The Differential CMA Adaptive Array Antenna Using an Eigen-Beamspace System

Kentaro NISHIMORI; Nobuyoshi KIKUMA; Naoki INAGAKI

The Differential CMA Adaptive Array Antenna Using an Eigen-Beamspace System

Kentaro NISHIMORI, Nobuyoshi KIKUMA, Naoki INAGAKI

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This paper addresses approaches to enhancement of performance of the CMA (Constant Modulus Algorithm) adaptive array antenna in multipath environments that characterize the mobile radio communications. The cost function of the CMA reveals that it has an AGC (Automatic Gain Control) procedure of holding the array output voltage at a constant value. Therefore, if the output voltage by the initial weights is different from the object value, then the CMA may suffer from slow convergence because suppression of the multipath waves is delayed by the AGC behavior. Our objective is to improve the convergence characteristics by adopting the differential CMA for the adaptive array algorithm. First, the basic performance of the differential CMA is clarified via computer simulation. Next, the differential CMA is incorporated into the eigen-beamspace system in which the eigenvectors of the correlation matrix of array inputs are used in the BFN (Beam Forming Network). This BFN creates the optimum orthogonal multibeams for radio environments and works helpfully as a preprocessor of the differential CMA. The computer simulation results have demonstrated that the differential CMA with the eigen-beamspace system has much better convergence characteristics than the conventional CMA with the element space system. Furthermore, a modified algorithm is introduced which gives the stable array output voltages after convergence, and it is confirmed that the algorithm can carry out more successful adaptation even if the radio environments are changed abruptly.

Publication: IEICE TRANSACTIONS on Communications Vol.E78-B No.11 pp.1480-1488

Publication Date: 1995/11/25

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Type of Manuscript: Special Section PAPER (Special Issue on Adaptive Signal Processing Technology in Antennas)

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Kentaro NISHIMORI, Nobuyoshi KIKUMA, Naoki INAGAKI, "The Differential CMA Adaptive Array Antenna Using an Eigen-Beamspace System" in IEICE TRANSACTIONS on Communications, vol. E78-B, no. 11, pp. 1480-1488, November 1995, doi: .
Abstract: This paper addresses approaches to enhancement of performance of the CMA (Constant Modulus Algorithm) adaptive array antenna in multipath environments that characterize the mobile radio communications. The cost function of the CMA reveals that it has an AGC (Automatic Gain Control) procedure of holding the array output voltage at a constant value. Therefore, if the output voltage by the initial weights is different from the object value, then the CMA may suffer from slow convergence because suppression of the multipath waves is delayed by the AGC behavior. Our objective is to improve the convergence characteristics by adopting the differential CMA for the adaptive array algorithm. First, the basic performance of the differential CMA is clarified via computer simulation. Next, the differential CMA is incorporated into the eigen-beamspace system in which the eigenvectors of the correlation matrix of array inputs are used in the BFN (Beam Forming Network). This BFN creates the optimum orthogonal multibeams for radio environments and works helpfully as a preprocessor of the differential CMA. The computer simulation results have demonstrated that the differential CMA with the eigen-beamspace system has much better convergence characteristics than the conventional CMA with the element space system. Furthermore, a modified algorithm is introduced which gives the stable array output voltages after convergence, and it is confirmed that the algorithm can carry out more successful adaptation even if the radio environments are changed abruptly.
URL: https://globals.ieice.org/en_transactions/communications/10.1587/e78-b_11_1480/_p

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@ARTICLE{e78-b_11_1480,
author={Kentaro NISHIMORI, Nobuyoshi KIKUMA, Naoki INAGAKI, },
journal={IEICE TRANSACTIONS on Communications},
title={The Differential CMA Adaptive Array Antenna Using an Eigen-Beamspace System},
year={1995},
volume={E78-B},
number={11},
pages={1480-1488},
abstract={This paper addresses approaches to enhancement of performance of the CMA (Constant Modulus Algorithm) adaptive array antenna in multipath environments that characterize the mobile radio communications. The cost function of the CMA reveals that it has an AGC (Automatic Gain Control) procedure of holding the array output voltage at a constant value. Therefore, if the output voltage by the initial weights is different from the object value, then the CMA may suffer from slow convergence because suppression of the multipath waves is delayed by the AGC behavior. Our objective is to improve the convergence characteristics by adopting the differential CMA for the adaptive array algorithm. First, the basic performance of the differential CMA is clarified via computer simulation. Next, the differential CMA is incorporated into the eigen-beamspace system in which the eigenvectors of the correlation matrix of array inputs are used in the BFN (Beam Forming Network). This BFN creates the optimum orthogonal multibeams for radio environments and works helpfully as a preprocessor of the differential CMA. The computer simulation results have demonstrated that the differential CMA with the eigen-beamspace system has much better convergence characteristics than the conventional CMA with the element space system. Furthermore, a modified algorithm is introduced which gives the stable array output voltages after convergence, and it is confirmed that the algorithm can carry out more successful adaptation even if the radio environments are changed abruptly.},
keywords={},
doi={},
ISSN={},
month={November},}

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TY - JOUR
TI - The Differential CMA Adaptive Array Antenna Using an Eigen-Beamspace System
T2 - IEICE TRANSACTIONS on Communications
SP - 1480
EP - 1488
AU - Kentaro NISHIMORI
AU - Nobuyoshi KIKUMA
AU - Naoki INAGAKI
PY - 1995
DO -
JO - IEICE TRANSACTIONS on Communications
SN -
VL - E78-B
IS - 11
JA - IEICE TRANSACTIONS on Communications
Y1 - November 1995
AB - This paper addresses approaches to enhancement of performance of the CMA (Constant Modulus Algorithm) adaptive array antenna in multipath environments that characterize the mobile radio communications. The cost function of the CMA reveals that it has an AGC (Automatic Gain Control) procedure of holding the array output voltage at a constant value. Therefore, if the output voltage by the initial weights is different from the object value, then the CMA may suffer from slow convergence because suppression of the multipath waves is delayed by the AGC behavior. Our objective is to improve the convergence characteristics by adopting the differential CMA for the adaptive array algorithm. First, the basic performance of the differential CMA is clarified via computer simulation. Next, the differential CMA is incorporated into the eigen-beamspace system in which the eigenvectors of the correlation matrix of array inputs are used in the BFN (Beam Forming Network). This BFN creates the optimum orthogonal multibeams for radio environments and works helpfully as a preprocessor of the differential CMA. The computer simulation results have demonstrated that the differential CMA with the eigen-beamspace system has much better convergence characteristics than the conventional CMA with the element space system. Furthermore, a modified algorithm is introduced which gives the stable array output voltages after convergence, and it is confirmed that the algorithm can carry out more successful adaptation even if the radio environments are changed abruptly.
ER -