A novel antenna configuration method that improves degree of arrival (DOA) estimation through a sparse antenna array (SAA)

Abstract

This invention introduces a novel concept for configuring an array composed of subarrays within the Terahertz (THz) frequency range. This innovative design aims to enhance the precision of Degree of Arrival (DoA) estimation while simultaneously minimizing power usage and mitigating Radio Frequency (RF) chain interference.

Description

[0001] A NOVEL ANTENNA CONFIGURATION METHOD THAT IMPROVES DEGREE OF ARRIVAL (DOA) ESTIMATION THROUGH A SPARSE ANTENNA ARRAY (SAA)

[0002] Technical Field:

[0003] The present invention relates to a novel antenna configuration method that improves degree of arrival (DoA) estimation through a sparse antenna array (SAA), which enhances the accuracy of direction of arrival (DoA) estimation, reduces power consumption and minimizes radio frequency (RF) chain interference and can be applied in the realm of Internet of Things (loT) networks.

[0004] State of The Art:

[0005] To enable the support of high data rates within the forthcoming 6G wireless networks, the integration of the Terahertz (THz) band is envisioned to work in tandem with other advanced technologies. However, it's crucial to address the formidable challenge posed by the considerable propagation loss inherent to THz frequencies. To tackle this hurdle, an ultra-massive multiple input multiple output (UM-MIMO) system is being considered. Within the context of UM-MIMO, the transmitted signal assumes the characteristics of a pencil beam, necessitating a remarkably high level of precision for beam tracking and degree of arrival (DoA) estimation.

[0006] Regrettably, due to the pronounced directivity and substantial signal attenuation experienced by THz waves, the number of viable propagation paths is typically limited to just a few within the THz spectrum. Consequently, the resulting THz channel matrix often exhibits a low-rank structure, which significantly constrains the overall channel capacity of THz -based communication systems.

[0007] In response to this limitation, researchers have proposed the utilization of the array-of- subarray (AoSA) technique, which leverages a collection of antenna subarrays. While AoSA holds promise in enhancing THz system channel capacity, it introduces a notable challenge. Implementing this scheme necessitates the deployment of a substantial number of subarrays at the base station (BS), each requiring dedicated radio frequency (RF) chains. This, in turn, leads to a considerable increase in power consumption.

[0008] Furthermore, the presence of numerous closely spaced antenna arrays in compact configurations results in substantial mutual coupling between the RF chains. Consequently, even when employing hybrid beamforming techniques for such systems, performance degradation becomes a concern due to the non-convex nature introduced by RF coupling within the hybrid beamforming system model (1). Therefore, achieving necessitate high-capacity THz communication systems necessitates addressing these multifaceted challenges in a comprehensive manner.

[0009] To address the intricate challenges inherent to such systems, an innovative approach is presented in (2), it introduces a novel solution, encompassing an off-grid ultra-high- resolution Direction of Arrival (DoA) estimation method and a tracking algorithm meticulously designed to achieve millidegree-level precision in direction estimation and tracking for Terahertz wireless communications. This approach leverages an Array of Subarrays (AoSA) antenna configurations, combined with the MUSIC algorithm, resulting in the development of the AoSA-MUSIC-T algorithm. This algorithm not only offers superior performance but also significantly reduces the operational overhead by a noteworthy 50% when compared to the previously established AoSA-MUSIC approach. In this work, the antenna array configurations follow a Uniform Planar Array (UP A). While UP As are known for their high power consumption and complexity, they prove to be a strategic choice in this context.

