[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-84179-en":3,"doc-seo-84179-105":29,"detail-sidebar-cat-0-en-105":91},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":20,"is_deleted":4,"is_public":20,"is_downloadable":20,"audit_status":20,"page_count":21,"language":22,"language_code":23,"site_id":24,"html_lang":23,"table_of_contents":25,"faqs":26,"seo_title":13,"seo_description":14,"update_tm":27,"read_time":28},84179,1374391974468,"Eden","https://ap-avatar.wpscdn.com/davatar_29158cc5080c5b710cf443261637dec0",8,"Research & Report","Bessel Beam Optimization for Near-Field THz Communications Under UE Location Uncertainty","Future terahertz (THz) wireless systems target high coverage and capacity using extremely large antenna arrays, yet far-field assumptions break down at THz due to short wavelengths and large array apertures. Many user equipments (UEs) then operate in the radiative near-field, enabling near-field beam synthesis. This paper optimizes phase-only Bessel-like downlink beams for THz MIMO under imperfect UE location knowledge by maximizing spectral efficiency via a Bessel cone angle and deriving low-complexity closed-form solutions for deterministic and stochastic UE location errors. Extensive simulations across frequencies, locations, and array sizes confirm near-optimal performance with about 0.1% difference versus exhaustive search while reducing complexity to O(1).","Bessel Beam Optimization for Near-Field THz Communications under UE Location Uncertainty  \nAditya Jolly∗†, Vitaly Petrov†, Gbor Fodor∗† and Emil Bjrnson†  \n∗ Ericsson Research, Sweden †KTH Royal Institute of Technology, Sweden  \nEmail: {aditya.jolly, [gabor.fodor](gabor.fodor}@ericsson.com)[}](gabor.fodor}@ericsson.com)[@ericsson.com](gabor.fodor}@ericsson.com), {vitalyp, [emilbjo](emilbjo}@kth.se)[}](emilbjo}@kth.se)[@kth.se](emilbjo}@kth.se)  \narXiv :2607 .07069v2 [ ee ss . SP] 9 Jul 2026  \nAbstract—To achieve the desired coverage and capacity levels, future terahertz (THz) wireless systems are envisioned to utilize extremely large antenna arrays. At THz frequencies, the combination of short wavelengths and large array apertures often makes many of the conventional far-field assumptions invalid in practice. As a result, many UEs operate in the radiative nearfield zone, where novel near-field beam synthesis methods become viable. This paper studies phase-only Bessel-like near-field beam configurations for downlink THz multiple-input multiple-output links under imperfect UE location knowledge. We first formulatea spectral efficiency maximization problem with respect to the“Bessel cone angle”. We then derive low-complexity closed-form approximations for the optimal Bessel beam configuration for:(i) deterministic UE location; (ii) Gaussian and (iii) uniform error in the UE location. Finally, through extensive simulations across multiple signal frequencies, UE locations, and array sizes, we show that our proposed simple closed-form approximations closely match (under 0. 1% difference) the best performance achieved via exhaustive search, while simultaneously reducing the configuration complexity down to as low as O(1).  \nI. INTRODUCTION  \nTerahertz (THz) (0 .3–3 THz) communications can theoretically support up to terabit-per-second data rates by leveraging the large available bandwidth [1] . However, severe propagation losses make practical mobile THz deployments challenging and necessitate the use of steerable high-gain antennas (e.g., large-scale antenna arrays) to maintain a sufficient link budget [2] . As wavelengths shrink and large-scale arrays become more prevalent, the so-called radiative near-field zone can extend to several hundred meters [3] . As a result, a substantial fraction of user equipments (UEs) may operate in this zone, where conventional far-field beamforming based on planewave assumptions can incur significant performance losses [4] .  \nMotivated by this, recent work has increasingly focused on near-field-specific beams, such as beam focusing [3], which concentrates array energy at a spatial focal point rather than only an angular direction [5] . Prior works have quantified its achievable gains, developed phase-optimization algorithms and near-field codebooks [4]–[9], among others. However, beyond single-point energy concentration offered by beam focusing, near-field operation also enables a much broader class of beams with distinct propagation characteristics, including Airy beams [10], Weber/Mathieu beams [11], Hermite–Gaussian beams [12], and vortex beams [13], among others.  \nIn this context, Bessel-like beams [14] (hereafter Bessel beams) have attracted significant attention for applications in mobile THz links. This is primarily due to two key properties of Bessel beams. First, their “non-diffracting behavior” [15],  \nmeaning that they sustain axial power over a finite range and can therefore provide robustness to UE location uncertainty [1], [16], [17], and second, their “self-healing capability” [18], meaning that they can reconstruct the signal after partial link occlusion and thereby improve resilience to smallscale blockage [1], [17], [19] .  \nRecent work spans efficient beam generation and hardwareoriented synthesis to experimental demonstrations showing that Bessel beam-based transmission can enhance spectral efficiency (SE) in ultra-wideband THz systems [14],[20],[21] .  \nHowever, the use of Bes","cbCaias2iMF7VGsE","https://ap.wps.com/l/cbCaias2iMF7VGsE","pdf",2346149,1,7,"English","en",105,"# Introduction\n## Near-field THz and limitations of far-field assumptions\n## Near-field specific beams and prior related work\n## Motivation for Bessel-like beams in mobile THz links\n## Problem of Bessel beam configuration and UE location uncertainty","[{\"question\":\"Why do far-field beamforming assumptions fail in THz systems with large antenna arrays?\",\"answer\":\"At THz frequencies, short wavelengths combined with large array apertures make conventional far-field approximations invalid. This shifts many UEs into the radiative near-field zone where plane-wave-based beamforming can lose performance.\"},{\"question\":\"What new design parameter makes optimal Bessel beam configuration non-trivial?\",\"answer\":\"Unlike far-field steering based mainly on angle, and near-field focusing based on angle and distance, Bessel beams require choosing the “Bessel cone angle.” This additional parameter complicates finding the optimal configuration.\"},{\"question\":\"How does the paper handle imperfect UE location knowledge when optimizing Bessel beams?\",\"answer\":\"The paper models UE location uncertainty and formulates spectral efficiency maximization with respect to the Bessel cone angle. It then derives low-complexity closed-form approximations for deterministic UE location and for Gaussian and uniform location errors, validated by simulations.\"}]",1784193670,18,{"code":4,"msg":30,"data":31},"ok",{"site_id":24,"language":23,"slug":32,"title":13,"keywords":33,"description":14,"schema_data":34,"social_meta":86,"head_meta":88,"extra_data":90,"updated_unix":27},"bessel-beam-optimization-for-near-field-thz-communications-under-ue-location-uncertainty","",{"@graph":35,"@context":85},[36,53,68],{"@type":37,"itemListElement":38},"BreadcrumbList",[39,43,47,50],{"item":40,"name":41,"@type":42,"position":20},"https://docshare.wps.com","Home","ListItem",{"item":44,"name":45,"@type":42,"position":46},"https://docshare.wps.com/document/","Document",2,{"item":48,"name":12,"@type":42,"position":49},"https://docshare.wps.com/document/research-report/",3,{"item":51,"name":13,"@type":42,"position":52},"https://docshare.wps.com/document/bessel-beam-optimization-for-near-field-thz-communications-under-ue-location-uncertainty/84179/",4,{"url":51,"name":13,"@type":54,"author":55,"headline":13,"publisher":57,"fileFormat":60,"inLanguage":23,"description":14,"dateModified":61,"datePublished":62,"encodingFormat":60,"isAccessibleForFree":63,"interactionStatistic":64},"DigitalDocument",{"name":9,"@type":56},"Person",{"url":40,"name":58,"@type":59},"DocShare","Organization","application/pdf","2026-07-17","2026-07-16",true,{"@type":65,"interactionType":66,"userInteractionCount":20},"InteractionCounter",{"@type":67},"ViewAction",{"@type":69,"mainEntity":70},"FAQPage",[71,77,81],{"name":72,"@type":73,"acceptedAnswer":74},"Why do far-field beamforming assumptions fail in THz systems with large antenna arrays?","Question",{"text":75,"@type":76},"At THz frequencies, short wavelengths combined with large array apertures make conventional far-field approximations invalid. This shifts many UEs into the radiative near-field zone where plane-wave-based beamforming can lose performance.","Answer",{"name":78,"@type":73,"acceptedAnswer":79},"What new design parameter makes optimal Bessel beam configuration non-trivial?",{"text":80,"@type":76},"Unlike far-field steering based mainly on angle, and near-field focusing based on angle and distance, Bessel beams require choosing the “Bessel cone angle.” This additional parameter complicates finding the optimal configuration.",{"name":82,"@type":73,"acceptedAnswer":83},"How does the paper handle imperfect UE location knowledge when optimizing Bessel beams?",{"text":84,"@type":76},"The paper models UE location uncertainty and formulates spectral efficiency maximization with respect to the Bessel cone angle. It then derives low-complexity closed-form approximations for deterministic UE location and for Gaussian and uniform location errors, validated by simulations.","https://schema.org",{"og:url":51,"og:type":87,"og:title":13,"og:site_name":58,"og:description":14},"article",{"robots":89,"canonical":51},"index,follow",{"doc_id":7,"site_id":24},{"code":4,"msg":5,"data":92},[93,97,101,105,110,115,119,122,127,130,134],{"id":20,"doc_module":4,"doc_module_name":45,"category_name":94,"show_sort_weight":95,"slug":96},"Story & Novel",90,"story-novel",{"id":46,"doc_module":4,"doc_module_name":45,"category_name":98,"show_sort_weight":99,"slug":100},"Literature",80,"literature",{"id":52,"doc_module":4,"doc_module_name":45,"category_name":102,"show_sort_weight":103,"slug":104},"Exam",70,"exam",{"id":106,"doc_module":4,"doc_module_name":45,"category_name":107,"show_sort_weight":108,"slug":109},5,"Comic",60,"comic",{"id":111,"doc_module":4,"doc_module_name":45,"category_name":112,"show_sort_weight":113,"slug":114},6,"Technology",50,"technology",{"id":21,"doc_module":4,"doc_module_name":45,"category_name":116,"show_sort_weight":117,"slug":118},"Healthcare",40,"healthcare",{"id":11,"doc_module":4,"doc_module_name":45,"category_name":12,"show_sort_weight":120,"slug":121},30,"research-report",{"id":123,"doc_module":4,"doc_module_name":45,"category_name":124,"show_sort_weight":125,"slug":126},9,"Religion & Spirituality",20,"religion-spirituality",{"id":125,"doc_module":4,"doc_module_name":45,"category_name":128,"show_sort_weight":125,"slug":129},"World Cup","world-cup",{"id":131,"doc_module":4,"doc_module_name":45,"category_name":132,"show_sort_weight":131,"slug":133},10,"Lifestyle","lifestyle",{"id":135,"doc_module":4,"doc_module_name":45,"category_name":136,"show_sort_weight":106,"slug":137},19,"General","general"]