Efficient Radio Transmission with Adaptive and Distributed Beamforming for Intelligent WiMAX

Lian, Xiaohua; Nikookar, H.; Ligthart, L.P.

doi:10.1007/s11277-011-0237-3

Cited by 9 publications

(8 citation statements)

References 58 publications

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“…Part I of this paper [1] is focused on a comparative analysis of empirical and geometrical (theoretical) models of the probability density function (PDF) of azimuth AOA (AAOA) for different environmental conditions. Empirical models are based on standard distributions such as Gaussian [2][3][4][5], Laplacian [2,3,[6][7][8][9][10][11][12], logistic [13][14][15][16], and von Mises [3,[17][18][19][20][21], which are being modified due to limited support of PDF of AAOA. The theoretical models are defined by the geometrical structures that describe the spatial position of scattering elements.…”

Section: Introductionmentioning

confidence: 99%

Empirical Models of the Azimuthal Reception Angle—Part II: Adaptation of the Empirical Models in Analytical and Simulation Studies

Ziółkowski

Kelner

2016

Wireless Pers Commun

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This paper focuses on modeling of the statistical reception angle properties that are the result of the environmental influence on transmitted signals. Numerous measurements have shown that the statistical properties of angle of arrival (AOA) significantly depend on the type of propagation environment. In practice, this means that in the analytical and simulation studies, the use of statistical models of AOA required their adaptation to propagation conditions in research scenario. Despite the large number of papers that are devoted to the AOA modeling, the method of fitting models to the environment is not presented in any of the publications. This paper fills this gap. For the assessment of the propagation properties and environment type classification, the basis is the rms delay spread (DS). Therefore, the presented method of the model adaptation to the environment type consists of determining the relationship between the model parameter and DS of environment. Here, the probability density function (PDF) of models such as the modified Gaussian, modified Laplacian, modified logistic, and von Mises distribution are considered as the statistical models of azimuth AOA. For seven different propagation environments, the measurement results are used as a reference data. A comparative analysis shows that the modified Laplacian PDF provides the smallest error fit to measurement data. However, in theoretical analysis and simulation studies, other empirical models can be used due to relatively low approximation errors. The presented results are the basis for the adaptation error assessment of the empirical model for any of the research scenario.

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Section: Introductionmentioning

confidence: 99%

Empirical Models of the Azimuthal Reception Angle—Part II: Adaptation of the Empirical Models in Analytical and Simulation Studies

Ziółkowski

Kelner

2016

Wireless Pers Commun

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“…The principle of the necessity of generating spread nulls has been explained in [25]. In wireless communication systems, the received signal and power spectra at the mobile station at wireless communication depend on the pdf of the AOA of the scattered wave.…”

Section: Podb Methods With Spread Nullsmentioning

confidence: 99%

“…In case L > 1, we show in [25] how to generate more than one main beam towards ) by (A 0 , j 0 ) when there is only one DCR user.…”

Section: Necessary Assumptionsmentioning

confidence: 99%

Distributed beam forming with phase-only control for green cognitive radio networks

Lian

Nikookar

Ligthart

2012

J Wireless Com Network

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Cognitive radio (CR) is an intelligent radio system and is able to share the spectrum with licensed users (LU). By adopting adaptive beam forming techniques, CR can reuse the spectrum with LU via directing main beams towards CR users while displaying nulls towards LU. In this article, we present a new distributed beam forming (DB) technique, and study the performance of its application to decentralized CR networks. The presented DB method only controls the phase of the transmitted signal of each CR node in the CR network, and therefore, it is called phase-only DB (PODB) method. It can be implemented at each node independently with only prior knowledge of its own location, and directions of distant CR (DCR) users and LU. The average beam pattern and the average gains for an arbitrary number of CR nodes of PODB method are discussed, showing that CR nodes can constructively transmit signals to DCR users with less interferences to LU via employing the PODB method to form and direct main beams towards directions of DCR users while nulls towards directions of LU. PODB proves to be a green DB method by prolonging the lifetime of the CR network due to effective battery power consumptions at CR nodes. The cumulative distributed function of the beam pattern for a large number of CR nodes is derived and analysed to demonstrate that the PODB method increases the possibility that the transmitted power of the whole CR network at the directions of LU is lower than a certain threshold, which guarantees that CR network causes less disturbing effect to LU.Keywords: distributed beam forming, collaborative beam forming, cognitive radio networks, phase-only distributed beam forming, null-steering distributed beam forming, green cognitive radio networks

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“…In the open literature, the statistical AAOA analysis shows that the empirical data approximation is based on PDF such as the Laplacian [15,21,22,[24][25][26][27][28][29], Gaussian [22,24,30,31], and von Mises [22,[32][33][34][35][36]. In this paper, the logistic distribution [37][38][39][40] …”

Section: Empirical Models Of Aaoamentioning

confidence: 97%

Empirical Models of the Azimuthal Reception Angle—Part I: Comparative Analysis of Empirical Models for Different Propagation Environments

Ziółkowski

Kelner

2016

Wireless Pers Commun

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Statistical properties of the reception angle have a significant impact on the choice of the antenna system patterns and decide on the received signal-processing methods. For angle of arrival in azimuth plane, comparative analysis of the empirical models and the approximation error evaluation are the purpose of this paper. Here, the presented analysis is focused on models such as the von Mises, modified Gaussian, modified Laplacian, and modified logistic. For each model, the approximation accuracy is determined with respect to measurement data for seven different propagation scenarios. The measures such as the least-squares error, difference of standard deviations, Kolmogorov-Smirnov statistic, and Cramer-von Mises statistic are used for evaluation of the approximation errors. Comparative analysis for four empirical models, differentiation of propagation environments, multi-criterial evaluation of approximation errors in significant degree fill a gap in the previous analysis presented in the literature. The obtained results show that the empirical models provide a better fit to the measurement data than the geometrical models, and the smallest errors of approximation are for the modified Laplacian and logistic distributions.

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Efficient Radio Transmission with Adaptive and Distributed Beamforming for Intelligent WiMAX

Cited by 9 publications

References 58 publications

Empirical Models of the Azimuthal Reception Angle—Part II: Adaptation of the Empirical Models in Analytical and Simulation Studies

Empirical Models of the Azimuthal Reception Angle—Part II: Adaptation of the Empirical Models in Analytical and Simulation Studies

Distributed beam forming with phase-only control for green cognitive radio networks

Empirical Models of the Azimuthal Reception Angle—Part I: Comparative Analysis of Empirical Models for Different Propagation Environments

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