[0010] Furthermore, in reference (3), another notable advancement is introduced in the form of a Dynamic AoSA (DAoSA) architecture. This architecture is specifically tailored for hybrid precoding in the millimeter-wave (mm-wave) and Terahertz (THz) bands, with a primary objective of striking a harmonious balance between spectral efficiency and power consumption. Notably, this approach incorporates switches within the hybrid precoding architecture, enabling dynamic adjustments in the connections between the Radio Frequency (RF) chains and subarrays. As part of this configuration, the Uniform Planar Array (UP A) also takes on the role of a sub-array, showcasing the versatility and adaptability of this innovative approach to antenna design and system optimization. These concerted efforts in research and development signify significant strides toward overcoming the challenges posed by advanced Terahertz communication systems.

[0011] Lately, in (4) they proposed a scheme referred to as distance-aware subarray selection (DSS), to choose a small number of subarrays maximizing the channel capacity, and then activate only the RF chains connected to the chosen subarrays. In this work (UP A) is considered too.

[0012] According to prior research, the antenna elements inside the antenna array are equally separated with a space distance of / 2, which adds complexity to the system in terms of power consumption and degradation in DoA estimation. In order to obtain the desired performance, additional components such as switches are installed in some works. As a result, a new method is needed that can overcome the this mentioned disadvantages.

[0013] References:

[0014] [1] Elbir, A. M., Mishra, K. V., Chatzinotas, S., & Bennis, M. (2022). Terahertz-band integrated sensing and communications: Challenges and opportunities. arXiv preprint arXiv:2208.01235

[0015] [2] Y. Chen, L. Yan and C. Han, "Millidegree-Level Direction-of-Arrival (DoA) Estimation and Tracking for Terahertz Wireless Communications," 2020 17th Annual IEEE International Conference on Sensing, Communication, and Networking (SECON), Como, Italy, 2020, pp. 1-9, doi: 10.1109 / SECON48991.2020.9158439.

[0016] [3] L. Yan, C. Han and J. Yuan, "A Dynamic Array of Sub-Array Architecture for Hybrid Precoding in the Millimeter Wave and Terahertz Bands," 2019 IEEE International Conference on Communications Workshops (ICC Workshops), Shanghai, China, 2019, pp. 1-5, doi: 10.1109 / ICCW.2019.8756936.

[0017] [4] Y. Liu, J. Wu, S. Kim and B. Shim, "Distance-Aware Subarray Selection for Terahertz Ultra-Massive MIMO Systems," 2023 IEEE 97th Vehicular Technology Conference (VTC2023- Spring), Florence, Italy, 2023, pp. 1-5, doi: 10.1109 / VTC2023- Spring57618.2023.10200814. Description of The Invention:

[0018] The invention to realize all the objectives mentioned above and which will emerge from the detailed description below; it had been put forth a novel antenna configuration designed to mitigate the complexities. This configuration is rooted in the concept of Array of Subarrays (AoSA), offering a strategic approach to address the intricate issues associated with THz -based communication systems.

[0019] The primary objective of this innovation is to achieve a substantial reduction in power consumption within the Terahertz (THz) network infrastructure, all the while maintaining a high level of accuracy in Direction of Arrival (DoA) estimation. This dual focus on energy efficiency and precise DoA estimation holds significant importance, particularly in the context of THz beam tracking. By accomplishing this goal, the invention not only contributes to the sustainability and longevity of THz networks but also ensures their capability to effectively track and maintain communication with THz beams, which is paramount for their reliable operation and connectivity. In essence, this innovation plays a pivotal role in enhancing the overall efficiency and functionality of THz networks by addressing the crucial aspects of power consumption and DoA estimation.

[0020] To achieve a reduction in power consumption while capitalizing on the benefits of improving Degree of Arrival (DoA) estimation through Sparsity Antenna Array (SAA), it had been intended an SAA as the antenna configuration, departing from the conventional Uniform Antenna Array (UAA). Additionally, considering the specific performance requirements, it had been planned to selectively activate or deactivate subarrays. This dynamic control over sub-array activation reduces the number of active Radio Frequency (RF) chains, consequently minimizing mutual coupling among RF chains, to sum up, it is a two-tier sparsity approach the first one is between the antenna element within the sub-array, and the second tier is between the sub-arrays.

