基于太赫茲智能反射面波束色散和分裂的快速感知方法

郝萬明; 楊蘭; 朱政宇; 李興旺

doi:10.11999/JEIT240789

基于太赫茲智能反射面波束色散和分裂的快速感知方法

doi: 10.11999/JEIT240789

郝萬明^{1, 2, ,},
楊蘭¹,
朱政宇¹,
李興旺³

1.
鄭州大學(xué)電氣與信息工程學(xué)院鄭州 450001
2.
東南大學(xué)移動(dòng)通信全國(guó)重點(diǎn)實(shí)驗(yàn)室南京 210096
3.
河南理工大學(xué)物理與電子信息學(xué)院焦作 454000

基金項(xiàng)目: 國(guó)家自然科學(xué)基金(62471440)，東南大學(xué)移動(dòng)通信全國(guó)重點(diǎn)實(shí)驗(yàn)室開放研究基金(2024D12)

詳細(xì)信息

作者簡(jiǎn)介:
郝萬明：男，副教授，研究方向?yàn)楹撩撞ㄍㄐ?、太赫茲通信、大?guī)模MIMO技術(shù)、物理層安全技術(shù)、智能超表面技術(shù)等

楊蘭：女，碩士生，研究方向?yàn)樘掌澩ㄐ?、智能反射面技術(shù)等

朱政宇：男，副教授，研究方向?yàn)橹悄芊瓷涿婕夹g(shù)、物理層安全技術(shù)、無線通信與信號(hào)處理等

李興旺：男，副教授，研究方向?yàn)榉钦欢嘀方尤?NOMA)、智能反射面通信、物理層安全、無線信息與能量協(xié)同傳輸?shù)?/p>

通訊作者:
郝萬明　iewmhao@zzu.edu.cn

中圖分類號(hào): TN92
計(jì)量
- 文章訪問數(shù): 84
- HTML全文瀏覽量: 29
- PDF下載量: 8
- 被引次數(shù): 0
出版歷程
- 收稿日期: 2024-09-12
- 修回日期: 2025-02-17
- 網(wǎng)絡(luò)出版日期: 2025-02-26

Fast Sensing Method Based on Beam Squint and Beam Split of Terahertz Reflective Intelligent Surfaces

1.
School of Electrical and Information Engineering, Zhengzhou University, Zhengzhou 450001, China
2.
National Mobile Communications Research Laboratory, Southeast University, Nanjing 210096, China
3.
School of Physics and Electronic Information Engineering, Henan Polytechnic University, Jiaozuo 454000, China

Funds: The National Natural Science Foundation of China (62471440), The Open Research Fund of the National Mobile Communications Research Laboratory, Southeast University (2024D12)

