Simple initialization scheme for CMA adaptive antenna by using digital beam synthesis

Tantisopharak, Tanawut; Boonpoonga, Akkarat; Sirisuk, P.; Krairiksh, M.

doi:10.1109/ecticon.2008.4600429

Cited by 4 publications

(4 citation statements)

References 6 publications

(10 reference statements)

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“…This approach strengthens the desired signal level and thus contributes to improve convergence characteristics. Its effectiveness was validated via experimental work [21] and extension to the digital-domain beamformer was further investigated [22]. Digital beamforming yields more diversified beam pattern bringing further improvement.…”

Section: Related Workmentioning

confidence: 99%

Stabilised blind interference suppression of constant modulus‐based adaptive array over Rayleigh fading channels by initial antenna selection

Maruta¹,

Ahn²

2019

IET Microwaves, Antennas & Propagation

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This article proposes an initial antenna selection for constant modulus‐based blind interference suppression algorithms to stabilise their prominent interference suppression performance. Constant modulus algorithm (CMA) is a well‐known blind adaptive array scheme, but it cannot suppress the interference when signal‐to‐interference power ratio (SIR) is <0 dB. It faces strong limits on their applicable region over Rayleigh fading channels where instantaneous channel gain fluctuates over 10 dB range. Even if the expected desired signal strength is larger than interference, CMA may still miscapture the interference and incorrectly suppress the desired signal. The authors’ proposal is simplified approach to select the antenna element whose reception power is maximal. Certain antenna element can be expected to capture the desired signal precisely under the condition where SIR is statistically positive, so that the CMA processor can utilise it as an initial input. This condition will be ensured by increasing antenna element number, supported by the trends that base station antenna elements are going massive. Computer simulations verifies improved interference suppression performance provided by the proposed scheme. This article also verified applicability for multi‐modulus algorithm to accommodate M‐ary quadrature amplitude modulation (QAM) use.

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Section: Related Workmentioning

confidence: 99%

Stabilised blind interference suppression of constant modulus‐based adaptive array over Rayleigh fading channels by initial antenna selection

Maruta¹,

Ahn²

2019

IET Microwaves, Antennas & Propagation

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“…The main research directions of the blind algorithm contain the constant modulus algorithm (CMA) [11], decision-oriented algorithm (DDA), de-spread re-spread algorithm, the algorithm based on the cyclic and finite symbol set algorithm and so on. However, they can not meet the high stability, convergence speed, and little amount of calculation at the same time.…”

Section: Introductionmentioning

confidence: 99%

The research on new adaptive beamforming algorithms

Gong

Shen

Ren

et al. 2012

2012 International Conference on Microwave and Millimeter Wave Technology (ICMMT)

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In this paper, we propose a novel semi-blind algorithm and a novel transform domain algorithm. The feasibility, stability, complexity and other characteristics of the semi-blind algorithm were analyzed. The novel semi-blind algorithm integrates LMS Least mean square and CMA (Constant modulus algorithm). It uses the LMS algorithm, which is simple to implement and not computationally intensive, but with CMA initialization in order to ensure desirable robustness properties. Then the new transform domain least mean-square adaptive algorithm employing a new adaptive step size control technique is proposed. The variable step size approximates a theoretical optimal one based on a proposed cost function. As a result, considerable improvement in convergence speed is attained in early stages of convergence with small misadjustment near the optimum. Simulation experiments clearly demonstrate the enhanced convergence characteristics of the proposed algorithm.Index Terms: semi-blind algorithm, beamforming ,transform domain , new adaptive step size, variable step size . INTRODUCTIONThe ever-increasing demand for increased capacity in wireless communications services has led to developments of new technologies that exploit space selectivity. This is done through smart-antenna arrays [1-2] and the associated adaptive beamforming algorithms [3][4][5][6][7][8].Adaptive beamforming algorithm is the core of smart antenna technology, now it has been proposed based on the main methods which are non-blind algorithm including least mean square (LMS) [9], normalized least mean square (NLMS) sample matrix inversion method (SMI), recursive least squares (RLS) [10]. The main research directions of the blind algorithm contain the constant modulus algorithm (CMA) [11], decision-oriented algorithm (DDA), de-spread re-spread algorithm, the algorithm based on the cyclic and finite symbol set algorithm and so on. However, they can not meet the high stability, convergence speed, and little amount of calculation at the same time.Common transform domain LMS adaptive filtering is a very popular alternative technique to LMS-type algorithms when the input signal is colored [12][13][14]. The transform domain LMS algorithm attempts to decorrelate the input signal where gains in convergence speed are obtained only after power normalization of the transformed input vector is applied to reduce the eigenvalue disparity of the transformed signal autocorrelation matrix [14]. However, little attention has been paid to the fact that the transform domain LMS inherits the LMS algorithm limitation of having to establish a tradeoff between convergence speed and misadjustment level [15].In this paper, we focus on a new semi-blind algorithm and a new transform domain LMS algorithm with an adaptive step size control method. The first algorithm not only can make full use of the fast convergence of LMS algorithm, small error and high system resource utilization of CMA algorithm, but also can improve the speed and accuracy of the beamforming of next communication system. ...

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“…The weights are automatically varied such that the maximum signal power is achieved. The weights are defined according to [21] as…”

Section: System Architecturementioning

confidence: 99%

“…Digital beam synthesis [21] was proposed to digitally synthesize beams in different directions instead of using phase shifters. This technique utilizes complex weight vectors to multiply the received signal from the antenna in order to adjust the main beam to the desired direction.…”

Section: Introductionmentioning

confidence: 99%

Adaptive Array Antenna Using On-Off and CMA Algorithms for Microwave RFID Readers

Tantisopharak

Boonpoonga

Phongcharoenpanich

et al. 2011

IEICE Trans. Commun.

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SUMMARYThis paper proposes an adaptive antenna using a combination of on-off and CMA algorithms. With the proposed technique, the on-off algorithm is first employed to search for a desired signal direction in which maximum received power is achieved. Then, interference is suppressed by performing CMA. Simulations are conducted according to the potential application of the proposed adaptive antenna. The simulation results show the SINR improvement implying that the proposed adaptive antenna can be applied to microwave RFID systems in order to resolve reader collision. Furthermore, the proposed adaptive antenna is implemented and then experimented. The experimental results verify that the proposed adaptive antenna can reduce interference resulting in the collision problem.

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Simple initialization scheme for CMA adaptive antenna by using digital beam synthesis

Cited by 4 publications

References 6 publications

Stabilised blind interference suppression of constant modulus‐based adaptive array over Rayleigh fading channels by initial antenna selection

Stabilised blind interference suppression of constant modulus‐based adaptive array over Rayleigh fading channels by initial antenna selection

The research on new adaptive beamforming algorithms

Adaptive Array Antenna Using On-Off and CMA Algorithms for Microwave RFID Readers

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