient network architectures. To meet this need, this paper proposes a one-bit bi-static integrated sensing and communication (ISAC) system architecture designed to cover sensing blind spots in a cost-effective and energy-efficient manner. The system employs micro receiving nodes equipped with one-bit analog-to-digital converters to minimize hardware cost and power consumption. However, this design introduces the dual challenges: severe signal distortion from one-bit quantization and parameter ambiguity from clock asynchronism between the transmitter and receiver. These issues render conventional synchronization and parameter estimation methods ineffective. This paper presents a novel algorithm that directly tackles these challenges by processing the one-bit temporal data. Our method first estimates the direction of arrival (DOA) using the one-bit MUSIC algorithm, and leverages it to coherently accumulate signal energy in the spatial domain for each preamble. Aided by the DOA, a compressive sensing-based approach then estimates the combined delay and timing offset, followed by the extraction of the Doppler shift mixed with carrier frequency offset. By systematically processing these estimates, our algorithm obtains absolute target delays and relative Doppler shifts without requiring a dedicated reference path. The Cramér-Rao lower bound (CRLB) is derived, and simulations validate that the proposed method achieves high-accuracy parameter estimation, i.e., the optimization result reaches the CRLB. In addition, simulation under practical settings illustrates that the sensing range is extended from 400 m to 900 m, increased by 125%, demonstrating the feasibility of low-cost, one-bit bi-static ISAC systems.