摘要

摘要: 針對(duì)太赫茲智能反射面(RIS)系統(tǒng)中基于波束掃描感知耗時(shí)較長(zhǎng)問題，該文提出一種基于太赫茲RIS波束色散和分裂的快速感知方法。通過在每個(gè)RIS元件處部署實(shí)時(shí)延(TTD)以動(dòng)態(tài)調(diào)整波束色散程度，設(shè)置大陣列RIS單元間距以形成波束分裂效應(yīng)，進(jìn)而聯(lián)合波束色散和分裂實(shí)現(xiàn)目標(biāo)區(qū)域快速感知。具體地，將感知區(qū)域分為多個(gè)子區(qū)域，并基于RIS波束色散優(yōu)化TTD和RIS反射元件相移，以覆蓋單一子區(qū)域。同時(shí)，利用波束分裂無縫覆蓋多個(gè)子區(qū)域，相比使用單一波束掃描感知顯著降低了時(shí)間開銷。而后，為減少回波信號(hào)路徑損耗，在RIS處配置主動(dòng)感知元件，用于直接接收并分析回波信號(hào)。在此基礎(chǔ)上，推導(dǎo)出感知目標(biāo)角度估計(jì)值及其均方根誤差(RMSE)。仿真結(jié)果表明了所提快速感知方案的有效性。
- 太赫茲 /
- 智能反射面 /
- 波束色散 /
- 波束分裂 /
- 快速感知
Abstract: Objective Re?ecting Intelligent Surface (RIS)-aided Terahertz (THz) communications are considered a key technology for future Sixth-Generation (6G) mobile communication systems addressing issues such as signal attenuation and Line-of-Sight (LoS) link blockage issues, due to their ultra-large bandwidth and low power consumption. However, the frequency independent characteristics of RIS elements can cause beam squint effects, where beams of different carriers are directed at different angles. Although this reduces the beam gain received by users, it can be leveraged to enhance sensing capabilities in sensing applications. Specifically, beam squint allows for simultaneous sensing of a target using multiple carrier beams directed in different directions. Existing studies have explored beam squint for beam training. For example, by studying near-field beam squint and True Time Delay (TTD) to generate beams that focus at multiple positions across different frequencies, enabling rapid beam training with reduced overhead. Additionally, combining TTD with beam squint and beam split for sensing extends the beam coverage area and enables the quick acquisition of user locations through feedback. However, there is no research on jointly utilizing beam squint and beam split for sensing in RIS-assisted THz systems, thus understanding the full potential of beam squint in sensing. This paper aims to conduct detailed research on the use of beam squint for sensing in such systems. Methods To address the time-consuming issue of beam scanning in RIS-assisted THz systems, a fast sensing method based on RIS beam squint and split effects is proposed. Each RIS element is equipped with a TTD mechanism to dynamically adjust the degree of beam squint, while the large array RIS units are spaced to induce the beam split effect. By combining beam quint and beam split, the method enables rapid sensing of the target area. Specifically, the sensing area is divided into multiple sub-areas, with the TTD and the phase shift at the RIS elements optimized to cover each sub-area based on beam squint. The beam split effect is then used to seamlessly cover multiple sub-areas, significantly reducing time overhead compared to single beam scanning. To further mitigate echo signal path loss, active sensing elements are configured at the RIS for direct reception and analysis of the echo signals. The estimation of the sensing target’s angle, along with its root mean square error (RMSE), is derived based on this approach. Results and Discussions Consider the RIS-assisted THz sensing system model (Fig. 1). By deriving the channel and beam gain expressions, the beam patterns under the beam squint effect are analyzed (Fig. 2). Based on the internal structural diagram of the RIS (Fig. 4), the beam split effect is examined by varying the spacings between RIS elements (Fig. 5), with corresponding beam patterns (Fig. 3) presented for different spacings. Next, the RIS structure utilizing TTD (Fig. 6) allows for flexible adjustment of the beam squint and split degrees, significantly expanding the beam coverage area compared to traditional beam squint and split methods (Fig. 7, Fig. 8). Additionally, to fine-tune the gaps between adjacent split beams, the ATDS method is proposed. By combining beam squint and beam split, this method achieves near-seamless coverage of all subareas (Fig. 9). Finally, the target direction is estimated by analyzing the echo signals received at the RIS-SE, based on the RSME. The simulation results demonstrate the relationship between sensing accuracy and the number of carriers (Fig.10, Fig. 11), confirming the effectiveness and feasibility of the rapid sensing method combining beam squint and split. Conclusions This paper investigates the issues of beam squint and beam split in RIS-assisted THz systems and proposes a rapid sensing method that combines both effects. Specifically, TTD is used to adjust the direction of subcarrier beams based on beam squint. To expand the sensing area, the combined effects of beam squint and beam split, divide the sensing area into multiple subareas, which are simultaneously covered by multiple carrier beams within a single OFDM block. The target direction is then estimated based on echo signals received at the RIS-SE, with sensing error measured using the RMSE between the true and estimated values. Simulation results demonstrate the feasibility and effectiveness of the proposed rapid sensing method. However, it is found that while the beam squint effect significantly reduces beam gain and communication performance, it expands the beam coverage area and enhances sensing capabilities. Therefore, in an integrated sensing and communication system, the impact of beam squint should be considered at different stages. Future research will focus on improving the performance of such integrated systems.
- Terahertz (THz) /
- Reflecting Intelligent Surface (RIS) /
- Beam squint /
- Beam split /
- Fast sensing

HTML全文

圖 1 RIS輔助太赫茲感知系統(tǒng)模型

下載: 全尺寸圖片幻燈片

圖 2 波束色散效應(yīng)下的波束圖樣

下載: 全尺寸圖片幻燈片

圖 3 波束分裂效應(yīng)下的波束圖樣($P = 3$)

下載: 全尺寸圖片幻燈片

圖 4 RIS元件中有關(guān)二極管結(jié)構(gòu)電路圖

下載: 全尺寸圖片幻燈片

圖 5 RIS元件不同間距的陣列圖

下載: 全尺寸圖片幻燈片

圖 6 基于TTD的RIS元件結(jié)構(gòu)圖

下載: 全尺寸圖片幻燈片

圖 7 基于TTD的波束色散

下載: 全尺寸圖片幻燈片

圖 8 基于TDS的聯(lián)合RIS波束色散和分裂 (P=2)

下載: 全尺寸圖片幻燈片

圖 9 基于ATDS的聯(lián)合RIS波束色散和分裂 ($P = 2$)

下載: 全尺寸圖片幻燈片

圖 10 基于TDS的RMSE與載波數(shù)目之間的關(guān)系

下載: 全尺寸圖片幻燈片

圖 11 基于ATDS的RMSE與載波數(shù)目之間的關(guān)系

下載: 全尺寸圖片幻燈片

參考文獻(xiàn)(15)