[0021] This invention a configuration of this nature, which places a primary emphasis on the reduction of power consumption and the minimization of radio frequency (RF) chain interference, all the while enhancing the accuracy of Direction of Arrival (DoA) estimation, finds its applicability in the realm of Internet of Things (loT) networks. In essence, this setup is well-suited to cater to the specific needs and demands of loT systems, where energy efficiency and precise DoA estimation play pivotal roles in ensuring optimal functionality and connectivity.

[0022] This invention the power consumption had been reduced by reducing the number of antenna elements used within the subarray, and the RF chain coupling had been reduced by creating second-tier sparsity, which had been led to a reduction in the complexity caused by the non-convex optimization problem caused by the RF chain coupling.

[0023] The advantages of this invention can be summarized as follows:

[0024] 1. Reduce power consumption by reducing the number of antenna elements,

[0025] 2. Reduce the RF chain coupling by adding scarcity between the sub-arrays themselves,

[0026] 3. Increase the DoA estimation accuracy compared with the uniform array by adding sparsity between the elements.

[0027] The structural and characteristic features and all advantages of the method subject to the invention will be understood more clearly thanks to the figures given below and the detailed explanation written by making reference to these figures, and therefore the evaluation should be made by taking these figures and detailed explanation into consideration.

[0028] Description of the Figures:

[0029] The invention will be described with reference to the accompanying figures, so that the features of the invention will be more clearly understood and appreciated, but the purpose of this is not to limit the invention to these certain regulations. On the contrary, it is intended to cover all alternatives, changes and equivalences that can be included in the area of the invention defined by the accompanying claims. The details shown should be understood that they are shown only for the purpose of describing the preferred embodiments of the present invention and are presented in order to provide the most convenient and easily understandable description of both the shaping of methods and the rules and conceptual features of the invention. In these drawings;

[0030] Figure 1 Graphical view of DoA estimation for ULA and SLA with the same number of antennas.

[0031] Figure 2 Graphical view of DoA estimation for ULA and SLA with the same aperture length.

[0032] Figure 3 Sample view of Two-Tier Array of Sparse Arrays (2TAoSA) Configuration Model.

[0033] The figures to help understand the present invention are numbered as indicated in the attached image and are given below along with their names.

[0034] Disclosure of References:

[0035] RF. Radio Frequency

[0036] UAA. Uniform Antenna Array

[0037] SAA. Sparse Antenna Array

[0038] ULA. Uniform Linear Arrays

[0039] SA. Sparse Antenna

[0040] Description of The Invention:

[0041] Before starting to explain the invention, the following concepts are explained:

[0042] RF chain: A chain of electronic components, including amplifiers, filters, mixers, attenuators, and detectors, is crucial in digital receiver designs, enabling the conversion of passband communication signals to baseband. However, at high frequencies, these circuits can be expensive.

[0043] UAA: Uniformly spaced antenna array with d= X / 2.

[0044] SAA: Non-uniform spaced antenna array with d X / 2

[0045] THz: electromagnetic waves band of frequencies from 0.3 to 3 terahertz. Beamforming: a type of (RF) management in which a wireless signal is directed toward a specific receiving device.

[0046] MUSIC: Multiple signal specification it is an algorithm used for frequency estimation and DoA.

[0047] This invention, to enhance the performance of Terahertz communication systems, it had been introduced a comprehensive two-tier sparsity approach, designed to accomplish two vital objectives. First and foremost, this innovative approach aims to significantly enhance the accuracy of Direction of Arrival (DoA) estimation while concurrently mitigating the challenges associated with (RF) chain coupling, thereby reducing both the complexity of hybrid beamforming and the overall power consumption.

