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This paper describes the demonstration of a four-channel digital beamforming system incorporating highly integrated silicon germanium downconverter modules. The downconverter modules are designed to translate X-band frequencies (9 to 10.5 GHz) down to a common 1.0 GHz IF output. The modules were integrated with an X-band antenna array and high-speed digitizer system to form a rudimentary digital beamforming...
MIMO radar has seen growing interest in recent years owing to the many advantages that it offers over conventional radar, including spatial diversity and enhanced target direction resolution. Unlike standard phased array (SIMO) radar that transmits scaled versions of a single waveform from its many transmit antennas, a MIMO radar can transmit distinct waveforms from each antenna. Such an increase...
We have seen in the above that the SweepSAR technique offers the potential for significant reductions in the transmit peak and average power required for a SAR system. This is achieved by making full use of the areal extent of a reflector antenna on receive. The SweepSAR rate is not as big a problem as it might appear initially: note that in the 30 years since Seasat launched downlink rates for LEO...
We propose an architecture which reduce the circuit size to concurrently cancel co-channel interference and image- band interference. We adopt analogue Hilbert transformers to cancel image-band interference and adaptive array antennas to cancel co-channel interference. Furthermore, we can miniaturize the receiver by mixing all signals at the IF stage. We also show performance of the proposed system...
We consider the fundamental ability of multisensor receiver of finite spatial extent to localize a wireless transmitter in space. Spatial localization is identified with a multisensor receiver's ability to distinguish source transmitters from different regions in space based on imperfect measurements within the finite spatial extent spanned by the receiver's sensors. Two transmitters positioned within...
Recently, the attentions of communication societies are paid to MIMO-OFDM systems. In this paper we propose a new beamforming method to the receive end of MIMO-OFDM systems. To make the method work with fewer known OFDM symbols, oversampling samples are employed and multistage decomposition based on orthogonality of sub-carriers of OFDM signal is used to formulate the beamforming weight vector for...
This paper studies efficient complex valued matrix manipulations for multi-user STBC-MIMO decoding. A novel method called Alamouti blockwise analytical matrix inversion (ABAMI) is proposed for the inversion of large complex matrices that are based on Alamouti sub-blocks. Another method using a variant of Givens rotation is proposed for fast QR decomposition of this kind of matrices. Our solutions...
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