Shannon Wireless’ Post

In this paper, the authors devise a sparse array design algorithm for adaptive beamforming. Their strategy is based on finding a #sparse #beamformer #weight to maximize the output signal-to-interference-plus-noise ratio (SINR). The proposed method utilizes the #alternating #direction #method #of #multipliers (#ADMM), and admits closed-form solutions at each ADMM iteration. The algorithm convergence properties are analyzed by showing the monotonicity and boundedness of the augmented Lagrangian function. In addition, the authors prove that the proposed algorithm converges to the set of Karush-Kuhn-Tucker stationary points. ---- Huiping Huang, Hing Cheung So, Abdelhak M. Zoubir More details can be found at this link: https://lnkd.in/gdeHCfq7

This paper design a low-complexity #linear #minimum #mean #squared #error (#LMMSE) receiver for practical-pulse-shaped multiple-input multiple-output (#MIMO)-#orthogonal #time #frequency #space #modulation (#OTFS) systems. The proposed receiver exploits the inherent channel sparsity and the channel-agnostic structure of matrices involved in the LMMSE receiver, and has only a log-linear complexity. It provides exactly the same solution, and hence the same bit error rate (BER), as that of the conventional LMMSE receiver with a cubic order of complexity. The authors also derive, by using the Taylor series expansion and the results from random matrix theory, a tight closed-form approximation for the post-processing signal-to-noise-plus-interference ratio (SINR) expression of the proposed receiver. This expression is derived by assuming imperfect receive channel state information. ---- Prem Singh, Shashank Tiwari, Rohit Budhiraja More details can be found at this link: https://lnkd.in/ezftqEKD

This paper proposes a semi-blind technique to design beamforming in downlink power-domain #non-#orthogonal #multiple #access (#NOMA) for mmWave communication which only requires statistical #channel #state #information (#CSI). In the first step, the sum outage probability is derived by using the exact characterization of ratio of the #indefinite #quadratic #form (#IQF). In the second step, a heuristic approach with the aid of the #interior #point (#IP) algorithm is developed to find the optimal solution for beam vectors by minimizing the derived sum outage probability. ---- MUHAMMAD AHSAN SHAIKH, Anwaar Manzar, Muhammad Moinuddin, Dr. Engr. Sadiq Ur Rehman, Halar Mustafa More details can be found at this link: https://lnkd.in/gPYJyiUt

This paper proposes a semi-blind technique to design beamforming in downlink power-domain #non-#orthogonal #multiple #access (#NOMA) for mmWave communication which only requires statistical #channel #state #information (#CSI). In the first step, the sum outage probability is derived by using the exact characterization of ratio of the #indefinite #quadratic #form (#IQF). In the second step, a heuristic approach with the aid of the #interior #point (#IP) algorithm is developed to find the optimal solution for beam vectors by minimizing the derived sum outage probability. Moreover, a closed-form statistical beamforming solution is derived which is established on statistical signal-to-leakage-noise-ratio (SLNR) maximization. These two proposed methods are compared with the classical principle eigenvector-based solution. ---- MUHAMMAD AHSAN SHAIKH, Anwaar Manzar, Sadiq Ur Rehman, Halar Mustafa, Muhammad Moinuddin More details can be found at this link: https://lnkd.in/gPYJyiUt

Our new paper considering antenna design using PSO particle swarm optimization. https://lnkd.in/eHMcB6ts

This work presents a novel and simple multi-path wireless channel parametrization where each path is replaced by a #line-#of-#sight (#LOS) path with a reflected image source. The model is fully valid for all paths with specular planar reflections, and captures the spherical nature of each wave front. Importantly, it is shown that the model uses only two additional parameters relative to the standard plane wave model. Moreover, the parameters can be easily captured in standard ray tracing. The accuracy of the approach is demonstrated on detailed ray tracing simulations at 28GHz and 140GHz in a dense urban area. ---- YAQI HU, Mingsheng Yin, Sundeep Rangan, Marco Mezzavilla More details can be found at this link: https://lnkd.in/gKjq4UpG

We are delighted to announce the publication of our recent article, titled "Cusp Phased Metasurfaces for Wideband RCS Reduction Under Broad Angles of Incidence" in the IEEE Open Journal of Antennas and Propagation. The article is now accessible to the public free of charge on the journal's website. We extend our sincere thanks to all the authors for their valuable contributions. To access the full article, link: https://lnkd.in/eRW2sRBc Abstract: This article presents an efficient and effective design approach of the phase distribution calculation across metasurface for significant radar cross section (RCS) reduction of a circular polarization (CP) and liner polarization (LP) radar waves. The RCS reduction using the proposed design approach is achieved by imposing a novel cusp phase mask (which is usually used to generate 3D self-accelerating and self-healing cusp beams) at each geometric phased anisotropic unit cell composing the proposed cusp phased metasurface. By solving the cusp phase formula using MATLAB, it is found that the cusp phase mask required to achieve more than 10 dB of RCS reduction over a wide frequency band can be calculated without the need of significant lengthy optimizations or huge computer resources. The ability of such cusp phase mask metasurfaces to achieve significant backward scattering and RCS reduction has been rigorously investigated by means of simulations and measurements. When illuminated by a far-field radar CP or LP plane wave, the proposed cusp phased metasurface realizes more than 10 dB of RCS reduction from 10.9 to 26 GHz, corresponding to a fractional bandwidth of FBW = 81.8%. The 10 dB RCS reduction bandwidth of the cusp metasurface is maintained under both normal and wide angular incidence up to 75∘. The proposed cusp metasurfaces have potential applications to make objects stealthy where the incidence radar signal has an unknown frequency, polarization, or angle of incidence.  

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This article proposes a #ray-#tracing and #physical-#optics (#RT-#PO) model that allows for an accurate and time-efficient evaluation of planar Mikaelian lens antennas implemented by #parallel #plate #waveguides (#PPWs). With an intrinsic flat shape and axis-symmetry of refractive-index distribution characteristics, the planar Mikaelian lens antennas are easy to fabricate and integrate into standard planar feeds. A numerical computation of the ray paths based on Snell’s law describes the phase of the electric field in the lens aperture, while the ray-tube power conservation theory is employed to evaluate the amplitude. The field equivalence principle is then used to calculate the far-field of the lens antenna. The information on far-field directivity, gain, and dielectric efficiency is further obtained, considering a small loss in the dielectric materials. ---- Mingzheng Chen 陈明正, Ozum Habiboglu, Francisco Mesa, Oscar Quevedo Teruel More details can be found at this link: https://lnkd.in/dTSQxkgg

This letter proposes a novel #l0-norm constrained #maximum #Versoria #criterion ( #l0-#MVC) based channel estimator for the #orthogonal #time #frequency #space (#OTFS) systems impaired by #impulsive #noise (#IN) with an optimal adaptive tuning of the sparsity regularization parameter. Furthermore, the authors propose a robust #message-#passing based on the #maximum #Versoria #criterion (#MP-#MVC) for OTFS symbol detection in the presence of IN. Analytical and simulation results indicate that the proposed l0-MVC channel estimator and MP-MVC symbol detector outperforms the existing state-of-the-art approaches. ---- Ajay Kumar, Sandesh Jain, Dr. Sudhan Majhi More details can be found at this link: https://lnkd.in/dhHuQ--x