[1]	RAPPAPORT T S, XING Yunchou, KANHERE O, et al. Wireless communications and applications above 100 GHz: Opportunities and challenges for 6G and beyond[J]. IEEE Access, 2019, 7: 78729–78757. doi: 10.1109/ACCESS.2019.2921522.
[2]	XUE Qing, JI Chengwang, MA Shaodan, et al. A survey of beam management for mmWave and THz communications towards 6G[J]. IEEE Communications Surveys & Tutorials, 2024, 26(3): 1520–1559. doi: 10.1109/COMST.2024.3361991.
[3]	SU Xin, HE Ruisi, ZHANG Peng, et al. Joint precoding for RIS-assisted wideband THz cell-free massive MIMO systems[J]. IEEE Internet of Things Journal, 2024, 11(20): 33361–33370. doi: 10.1109/JIOT.2024.3426937.
[4]	WU Qingqing, ZHANG Shuowen, ZHENG Beixiong, et al. Intelligent reflecting surface-aided wireless communications: A tutorial[J]. IEEE Transactions on Communications, 2021, 69(5): 3313–3351. doi: 10.1109/TCOMM.2021.3051897.
[5]	HUANG Chongwen, ZAPPONE A, ALEXANDROPOULOS G C, et al. Reconfigurable intelligent surfaces for energy efficiency in wireless communication[J]. IEEE Transactions on Wireless Communications, 2019, 18(8): 4157–4170. doi: 10.1109/TWC.2019.2922609.
[6]	YAN Wencai, HAO Wanming, HUANG Chongwen, et al. Beamforming analysis and design for wideband THz reconfigurable intelligent surface communications[J]. IEEE Journal on Selected Areas in Communications, 2023, 41(8): 2306–2320. doi: 10.1109/JSAC.2023.3288235.
[7]	LI Jinyang, ZHANG Shun, LI Zan, et al. User sensing in RIS-aided wideband mmWave system with beam-squint and beam-split[J]. IEEE Transactions on Communications, 2025, 73(2): 1304–1319. doi: 10.1109/TCOMM.2024.3439445.
[8]	HAO Wanming, YOU Xiaobei, ZHOU Fuhui, et al. The far-/near-field beam squint and solutions for THz intelligent reflecting surface communications[J]. IEEE Transactions on Vehicular Technology, 2023, 72(8): 10107–10118. doi: 10.1109/TVT.2023.3254153.
[9]	ELBIR A M, SHI Wei, PAPAZAFEIROPOULOS A K, et al. Terahertz-band channel and beam split estimation via array perturbation model[J]. IEEE Open Journal of the communications society, 2023, 4: 892–907. doi: 10.1109/OJCOMS.2023.3263625.
[10]	郝萬明, 尤曉蓓, 孫鋼燦, 等. 超寬帶太赫茲通信中天線結(jié)構(gòu)設(shè)計(jì)及其波束色散影響分析[J]. 電子與信息學(xué)報(bào), 2023, 45(1): 200–207. doi: 10.11999/JEIT211290. HAO Wanming, YOU Xiaobei, SUN Gangcan, et al. Design of antenna structure and analysis of beam split effect in ultra-band width terahertz communications[J]. Journal of Electronics & Information Technology, 2023, 45(1): 200–207. doi: 10.11999/JEIT211290.
[11]	ZHAI Bangzhao, ZHU Yilun, TANG Aimin, et al. THzPrism: Frequency-based beam spreading for terahertz communication systems[J]. IEEE Wireless Communications Letters, 2020, 9(6): 897–900. doi: 10.1109/LWC.2020.2974468.
[12]	TAN Jinbo and DAI Linglong. Wideband beam tracking based on beam zooming for THz massive MIMO[C]. GLOBECOM 2020 - 2020 IEEE Global Communications Conference, Taipei, China, 2020: 1–6. doi: 10.1109/GLOBECOM42002.2020.9348222.
[13]	GAO Feifei, XU Liangyuan, and MA Shaodan. Integrated sensing and communications with joint beam-squint and beam-split for mmWave/THz massive MIMO[J]. IEEE Transactions on Communications, 2023, 71(5): 2963–2976. doi: 10.1109/TCOMM.2023.3252584.
[14]	CAI Wenhao, LI Hongyu, LI Ming, et al. Practical modeling and beamforming for intelligent reflecting surface aided wideband systems[J]. IEEE Communications Letters, 2020, 24(7): 1568–1571. doi: 10.1109/LCOMM.2020.2987322.
[15]	LI Renwang, SHAO Xiaodan, SUN Shu, et al. Beam scanning for integrated sensing and communication in IRS-aided mmWave systems[C]. 2023 IEEE 24th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), Shanghai, China, 2023: 196–200. doi: 10.1109/SPAWC53906.2023.10304548.