Shannon Wireless’ Post

#Low #earth #orbit (#LEO) satellite communication systems have gained increasing attention as a crucial supplement to terrestrial wireless networks due to their extensive coverage area. This letter presents a novel system design for LEO satellite systems by leveraging #stacked #intelligent #metasurface (#SIM) technology. Specifically, the lightweight and energy-efficient SIM is mounted on a satellite to achieve multiuser beamforming directly in the electromagnetic wave domain, which substantially reduces the processing delay and computational load of the satellite compared to the traditional digital beamforming scheme. To overcome the challenges of obtaining instantaneous #channel #state #information (#CSI) at the transmitter and maximize the system's performance, a joint power allocation and SIM phase shift optimization problem for maximizing the ergodic sum rate is formulated based on statistical CSI, and an #alternating #optimization (#AO) algorithm is customized to solve it efficiently. Additionally, a user grouping method based on channel correlation and an antenna selection algorithm are proposed to further improve the system performance. ---- Jiancheng An, Merouane Debbah More details can be found at this link: https://lnkd.in/gKy8EaHa

#Low #earth #orbit (#LEO) satellite communication systems have gained increasing attention as a crucial supplement to terrestrial wireless networks due to their extensive coverage area. This letter presents a novel system design for LEO satellite systems by leveraging #stacked #intelligent #metasurface (#SIM) technology. Specifically, the lightweight and energy-efficient SIM is mounted on a satellite to achieve multiuser beamforming directly in the electromagnetic #wave #domain, which substantially reduces the processing delay and computational load of the satellite compared to the traditional digital beamforming scheme. To overcome the challenges of obtaining instantaneous #channel #state #information (#CSI) at the transmitter and maximize the system’s performance, a joint power allocation and SIM phase shift optimization problem for maximizing the ergodic sum rate is formulated based on statistical CSI, and an #alternating #optimization (#AO) algorithm is customized to solve it efficiently. Additionally, a user grouping method based on channel correlation and an antenna selection algorithm are proposed to further improve the system performance. ---- Shining Lin, Jiancheng An, Lu Gan, Mérouane Debbah, Chau Yuen More details can be found at this link: https://lnkd.in/gKy8EaHa

🎉 Honored to announce that our research paper, "𝘙𝘰𝘣𝘶𝘴𝘵 𝘚𝘱𝘰𝘰𝘧𝘪𝘯𝘨 𝘋𝘦𝘵𝘦𝘤𝘵𝘪𝘰𝘯 𝘪𝘯 𝘎𝘕𝘚𝘚-𝘚𝘋𝘙 𝘚𝘺𝘴𝘵𝘦𝘮𝘴: 𝘈 𝘛𝘸𝘰-𝘚𝘵𝘢𝘨𝘦 𝘔𝘦𝘵𝘩𝘰𝘥 𝘧𝘰𝘳 𝘙𝘦𝘢𝘭-𝘛𝘪𝘮𝘦 𝘚𝘪𝘨𝘯𝘢𝘭 𝘐𝘯𝘵𝘦𝘨𝘳𝘪𝘵𝘺," has been published on IEEE Xplore! 🎉 This collaborative effort with Fatima Tuz Zahra and Adil Ali Raja, Ph.D. dives into methods on how to improve and maintain the integrity of GNSS Systems. 𝗘𝘅𝗽𝗹𝗼𝗿𝗲 𝘁𝗵𝗲 𝗱𝗲𝘁𝗮𝗶𝗹𝘀 𝗵𝗲𝗿𝗲: https://lnkd.in/e_Fnp9xR #GNSS #SpoofingDetection #SignalProcessing #SDR #IEEE

#Extremely #large-#scale #antenna #arrays (#ELAAs) are indispensable to meet the elevated #key #performance #indicators (#KPIs) for the #sixth #generation (#6G) networks while leading to new challenges in the exploration of near-field system models. In response, they propose a near-field #integrated #sensing #and #communications (#ISAC) system aided by an #extremely #large-#scale #simultaneously #transmitting #and #reflecting #reconfigurable #intelligent #surface (#XL-#STAR-#RIS) and the #fluid #antenna (#FA) in this paper. To precisely estimate the distance and #angle #of #arrival (#AoA) of the target while concurrently ensuring effective signal transmission to communication users, they formulate a joint minimization problem for #Cramér-#Rao #bounds (#CRBs) of the distance and #AoA estimation #mean #square #errors (#MSEs). ----Jingxuan Zhou, @Yinchao Yang, @Zhaohui Yang, @Mohammad Shikh-Bahaei More details can be found at this link: https://lnkd.in/gdtkVTJm

