scholarly journals Spatial Domain Suppression of Co-Channel Interference: A Reflection Amplifiers Surface (RAS) Approach

2021 ◽  
Author(s):  
Linsong Du ◽  
Jianhui Ma ◽  
Chao Fan ◽  
Qingpeng Liang ◽  
Chenxing Li ◽  
...  
Keyword(s):  
Spatial Domain ◽  
Closed Form Expression ◽  
Maximization Problem ◽  
Reflection Coefficients ◽  
Interference Channel ◽  
Interference Power ◽  
Form Expression ◽  
Capacity Maximization ◽  
Channel Interference ◽  
Maximal Capacity

This paper adopts a novel reflection amplifiers surface (RAS) to suppress the co-channel interference in the spatial domain. The RAS can reflect and amplify the electromagnetic wave with phase shifts by designing the reflection coefficients, which enables it more flexibly reconfigure the wireless propagation environment, and even suppress interference channel gain. In this paper, a transmitter and an interferer send the desired signal and interference to the receiver, respectively, and a RAS is placed to suppress the unknown interference. First, we design the reflection coefficients for optimizing the interference suppression ratio, and prove that when the number of reflection amplifiers is greater than the number of antennas at the interferer, the interference can be perfectly suppressed. Next, a capacity maximization problem is formulated to design the optimal reflection coefficients, and an iterative algorithm based on fractional programming and the convex-concave procedure is proposed to obtain the solution for this problem. Moreover, the closed-form expression of the maximal capacity is obtained in the strong interference power case. In addition, this paper shows the upper and lower boundaries of the maximal capacity and discusses what kind of the channel conditions achieve the upper and lower boundaries. Lastly, the above results are generalized to the multiple interferer scenario.

Spatial Domain Suppression of Co-Channel Interference: A Reflection Amplifiers Surface (RAS) Approach

2021 ◽  
Author(s):  
Linsong Du ◽  
Jianhui Ma ◽  
Chao Fan ◽  
Qingpeng Liang ◽  
Chenxing Li ◽  
...  
Keyword(s):  
Spatial Domain ◽  
Closed Form Expression ◽  
Maximization Problem ◽  
Reflection Coefficients ◽  
Interference Channel ◽  
Interference Power ◽  
Form Expression ◽  
Capacity Maximization ◽  
Channel Interference ◽  
Maximal Capacity

This paper adopts a novel reflection amplifiers surface (RAS) to suppress the co-channel interference in the spatial domain. The RAS can reflect and amplify the electromagnetic wave with phase shifts by designing the reflection coefficients, which enables it more flexibly reconfigure the wireless propagation environment, and even suppress interference channel gain. In this paper, a transmitter and an interferer send the desired signal and interference to the receiver, respectively, and a RAS is placed to suppress the unknown interference. First, we design the reflection coefficients for optimizing the interference suppression ratio, and prove that when the number of reflection amplifiers is greater than the number of antennas at the interferer, the interference can be perfectly suppressed. Next, a capacity maximization problem is formulated to design the optimal reflection coefficients, and an iterative algorithm based on fractional programming and the convex-concave procedure is proposed to obtain the solution for this problem. Moreover, the closed-form expression of the maximal capacity is obtained in the strong interference power case. In addition, this paper shows the upper and lower boundaries of the maximal capacity and discusses what kind of the channel conditions achieve the upper and lower boundaries. Lastly, the above results are generalized to the multiple interferer scenario.

scholarly journals Synthesizing of Planar and Conformal Double-Sided Parallel-Cross Dipoles FSS Based on Closed-Form Expression

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Yassine Zouaoui ◽  
Larbi Talbi ◽  
Khelifa Hettak ◽  
Naresh K. Darimireddy
Keyword(s):  
Closed Form ◽  
Closed Form Expression ◽  
Form Expression

Distribution of Consensus in a Broadcasting-based Consensus-forming Algorithm

2021 ◽  
Vol 48 (3) ◽  
pp. 91-96
Author(s):  
Shigeo Shioda
Keyword(s):  
Distribution Function ◽  
Probability Density Function ◽  
Closed Form ◽  
Probability Density ◽  
Infinite Number ◽  
Stable Distribution ◽  
Random Variable ◽  
Cauchy Distribution ◽  
Closed Form Expression ◽  
Form Expression

