Reconfigurable intelligent surfaces (RISs), also known as reflecting (IRSs), or large (LISs), <xref ref-type="fn" rid="fn1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">¹</xref> have received significant attention for their potential to enhance the capacity and coverage of wireless networks by smartly reconfiguring propagation environment. Therefore, RISs are considered a promising technology sixth-generation (6G) communication...

The novel concept of simultaneously transmitting and reflecting (STAR) reconfigurable intelligent surfaces (RISs) is investigated, where the incident wireless signal divided into transmitted reflected signals passing both sides space surrounding surface, thus facilitating a <i>full-space</i> manipulation propagation. Based on introduced basic model &#x2018;STAR&#x2019;, three practical operating protocols for STAR-RISs are proposed, namely energy splitting (ES), mode switching (MS), time...

This paper investigates a downlink multiple-input single-output intelligent reflecting surface (IRS) aided non-orthogonal multiple access (NOMA) system, where base station (BS) serves users with the aid of IRSs. Our goal is to maximize sum rate all by jointly optimizing active beamforming at BS and passive IRS, subject successive interference cancellation decoding conditions IRS elements constraints. In term characteristics reflection amplitudes phase shifts, we consider ideal non-ideal...

A novel simultaneous transmitting and reflecting (STAR) system design relying on reconfigurable intelligent surfaces (RISs) is conceived. First, an existing prototype reviewed, the potential benefits of STAR-RISs are discussed. Then key differences between conventional reflecting-only RISs identified from perspectives hardware design, physical principles, communication design. Furthermore, basic signal model introduced, three practical protocols proposed for their operation, namely energy...

Due to the explosive growth in number of wireless devices and diverse services, such as virtual/augmented reality Internet-of-Everything, next generation networks face unprecedented challenges caused by heterogeneous data traffic, massive connectivity, ultra-high bandwidth efficiency ultra-low latency requirements. To address these challenges, advanced multiple access schemes are expected be developed, namely (NGMA), which capable supporting numbers users a more resource-...

In this letter, simultaneous transmitting and reflecting reconfigurable intelligent surfaces (STAR-RISs) are studied. Compared with the conventional reflecting-only RISs, coverage of STAR-RISs is extended to 360 degrees via transmission reflection. A general hardware model for presented. Then, channel models proposed near-field far-field scenarios, based on which diversity gain analyzed compared that RISs. Numerical simulations provided verify analytical results demonstrate full order can be...

The novel concept of simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) is investigated, where incident signals can be transmitted reflected to users located at different sides the surface. In particular, fundamental coverage range STAR-RIS aided two-user communication networks studied. A sum maximization problem formulated for both non-orthogonal multiple access (NOMA) orthogonal (OMA), resource allocation point transmission reflection coefficients are...

Intelligent reflecting surface (IRS) enhanced multi-unmanned aerial vehicle (UAV) non-orthogonal multiple access (NOMA) networks are investigated. A new transmission framework is proposed, where UAV-mounted base stations employ NOMA to serve groups of ground users with the aid an IRS. The three-dimensional (3D) placement and transmit power UAVs, reflection matrix IRS, decoding orders among jointly optimized for maximization sum rate considered networks. To tackle formulated mixed-integer...

The fundamental intelligent reflecting surface (IRS) deployment problem is investigated for IRS-assisted networks, where one IRS arranged to be deployed in a specific region assisting the communication between an access point (AP) and multiple users. Specifically, three schemes are considered, namely non-orthogonal (NOMA), frequency division (FDMA), time (TDMA). weighted sum rate maximization joint optimization of location reflection coefficients as well power allocation at AP formulated....

The fundamental capacity limits of intelligent reflecting surface (IRS)-assisted multi-user wireless communication systems are investigated in this article. Specifically, the and rate regions for both capacity-achieving non-orthogonal multiple access (NOMA) orthogonal (OMA) transmission schemes characterized by jointly optimizing IRS reflection matrix resource allocation under constraints a maximum number reconfiguration times. In NOMA, all users served same blocks employing superposition...

A non-orthogonal multiple access (NOMA) empowered integrated sensing and communication (ISAC) framework is investigated. dual-functional base station serves users employing NOMA, while the superimposed NOMA signal simultaneously exploited for target sensing. beamforming design problem formulated to maximize weighted sum of throughput effective power. To solve this problem, an efficient double-layer penalty-based algorithm proposed by invoking successive convex approximation. Numerical...

Simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) is a promising technology that aids in achieving full-space coverage on both sides of the surface, by splitting incident signal into transmitted reflected signals. This paper investigates resource allocation problem STAR-RIS-assisted multi-carrier communication networks. To maximize system sum-rate, joint optimization comprising channel assignment, power allocation, transmission reflection beamforming at...

