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This paper proposes a blanker with a threshold value that is adaptively updated based on average signal power in an impulsive noise environment. For conventional receivers, using a blanker as a preprocessor improves the bit error performance in an impulsive noise environment by removing received signal samples with large amplitudes in order to reduce the effect of impulsive noise. However, the conventional blanker shows a poor bit error performance in case of high signal-to-noise ratio (or large signal power) due to a fixed threshold. Therefore, the proposed blanker, called adaptive threshold blanker, overcomes this problem by adaptively updating the threshold and achieves an excellent bit error performance. In addition, this paper also introduces a simple method for calculating the quasi-optimal threshold value for the proposed blanker. This simple method allows an easy calculation of the threshold in practical systems. In order to evaluate the bit error performance of the proposed blanker, an approximated probability density function (PDF) using a sum of weighted Gaussian PDFs with different variances is also discussed. It is observed that simulation results agree well with the performance analysis.Index Terms-Adaptive blanker, impulsive noise, Middleton class A noise.

This article proposes an opportunistic scheduling scheme based on adaptive modulation for users in a mixed noise environment, where some users are under additive white Gaussian noise (AWGN) and other users are exposed to impulsive noise. Unlike the scenario, where all the users are in an AWGN environment, the maximum signal-to-noise ratio (SNR) scheduler does not provide the maximum capacity if users are in a mixed noise environment. In the proposed scheduling scheme, called maximum rate scheduler, the user with the highest rate (or highest modulation order), instead of highest SNR, is selected. To evaluate the performance of the proposed scheduling scheme, the analyses of average spectral efficiency, outage probability and system capacity are provided along with a simple calculation of SNR thresholds for adaptive modulation in an impulsive noise environment satisfying target symbol error rate (SER). Simulation results illustrate that system capacity with the proposed scheduling given target SER = 10 −2 and the average spectral efficiency are improved by 156% and 124%, respectively, at SNR = 5 dB when a strong impulsive noise is present.

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This paper proposes a new test method of detecting the presence of impulsive noise based on a complementary cumulative density function (CCDF). Impulsive noise severely degrades performance of communication systems and the conventional Kolmogorov–Smirnov (K–S) test may not perform well, because the test does not consider the characteristics of impulsive noise. In order to detect the presence of impulsive noise reliably, the CCDF of measurement samples is analyzed and compared with the CCDF of additive white Gaussian noise to find the difference between those CCDFs. Due to the nature of heavy-tails in impulsive noise, only the maximum difference may not be sufficient for the accurate detection of impulsive noise. Therefore, the proposed method applies the test hypothesis using the weighted sum of all the differences between those CCDFs. Simulation results justify that the proposed test is more robust and provides lower miss detection probability than the K–S test in the presence of impulsive noise.

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