Beamspace partially adaptive antenna

Takao, K.; Uchida, Kazuaki

doi:10.1049/ip-h-2.1989.0080

Cited by 30 publications

(11 citation statements)

References 1 publication

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“…Yet, the gain drop can be recovered by combining a beam-space adaptive processing to the beamselector output. By this combination, not only the more precise tracking, but also null-beam steering to undesired interference, can be achieved [7]- [9]. In this case, the multibeam former and the beam selector play the role of a preprocessor of adaptive processing, which improves the performance of the adaptive processor by providing it with input signals with reduced number and higher signal-to-noise ratio (SNR).…”

Section: Discussionmentioning

confidence: 99%

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Beamforming experiment with a DBF multibeam antenna in a mobile satellite environment

Miura¹,

Tanaka

Chiba

et al. 1997

IEEE Trans. Antennas Propagat.

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This paper describes a digital beamforming (DBF) multibeam antenna that incorporates a compact digital signal processor (DSP) engine, and the results of using it in a beamforming experiment receiving a satellite signal in a land-mobile environment. A considerable reduction in the scale of the DSP engine has been achieved by using field programmable gate arrays (FPGA's). To capture a satellite signal arriving from an unknown direction, a two-dimensional (2-D) spatial FFT signal processing provides orthogonal multibeam patterns on the broad side of a planar array antenna. The experimental results demonstrated the features of coarse acquisition and tracking of a signal arrival by selecting the strongest of the beams without assistance from direction finding sensors or microwave phase shifters. The DBF multibeam antenna will provide high-quality communications and increase traffic capacity if it is applied to a high-gain mobile antennas or a multispot-beam base station antennas in cellular or satellite mobile communications.

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Section: Discussionmentioning

confidence: 99%

“…If the DBF multibeam former is used as a preprocessor of adaptive or optimal beam-combining array processing, it is expected to improve convergence and stability even with many 0018-926X/97$10.00 © 1997 IEEE antenna elements and without a sufficient receiving power margin [7]- [9].…”

Section: Introductionmentioning

confidence: 99%

Beamforming experiment with a DBF multibeam antenna in a mobile satellite environment

Miura¹,

Tanaka

Chiba

et al. 1997

IEEE Trans. Antennas Propagat.

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“…The multiple beamformer of the reception part is not FFT/DFT, but its coefficients are computed a priori from the coefficients of the wideband digital multiple beamformer with the frequency-invariant radiation patterns shown in Figs This is for the purpose of selecting output signals with a large signal-to-noise power ratio (SNR) and interference-to-noise power ratio (INR) that will provide the desired signal extraction and interference signal suppression [8]. If only output signals with low SNR and INR are used, the subsequent weight coefficients will become large so that there is a possibility of degraded SNR of the output signal of the adaptive array.…”

Section: Proposed Receiving and Transmittingmentioning

confidence: 99%

Frequency‐invariant adaptive receiving and transmitting null beamforming*

Sekiguchi

Karasawa

2001

Electron. Comm. Jpn. Pt. I

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SUMMARYFor mobile communication antennas, it is important to form nulls in the radiation pattern so that the antenna does not interfere with other communication systems in transmission. In cases where the frequencies for transmission and reception are different, as in FDD (Frequency Division Duplex) systems, if the weighting in the reception mode is used directly for transmission when forming the radiation pattern adaptively during transmission, the null directions are deviated so that the transmission characteristics are degraded. In this paper, a receiving and transmitting adaptive null beamforming algorithm is proposed in which a digital multibeam forming network for propagating signals with wide fractional bandwidths, having radiation patterns not dependent on the frequency, is used for weight calculation. Since the radiation patterns of multibeams are almost identical at the transmission and reception frequencies, almost identical null depth can be obtained for both transmission and reception after convergence. By means of computer simulation, it is confirmed that the nulls are formed in the incident directions of the interference signals in both transmission and reception and that the null depths are almost identical.

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“…Nevertheless, broadband beamspace adaptive beamforming is an effective method to alleviate this problem. In this approach, the array elements are initialized with fixed weights to form several beams pointing in different directions; thereafter the output of each beam is followed by a single variable weight to adjust the output adaptively [3]. Since only one adaptive weight is required in each beam, it is computationally more efficient.…”

Section: Introductionmentioning

confidence: 99%

“…When the beams are not exactly orthogonal, the output will deteriorate. However, using eigendecomposition of the correlation matrix is an effective way to alleviate this problem [3].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the least squares approach to broadband beamspace beamforming

McLernon

Zaidi

2017

2017 International Conference on Recent Advances in Signal Processing, Telecommunications &Amp; Computing (SigTelCom)

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Abstract-In this paper, we present a comprehensive comparison of different structures for broadband beamforming. We focus on both the tapped delay line (TDL) and the least squares (LS), beamspace approaches. Through simulations we confirm the superiority of the beamspace method (i.e., less complex and better frequency invariance). However, its anti-jamming ability is reduced due to non-orthogonal beams. We show how to mitigate this via a reduced rank approximation of the autocorrelation matrix.

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Beamspace partially adaptive antenna

Cited by 30 publications

References 1 publication

Beamforming experiment with a DBF multibeam antenna in a mobile satellite environment

Beamforming experiment with a DBF multibeam antenna in a mobile satellite environment

Frequency‐invariant adaptive receiving and transmitting null beamforming*

Analysis of the least squares approach to broadband beamspace beamforming

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