Shannon Wireless’ Post

This paper presents new techniques that #enable #the #gains of #pilot-domain #non-#orthogonal #multiple #access (#NOMA) product superposition to be combined with #transmitter #beamforming #gain. The technical novelty of this paper lies in reconciling the requirements of transmit beamforming and product #superposition under perfect or imperfect channel state feedback, and demonstrating its effectiveness under #multi-#user #scenarios. The paper begins with a multi-user generalization of product superposition rate analysis in the absence of feedback. Then, a #novel #non-#orthogonal scheme is proposed that #harmoniously #combines with either perfect or #imperfect #feedback under disparity in coherence time or coherence bandwidth among users. The proposed scheme includes efficient pilot placement strategies under multi-user scenarios with arbitrary coherence time and coherence bandwidth for different users. ----Mehdi Karbalayghareh, Aria Nosratinia More details can be found at this link: https://lnkd.in/g3NSgk6y

This paper presents new techniques that enable the gains of pilot-domain #non-#orthogonal #multiple #access (#NOMA) product superposition to be combined with #transmitter #beamforming gain. The technical novelty of this paper lies in reconciling the requirements of transmit beamforming and product superposition under perfect or imperfect channel state feedback, and demonstrating its effectiveness under multi-user scenarios. The paper begins with a multi-user generalization of product superposition rate analysis in the absence of feedback. Then, a novel #non-#orthogonal #scheme is proposed that harmoniously combines with either perfect or imperfect feedback under disparity in coherence time or coherence bandwidth among users. The proposed scheme includes efficient pilot placement strategies under multi-user scenarios with arbitrary coherence time and coherence bandwidth for different users. ---- Mehdi Karbalayghareh, Aria Nosratinia More details can be found at this link: https://lnkd.in/eDYbZ9yW

This study introduces a #novel #approach that integrates a #hybrid #RIS and utilizes an #uplink #non-#orthogonal #multiple #access #transmission from the users to the #base-#station. The proposed scheme utilizes #supervised #learning for RIS partitioning to optimize RIS element distribution that minimizes interference between users situated in the RIS’s #non-#line-#of-#sight. The proposed system achieves similar achievable rates and fairness among users as the current advanced iterative algorithm described in existing literature, while significantly reducing the time and complexity involved. ----Yarkın Gevez, Emre Arslan, Ertugrul Basar More details can be found at this link: https://lnkd.in/gZrUy-qs

This work presents a novel #nonorthogonal #multiple #access (#NOMA) #cognitive #radio (#CR) system where the base station (BS) opportunistically multiplexes the #secondary #user (#SU) with the #primary #user (#PU) using power-domain NOMA. As the PU has the priority to transmit and SU is satisfied on best-effort basis, four different #transmission-#modes (#TMs) are produced at the BS, which are #PU #orthogonal #multiple #access (#PU-#OMA), SU-OMA, PU/SU-NOMA, and silent mode. Consequently, the considered protocol can be classified as a hybrid underlay-interweave CR-NOMA. The TM adaptation should be seamless for the PU where its detector configuration remains unchanged regardless of the active TM. In contrast, the SU has to identify the active TM blindly, i.e. without side information, to select the appropriate detector. The identification process is performed using a classifier that is designed based on the maximum likelihood criterion. The performance of the proposed system is analyzed in terms of throughput, #packet #error #rate (#PER), and classification error. The Binomial and Multinomial theorems are utilized to simplify and allow a tractable analysis. ---- Hamad Yahya, Emad Alsusa, Arafat Al-Dweik, Merouane Debbah More details can be found at this link: https://lnkd.in/eXhTkX_u

This paper comprehensively investigate the #optical #wireless #nano-#communication #channels by considering the #deterministic #geometric #losses (e.g., optical absorption and scattering in human tissues), and modeling the impact of #nano-#node #disorientation and #misalignment in #in-#body #nano-#networks. To this end, the authors analytically study the stochastic nature of disorientation and misalignment coefficient in terms of the position and orientation of the nano-node with reference to the out-of-body optical receiver. In particular, they study the statistics of the #joint #disorientation and misalignment coefficient in terms of the probability density function, which is given in closed-form expression, whereas its cumulative distribution function is introduced as a #semi-#infinite #series #expression. Building upon them, they extract novel analytical expressions for the average signal-to-noise-ratio and the outage probability, and a thorough study on the impact of the human tissues on the above performance metrics is conducted. ----Alexandros-Apostolos A. Boulogeorgos, Stylianos E. Trevlakis, Theodoros Tsiftsis, Angeliki ALEXIOU More details can be found at this link: https://lnkd.in/gUADBHmn