The consensus achieved in the consensus-forming algorithm is not generally a constant but rather a random variable, even if the initial opinions are the same. In the present paper, we investigate the statistical properties of the consensus in a broadcasting-based consensus-forming algorithm. We focus on two extreme cases: consensus forming by two agents and consensus forming by an infinite number of agents. In the two-agent case, we derive several properties of the distribution function of the consensus. In the infinite-numberof- agents case, we show that if the initial opinions follow a stable distribution, then the consensus also follows a stable distribution. In addition, we derive a closed-form expression of the probability density function of the consensus when the initial opinions follow a Gaussian distribution, a Cauchy distribution, or a L´evy distribution.

scholarly journals Colored HOMFLY-PT for hybrid weaving knot $$ {\hat{\mathrm{W}}}_3 $$(m, n)

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Vivek Kumar Singh ◽  
Rama Mishra ◽  
P. Ramadevi
Keyword(s):  
Closed Form ◽  
Topological Strings ◽  
Chebyshev Polynomials ◽  
Fibonacci Numbers ◽  
Infinite Family ◽  
Closed Form Expression ◽  
Two Dimensional ◽  
Laurent Polynomials ◽  
Form Expression ◽  
Torus Knots

Abstract Weaving knots W(p, n) of type (p, n) denote an infinite family of hyperbolic knots which have not been addressed by the knot theorists as yet. Unlike the well known (p, n) torus knots, we do not have a closed-form expression for HOMFLY-PT and the colored HOMFLY-PT for W(p, n). In this paper, we confine to a hybrid generalization of W(3, n) which we denote as $$ {\hat{W}}_3 $$ W ̂ 3 (m, n) and obtain closed form expression for HOMFLY-PT using the Reshitikhin and Turaev method involving $$ \mathrm{\mathcal{R}} $$ ℛ -matrices. Further, we also compute [r]-colored HOMFLY-PT for W(3, n). Surprisingly, we observe that trace of the product of two dimensional $$ \hat{\mathrm{\mathcal{R}}} $$ ℛ ̂ -matrices can be written in terms of infinite family of Laurent polynomials $$ {\mathcal{V}}_{n,t}\left[q\right] $$ V n , t q whose absolute coefficients has interesting relation to the Fibonacci numbers $$ {\mathrm{\mathcal{F}}}_n $$ ℱ n . We also computed reformulated invariants and the BPS integers in the context of topological strings. From our analysis, we propose that certain refined BPS integers for weaving knot W(3, n) can be explicitly derived from the coefficients of Chebyshev polynomials of first kind.

Simple Closed-Form Expression to Estimate the Ring Ratio of 16-APSK to Compensate for Distortion in Nonlinear Systems

2017 ◽  
Author(s):  
M.J. Cañavate-Sánchez ◽  
A. Segneri ◽  
S. Godi ◽  
A. Georgiadis ◽  
S. Kosmopoulos ◽  
...  
Keyword(s):  
Nonlinear Systems ◽  
Closed Form ◽  
Closed Form Expression ◽  
Form Expression ◽  
Ring Ratio

Approximate closed-form expression for the ergodic capacity of polarisation-diversity MIMO systems

2004 ◽  
Vol 40 (19) ◽  
pp. 1192 ◽  
Author(s):  
J. Pérez ◽  
J. Ibáñez ◽  
L. Vielva ◽  
I. Santamaría
Keyword(s):  
Closed Form ◽  
Mimo Systems ◽  
Ergodic Capacity ◽  
Closed Form Expression ◽  
Form Expression

Energy Harvesting Using the Rattleback: Theoretical Analysis and Simulations of Spin Resonance

2015 ◽  
Author(s):  
Aditya Nanda ◽  
M. Amin Karami ◽  
Puneet Singla
Keyword(s):  
Energy Harvesting ◽  
Closed Form Expression ◽  
Longitudinal Vibrations ◽  
Form Expression ◽  
Preferred Direction ◽  
Spin Resonance ◽  
Vibration Sensing ◽  
Inertia Parameters ◽  
Set Up ◽  
Linearized Model

This paper investigates the spin resonance of a rattleback subjected to base oscillations. The phenomenon of Spin resonance can transduce vibrations to rotations. The rattleback is an ellipsoidal top with a preferred direction of spin. If rotated anti to it, longitudinal vibrations are set up and spin direction is reversed. Simulations and results are presented which show that the rattleback has a mono-peak spin resonance with respect to base vibrations. Two frequencies that appear in the response are identified — the Coupled and Uncoupled frequencies. Spin resonance, it is deduced, occurs when the base frequency is twice the coupled frequency of the rattleback. A linearized model is developed and a closed form expression for the Resonant frequency in terms of the inertia parameters of the rattleback is derived. Novel ideas for applications in Energy harvesting and Vibration sensing that utilize the phenomenon of spin resonance are also included.

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