This survey provides an holistic overview of opportunistic #Low #Earth #Orbit (#LEO)-#Positioning, #Navigation, and #Timing (#PNT) and an exhaustive review of the academic work in the field. Error sources and challenges with respect to the development of operational systems are evaluated, and the state-of-the-art performance is analyzed. System-level strategies to mitigate the error sources and challenges are identified, including the combination of opportunistic LEO-PNT with #Global #Navigation #Satellite #Systems (#GNSS) or other sensors, or the use of base stations. Future research directions, such as the investigation of non-accuracy related #KPIs, the required receiver hardware, or the use in #low #SNR scenarios, are derived.----Winfried Stock, @Robert T. Schwarz, @Christian A. Hofmann, Andreas Knopp More details can be found at this link: https://lnkd.in/gvpHg3qx

This paper attempts to provide an initial assessment of the feasibility and potential gains of #adaptive #wideband #cellular #systems operating across the upper mid-band. The study includes: (1) a detailed ray tracing simulation to assess potential gains of multi-band systems in a representative dense urban environment and illustrate the value of a wideband system with dynamic frequency selectivity; (2) an evaluation of potential cross-interference between satellites and terrestrial cellular services and interference nulling to reduce that interference; and (3) design and evaluation of a compact multi-band antenna array structure. Leveraging these preliminary results, we identify potential future research directions to realize next-generation systems in these frequencies. ---- Seongjoon Kang, Marco Mezzavilla, Sundeep Rangan, Arjuna Madanayake, Satheesh Bojja Venkatakrishnan, Grégory Hellbourg, Monisha Ghosh, Hamed Rahmani, Aditya Dhananjay More details can be found at this link: https://lnkd.in/eRKpiu3R

In this paper, the authors focus on cooperative sensing where the transmitter and receivers are non-co-located, which includes the bistatic and multistatic sensing. Specifically, the system model of cooperative sensing based on mobile networks is established. To demonstrate the feasibility of cooperative sensing, the bistatic #radar #cross #section (#RCS) is provided. As for the sensing method, a #refined #orthogonal #matching #pursuit (#R-#OMP) method is proposed to estimate the channel parameters and data fusion is also provided to derive the objects’ positions and velocities. Considering the non-negligible interference in the cooperative #joint #sensing #and #communication (#JSAC) networks, they also discuss interference management in this paper. ---- Guangyi Liu, Rongyan Xi, Zixiang Han, Lincong Han, Xiaozhou Zhang, Liang Ma, Yajuan Wang, Mengting Lou, Jing Jin, Qixing Wang, Jiangzhou Wang More details can be found at this link: https://lnkd.in/gXfGq_9F

This paper proposed a novel #stochastic #geometry #framework to study the #downlink #coverage #performance in a #millimeter #wave (#mmWave) cellular network by jointly considering the polar coordinates of the #Base #Stations (#BSs) with respect to the typical user located at the origin. Specifically, both the Euclidean and the #angular #distances of the BSs in a maximum power-based association policy for the #user #equipment (#UE) are considered to account for realistic beam management considerations, which have been largely ignored in the literature, especially in the cell association phase. For completeness, two other association schemes are considered and exact-form expressions for the coverage probability are derived. Subsequently, the key role of angular distances is highlighted by defining the dominant interferer using angular distance-based criteria instead of Euclidean distance-based, and conducting a dominant interferer-based coverage probability analysis. ---- Harris K. Armeniakos, Athanasios (Thanasis) Kanatas, Harpreet Dhillon More details can be found at this link: https://lnkd.in/eGqS8DFC

💠[#SIM] An emerging #Stacked #Intelligent #Metasurface (SIM) technology consisting of multiple metasurfaces is capable of carrying out signal processing and computations naturally as electromagnetic waves pass through it, without causing additional latency and energy consumption. SIM offers a solution for ultra-fast downlink beamforming in the wave domain, which is beneficial for reducing processing delays in #satellite #communication systems. Recently, a SIM-enabled downlink satellite communication system has been developed to perform the #wave-#domain #beamforming relying on #statistical #channel #state #information (#CSI). To serve multiple users in the area with a higher sum rate, the authors proposed an effective user grouping method and an antenna selection scheme. ---- Merouane Debbah More details can be found at this link: https://lnkd.in/gKy8EaHa Please watch the presentation video at this link: https://lnkd.in/g3tRMVQQ

Check out our new publication "Multi-stream STGAN: A Spatiotemporal Image Fusion Model with Improved Temporal Transferability" published in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing (https://lnkd.in/gGyq5hVy). We proposed a multistream spatiotemporal fusion generative adversarial network (STGAN) model for spatiotemporal satellite image fusion that can produce accurate fused images and accommodate substantial temporal differences between the input images.