[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-83441-en":3,"doc-seo-83441-105":30,"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":21,"is_downloadable":21,"audit_status":21,"page_count":22,"language":23,"language_code":24,"site_id":25,"html_lang":24,"table_of_contents":26,"faqs":27,"seo_title":13,"seo_description":14,"update_tm":28,"read_time":29},83441,1099513958607,"Jiven","https://ap-avatar.wpscdn.com/avatar/100002390cf8733938c?x-image-process=image/resize,m_fixed,w_180,h_180&k=1778829742770036399",8,"Research & Report","Decision Feedback Differential Detection for Reconfigurable Intelligent Surfaces","A Differential Reflecting Modulation (DRM) scheme for Reconfigurable Intelligent Surfaces (RIS) enables operation without channel state information (CSI). In overtime-varying fading channels, conventional differential demodulation (CDD) receivers suffer high error floors and performance loss. This work proposes a Decision Feedback Differential Detection (DFDD) technique for RIS-DRM, validated through extensive Monte-Carlo simulations. The DFDD approach provides viable performance across multiple RIS scenarios and reduces error floors as SNR increases, trading off small added complexity, and is compared against uncoded and differential space-time modulation coded DRM using CDD-based receivers.","arXiv :2607 .00 12 1v 1 [ cs .IT] 30 Jun 2026  \nDecision Feedback Differential Detection for Reconfigurable Intelligent Surfaces  \nJiawei Qiu and Harry Leib  \nAbstract  \nThis work considers a Differential Reflecting Modulation (DRM) scheme for Reconfigurable Intelligent Surfaces (RIS) not requiring channel state information (CSI) . When operating overtime-varying fading channels, such schemes with Conventional Differential Demodulation (CDD) receivers experience high error floors and performance degradation. To address these issues, we propose a Decision Feedback Differential Detection (DFDD) technique for DRM. We explore the application of DFDD for RIS DRM and conduct extensive Monte-Carlo simulations to analyze performance. Results demonstrate the viability of our DFDD technique across various RIS scenarios and highlight the importance of proper parameter selection to achieve good performance. The DFDD scheme is also compared with uncoded and Differential Space-Time Modulation (DSTM) coded DRM using CDD based receivers. We observe that at low SNR, the DFDD scheme performs almost as well as the DRM with CDD scheme, but worse than the DSTM coded DRM. As the SNR increases however, both CDD-detected systems encounter high error floors while the error rate of DFDD based scheme continues to improve until it reaches a relatively low error floor. It is shown that the chief merits of employing DFDD receivers in such RIS systems is the low error floors they provide over time varying fading channels, albeit at expense of a small increased complexity.  \nI. Introduction  \nThe Reconfigurable Intelligent Surface (RIS) technology, also referred to as Intelligent Reflecting Surface (IRS), holds significant potential for facilitating an advantageous wireless communication environment [1]–[6] . An RIS system consists of a large number of passive  \nJiawei Qiu was with the Department of Electrical and Computer Eng. McGill University, Montreal QC Canada. He is now with INRS Telecomunications, University of Quebec, Montreal QC Canada.  \nHarry Leib is with the Department of Electrical and Computer Eng. , McGill University, Montreal, QC Canada, Email: [harry.leib@mcgill.ca](harry.leib@mcgill.ca)  \nreflecting units, each capable of altering the incident signals in terms of phase and amplitude. These units are made from electromagnetic material, with size and spacing much smaller than the wavelength. Unlike relays, RIS can be constructed with minimal hardware complexity and cost, employing low-power and low-complexity electronic circuits [7] . The primary characteristic of RIS is its reconfigurability after deployment in a wireless environment, allowing for a programmable and controllable communication environment [8] .  \nRecently, there has been a notable interest in research on RIS communication techniques. A substantial volume of literature has been dedicated to exploring RIS imodulation techniques [9]–[14], and channel state information (CSI) [15]–[19] . Alwazani et al in [15] introduced an RIS-assisted multi-user multiple-input single-output (MISO) communication system under imperfect CSI, demonstrating the efficiency of this scheme and its high sensitivity to the quality of the estimates. However, to the best of our knowledge, most schemes assume perfect CSI for detection [20]–[23] . Channel estimation in an RIS-based communication system has to consider the transmitter-RIS, RIS-receiver, and direct transmitter-receiver links. Such estimations schemes are complicated due to the absence of baseband signal processing capabilities in RIS units. While efforts have been made to address the challenges of channel estimation in RIS systems [15], [21], [24], [25], CSI acquisition remains a significant and challenging problem, making tranmission techniques not requiring CSI attractive..  \nNoncoherent detection is a demodulation technique that does not require CSI, thereby reducing the complexity of communication systems. Moreover, noncoherent demodulation ","cbCaillQH8R0I640","https://ap.wps.com/l/cbCaillQH8R0I640","pdf",504411,4,1,30,"English","en",105,"# Abstract\n# Introduction","[{\"question\":\"What problem does the DRM scheme address in RIS communications?\",\"answer\":\"The DRM scheme enables RIS operation without requiring channel state information (CSI), simplifying receiver requirements.\"},{\"question\":\"Why do conventional differential demodulation (CDD) receivers underperform on overtime-varying fading channels?\",\"answer\":\"CDD-based receivers experience high error floors and corresponding performance degradation when channels vary over time.\"},{\"question\":\"How does DFDD change the detection performance compared with CDD-based schemes?\",\"answer\":\"At low SNR, DFDD performs almost as well as DRM with CDD receivers, while at higher SNR CDD systems hit high error floors and DFDD continues improving until a lower error floor is reached.\"}]",1784187781,76,{"code":4,"msg":31,"data":32},"ok",{"site_id":25,"language":24,"slug":33,"title":13,"keywords":34,"description":14,"schema_data":35,"social_meta":86,"head_meta":88,"extra_data":90,"updated_unix":28},"decision-feedback-differential-detection-for-reconfigurable-intelligent-surfaces","",{"@graph":36,"@context":85},[37,53,68],{"@type":38,"itemListElement":39},"BreadcrumbList",[40,44,48,51],{"item":41,"name":42,"@type":43,"position":21},"https://docshare.wps.com","Home","ListItem",{"item":45,"name":46,"@type":43,"position":47},"https://docshare.wps.com/document/","Document",2,{"item":49,"name":12,"@type":43,"position":50},"https://docshare.wps.com/document/research-report/",3,{"item":52,"name":13,"@type":43,"position":20},"https://docshare.wps.com/document/decision-feedback-differential-detection-for-reconfigurable-intelligent-surfaces/83441/",{"url":52,"name":13,"@type":54,"author":55,"headline":13,"publisher":57,"fileFormat":60,"inLanguage":24,"description":14,"dateModified":61,"datePublished":62,"encodingFormat":60,"isAccessibleForFree":63,"interactionStatistic":64},"DigitalDocument",{"name":9,"@type":56},"Person",{"url":41,"name":58,"@type":59},"DocShare","Organization","application/pdf","2026-07-25","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},"What problem does the DRM scheme address in RIS communications?","Question",{"text":75,"@type":76},"The DRM scheme enables RIS operation without requiring channel state information (CSI), simplifying receiver requirements.","Answer",{"name":78,"@type":73,"acceptedAnswer":79},"Why do conventional differential demodulation (CDD) receivers underperform on overtime-varying fading channels?",{"text":80,"@type":76},"CDD-based receivers experience high error floors and corresponding performance degradation when channels vary over time.",{"name":82,"@type":73,"acceptedAnswer":83},"How does DFDD change the detection performance compared with CDD-based schemes?",{"text":84,"@type":76},"At low SNR, DFDD performs almost as well as DRM with CDD receivers, while at higher SNR CDD systems hit high error floors and DFDD continues improving until a lower error floor is reached.","https://schema.org",{"og:url":52,"og:type":87,"og:title":13,"og:site_name":58,"og:description":14},"article",{"robots":89,"canonical":52},"index,follow",{"doc_id":7,"site_id":25},{"code":4,"msg":5,"data":92},[93,97,101,105,110,115,120,122,127,130,134],{"id":21,"doc_module":4,"doc_module_name":46,"category_name":94,"show_sort_weight":95,"slug":96},"Story & Novel",90,"story-novel",{"id":47,"doc_module":4,"doc_module_name":46,"category_name":98,"show_sort_weight":99,"slug":100},"Literature",80,"literature",{"id":20,"doc_module":4,"doc_module_name":46,"category_name":102,"show_sort_weight":103,"slug":104},"Exam",70,"exam",{"id":106,"doc_module":4,"doc_module_name":46,"category_name":107,"show_sort_weight":108,"slug":109},5,"Comic",60,"comic",{"id":111,"doc_module":4,"doc_module_name":46,"category_name":112,"show_sort_weight":113,"slug":114},6,"Technology",50,"technology",{"id":116,"doc_module":4,"doc_module_name":46,"category_name":117,"show_sort_weight":118,"slug":119},7,"Healthcare",40,"healthcare",{"id":11,"doc_module":4,"doc_module_name":46,"category_name":12,"show_sort_weight":22,"slug":121},"research-report",{"id":123,"doc_module":4,"doc_module_name":46,"category_name":124,"show_sort_weight":125,"slug":126},9,"Religion & Spirituality",20,"religion-spirituality",{"id":125,"doc_module":4,"doc_module_name":46,"category_name":128,"show_sort_weight":125,"slug":129},"World Cup","world-cup",{"id":131,"doc_module":4,"doc_module_name":46,"category_name":132,"show_sort_weight":131,"slug":133},10,"Lifestyle","lifestyle",{"id":135,"doc_module":4,"doc_module_name":46,"category_name":136,"show_sort_weight":106,"slug":137},19,"General","general"]