[0048] The first tier of this approach is dedicated to optimizing the utilization of sparse antennas, as opposed to conventional uniform antenna arrays. This strategic choice not only contributes to the attainment of a markedly superior DoA estimation accuracy but also ensures that the system operates efficiently. To illustrate the impact of this decision, Figure 1 provides a comparative analysis of DoA estimation accuracy between Uniform Linear Arrays (ULA) and Sparse Linear Arrays (SLA), both evaluated using the MUSIC algorithm. The results underscore the substantial benefits of adopting a sparse antenna configuration. It's important to highlight that within this particular tier of our approach, you have the flexibility to work with the same quantity of antenna elements as you would in a Uniform Linear Array (ULA). However, you can extend their effective aperture size by strategically exploiting the inherent sparsity among these elements. Alternatively, you have the option to reduce the number of antenna elements within the sparse array configuration while still maintaining the same aperture length.

[0049] In the first approach, where you extend the aperture by capitalizing on element sparsity, you can achieve a notably higher level of accuracy in Direction of Arrival (DoA) estimation when compared to a traditional ULA setup as shown in Figure 1. Conversely, in the second approach, which involves reducing the number of antenna elements in the sparse array, you can achieve a similar level of DoA estimation accuracy while benefiting from the advantage of using fewer antennas as shown in Figure 2. This flexibility underscores the adaptability of our proposed system to different operational requirements. Furthermore, it's crucial to note that in the context of Terahertz (THz) band communication, the extension of aperture length is no longer constrained by physical limitations. This is due to the fact that the wavelength within the THz band ranges from 3mm down to 3 pm, providing ample room for extending aperture length as needed to optimize system performance.

[0050] Moving on to the second tier of our two-tier sparsity approach, the focus shifts towards optimizing the sparsity between sub-arrays. In this configuration, not all sub-arrays are active simultaneously; rather, their activation is tailored to match the specific performance requirements of the moment. This dynamic approach to sub-array activation not only conserves valuable resources but also plays a pivotal role in reducing the coupling between RF chains, thereby simplifying the intricate task of hybrid beamforming.

[0051] The holistic implementation of these two tiers culminates in the development of the innovative Two-Tier Array of Sparse Arrays (2TAoSA) configuration, as visually depicted in Figure 3. This configuration embodies the essence of our proposal, showcasing a meticulously designed system that leverages sparsity at multiple levels to optimize DoA accuracy, minimize RF chain coupling, and ultimately enhance the efficiency and effectiveness of Terahertz communication systems.

[0052] The foregoing descriptions of specific embodiments of the present technology have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present technology to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present technology and its practical software, to thereby enable others skilled in the art to best utilize the present technology and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the software or implementation without departing from the spirit or scope of the claims of the present technology.

[0053] In a case that no conflict occurs, the embodiments in the present disclosure and the features in the embodiments may be mutually combined. The foregoing descriptions are merely specific implementations of the present disclosure but are not intended to limit the protection scope of the present disclosure. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present disclosure shall fail within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

CLAIMS1- The invention is related to a novel antenna configuration method that improves degree of arrival (DoA) estimation through a sparse antenna array (SAA), its feature is;— in the first tier of a system with a two tiers antenna configuration, the partitioning of antenna arrays into sub-arrays,— obtaining a distribution in which each sub-array has a sparse antenna arrangement with an element spacing (d>X / 2) instead of a dense antenna distribution with an element spacing of (d=X / 2) to enhance the DoA estimation by using less number of antenna which will decrease the cost and power consumption ,— in the second tier, including process steps of adding sparsity between sub-arrays to reduce RF chain coupling without affecting the accuracy of the direction of arrival (DoA) estimation.2- The method according to claim 1, characterized in that the system operating in the THz band is equipped with an extensive array of antenna elements to generate a narrow beam which come with high power consumption and cost.3- The method according to claim 1, characterized that using sparsity within sub-array will enhance the DoA estimation with less number of antenna which will reduce the power consumption and the sparsity between sub-arrays will reduce the RF chain coupling.

Images