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Integrated sensing and communication (ISAC) technology stands as a pivotal enabler for the sixth-generation mobile communication systems (6G) to enable high data rate communication while ensuring accurate target sensing. Orthogonal time-frequency space (OTFS) modulation has emerged as a promising candidate for ISAC, owing to its remarkable performance in doubly-selective channels. However, the sensing resolutions of OTFS are limited by the available bandwidth and frame time. In cases of insufficient delay and Doppler resolutions, the channel response is spread along delay and Doppler axes, resulting in substantial sensing inaccuracies. In our previous research, we introduced the amplitude barycenter calibration (A-BC) algorithm as an effort to improve the accuracy of parameter estimation, albeit without a strategic design for OTFS windows. In this work, we delve into the receive window design of the OTFS-ISAC system and develop a barycenter calibration algorithm that explores the high-order spectra (HOS) of the DD domain channels, called the HOS-BC algorithm. The simulation results indicate that the proposed algorithm not only improves the sensing resolution under the given bandwidth and frame time but also achieves a higher sensing accuracy at a low pilot signal-to-noise ratio compared with the A-BC algorithm.

Radar, serving as a sensing technology, is anticipated to be integrated into the sixth-generation (6G) mobile communication system to facilitate high-precision sensing functions, potentially inciting spectrum competition between radar and wireless communication systems. To address this challenge, this study explores a code domain method for mitigating mutual interference caused by spectrum sharing between communication and radar systems. Particularly, this work designs a three-dimensional complementary scrambling code together with the transceiver structure that can simultaneously support communication and radar in a multi-user-multi-target scenario. The complementary scrambling code exhibits ideal correlation properties in both synchronous and asynchronous channels, seamlessly incorporating the time-frequency-space domain. The proposed scheme, referred to as the complementary coded scrambling radar and communication (CCS-RadCom) system, exhibits considerably higher spectral efficiency than that of the spread spectrum-based system due to the fact that it employs scrambling modulation to achieve processing gain. Additionally, this study conducts a joint evaluation of data rates and radar estimate rates. Simulation results indicate that the proposed system successfully achieves improved performance in terms of radar estimation rate and data rate.

Photocatalytic technology provided an environmentally friendly, green simple and efficient method to treat the pollutant. Interfacial interaction in heterojunction systems has significant effect on photocatalytic activity due to the large discrepancy in lattice parameters. In this work, the [Bi2O2]2+-containing materials was used to construct an Bi2O2S/Bi12TiO20(BOS/BTO) heterojunction via in-situ growth, and characterized by various approaches to analyze their structural, photoelectrochemical and optical properties. The BOS/BTO composite showed excellent visible light photodegradation of 2, 4-dichlorophenol (2, 4-DCP). Among, the optimal BOS/BTO composite exhibited the removal rates of 2, 4-DCP were 3.5 times and 1.6 times higher than pure BTO and BOS. Meanwhile, the density functional theory (DFT) calculations, GC/MS test and a series of experimental results confirmed the type-I photocatalytic mechanism and possible degradation pathway. This work offered a novel ideal for designing heterojunction photocatalyst with enhanced photocatalytic activity via the interfacial engineering of [Bi2O2]2+-layer structures.