This article focuses on the exploitation of reconfigurable intelligent surfaces (RISs) in multi-user networks employing orthogonal multiple access (OMA) or non-orthogonal (NOMA), with an emphasis investigating interplay between NOMA and RIS. Depending whether RIS reflection coefficients can be adjusted only once times during one transmission, we distinguish static dynamic configurations. In particular, capacity region aided single-antenna is characterized compared OMA rate from...

A simultaneously transmitting and reflecting intelligent surface (STARS) enabled integrated sensing communications (ISAC) framework is proposed, where the whole space divided by STARS into a communication space. novel sensing-at-STARS structure, dedicated sensors are installed at STARS, proposed to address significant path loss clutter interference for sensing. The Cramer-Rao bound (CRB) of 2-dimension (2D) direction-of-arrivals (DOAs) estimation target derived, which then minimized subject...

A simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) aided communication system is investigated, where an access point sends information to two users located on each side of the STAR-RIS. Different from current works assuming that phase-shift coefficients for transmission reflection can be independently adjusted, which non-trivial realize purely passive STAR-RISs, a coupled model considered. Based this model, power consumption minimization problem...

The novel concept of non-orthogonal multiple access (NOMA) aided joint radar and multicast-unicast communication (Rad-MU-Com) is investigated. Employing the same spectrum resource, a multi-input-multi-output (MIMO) dual-functional radar-communication (DFRC) base station detects radar-centric users (R-user), while transmitting mixed messages both to R-user communication-centric user (C-user). In particular, multicast information intended for R- C-users, whereas unicast only C-user. More...

A near-field integrated sensing and communications (ISAC) framework is proposed, which introduces an additional distance dimension for both compared to the conventional far-field system. In particular, Cramer-Rao bound joint angle derived, minimized subject minimum communication rate requirement of each user. Both fully digital antennas hybrid analog are investigated. For antennas, a globally optimal solution ISAC waveform obtained via semidefinite relaxation. high-quality through two-stage...

This article focuses on the development of integrated sensing and communications (ISAC) from a multiple access (MA) perspective, where idea non-orthogonal (NOMA) is exploited for harmoniously accommodating communication functionalities. We first reveal that developing trend ISAC \emph{orthogonality} to \emph{non-orthogonality}, introduce fundamental models downlink uplink while identifying design challenges MA perspective. (1) For ISAC, we propose two novel designs, namely...

Reconfigurable intelligent surface (RIS)-aided near-field communications are investigated. First, the necessity of investigating RIS-aided and advantages brought about by unique spherical wave-based propagation discussed. Then, family patch array-based RISs metasurface-based is introduced along with respective channel models. A pair fundamental performance limits communications, namely, their power scaling law effective degrees freedom (EDOF), analyzed for both RISs, which reveals potential...

A reconfigurable intelligent surface (RIS)-assisted multi-user downlink communication system over fading channels is investigated, where both non-orthogonal multiple access (NOMA) and orthogonal (OMA) schemes are employed. In particular, the time overhead for configuring RIS reflective elements at beginning of each channel considered. The optimization goal maximizing effective throughput entire transmission period by jointly optimizing phase shift power allocation AP block. an effort to...

A correlated transmission and reflection (T&R) phase-shift model is proposed for passive lossless simultaneously transmitting reflecting reconfigurable intelligent surfaces (STAR-RISs). STAR-RIS-aided two-user downlink communication system investigated both orthogonal multiple access (OMA) non-orthogonal (NOMA). To evaluate the impact of T&R on performance, three configuration strategies are developed, namely primary-secondary (PS-PSC), diversity preserving (DP-PSC), T/R-group (TR-PSC)...

A novel air-to-ground communication paradigm is conceived, where an unmanned aerial vehicle (UAV)-mounted base station (BS) equipped with multiple antennas sends information to ground users (GUs) the aid of a simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS). In contrast conventional RIS whose main function reflect incident signals, STAR-RIS capable both impinging signals from either side surface, thereby leading full-space 360 degree coverage. However,...

Given the rapid development of advanced electromagnetic (EM) manipulation technologies, researchers have turned their attention to investigation smart surfaces for enhancing radio coverage. Simultaneously transmitting and reflecting (STAR) intelligent omni-surfaces (IOSs) constitute one most promising categories. Although previous research contributions demonstrated benefits simultaneously (STAR-IOSs) in terms wireless communication performance gains, several important issues remain...

Multiple access (MA) design is investigated to facilitate the coexistence of emerging semantic transmission and conventional bit-based in future networks. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">semantic rate</i> adopted for measuring performance transmission. However, a key challenge that there no closed-form expression parameter, namely similarity</i> , which characterizes sentence similarity between an original corresponding...