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Adaptive TimeVarying Cancellation of Wideband Interferences in SpreadSpectrum Communications Based on TimeFrequency Distributions
 IEEE Trans. Signal Processing
, 1999
"... The aim of this paper is to propose an adaptive method for suppressing wideband interferences in spread spectrum (SS) communications. The proposed method is based on the timefrequency representation of the received signal from which the parameters of an adaptive timevarying interference excision ..."
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The aim of this paper is to propose an adaptive method for suppressing wideband interferences in spread spectrum (SS) communications. The proposed method is based on the timefrequency representation of the received signal from which the parameters of an adaptive timevarying interference excision filter are estimated. The approach is based on the generalized WignerHough transform as an effective way to estimate the instantaneous frequency of parametric signals embedded in noise. The performance of the proposed approach is evaluated in the presence of linear and sinusoidal FM interferences plus white Gaussian noise in terms of SNR improvement factor and bit error rate (BER).
Nonlinear Filtering of NonGaussian Noise
, 1997
"... This paper introduces a new nonlinear filter for a discrete time, linear system which is observed in additive nonGaussian measurement noise. The new filter is recursive, computationally efficient and has significantly improved performance over other linear and nonlinear schemes. The problem of na ..."
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Cited by 5 (0 self)
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This paper introduces a new nonlinear filter for a discrete time, linear system which is observed in additive nonGaussian measurement noise. The new filter is recursive, computationally efficient and has significantly improved performance over other linear and nonlinear schemes. The problem of narrowband interference suppression in additive noise is considered as an important example of nonGaussian noise filtering. It is shown that the new filter outperforms currently used approaches and at the same time offers simplicity in the design.
A Fuzzy Logic System for Interference Rejection in Code Division Multiple Access
 in Proceedings of the FuzzIEEE Conference, Sant Louis
, 2003
"... The spread spectrum modulation presents a more robust interference rejection capability than the non codebased modulations. However, the increasing of the communication services has augmented the power of the interference signals. In particular, the unlicensed bands such as the Industrial Scientifi ..."
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Cited by 2 (1 self)
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The spread spectrum modulation presents a more robust interference rejection capability than the non codebased modulations. However, the increasing of the communication services has augmented the power of the interference signals. In particular, the unlicensed bands such as the Industrial Scientific and Medical (ISM) can seriously saturate the interference rejection capability of the spread spectrum systems. To overcome this drawback it is possible to resort to an Interference Canceller (IC) previously to the detection. Then to design an IC the Conditional Mean (CM) and the MaximumAPosteriori criteria are the optimum methods to suppress analog and digital interferences respectively. However, in general both criteria present a high computational burden which reduces their real feasibility. In addition, the communication scenery can be corrupted by Gaussian or NonGaussian noise, which makes more complex the structure of the optimum detector. This paper proposes an interference canceller based on Fuzzy Logic and set theory that allows to suppress either analog or digital interferences and reduces the computational burden of the CM estimator and MAP detector.
An Scalable Fuzzy Interference Canceller for DSCDMA Systems, accepted at Intelligent System
 Special Issue on Soft computing for Modelling, Simulation and Control on Nonlinear Dynamical Systems
"... The spread spectrum modulation presents a more robust interference rejection capability than noncode–based modulations. However, the increase of the communication services has augmented the power of the interference signals. One example is unlicensed bands such as the 2.4–2.5 GHz one, where the DS ..."
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The spread spectrum modulation presents a more robust interference rejection capability than noncode–based modulations. However, the increase of the communication services has augmented the power of the interference signals. One example is unlicensed bands such as the 2.4–2.5 GHz one, where the DSCDMA communications of the IEEE 802.11b standard are interfered with by other Industrial Scientific and Medical (ISM) services. One way of improving the interference robustness of the DSCDMA receivers is introducing an interference canceler (IC) before the despreading stage. The optimum criterion to estimate or detect the interference is the maximumaposteriori (MAP) one. However, it requires a high computational burden and a complete knowledge of the statistical model, which reduce its feasibility. To overcome these drawbacks this article proposes an interference canceler based on Fuzzy Logic that allows (1) suppressing both analog and digital interferences, and (2) easily controlling the complexity versus performance tradeoff. In other words, the design of the fuzzy canceler follows a down/ top strategy; that is, a first low complex design is possible just departing from linguistic information and, in a second stage, we refine it, incorporating the available statistical information into its structure. Finally, to assess the proposed fuzzy canceler we have derived asymptotic performance bounds. © 2005 Wiley Periodicals, Inc. 1.
A DSPBASED FUZZY SYSTEM FOR REALTIME INTERFERENCE CANCELLATION IN DSSS SYSTEMS.
"... This work demonstrates that highend classical programmable digital signal processors (DSPs) can implement fuzzy systems for realtime communication processing. A systematic procedure to program the DSP is also described. A Fuzzy Narrowband Interference Canceller (NBI) has been designed and its perf ..."
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This work demonstrates that highend classical programmable digital signal processors (DSPs) can implement fuzzy systems for realtime communication processing. A systematic procedure to program the DSP is also described. A Fuzzy Narrowband Interference Canceller (NBI) has been designed and its performance compared when its membership functions are triangular or gaussian. Furthermore a comparative study with other cancellers has been carried out.