Mitigating Near-field Interference in Laptop Embedded Wireless Transceivers

Abstract

Abstract-In laptop and desktop computers, clocks and busses generate significant radio frequency interference (RFI) for the embedded wireless data transceivers. RFI is impulsive in nature. When detecting a signal in additive impulsive noise, Spaulding and Middleton showed a potential improvement in detection of 25 dB at a bit error rate of 10 −5 when using a Bayesian detector instead of a standard correlation receiver. In this paper, we model impulsive noise using Middleton Class A and Symmetric Alpha Stable (SαS) models. The contributions of this paper are to evaluate (1) the performance vs. complexity of parameter estimation algorithms, (2) the closeness of fit of parameter estimation algorithms to measured RFI data from the computer platform, (3) the communication performance vs. computational complexity tradeoffs for the correlation receiver, Wiener filter, and Bayesian detector, and (4) the performance of myriad filtering in combating RFI interference modeled as SαS interference.

Robust Nonparametric Cyclic Correlation-Based Spectrum Sensing for Cognitive Radio

“…In [8], the symmetric alpha-stable distribution with α = 1.4329 was found to provide a good match to measurement data of the radio frequency interference experienced in embedded laptop wireless receivers. The non-Gaussian impulsive interference due to the internal components, for example in the ISM band at 2.4 GHz, is caused mainly by the LCD pixel clock harmonics [7].…”

“…The non-Gaussian impulsive interference due to the internal components, for example in the ISM band at 2.4 GHz, is caused mainly by the LCD pixel clock harmonics [7]. Other possible sources of interference on a computer platform are, for example, the gigabit ethernet and PCI express bus [8]. signal.…”

“…For example, indoor measurements in the industrial, scientific, and medical (ISM) bands reported in [5] show the impulsive nature of the noise and interference due to, e.g., microwave ovens and devices with electromechanical switches (electric motors in elevators, printers, copy machines, etc.) Moreover, on a computer platform various components, such as the LCD pixel clock and the PCI express bus, cause impulsive interference that degrades the performance of the embedded wireless devices [7], [8]. The impulsive interference on a computer platform is well modeled by a symmetric alpha-stable distribution [8].…”

“…Moreover, on a computer platform various components, such as the LCD pixel clock and the PCI express bus, cause impulsive interference that degrades the performance of the embedded wireless devices [7], [8]. The impulsive interference on a computer platform is well modeled by a symmetric alpha-stable distribution [8]. As an example of outdoor measurements in urban environments, impulsive noise measurements in a digital television band (10 MHz bandwidth with a central frequency of 762 MHz) have been reported in [6].…”

Low complexity EM-based decoding for OFDM systems with impulsive noise

“…Different statistical models for impulsive noise have been proposed in order to help in designing receivers that mitigate the impulsive noise. Middleton class-A model, symmetric alpha stable, and the more general Gaussian mixture model have been shown to accurately model interference in uncoordinated wireless networks [1], [2], [3], [4] and PLC networks [5].…”