powerinversion (PI) is a known adaptive beamforming algorithm that is widely used in wireless communication systems for anti-jamming purposes. The PI algorithm is typically implemented in a digital domain, which requ...
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powerinversion (PI) is a known adaptive beamforming algorithm that is widely used in wireless communication systems for anti-jamming purposes. The PI algorithm is typically implemented in a digital domain, which requires the radio-frequency signals to be down-converted into base-band signals, and then sampled by ADCs. In practice, the down-conversion circuit will introduce phase noises into the base-band signals, which may degrade the performance of the algorithm. At present, the impacts of phase noise on the PI algorithm have not been studied, according to the open literature, which is, however, important for practical design. Therefore, in this paper, we present a theoretical analysis on the impacts, provide a new mathematical model of the PI algorithm, and offer a closed-form formula of the interference cancellation ratio (ICR) to quantify the relations between the algorithm performance and the phase noise level, as well as the number of auxiliary antennas. We find that the ICR in decibel decreases logarithmically linearly with the phase noise variance. In addition, the ICR improves with an increasing number of auxiliary antennas, but the increment is upper-bounded. The above findings are verified with both simulated and measured phase noise data.
This paper presents a new algorithm based on the powerinversion （PI） and the linearly constrained minimum variance （LCMV）. This algorithm is capable of adjusting the weights of the antenna array in real time to r...
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This paper presents a new algorithm based on the powerinversion （PI） and the linearly constrained minimum variance （LCMV）. This algorithm is capable of adjusting the weights of the antenna array in real time to respond to and improve the global positioning system （GPS） received signals coming from the desired directions and at the same time to highly suppress the jammers coming from the other directions. The simulation is performed for fixed and moving jammers. It indicates that this structure can give deeper nulls, more than 115 dB depths for fixed jammers and more than 94 dB depths for moving jammers.
An adaptive array antenna for the suppression of high-power interference in direct-sequence code-division multiple access (DS-CDMA) systems is presented. Although DS-CDMA has sufficient flexibility to support a variet...
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An adaptive array antenna for the suppression of high-power interference in direct-sequence code-division multiple access (DS-CDMA) systems is presented. Although DS-CDMA has sufficient flexibility to support a variety of services, from voice to moving-pictures, with high levels of quality, multiple access interference (MAI) is a problem. This is particularly so of the high-power interference which accompanies highspeed transmission in DS-CDMA. While the application of adaptive array antennas is an effective way of improving signal-to-interference-plus-noise ratio (SINR), problems with this approach include large levels of power consumption and the high costs of hardware and of implementing the antennas. Therefore, our main purpose is to realize a simple configuration for an adaptive array system. In order to reduce the required amounts of processing, a common beam provides suppression of high-power interference for the low-bit-rate users;, this makes per-user preparation of weights unnecessary. This approach also reduces the consumption of power by the system. Interference is cancelled by minimization of the array output power (i.e., the application of a power inversion algorithm) before despreading. The approach also allows us to improve the implementation of the antenna elements by using small auxiliary antennas. The basic performance of the system is confirmed through numerical calculation and computer simulation. Furthermore, a real-time processing unit has been developed and the effectiveness of the approach is confirmed by an experiment in a radio-anechoic chamber.
The anti-jamming antenna is one of the most efficient ways to resist the adversary effect of the interference signal in GNSS positioning. Most anti-jamming antennas can adaptively adjust the radiation figure of the an...
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The anti-jamming antenna is one of the most efficient ways to resist the adversary effect of the interference signal in GNSS positioning. Most anti-jamming antennas can adaptively adjust the radiation figure of the antenna to minimize the interference impact. A side effect of changing the radiation figure is that the antenna phase center (APC) is also changed accordingly. Meanwhile, a stable phase center is a prerequisite for high precision GNSS positioning, thus the anti-jamming and high-precision becomes a dilemma for the GNSS antenna design. This study proposed an efficient antenna phase center variation (PCV) compensation algorithm for the anti-jamming antennas which enables real-time high-precision applications with the anti-jamming antennas. The performance of the algorithm is evaluated with the short baseline tests, and the results indicate that the proposed algorithm can reduce the carrier phase residuals by compensation of the anti-jamming antenna PCV and consequently, the 3D root mean squares (RMS) of real-time kinematic (RTK) positioning in two experiments is improved by 42.3% and 9.7% respectively. After PCV correction, the RTK positioning with the anti-jamming antennas achieves better than 4 cm accuracy.
This paper put forward a comparison between power inversion algorithm and MVDR algorithm used in the STAP-Digital beamforming. The results of MATLAB simulation about this two algorithms show that: PI has almost the sa...
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This paper put forward a comparison between power inversion algorithm and MVDR algorithm used in the STAP-Digital beamforming. The results of MATLAB simulation about this two algorithms show that: PI has almost the same ability in resisting static jams as MVDR with the angle of navigation signals is known;If the jam is a moving one ,MVDR will show its advantage over PI .So MVDR is a effective anti-jamming method.
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