The Experts below are selected from a list of 5169 Experts worldwide ranked by ideXlab platform
Heidi Steendam - One of the best experts on this subject based on the ideXlab platform.
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VTC Spring - Interference Cancellation of AM Narrowband Interference Signals
2007 IEEE 65th Vehicular Technology Conference - VTC2007-Spring, 2007Co-Authors: D. Van Welden, Heidi SteendamAbstract:In this paper, we consider an overlay system where Narrowband AM signals interfere with a broadband multicarrier system (M. Schnell et al., 2004). To reduce the effect of the AM Narrowband Interference on the multicarrier system, we propose a low complexity algorithm to estimate AM Narrowband Interference. We derive analytical expressions for the performance of the estimator and verify the results with simulations. The proposed estimator is able to produce accurate estimates of the frequencies, and track the time-varying amplitudes of the AM signals. The estimator can reduce the power of the AM signal to a level that is approximately 20 dB lower than the multicarrier power, independent of the AM signal power.
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The effect of Narrowband Interference on timing synchronization for OFDM systems
2005Co-Authors: Mohamed Marey, Heidi SteendamAbstract:Orthogonal frequency division multiplexing (OFDM) has been of major interest for both wire line and wireless applications due its high data rate transmission capability and its robustness to multipath delay spread. However, OFDM systems can be extremely sensitive and vulnerable to synchronization errors. This paper investigates the effect of Narrowband Interference on timing synchronization for OFDM systems. The performance of the Schmidl & Cox (S&C) symbol timing synchronizer [1] is evaluated in an analytical way in the presence of Narrowband interferers. Further, simulations have been carried out to verify the validity of approximations in the analysis. It is shown that the S&C algorithm is robust to Narrowband Interference as long as the signal to Interference ratio is not too low.
P. Yaddanapudi - One of the best experts on this subject based on the ideXlab platform.
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Narrowband Interference Avoidance in OFDM-Based UWB Communication Systems
IEEE Transactions on Communications, 2007Co-Authors: Dimitrie C. Popescu, P. YaddanapudiAbstract:In this letter we present a new method for mitigating Narrowband Interference in orthogonal frequency-division multiplexing-based ultra-wideband communication systems. The proposed Narrowband Interference avoidance (NBIA) method performs spectral shaping of the transmitted signal using binary signature sequences with minimum total squared correlation (TSC) to avoid the Narrowband interfering signal. We illustrate the proposed method with plots that show the spectrum of the transmitted signal with and without NBIA, and also present numerical results obtained from simulations showing improvement in the bit error rate (BER) performance of the system when NBIA is employed.
Hagit Messer - One of the best experts on this subject based on the ideXlab platform.
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Narrowband Interference mitigation in impulse radio
IEEE Transactions on Communications, 2005Co-Authors: Itsik Bergel, E. Fishler, Hagit MesserAbstract:Impulse radio (IR) systems have drawn attention during the last few years. These systems are planned to coexist with Narrowband systems without interfering them. Nevertheless, the Narrowband systems can cause Interference which may jam the IR receiver. This letter analyzes a low-complexity Narrowband Interference (NBI)-mitigation algorithm for IR systems, based on minimal mean-square error combining. Theoretical analysis reveals that these algorithms nearly eliminate the NBI. The concept is also extended to the case where the receiver has more correlators than channel taps.
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Narrowband Interference suppression in time-hopping impulse-radio systems
2002 IEEE Conference on Ultra Wideband Systems and Technologies (IEEE Cat. No.02EX580), 2002Co-Authors: Itsik Bergel, E. Fishler, Hagit MesserAbstract:Ultra-wideband (UWB) radio systems have drawn a lot of attention during the last few years. These systems use very low transmission power, spread over a bandwidth of several gigahertz. The very low transmission power and the large bandwidth used enable UWB radio systems to coexist with other Narrowband systems over the same frequency band without interfering with the Narrowband systems. Nevertheless, these Narrowband systems may cause Interference which jams the UWB receiver completely. Since standard Narrowband Interference suppression techniques are not applicable, techniques for Interference suppression have to be developed. This paper presents novel Narrowband Interference suppression algorithms for UWB radio systems. Theoretical analysis of these algorithms reveal that they can eliminate the Narrowband Interference almost completely.
H. Vincent Poor - One of the best experts on this subject based on the ideXlab platform.
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Narrowband Interference suppression in cdma spread spectrum communications
IEEE Transactions on Communications, 1994Co-Authors: Leslie A. Rusch, H. Vincent PoorAbstract:Spread spectrum (SS) communications offers a promising solution to an overcrowded frequency spectrum amid growing demand for mobile and personal communications services. The proposed overlay of spread spectrum signals on existing Narrowband users implies strong Interference for the SS system. The paper discusses how system performance can be improved by preprocessing to suppress Narrowband Interference. Linear prediction filters have been proposed since the 1980s for suppression of Narrowband Interference. Vijayan and Poor (1991) proposed nonlinear methods of suppressing the Narrowband signal with significant increase in the SNR improvement. The present authors derive an enhancement to this nonlinear prediction and achieve further improvement by applying the technique to interpolating filter structures. Finally, they extend results to the case of multiple spread spectrum users and demonstrate how nonlinear filtering can dramatically outperform linear filtering. >
L.b. Milstein - One of the best experts on this subject based on the ideXlab platform.
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The effects of Narrowband Interference on UWB communication systems with imperfect channel estimation
IEEE Journal on Selected Areas in Communications, 2006Co-Authors: C.r.c.m. Da Silva, L.b. MilsteinAbstract:The proposed spectrum-overlay scenario for ultra-wideband systems brings new technical challenges that must be considered during the system design. In this scenario, the receiver has to perform functions, such as multipath combining and channel estimation, on a large number of low-energy multipath components in the possible presence of strong in-band Interference. This paper proposes an analytical formulation that allows for the analysis of the channel estimation in the presence of Narrowband Interference. It is shown that the affect of Narrowband Interference is exacerbated by channel estimation errors, and that the number of training bits used for channel estimation is strongly dependent on whether or not Interference suppression is employed. It is also shown that sources of degradation, such as imperfect channel estimation and the presence of Narrowband Interference, impose a practical limit on the number of multipath components that should be combined.