This study explores the utilization of #simultaneous #transmitting and #reflecting #reconfigurable #intelligent #surface (#STAR-#RIS) in #non-#orthogonal #multiple #access (#NOMA) systems to enable spectrally efficient #ultra-#reliable #low-#latency #communication (#URLLC), even under the imperfect channel state information. In particular, the authors focus on #maximizing #spectral #efficiency by jointly designing robust beamforming at the base station and STAR-RIS subject to given URLLC requirements. Due to the #non-#convexity of the formulated problem, they propose an #alternating #optimization framework that obtains #sub-#optimal solutions to the problems of beamforming design at the BS and STAR-RIS, respectively by exploiting #S -#procedure and successive convex approximation.----Mayur Katwe, Rasika Deshpande (羅希卡), Keshav Singh, Cunhua Pan, @Pradnya H. Ghare, Trung Q. Duong More details can be found at this link: https://lnkd.in/dHTtYUzB

In this letter, the authors conduct a thorough analytical assessment of a #simultaneously #transmitting and #reflecting #reconfigurable #intelligent #surface (#STAR-#RIS) assisted #non-#orthogonal #multiple #access (#NOMA) enhanced #coordinated #multipoint (#CoMP) multi-cell network under Nakagami- m fading. Using the #central #limit #theorem (#CLT) and moment-matching based Gamma approximation method, they derive the distributions of effective and cascaded channel gains. Subsequently, leveraging these results, the authors formulate tractable equations for ergodic rates and outage probabilities across all users in the network. ---- Muhammad Umer, Mikael Gidlund More details can be found at this link: https://lnkd.in/eNiTidZT

In this letter, motivated by the superiority of #continuous #phase #modulation (#CPM) signals, a binary CPM with modulation index 0.5 is considered into downlink symbol- #asynchronous #non-#orthogonal #multiple #access (#ANOMA) to enhance power and spectral efficiency, especially for resource-limited wireless communications. According to the #maximum #likelihood (#ML) criterion, a #Viterbi-#based #block-#by-#block #detector (#VB-#BBD) is first proposed. Considering the asymptotics of Toeplitz matrices, a #DFT #matrix #diagonalization-#based #symbol-#by-#symbol #detector (#DFTD-#SSD) is also given. Finally, the detection complexity analysis is provided. ---- Sai Li, Xiaoyu Dang, Guanjun Xu, Xiangbin Yu, Chongzheng Hao, Jie Li More details can be found at this link: https://lnkd.in/dCDsshPr

In this study, considering the importance of #index #modulation (#IM) and #reconfigurable #intelligent #surface (#RIS)-aided schemes in 6G networks, first, an RIS-aided #orthogonal #frequency #division #multiplexing (#OFDM)-IM system design is proposed. Previous studies focusing on RIS-aided OFDM systems are based on an ideal reflection model, where the constant amplitude and variable phase shift of the RIS are independent of the frequency of the incoming signal. However, in realistic applications, this ideal RIS model may not be accurate since both the phase shift and amplitude of RIS elements depend on the frequency, which makes their effect significant, especially for wideband systems. Therefore, this study primarily considers a practical RIS model through designing the RIS reflection coefficients for OFDM-IM systems. In order to further enhance the #bit #error #rate (#BER) performance of the RIS-aided OFDM-IM system, an exhaustive search-based optimization algorithm that maximizes the #average #minimum #Euclidean #distance (#AMED) within the subblocks is also proposed. ---- Elvan Kuzucu Hıdır, Ertugrul Basar, Hakan Ali Çırpan More details can be found at this link: https://lnkd.in/egYgHJqj

We are pleased to announce the publication of our recent work on the development of a 500 kHz pulse-echo acquisition system for three-dimensional ultrasound imaging of objects immersed in water. This paper introduces the conceptualization and implementation of a low-cost and easy-to-implement acquisition system for 3D underwater imaging. The system utilizes an STM32 microcontroller as its core, which sequentially captures sixteen raw echo signals and sends them to a personal computer through an Ethernet cable. This configuration proves particularly useful for underwater applications where real-time imaging is not essential, such as the inspection of stationary underwater infrastructure and pipeline occlusions. These benefits arise from the sequential nature of data acquisition and the offline implementation of beamforming. You can find the article at https://lnkd.in/ddUTp4_t