| 1. |
- Falk, Johan, et al.
(författare)
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Multisource time delay estimation subject to receiver frequency errors
- 2003
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Ingår i: CONFERENCE RECORD OF THE THIRTY-SEVENTH ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS & COMPUTERS, VOLS 1 AND 2. - 0780381041 ; , s. 1156-1160
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Konferensbidrag (refereegranskat)abstract
- An electronic warfare (EW) system with two spatially separated intercept receivers, targeting military communication systems is considered. The EW system estimates the direct ion-of-arrival via a correlation-based time-difference-of-arrival (TDOA) method without any prior knowledge of the signals-of-interest. An important practical consideration is the oscillator frequencies of the two intercept receivers where a difference, or error, degrades the TDOA estimator performance. A measure of this degradation, or loss in power due to the frequency error, is derived and used to describe the robustness against receiver frequency errors. In the multisource scenario, time and frequency overlapping sources can be separated using direction-filtering of the cross-correlation function between the receiver outputs with good result if one signal at a time can be selected by the direction-filter. However, the performance of the considered estimator is degraded in a multisource scenario compared to the single source case.
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| 2. |
- Samuelsson, David, et al.
(författare)
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Optimal downlink beamforming with additional constraints
- 2003
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Ingår i: CONFERENCE RECORD OF THE THIRTY-SEVENTH ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS & COMPUTERS. - 0780381041 ; , s. 1811-1814
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Konferensbidrag (refereegranskat)abstract
- This work addresses the problem of joint downlink beamforming and power control with general Quality of Service (QoS) constraints. Previous work on downlink beamforming does not provide a framework to handle the additional constraints in a straightforward fashion. Herein, it is shown that the QoS requirements can be formulated as quadratic constraints to a convex optimization problem. An efficient algorithm for solving the problem, based on semidefinite optimization is presented. To demonstrate the performance of the proposed approach, we present an example using quadratic constraints to greatly decrease the probability of a low instantaneous Signal to Interference and Noise Ratio (SINR) for a receiver equipped with a RAKE combiner.
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